Release version 0.3.1

According to https://forum.f-droid.org/t/syncthing-lite/4394 this is required to make this App build correctly for F-Droid

.travis.yml

@@ -0,0 +1,32 @@
+sudo: required
+language: android
+jdk: oraclejdk8
+dist: trusty
+
+# Install Android SDK
+android:
+  components:
+    - tools
+    - platform-tools
+    - build-tools-28.0.2
+    - android-28
+    - extra-android-m2repository
+
+before_install:
+  # Hack to accept Android licenses
+  - yes | sdkmanager "platforms;android-27"
+  - yes | sdkmanager "platforms;android-28"
+
+# Cache gradle dependencies
+# https://docs.travis-ci.com/user/languages/android/#Caching
+before_cache:
+  - rm -f  $HOME/.gradle/caches/modules-2/modules-2.lock
+  - rm -fr $HOME/.gradle/caches/*/plugin-resolution/
+cache:
+  directories:
+    - $HOME/.gradle/caches/
+    - $HOME/.gradle/wrapper/
+
+script:
+  - ./gradlew lint
+  - ./gradlew assembleDebug

README.md

@@ -1,5 +1,6 @@
 # Syncthing Lite
 
+[![Build Status](https://travis-ci.org/syncthing/syncthing-lite.svg?branch=master)](https://travis-ci.org/syncthing/syncthing-lite)
 [![MPLv2 License](https://img.shields.io/badge/license-MPLv2-blue.svg?style=flat-square)](https://www.mozilla.org/MPL/2.0/)
 
 This project is an Android app, that works as a client for a [Syncthing][1] share (accessing 
@@ -13,11 +14,16 @@ example, mobile devices with limited storage available, wishing to access a sync
 
 This project is based on [syncthing-java][3], a java implementation of Syncthing protocols.
 
+Due to the behaviour of this App and the [behaviour of the Syncthing Server](https://github.com/syncthing/syncthing/issues/5224),
+you can't reconnct for some minutes if the App was killed (due to removing from the recent App list) or the connection was interrupted.
+This does not apply to local discovery connections.
+
+[<img alt="Get it on F-Droid" src="https://f-droid.org/badge/get-it-on.png" height="80">](https://f-droid.org/packages/net.syncthing.lite/)
 [<img alt="Get it on Google Play" src="https://play.google.com/intl/en_us/badges/images/generic/en_badge_web_generic.png" height="80">](https://play.google.com/store/apps/details?id=net.syncthing.lite)
 
 ## Translations
 
-The project is translated on [Transifex](https://www.transifex.com/syncthing-android/syncthing-lite/).
+The project is translated on [Transifex](https://www.transifex.com/syncthing/syncthing-lite/).
 
 ## Building
 

app/build.gradle

@@ -1,18 +1,18 @@
 apply plugin: 'com.android.application'
 apply plugin: 'kotlin-android'
-apply plugin: 'kotlin-kapt'
 apply plugin: 'com.github.ben-manes.versions'
+apply plugin: 'kotlin-android-extensions'
 
 android {
     compileSdkVersion 27
-    buildToolsVersion "27.0.2"
+    buildToolsVersion "28.0.2"
     dataBinding.enabled = true
     defaultConfig {
         applicationId "net.syncthing.lite"
-        minSdkVersion 19
-        targetSdkVersion 25
-        versionCode 6
-        versionName "0.1.4"
+        minSdkVersion 21
+        targetSdkVersion 26
+        versionCode 11
+        versionName "0.3.1"
         multiDexEnabled true
     }
     sourceSets {
@@ -34,32 +34,55 @@ android {
         }
     }
     buildTypes {
+        debug {
+            minifyEnabled false
+        }
         release {
             signingConfig signingConfigs.release
+            minifyEnabled true
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
         }
     }
+    packagingOptions {
+        exclude 'META-INF/*'
+    }
+    dataBinding {
+        enabled = true
+    }
 }
 
 dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
     implementation "org.jetbrains.anko:anko-commons:$anko_version"
     implementation "org.jetbrains.anko:anko-coroutines:$anko_version"
-    kapt "com.android.databinding:compiler:$build_tools_version"
-    implementation "com.android.support:appcompat-v7:$support_version"
+    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:0.30.2'
     implementation "com.android.support:design:$support_version"
-    implementation "com.android.support:cardview-v7:$support_version"
-    implementation ("com.github.Nutomic:syncthing-java:0.1.4") {
-        exclude group: 'commons-logging', module:'commons-logging'
-        exclude group: 'org.apache.httpcomponents', module:'httpclient'
+    implementation "com.android.support:preference-v14:$support_version"
+    implementation "com.android.support:support-v4:$support_version"
+    implementation 'android.arch.lifecycle:extensions:1.1.1'
+
+    /**
+     * syncthing-java depends on the Apache HTTP Client
+     * https://github.com/syncthing/syncthing-java/blob/dd020737ba5fc6a7c681a1d258025b8ddb2e8f67/core/build.gradle#L9
+     *
+     * Android itself contains an older version of this HTTP Client. Due to that, there is an
+     * extra version of it which does not cause conflicts with the builtin client of Android.
+     *
+     * This extra implementation is included below. As this other version is used,
+     * it's ignored as dependency of syncthing-java.
+     */
+    implementation(project(':syncthing-client')) {
+        exclude group: 'commons-logging', module: 'commons-logging'
+        exclude group: 'org.apache.httpcomponents', module: 'httpclient'
         exclude group: 'org.slf4j'
         exclude group: 'ch.qos.logback'
     }
-    // NOTE: httpclient-android seems to be used via reflection somehow. Removing this dependency
-    //       silently breaks the app.
     implementation 'org.apache.httpcomponents:httpclient-android:4.3.5.1'
+
     implementation 'sk.baka.slf4j:slf4j-handroid:1.7.26'
     implementation 'com.google.zxing:android-integration:3.3.0'
-    implementation ('uk.co.markormesher:android-fab:2.0.0') {
-        exclude group: "org.jetbrains.kotlin"
-    }
+    implementation 'com.google.zxing:core:3.3.0'
+    implementation 'com.github.apl-devs:appintro:v4.2.3'
+
+    implementation project(':syncthing-repository-android')
 }

app/lint.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<lint>
+    <issue id="MissingTranslation" severity="ignore" />
+
+	<issue id="GoogleAppIndexingWarning" severity="ignore" />
+
+	<issue id="InvalidPackage" severity="ignore" />
+
+	<issue id="OldTargetApi" severity="ignore" />
+</lint>

app/proguard-rules.pro

@@ -0,0 +1,89 @@
+# Add project specific ProGuard rules here.
+# By default, the flags in this file are appended to flags specified
+# in /home/jonas/android-studio/sdk/tools/proguard/proguard-android.txt
+# You can edit the include path and order by changing the proguardFiles
+# directive in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# Add any project specific keep options here:
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# ensure that stack traces make sense
+-keepattributes SourceFile,LineNumberTable
+
+# this library uses factories with reflection
+-keep class net.jpountz.lz4.** { *; }
+
+# from https://github.com/Kotlin/kotlinx.coroutines/blob/master/ui/kotlinx-coroutines-android/example-app/app/proguard-rules.pro
+# kotlin coroutines crash without it
+-keepclassmembernames class kotlinx.** {
+  volatile <fields>;
+}
+
+# disable warnings
+-dontwarn com.google.protobuf.UnsafeUtil
+-dontwarn com.google.protobuf.UnsafeUtil$1
+-dontwarn net.jpountz.util.UnsafeUtils
+-dontwarn org.bouncycastle.cert.dane.fetcher.JndiDANEFetcherFactory
+-dontwarn org.bouncycastle.cert.dane.fetcher.JndiDANEFetcherFactory$1
+-dontwarn org.bouncycastle.jce.provider.X509LDAPCertStoreSpi
+-dontwarn org.bouncycastle.mail.smime.CMSProcessableBodyPart
+-dontwarn org.bouncycastle.mail.smime.CMSProcessableBodyPartInbound
+-dontwarn org.bouncycastle.mail.smime.CMSProcessableBodyPartOutbound
+-dontwarn org.bouncycastle.mail.smime.examples.CreateCompressedMail
+-dontwarn org.bouncycastle.mail.smime.examples.CreateEncryptedMail
+-dontwarn org.bouncycastle.mail.smime.examples.CreateLargeCompressedMail
+-dontwarn org.bouncycastle.mail.smime.examples.CreateLargeEncryptedMail
+-dontwarn org.bouncycastle.mail.smime.examples.CreateLargeSignedMail
+-dontwarn org.bouncycastle.mail.smime.examples.CreateSignedMail
+-dontwarn org.bouncycastle.mail.smime.examples.CreateSignedMultipartMail
+-dontwarn org.bouncycastle.mail.smime.examples.ExampleUtils
+-dontwarn org.bouncycastle.mail.smime.examples.ReadCompressedMail
+-dontwarn org.bouncycastle.mail.smime.examples.ReadEncryptedMail
+-dontwarn org.bouncycastle.mail.smime.examples.ReadLargeCompressedMail
+-dontwarn org.bouncycastle.mail.smime.examples.ReadLargeEncryptedMail
+-dontwarn org.bouncycastle.mail.smime.examples.ReadLargeSignedMail
+-dontwarn org.bouncycastle.mail.smime.examples.ReadSignedMail
+-dontwarn org.bouncycastle.mail.smime.examples.SendSignedAndEncryptedMail
+-dontwarn org.bouncycastle.mail.smime.examples.ValidateSignedMail
+-dontwarn org.bouncycastle.mail.smime.handlers.multipart_signed
+-dontwarn org.bouncycastle.mail.smime.handlers.multipart_signed$LineOutputStream
+-dontwarn org.bouncycastle.mail.smime.handlers.PKCS7ContentHandler
+-dontwarn org.bouncycastle.mail.smime.handlers.pkcs7_mime
+-dontwarn org.bouncycastle.mail.smime.handlers.pkcs7_signature
+-dontwarn org.bouncycastle.mail.smime.handlers.x_pkcs7_mime
+-dontwarn org.bouncycastle.mail.smime.handlers.x_pkcs7_signature
+-dontwarn org.bouncycastle.mail.smime.SMIMECompressed
+-dontwarn org.bouncycastle.mail.smime.SMIMECompressedGenerator
+-dontwarn org.bouncycastle.mail.smime.SMIMECompressedGenerator$1
+-dontwarn org.bouncycastle.mail.smime.SMIMECompressedGenerator$ContentCompressor
+-dontwarn org.bouncycastle.mail.smime.SMIMECompressedParser
+-dontwarn org.bouncycastle.mail.smime.SMIMEEnveloped
+-dontwarn org.bouncycastle.mail.smime.SMIMEEnvelopedGenerator
+-dontwarn org.bouncycastle.mail.smime.SMIMEEnvelopedGenerator$1
+-dontwarn org.bouncycastle.mail.smime.SMIMEEnvelopedGenerator$ContentEncryptor
+-dontwarn org.bouncycastle.mail.smime.SMIMEEnvelopedParser
+-dontwarn org.bouncycastle.mail.smime.SMIMEGenerator
+-dontwarn org.bouncycastle.mail.smime.SMIMESigned
+-dontwarn org.bouncycastle.mail.smime.SMIMESigned$1
+-dontwarn org.bouncycastle.mail.smime.SMIMESignedGenerator
+-dontwarn org.bouncycastle.mail.smime.SMIMESignedGenerator$1
+-dontwarn org.bouncycastle.mail.smime.SMIMESignedGenerator$ContentSigner
+-dontwarn org.bouncycastle.mail.smime.SMIMESignedParser
+-dontwarn org.bouncycastle.mail.smime.SMIMESignedParser$1
+-dontwarn org.bouncycastle.mail.smime.SMIMEToolkit
+-dontwarn org.bouncycastle.mail.smime.SMIMEUtil
+-dontwarn org.bouncycastle.mail.smime.SMIMEUtil$LineOutputStream
+-dontwarn org.bouncycastle.mail.smime.SMIMEUtil$WriteOnceFileBackedMimeBodyPart
+-dontwarn org.bouncycastle.mail.smime.util.FileBackedMimeBodyPart
+-dontwarn org.bouncycastle.mail.smime.util.SharedFileInputStream
+-dontwarn org.bouncycastle.mail.smime.validator.SignedMailValidator
+-dontwarn org.bouncycastle.x509.util.LDAPStoreHelper

app/src/main/AndroidManifest.xml

@@ -2,7 +2,6 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="net.syncthing.lite">
 
     <uses-permission android:name="android.permission.INTERNET"/>
-    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
 
     <application
         android:allowBackup="true"
@@ -18,10 +17,10 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
+        <activity android:name=".activities.IntroActivity"
+            android:theme="@style/Theme.Syncthing.NoActionBar"/>
         <activity android:name=".activities.FolderBrowserActivity"
             android:parentActivityName=".activities.MainActivity"/>
-        <activity android:name=".activities.FilePickerActivity"
-            android:parentActivityName=".activities.FolderBrowserActivity" />
         <provider
             android:name="android.support.v4.content.FileProvider"
             android:authorities="net.syncthing.lite.fileprovider"
@@ -31,7 +30,16 @@
                 android:name="android.support.FILE_PROVIDER_PATHS"
                 android:resource="@xml/filepaths" />
         </provider>
-
+        <provider
+            android:name=".library.SyncthingProvider"
+            android:authorities="net.syncthing.lite.documents"
+            android:grantUriPermissions="true"
+            android:exported="true"
+            android:permission="android.permission.MANAGE_DOCUMENTS">
+            <intent-filter>
+                <action android:name="android.content.action.DOCUMENTS_PROVIDER" />
+            </intent-filter>
+        </provider>
     </application>
 
 </manifest>

app/src/main/kotlin/net/syncthing/lite/activities/FilePickerActivity.kt

@@ -1,101 +0,0 @@
-package net.syncthing.lite.activities
-
-import android.app.Activity
-import android.content.Context
-import android.content.Intent
-import android.net.Uri
-import android.os.Bundle
-import android.os.Environment
-import android.view.View
-import android.view.ViewGroup
-import android.widget.AdapterView
-import android.widget.ArrayAdapter
-import android.widget.ListView
-import android.widget.TextView
-import net.syncthing.lite.R
-import java.io.File
-import java.util.*
-
-/**
- * Activity that allows selecting a directory in the local file system.
- */
-class FilePickerActivity : SyncthingActivity(), AdapterView.OnItemClickListener {
-
-    private lateinit var mListView: ListView
-    private lateinit var mFilesAdapter: FileAdapter
-    private lateinit var mLocation: File
-
-    override fun onCreate(savedInstanceState: Bundle?) {
-        super.onCreate(savedInstanceState)
-
-        setContentView(R.layout.activity_folder_picker)
-        mListView = findViewById(android.R.id.list)
-        mListView.onItemClickListener = this
-        mListView.emptyView = findViewById(android.R.id.empty)
-        mFilesAdapter = FileAdapter(this)
-        mListView.adapter = mFilesAdapter
-
-        displayFolder(Environment.getExternalStorageDirectory())
-    }
-
-    /**
-     * Refreshes the ListView to show the contents of the location in ``mLocation.peek()}.
-     */
-    private fun displayFolder(location: File) {
-        mLocation = location
-        mFilesAdapter.clear()
-        // In case we don't have read access to the location, just display nothing.
-        val contents = location.listFiles() ?: arrayOf()
-
-        Arrays.sort(contents) { f1, f2 ->
-            if (f1.isDirectory && f2.isFile)
-                return@sort -1
-            if (f1.isFile && f2.isDirectory)
-                return@sort 1
-            f1.name.compareTo(f2.name)
-        }
-
-        for (f in contents) {
-            mFilesAdapter.add(f)
-        }
-        mListView.adapter = mFilesAdapter
-    }
-
-    override fun onItemClick(adapterView: AdapterView<*>, view: View, i: Int, l: Long) {
-        val f = mFilesAdapter.getItem(i)
-        if (f!!.isDirectory) {
-            displayFolder(f)
-        } else {
-            val intent = Intent()
-            intent.data = Uri.fromFile(f)
-            setResult(Activity.RESULT_OK, intent)
-            finish()
-        }
-    }
-
-    private inner class FileAdapter(context: Context) : ArrayAdapter<File>(context, R.layout.item_folder_picker) {
-
-        override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {
-            val view = super.getView(position, convertView, parent)
-            val title = view.findViewById<TextView>(android.R.id.text1)
-            val f = getItem(position)!!
-            title.text = f.name
-            val icon =
-                    if (f.isDirectory) R.drawable.ic_folder_black_24dp
-                    else               R.drawable.ic_image_black_24dp
-            title.setCompoundDrawablesWithIntrinsicBounds(icon, 0, 0, 0)
-
-            return view
-        }
-    }
-
-    override fun onBackPressed() {
-        if (mLocation != Environment.getExternalStorageDirectory()) {
-            displayFolder(mLocation.parentFile)
-        } else {
-            setResult(Activity.RESULT_CANCELED)
-            finish()
-        }
-    }
-
-}

app/src/main/kotlin/net/syncthing/lite/activities/FolderBrowserActivity.kt

@@ -1,57 +1,57 @@
 package net.syncthing.lite.activities
 
-import android.Manifest
 import android.app.Activity
 import android.content.Intent
-import android.content.pm.PackageManager
 import android.databinding.DataBindingUtil
 import android.os.Bundle
-import android.support.v4.app.ActivityCompat
-import android.support.v4.content.ContextCompat
 import android.util.Log
-import android.view.View
-import android.widget.Toast
+import kotlinx.coroutines.experimental.android.UI
+import kotlinx.coroutines.experimental.async
 import net.syncthing.java.bep.IndexBrowser
 import net.syncthing.java.core.beans.FileInfo
+import net.syncthing.java.core.beans.FolderInfo
 import net.syncthing.java.core.utils.PathUtils
+import net.syncthing.lite.BuildConfig
 import net.syncthing.lite.R
 import net.syncthing.lite.adapters.FolderContentsAdapter
+import net.syncthing.lite.adapters.FolderContentsListener
 import net.syncthing.lite.databinding.ActivityFolderBrowserBinding
-import net.syncthing.lite.library.DownloadFileTask
-import net.syncthing.lite.library.UploadFileTask
-import org.jetbrains.anko.intentFor
+import net.syncthing.lite.dialogs.FileUploadDialog
+import net.syncthing.lite.dialogs.ReconnectIssueDialogFragment
+import net.syncthing.lite.dialogs.downloadfile.DownloadFileDialogFragment
+import org.jetbrains.anko.custom.async
 
 class FolderBrowserActivity : SyncthingActivity() {
 
     companion object {
 
-        private val TAG = "FolderBrowserActivity"
-        private val REQUEST_WRITE_STORAGE = 142
-        private val REQUEST_SELECT_UPLOAD_FILE = 171
+        private const val TAG = "FolderBrowserActivity"
+        private const val REQUEST_SELECT_UPLOAD_FILE = 171
 
-        val EXTRA_FOLDER_NAME = "folder_name"
+        const val EXTRA_FOLDER_NAME = "folder_name"
     }
 
     private lateinit var binding: ActivityFolderBrowserBinding
     private lateinit var indexBrowser: IndexBrowser
-    private lateinit var adapter: FolderContentsAdapter
-    private var runWhenPermissionsReceived: Runnable? = null
+    private val adapter = FolderContentsAdapter()
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         binding = DataBindingUtil.setContentView(this, R.layout.activity_folder_browser)
         binding.mainListViewUploadHereButton.setOnClickListener { showUploadHereDialog() }
-        adapter = FolderContentsAdapter(this)
         binding.listView.adapter = adapter
-        binding.listView.setOnItemClickListener { _, _, position, _ ->
-            val fileInfo = binding.listView.getItemAtPosition(position) as FileInfo
-            navigateToFolder(fileInfo)
+        adapter.listener = object: FolderContentsListener {
+            override fun onItemClicked(fileInfo: FileInfo) {
+                navigateToFolder(fileInfo)
+            }
         }
         val folder = intent.getStringExtra(EXTRA_FOLDER_NAME)
         libraryHandler?.syncthingClient {
             indexBrowser = it.indexHandler.newIndexBrowser(folder, true, true)
             indexBrowser.setOnFolderChangedListener(this::onFolderChanged)
         }
+
+        ReconnectIssueDialogFragment.showIfNeeded(this)
     }
 
     override fun onDestroy() {
@@ -63,17 +63,19 @@ class FolderBrowserActivity : SyncthingActivity() {
     }
 
     override fun onBackPressed() {
-        val listView = binding.listView
         //click item '0', ie '..' (go to parent)
-        listView.performItemClick(adapter.getView(0, null, listView), 0, listView.getItemIdAtPosition(0))
+        navigateToFolder(adapter.data[0])
     }
 
     override fun onActivityResult(requestCode: Int, resultCode: Int, intent: Intent?) {
         if (requestCode == REQUEST_SELECT_UPLOAD_FILE && resultCode == Activity.RESULT_OK) {
             libraryHandler?.syncthingClient { syncthingClient ->
-                UploadFileTask(this@FolderBrowserActivity, syncthingClient, intent!!.data,
-                        indexBrowser.folder, indexBrowser.currentPath,
-                        this@FolderBrowserActivity::showUploadHereDialog).uploadFile()
+                async (UI) {
+                    // FIXME: it would be better if the dialog would use the library handler
+                    FileUploadDialog(this@FolderBrowserActivity, syncthingClient, intent!!.data,
+                            indexBrowser.folder, indexBrowser.currentPath,
+                            { showFolderListView(indexBrowser.currentPath) }).show()
+                }
             }
         }
     }
@@ -89,36 +91,47 @@ class FolderBrowserActivity : SyncthingActivity() {
             finish()
         } else {
             if (fileInfo.isDirectory()) {
-                indexBrowser.navigateTo(fileInfo)
+                async {
+                    indexBrowser.navigateTo(fileInfo)
+                }
+
                 Log.d(TAG, "load folder cache bg")
-                binding.listView.visibility = View.GONE
-                binding.progressBar.visibility = View.VISIBLE
+                binding.isLoading = true
             } else {
-                Log.i(TAG, "pulling file = " + fileInfo)
-                executeWithPermissions(
-                        Runnable { libraryHandler?.syncthingClient { DownloadFileTask(this, it, fileInfo).downloadFile() } })
+                if (BuildConfig.DEBUG) {
+                    Log.i(TAG, "pulling file = " + fileInfo)
+                }
+
+                DownloadFileDialogFragment.newInstance(fileInfo).show(supportFragmentManager)
             }
         }
     }
 
     private fun onFolderChanged() {
         runOnUiThread {
-            binding.progressBar.visibility = View.GONE
-            binding.listView.visibility = View.VISIBLE
-            val list = indexBrowser.listFiles()
-            Log.i("navigateToFolder", "list for path = '" + indexBrowser.currentPath + "' list = " + list.size + " records")
-            Log.d("navigateToFolder", "list for path = '" + indexBrowser.currentPath + "' list = " + list)
-            assert(!list.isEmpty())//list must contain at least the 'parent' path
-            adapter.clear()
-            adapter.addAll(list)
-            adapter.notifyDataSetChanged()
-            binding.listView.setSelection(0)
-            if (indexBrowser.isRoot())
-                libraryHandler?.folderBrowser {
-                    supportActionBar?.title = it.getFolderInfo(indexBrowser.folder)?.label
+            binding.isLoading = false
+
+            async {
+                val list = indexBrowser.listFiles()
+
+                async (UI) {
+                    Log.i("navigateToFolder", "list for path = '" + indexBrowser.currentPath + "' list = " + list.size + " records")
+                    Log.d("navigateToFolder", "list for path = '" + indexBrowser.currentPath + "' list = " + list)
+                    assert(!list.isEmpty())//list must contain at least the 'parent' path
+                    adapter.data = list
+                    binding.listView.scrollToPosition(0)
+                    if (indexBrowser.isRoot())
+                        libraryHandler?.folderBrowser {
+                            val title = it.getFolderInfo(indexBrowser.folder)?.label
+
+                            async(UI) {
+                                supportActionBar?.title = title
+                            }
+                        }
+                    else
+                        supportActionBar?.title = indexBrowser.currentPathInfo().fileName
                 }
-            else
-                supportActionBar?.title = indexBrowser.currentPathInfo().fileName
+            }
         }
 }
 
@@ -127,48 +140,14 @@ class FolderBrowserActivity : SyncthingActivity() {
     }
 
     private fun showUploadHereDialog() {
-        executeWithPermissions(Runnable {
-            startActivityForResult(intentFor<FilePickerActivity>(), REQUEST_SELECT_UPLOAD_FILE)
-        })
+        val intent = Intent(Intent.ACTION_OPEN_DOCUMENT)
+        intent.addCategory(Intent.CATEGORY_OPENABLE)
+        intent.type = "*/*"
+        startActivityForResult(intent, REQUEST_SELECT_UPLOAD_FILE)
     }
 
-    override fun onIndexUpdateProgress(folder: String, percentage: Int) {
-        binding.indexUpdate.visibility = View.VISIBLE
-        binding.indexUpdateLabel.text = getString(R.string.index_update_progress_label, folder, percentage)
+    override fun onIndexUpdateComplete(folderInfo: FolderInfo) {
+        super.onIndexUpdateComplete(folderInfo)
         updateFolderListView()
     }
-
-    override fun onIndexUpdateComplete() {
-        binding.indexUpdate.visibility = View.GONE
-        updateFolderListView()
-    }
-
-    private fun executeWithPermissions(runnable: Runnable) {
-        val permissionState = ContextCompat.checkSelfPermission(this,
-                Manifest.permission.WRITE_EXTERNAL_STORAGE)
-        if (permissionState != PackageManager.PERMISSION_GRANTED) {
-            ActivityCompat.requestPermissions(this,
-                    arrayOf(Manifest.permission.WRITE_EXTERNAL_STORAGE),
-                    REQUEST_WRITE_STORAGE)
-            runWhenPermissionsReceived = runnable
-        } else {
-            runnable.run()
-        }
-    }
-
-    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<String>,
-                                            grantResults: IntArray) {
-        when (requestCode) {
-            REQUEST_WRITE_STORAGE -> {
-                if (grantResults.isEmpty() || grantResults[0] != PackageManager.PERMISSION_GRANTED) {
-                    Toast.makeText(this, R.string.toast_write_storage_permission_required,
-                            Toast.LENGTH_LONG).show()
-                } else {
-                    runWhenPermissionsReceived!!.run()
-                }
-                runWhenPermissionsReceived = null
-            }
-            else -> super.onRequestPermissionsResult(requestCode, permissions, grantResults)
-        }
-    }
 }

app/src/main/kotlin/net/syncthing/lite/activities/IntroActivity.kt

@@ -0,0 +1,208 @@
+package net.syncthing.lite.activities
+
+import android.arch.lifecycle.Observer
+import android.content.Intent
+import android.databinding.DataBindingUtil
+import android.os.Bundle
+import android.os.Handler
+import android.os.Looper
+import android.support.v4.app.Fragment
+import android.support.v4.content.ContextCompat
+import android.text.Html
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.Button
+import com.github.paolorotolo.appintro.AppIntro
+import com.google.zxing.integration.android.IntentIntegrator
+import kotlinx.coroutines.experimental.android.UI
+import kotlinx.coroutines.experimental.async
+import net.syncthing.java.core.beans.DeviceId
+import net.syncthing.lite.R
+import net.syncthing.lite.databinding.FragmentIntroOneBinding
+import net.syncthing.lite.databinding.FragmentIntroThreeBinding
+import net.syncthing.lite.databinding.FragmentIntroTwoBinding
+import net.syncthing.lite.fragments.SyncthingFragment
+import net.syncthing.lite.utils.FragmentIntentIntegrator
+import net.syncthing.lite.utils.Util
+import org.jetbrains.anko.defaultSharedPreferences
+import org.jetbrains.anko.intentFor
+import java.io.IOException
+
+/**
+ * Shown when a user first starts the app. Shows some info and helps the user to add their first
+ * device and folder.
+ */
+class IntroActivity : AppIntro() {
+
+    /**
+     * Initialize fragments and library parameters.
+     */
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        // Disable continue button on second slide until a valid device ID is entered.
+        nextButton.setOnClickListener {
+            val fragment = fragments[pager.currentItem]
+            if (fragment !is IntroFragmentTwo || fragment.isDeviceIdValid()) {
+                pager.goToNextSlide()
+            }
+        }
+
+        addSlide(IntroFragmentOne())
+        addSlide(IntroFragmentTwo())
+        addSlide(IntroFragmentThree())
+
+        setSeparatorColor(ContextCompat.getColor(this, android.R.color.primary_text_dark))
+        showSkipButton(true)
+        isProgressButtonEnabled = true
+        pager.isPagingEnabled = false
+    }
+
+    override fun onSkipPressed(currentFragment: Fragment) {
+        onDonePressed(currentFragment)
+    }
+
+    override fun onDonePressed(currentFragment: Fragment) {
+        defaultSharedPreferences.edit().putBoolean(MainActivity.PREF_IS_FIRST_START, false).apply()
+        startActivity(intentFor<MainActivity>())
+        finish()
+    }
+
+    /**
+     * Display some simple welcome text.
+     */
+    class IntroFragmentOne : SyncthingFragment() {
+
+        override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
+            val binding = FragmentIntroOneBinding.inflate(inflater, container, false)
+
+            libraryHandler.isListeningPortTaken.observe(this, Observer { binding.listeningPortTaken = it })
+
+            return binding.root
+        }
+
+        override fun onLibraryLoaded() {
+            super.onLibraryLoaded()
+
+            libraryHandler.configuration { config ->
+                config.localDeviceName = Util.getDeviceName()
+                config.persistLater()
+            }
+        }
+    }
+
+    /**
+     * Display device ID entry field and QR scanner option.
+     */
+    class IntroFragmentTwo : SyncthingFragment() {
+
+        private lateinit var binding: FragmentIntroTwoBinding
+
+        override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
+            binding = DataBindingUtil.inflate(inflater, R.layout.fragment_intro_two, container, false)
+            binding.enterDeviceId!!.scanQrCode.setOnClickListener {
+                FragmentIntentIntegrator(this@IntroFragmentTwo).initiateScan()
+            }
+            binding.enterDeviceId!!.scanQrCode.setImageResource(R.drawable.ic_qr_code_white_24dp)
+            return binding.root
+        }
+
+        override fun onActivityResult(requestCode: Int, resultCode: Int, intent: Intent?) {
+            val scanResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, intent)
+            if (scanResult?.contents != null && scanResult.contents.isNotBlank()) {
+                binding.enterDeviceId!!.deviceId.setText(scanResult.contents)
+                binding.enterDeviceId!!.deviceIdHolder.isErrorEnabled = false
+            }
+        }
+
+        /**
+         * Checks if the entered device ID is valid. If yes, imports it and returns true. If not,
+         * sets an error on the textview and returns false.
+         */
+        fun isDeviceIdValid(): Boolean {
+            return try {
+                val deviceId = binding.enterDeviceId!!.deviceId.text.toString()
+                Util.importDeviceId(libraryHandler, context, deviceId, { })
+                true
+            } catch (e: IOException) {
+                binding.enterDeviceId!!.deviceId.error = getString(R.string.invalid_device_id)
+                false
+            }
+        }
+
+        private val addedDeviceIds = HashSet<DeviceId>()
+
+        override fun onResume() {
+            super.onResume()
+
+            binding.foundDevices.removeAllViews()
+            addedDeviceIds.clear()
+
+            libraryHandler.registerMessageFromUnknownDeviceListener(onDeviceFound)
+        }
+
+        override fun onPause() {
+            super.onPause()
+
+            libraryHandler.unregisterMessageFromUnknownDeviceListener(onDeviceFound)
+        }
+
+        private val onDeviceFound: (DeviceId) -> Unit = {
+            deviceId ->
+
+                if (addedDeviceIds.add(deviceId)) {
+                    binding.foundDevices.addView(
+                            Button(context).apply {
+                                layoutParams = ViewGroup.LayoutParams(
+                                        ViewGroup.LayoutParams.MATCH_PARENT,
+                                        ViewGroup.LayoutParams.WRAP_CONTENT
+                                )
+                                text = deviceId.deviceId
+
+                                setOnClickListener {
+                                    binding.enterDeviceId.deviceId.setText(deviceId.deviceId)
+                                    binding.enterDeviceId.deviceIdHolder.isErrorEnabled = false
+
+                                    binding.scroll.scrollTo(0, 0)
+                                }
+                            }
+                    )
+                }
+        }
+    }
+
+    /**
+     * Waits until remote device connects with new folder.
+     */
+    class IntroFragmentThree : SyncthingFragment() {
+
+        private lateinit var binding: FragmentIntroThreeBinding
+
+        override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
+            binding = DataBindingUtil.inflate(inflater, R.layout.fragment_intro_three, container, false)
+
+            libraryHandler.library { config, client, _ ->
+                async(UI) {
+                    client.addOnConnectionChangedListener(this@IntroFragmentThree::onConnectionChanged)
+                    val deviceId = config.localDeviceId.deviceId
+                    val desc = activity?.getString(R.string.intro_page_three_description, "<b>$deviceId</b>")
+                    binding.description.text = Html.fromHtml(desc)
+                }
+            }
+
+            return binding.root
+        }
+
+        private fun onConnectionChanged(deviceId: DeviceId) {
+            libraryHandler.library { config, client, _ ->
+                async(UI) {
+                    if (config.folders.isNotEmpty()) {
+                        client.removeOnConnectionChangedListener(this@IntroFragmentThree::onConnectionChanged)
+                        (activity as IntroActivity?)?.onDonePressed(this@IntroFragmentThree)
+                    }
+                }
+            }
+        }
+    }
+}

app/src/main/kotlin/net/syncthing/lite/activities/MainActivity.kt

@@ -4,28 +4,38 @@ import android.app.AlertDialog
 import android.content.res.Configuration
 import android.databinding.DataBindingUtil
 import android.os.Bundle
+import android.support.v4.app.Fragment
 import android.support.v7.app.ActionBarDrawerToggle
 import android.view.Gravity
 import android.view.MenuItem
-import android.view.View
 import kotlinx.coroutines.experimental.android.UI
 import kotlinx.coroutines.experimental.async
 import net.syncthing.lite.R
 import net.syncthing.lite.databinding.ActivityMainBinding
+import net.syncthing.lite.dialogs.DeviceIdDialogFragment
 import net.syncthing.lite.fragments.DevicesFragment
 import net.syncthing.lite.fragments.FoldersFragment
-import net.syncthing.lite.fragments.SyncthingFragment
-import net.syncthing.lite.library.UpdateIndexTask
+import net.syncthing.lite.fragments.SettingsFragment
+import org.jetbrains.anko.defaultSharedPreferences
+import org.jetbrains.anko.intentFor
 
 class MainActivity : SyncthingActivity() {
 
+    companion object {
+        const val PREF_IS_FIRST_START = "net.syncthing.lite.activities.MainActivity.IS_FIRST_START"
+    }
+
     private lateinit var binding: ActivityMainBinding
     private var drawerToggle: ActionBarDrawerToggle? = null
-    private var currentFragment: SyncthingFragment? = null
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
 
+        if (defaultSharedPreferences.getBoolean(PREF_IS_FIRST_START, true)) {
+            startActivity(intentFor<IntroActivity>())
+            finish()
+        }
+
         binding = DataBindingUtil.setContentView(this, R.layout.activity_main)
 
         drawerToggle = ActionBarDrawerToggle(
@@ -69,7 +79,8 @@ class MainActivity : SyncthingActivity() {
         when (menuItem.itemId) {
             R.id.folders -> setContentFragment(FoldersFragment())
             R.id.devices -> setContentFragment(DevicesFragment())
-            R.id.update_index -> libraryHandler?.syncthingClient { UpdateIndexTask(this@MainActivity, it).updateIndex() }
+            R.id.settings -> setContentFragment(SettingsFragment())
+            R.id.device_id -> DeviceIdDialogFragment().show(supportFragmentManager)
             R.id.clear_index -> AlertDialog.Builder(this)
                     .setTitle(getString(R.string.clear_cache_and_index_title))
                     .setMessage(getString(R.string.clear_cache_and_index_body))
@@ -82,8 +93,7 @@ class MainActivity : SyncthingActivity() {
         return true
     }
 
-    private fun setContentFragment(fragment: SyncthingFragment) {
-        currentFragment = fragment
+    private fun setContentFragment(fragment: Fragment) {
         supportFragmentManager
                 .beginTransaction()
                 .replace(R.id.content_frame, fragment)
@@ -92,21 +102,8 @@ class MainActivity : SyncthingActivity() {
 
     private fun cleanCacheAndIndex() {
         async(UI) {
-            libraryHandler?.syncthingClient { it.clearCacheAndIndex() }
+            libraryHandler.syncthingClient { it.clearCacheAndIndex() }
             recreate()
         }
     }
-
-    override fun onIndexUpdateProgress(folder: String, percentage: Int) {
-        async(UI) {
-            binding.indexUpdate.visibility = View.VISIBLE
-            binding.indexUpdateLabel.text = getString(R.string.index_update_progress_label, folder, percentage)
-        }
-    }
-
-    override fun onIndexUpdateComplete() {
-        async(UI) {
-            binding.indexUpdate.visibility = View.GONE
-        }
-    }
 }

app/src/main/kotlin/net/syncthing/lite/activities/SyncthingActivity.kt

@@ -1,54 +1,78 @@
 package net.syncthing.lite.activities
 
 import android.app.AlertDialog
+import android.content.Context
 import android.databinding.DataBindingUtil
 import android.os.Bundle
+import android.support.design.widget.Snackbar
 import android.support.v7.app.AppCompatActivity
 import android.view.LayoutInflater
+import net.syncthing.java.core.beans.FolderInfo
 import net.syncthing.lite.BuildConfig
 import net.syncthing.lite.R
 import net.syncthing.lite.databinding.DialogLoadingBinding
 import net.syncthing.lite.library.LibraryHandler
+import org.jetbrains.anko.contentView
 import org.slf4j.impl.HandroidLoggerAdapter
 
 abstract class SyncthingActivity : AppCompatActivity() {
-
-    var libraryHandler: LibraryHandler? = null
-        private set
+    val libraryHandler: LibraryHandler by lazy {
+        LibraryHandler(
+                context = this@SyncthingActivity,
+                onIndexUpdateProgressListener = this::onIndexUpdateProgress,
+                onIndexUpdateCompleteListener = this::onIndexUpdateComplete
+        )
+    }
     private var loadingDialog: AlertDialog? = null
+    private var snackBar: Snackbar? = null
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         HandroidLoggerAdapter.DEBUG = BuildConfig.DEBUG
+    }
+
+    override fun onStart() {
+        super.onStart()
 
         val binding = DataBindingUtil.inflate<DialogLoadingBinding>(
                 LayoutInflater.from(this), R.layout.dialog_loading, null, false)
         binding.loadingText.text = getString(R.string.loading_config_starting_syncthing_client)
+
         loadingDialog = AlertDialog.Builder(this)
                 .setCancelable(false)
                 .setView(binding.root)
                 .show()
-        LibraryHandler(this, this::onLibraryLoadedInternal,
-                                        this::onIndexUpdateProgress, this::onIndexUpdateComplete)
+
+        libraryHandler.start {
+            if (!isDestroyed) {
+                loadingDialog?.dismiss()
+            }
+
+            onLibraryLoaded()
+        }
     }
 
-    override fun onDestroy() {
-        super.onDestroy()
-        libraryHandler?.close()
+    override fun onStop() {
+        super.onStop()
+
+        libraryHandler.stop()
         loadingDialog?.dismiss()
     }
 
-    private fun onLibraryLoadedInternal(libraryHandler: LibraryHandler) {
-        this.libraryHandler = libraryHandler
-        if (!isDestroyed) {
-            loadingDialog?.dismiss()
+    open fun onIndexUpdateProgress(folderInfo: FolderInfo, percentage: Int) {
+        val message = getString(R.string.index_update_progress_label, folderInfo.label, percentage)
+        snackBar?.setText(message) ?: run {
+            snackBar = Snackbar.make(contentView!!, message, Snackbar.LENGTH_INDEFINITE)
+            snackBar?.show()
         }
-        onLibraryLoaded()
     }
 
-    open fun onIndexUpdateProgress(folder: String, percentage: Int) {}
+    open fun onIndexUpdateComplete(folderInfo: FolderInfo) {
+        snackBar?.dismiss()
+        snackBar = null
+    }
 
-    open fun onIndexUpdateComplete() {}
-
-    open fun onLibraryLoaded() {}
+    open fun onLibraryLoaded() {
+        // nothing to do
+    }
 }

app/src/main/kotlin/net/syncthing/lite/adapters/DevicesAdapter.kt

@@ -1,34 +1,47 @@
 package net.syncthing.lite.adapters
 
-import android.content.Context
-import android.databinding.DataBindingUtil
+import android.support.v7.widget.RecyclerView
 import android.view.LayoutInflater
-import android.view.View
 import android.view.ViewGroup
-import android.widget.ArrayAdapter
-import net.syncthing.java.core.beans.DeviceStats
-import net.syncthing.lite.R
+import net.syncthing.java.core.beans.DeviceInfo
 import net.syncthing.lite.databinding.ListviewDeviceBinding
+import kotlin.properties.Delegates
 
-class DevicesAdapter(context: Context) :
-        ArrayAdapter<DeviceStats>(context, R.layout.listview_device, mutableListOf()) {
+class DevicesAdapter: RecyclerView.Adapter<DeviceViewHolder>() {
+    var data: List<DeviceInfo> by Delegates.observable(listOf()) {
+        _, _, _ -> notifyDataSetChanged()
+    }
 
-    override fun getView(position: Int, v: View?, parent: ViewGroup): View {
-        val binding: ListviewDeviceBinding
-            = if (v == null) {
-                DataBindingUtil.inflate(LayoutInflater.from(context), R.layout.listview_device, parent, false)
-            } else {
-                DataBindingUtil.bind(v)
-            }
-        val deviceStats = getItem(position)
-        binding.deviceName.text = deviceStats!!.name
-        val icon =
-            when (deviceStats.status) {
-                DeviceStats.DeviceStatus.OFFLINE -> R.drawable.ic_laptop_red_24dp
-                DeviceStats.DeviceStatus.ONLINE_INACTIVE,
-                DeviceStats.DeviceStatus.ONLINE_ACTIVE -> R.drawable.ic_laptop_green_24dp
-            }
-        binding.deviceIcon.setImageResource(icon)
-        return binding.root
+    var listener: DeviceAdapterListener? = null
+
+    init {
+        setHasStableIds(true)
+    }
+
+    override fun getItemCount() = data.size
+    override fun getItemId(position: Int) = data[position].deviceId.deviceId.hashCode().toLong()
+
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) = DeviceViewHolder(
+            ListviewDeviceBinding.inflate(
+                    LayoutInflater.from(parent.context), parent, false
+            )
+    )
+
+    override fun onBindViewHolder(holder: DeviceViewHolder, position: Int) {
+        val deviceStats = data[position]
+        val binding = holder.binding
+
+        binding.name = deviceStats.name
+        binding.isConnected = deviceStats.isConnected
+
+        binding.root.setOnLongClickListener { listener?.onDeviceLongClicked(deviceStats) ?: false }
+
+        binding.executePendingBindings()
     }
 }
+
+interface DeviceAdapterListener {
+    fun onDeviceLongClicked(deviceInfo: DeviceInfo): Boolean
+}
+
+class DeviceViewHolder(val binding: ListviewDeviceBinding): RecyclerView.ViewHolder(binding.root)

app/src/main/kotlin/net/syncthing/lite/adapters/FolderContentsAdapter.kt

@@ -1,39 +1,64 @@
 package net.syncthing.lite.adapters
 
-import android.content.Context
-import android.databinding.DataBindingUtil
+import android.support.v7.widget.RecyclerView
 import android.text.format.DateUtils
 import android.view.LayoutInflater
-import android.view.View
 import android.view.ViewGroup
-import android.widget.ArrayAdapter
 import net.syncthing.java.core.beans.FileInfo
 import net.syncthing.lite.R
 import net.syncthing.lite.databinding.ListviewFileBinding
 import org.apache.commons.io.FileUtils
+import kotlin.properties.Delegates
 
-class FolderContentsAdapter(context: Context) :
-        ArrayAdapter<FileInfo>(context, R.layout.listview_file, mutableListOf()) {
+// TODO: enable setHasStableIds and add a good way to get an id
+class FolderContentsAdapter: RecyclerView.Adapter<FolderContentsViewHolder>() {
+    var data: List<FileInfo> by Delegates.observable(listOf()) {
+        _, _, _ -> notifyDataSetChanged()
+    }
+
+    var listener: FolderContentsListener? = null
+
+    init {
+        // setHasStableIds(true)
+    }
+
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) = FolderContentsViewHolder(
+            ListviewFileBinding.inflate(
+                    LayoutInflater.from(parent.context),
+                    parent,
+                    false
+            )
+    )
+
+    override fun onBindViewHolder(holder: FolderContentsViewHolder, position: Int) {
+        val binding = holder.binding
+        val fileInfo = data[position]
+
+        binding.fileName = fileInfo.fileName
 
-    override fun getView(position: Int, v: View?, parent: ViewGroup): View {
-        val binding: ListviewFileBinding =
-            if (v == null) {
-                DataBindingUtil.inflate(LayoutInflater.from(context), R.layout.listview_file, parent, false)
-            } else {
-                DataBindingUtil.bind(v)
-            }
-        val fileInfo = getItem(position)
-        binding.fileLabel.text = fileInfo!!.fileName
         if (fileInfo.isDirectory()) {
             binding.fileIcon.setImageResource(R.drawable.ic_folder_black_24dp)
-            binding.fileSize.visibility = View.GONE
+            binding.fileSize = null
         } else {
             binding.fileIcon.setImageResource(R.drawable.ic_image_black_24dp)
-            binding.fileSize.visibility = View.VISIBLE
-            binding.fileSize.text = context.getString(R.string.file_info,
+            binding.fileSize = binding.root.context.getString(R.string.file_info,
                     FileUtils.byteCountToDisplaySize(fileInfo.size!!),
-                    DateUtils.getRelativeDateTimeString(context, fileInfo.lastModified.time, DateUtils.MINUTE_IN_MILLIS, DateUtils.WEEK_IN_MILLIS, 0))
+                    DateUtils.getRelativeDateTimeString(binding.root.context, fileInfo.lastModified.time, DateUtils.MINUTE_IN_MILLIS, DateUtils.WEEK_IN_MILLIS, 0))
         }
-        return binding.root
+
+        binding.root.setOnClickListener {
+            listener?.onItemClicked(fileInfo)
+        }
+
+        binding.executePendingBindings()
     }
+
+    override fun getItemCount() = data.size
+    // override fun getItemId(position: Int) = data[position].fileName.hashCode().toLong()
 }
+
+interface FolderContentsListener {
+    fun onItemClicked(fileInfo: FileInfo)
+}
+
+class FolderContentsViewHolder(val binding: ListviewFileBinding): RecyclerView.ViewHolder(binding.root)

app/src/main/kotlin/net/syncthing/lite/adapters/FoldersListAdapter.kt

@@ -1,39 +1,55 @@
 package net.syncthing.lite.adapters
 
-import android.content.Context
-import android.databinding.DataBindingUtil
+import android.support.v7.widget.RecyclerView
 import android.text.format.DateUtils
 import android.view.LayoutInflater
-import android.view.View
 import android.view.ViewGroup
-import android.widget.ArrayAdapter
 import net.syncthing.java.core.beans.FolderInfo
 import net.syncthing.java.core.beans.FolderStats
 import net.syncthing.lite.R
 import net.syncthing.lite.databinding.ListviewFolderBinding
-import org.apache.commons.lang3.tuple.Pair
+import kotlin.properties.Delegates
 
-class FoldersListAdapter(context: Context?, list: List<Pair<FolderInfo, FolderStats>>) :
-        ArrayAdapter<Pair<FolderInfo, FolderStats>>(context, R.layout.listview_folder, list) {
-
-    override fun getView(position: Int, v: View?, parent: ViewGroup): View {
-        val binding: ListviewFolderBinding =
-            if (v == null) {
-                DataBindingUtil.inflate(LayoutInflater.from(context), R.layout.listview_folder, parent, false)
-            } else {
-                DataBindingUtil.bind(v)
-            }
-        val folderInfo = getItem(position)!!.left
-        val folderStats = getItem(position)!!.right
-        binding.folderName.text = context.getString(R.string.folder_label_format, folderInfo.label, folderInfo.folder)
-
-        binding.folderLastmodInfo.text =
-                if (folderStats.lastUpdate == null)
-                    context.getString(R.string.last_modified_unknown)
-                else context.getString(R.string.last_modified_time,
-                        DateUtils.getRelativeDateTimeString(context, folderStats.lastUpdate.time, DateUtils.MINUTE_IN_MILLIS, DateUtils.WEEK_IN_MILLIS, 0))
-        binding.folderContentInfo.text = context.getString(R.string.folder_content_info, folderStats.describeSize(), folderStats.fileCount, folderStats.dirCount)
-        return binding.root
+class FoldersListAdapter: RecyclerView.Adapter<FolderListViewHolder>() {
+    var data: List<Pair<FolderInfo, FolderStats>> by Delegates.observable(listOf()) {
+        _, _, _ -> notifyDataSetChanged()
     }
 
+    var listener: FolderListAdapterListener? = null
+
+    init {
+        setHasStableIds(true)
+    }
+
+    override fun getItemCount() = data.size
+    override fun getItemId(position: Int) = data[position].first.folderId.hashCode().toLong()
+
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) = FolderListViewHolder (
+            ListviewFolderBinding.inflate(
+                    LayoutInflater.from(parent.context), parent, false
+            )
+    )
+
+    override fun onBindViewHolder(holder: FolderListViewHolder, position: Int) {
+        val binding = holder.binding
+        val (folderInfo, folderStats) = data[position]
+        val context = holder.itemView.context
+
+        binding.folderName = context.getString(R.string.folder_label_format, folderInfo.label, folderInfo.folderId)
+
+        binding.lastModification = context.getString(R.string.last_modified_time,
+                DateUtils.getRelativeDateTimeString(context, folderStats.lastUpdate.time, DateUtils.MINUTE_IN_MILLIS, DateUtils.WEEK_IN_MILLIS, 0))
+
+        binding.info = context.getString(R.string.folder_content_info, folderStats.describeSize(), folderStats.fileCount, folderStats.dirCount)
+
+        binding.root.setOnClickListener {
+            listener?.onFolderClicked(folderInfo, folderStats)
+        }
+    }
 }
+
+class FolderListViewHolder(val binding: ListviewFolderBinding): RecyclerView.ViewHolder(binding.root)
+
+interface FolderListAdapterListener {
+    fun onFolderClicked(folderInfo: FolderInfo, folderStats: FolderStats)
+}

app/src/main/kotlin/net/syncthing/lite/dialogs/DeviceIdDialogFragment.kt

@@ -0,0 +1,106 @@
+package net.syncthing.lite.dialogs
+
+import android.app.AlertDialog
+import android.app.Dialog
+import android.content.ClipData
+import android.content.ClipboardManager
+import android.content.Context
+import android.content.Intent
+import android.graphics.Bitmap
+import android.graphics.Color
+import android.os.Bundle
+import android.support.v4.app.FragmentManager
+import android.util.Log
+import android.view.LayoutInflater
+import android.view.View
+import android.widget.Toast
+import com.google.zxing.BarcodeFormat
+import com.google.zxing.WriterException
+import com.google.zxing.qrcode.QRCodeWriter
+import kotlinx.coroutines.experimental.android.UI
+import kotlinx.coroutines.experimental.async
+import net.syncthing.lite.R
+import net.syncthing.lite.databinding.DialogDeviceIdBinding
+import net.syncthing.lite.fragments.SyncthingDialogFragment
+import org.jetbrains.anko.doAsync
+
+class DeviceIdDialogFragment: SyncthingDialogFragment() {
+    companion object {
+        private const val QR_RESOLUTION = 512
+        private const val TAG = "DeviceIdDialog"
+    }
+
+    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
+        val binding = DialogDeviceIdBinding.inflate(LayoutInflater.from(context), null, false)
+
+        // use an placeholder to prevent size changes; this string is never shown
+        binding.deviceId.text = "XXXXXXX-XXXXXXX-XXXXXXX-XXXXXXX-XXXXXXX-XXXXXXX-XXXXXXX-XXXXXXX"
+        binding.deviceId.visibility = View.INVISIBLE
+
+        binding.qrCode.setImageBitmap(Bitmap.createBitmap(QR_RESOLUTION, QR_RESOLUTION, Bitmap.Config.RGB_565))
+
+        libraryHandler.library { configuration, _, _ ->
+            val deviceId = configuration.localDeviceId
+
+            fun copyDeviceId() {
+                val clipboard = context!!.getSystemService(Context.CLIPBOARD_SERVICE) as ClipboardManager
+                val clip = ClipData.newPlainText(context!!.getString(R.string.device_id), deviceId.deviceId)
+
+                clipboard.primaryClip = clip
+
+                Toast.makeText(context, context!!.getString(R.string.device_id_copied), Toast.LENGTH_SHORT)
+                        .show()
+            }
+
+            fun shareDeviceId() {
+                context!!.startActivity(Intent.createChooser(
+                        Intent(Intent.ACTION_SEND).apply {
+                            type = "text/plain"
+                            putExtra(Intent.EXTRA_TEXT, deviceId.deviceId)
+                        },
+                        context!!.getString(R.string.share_device_id_chooser)
+                ))
+            }
+
+            async (UI) {
+                binding.deviceId.text = deviceId.deviceId
+                binding.deviceId.visibility = View.VISIBLE
+
+                binding.deviceId.setOnClickListener { copyDeviceId() }
+                binding.share.setOnClickListener { shareDeviceId() }
+            }
+
+            doAsync {
+                val writer = QRCodeWriter()
+                try {
+                    val bitMatrix = writer.encode(deviceId.deviceId, BarcodeFormat.QR_CODE, QR_RESOLUTION, QR_RESOLUTION)
+                    val width = bitMatrix.width
+                    val height = bitMatrix.height
+                    val bmp = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565)
+                    for (x in 0 until width) {
+                        for (y in 0 until height) {
+                            bmp.setPixel(x, y, if (bitMatrix.get(x, y)) Color.BLACK else Color.WHITE)
+                        }
+                    }
+
+                    async(UI) {
+                        binding.flipper.displayedChild = 1
+                        binding.qrCode.setImageBitmap(bmp)
+                    }
+                } catch (e: WriterException) {
+                    Log.w(TAG, e)
+                }
+            }
+        }
+
+        return AlertDialog.Builder(context!!, theme)
+                .setTitle(context!!.getString(R.string.device_id))
+                .setView(binding.root)
+                .setPositiveButton(android.R.string.ok, null)
+                .create()
+    }
+
+    fun show(manager: FragmentManager?) {
+        super.show(manager, TAG)
+    }
+}

app/src/main/kotlin/net/syncthing/lite/dialogs/FileUploadDialog.kt

@@ -0,0 +1,59 @@
+package net.syncthing.lite.dialogs
+
+import android.app.ProgressDialog
+import android.content.Context
+import android.net.Uri
+import kotlinx.coroutines.experimental.android.UI
+import kotlinx.coroutines.experimental.async
+import net.syncthing.java.bep.BlockPusher
+import net.syncthing.java.client.SyncthingClient
+import net.syncthing.lite.R
+import net.syncthing.lite.library.UploadFileTask
+import net.syncthing.lite.utils.Util
+import org.jetbrains.anko.doAsync
+import org.jetbrains.anko.toast
+
+class FileUploadDialog(private val context: Context, private val syncthingClient: SyncthingClient,
+                       private val localFile: Uri, private val syncthingFolder: String,
+                       private val syncthingSubFolder: String,
+                       private val onUploadCompleteListener: () -> Unit) {
+
+    private lateinit var progressDialog: ProgressDialog
+    private var uploadFileTask: UploadFileTask? = null
+
+    fun show() {
+        showDialog()
+        doAsync {
+            uploadFileTask = UploadFileTask(context, syncthingClient, localFile, syncthingFolder,
+                    syncthingSubFolder, this@FileUploadDialog::onProgress,
+                    this@FileUploadDialog::onComplete, this@FileUploadDialog::onError)
+        }
+    }
+
+    private fun showDialog() {
+        progressDialog = ProgressDialog(context)
+        progressDialog.setMessage(context.getString(R.string.dialog_uploading_file, Util.getContentFileName(context, localFile)))
+        progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL)
+        progressDialog.setCancelable(true)
+        progressDialog.setOnCancelListener { uploadFileTask?.cancel() }
+        progressDialog.isIndeterminate = true
+        progressDialog.show()
+    }
+
+    private fun onProgress(observer: BlockPusher.FileUploadObserver) {
+        progressDialog.isIndeterminate = false
+        progressDialog.progress = observer.progressPercentage()
+        progressDialog.max = 100
+    }
+
+    private fun onComplete() {
+        progressDialog.dismiss()
+        this@FileUploadDialog.context.toast(R.string.toast_upload_complete)
+        onUploadCompleteListener()
+    }
+
+    private fun onError() {
+        progressDialog.dismiss()
+        this@FileUploadDialog.context.toast(R.string.toast_file_upload_failed)
+    }
+}

app/src/main/kotlin/net/syncthing/lite/dialogs/ReconnectIssueDialogFragment.kt

@@ -0,0 +1,32 @@
+package net.syncthing.lite.dialogs
+
+import android.os.Bundle
+import android.support.v4.app.DialogFragment
+import android.support.v4.app.FragmentActivity
+import android.support.v7.app.AlertDialog
+import net.syncthing.lite.R
+import org.jetbrains.anko.defaultSharedPreferences
+
+class ReconnectIssueDialogFragment: DialogFragment() {
+    override fun onCreateDialog(savedInstanceState: Bundle?) = AlertDialog.Builder(context!!, theme)
+            .setMessage(R.string.dialog_warning_reconnect_problem)
+            .setPositiveButton(android.R.string.ok) { _, _ ->
+                context!!.defaultSharedPreferences.edit()
+                        .putBoolean(SETTINGS_PARAM, true)
+                        .apply()
+            }
+            .create()
+
+    companion object {
+        private const val DIALOG_TAG = "ReconnectIssueDialog"
+        private const val SETTINGS_PARAM = "has_educated_about_reconnect_issues"
+
+        fun showIfNeeded(activity: FragmentActivity) {
+            if (!activity.defaultSharedPreferences.getBoolean(SETTINGS_PARAM, false)) {
+                if (activity.supportFragmentManager.findFragmentByTag(DIALOG_TAG) == null) {
+                    ReconnectIssueDialogFragment().show(activity.supportFragmentManager, DIALOG_TAG)
+                }
+            }
+        }
+    }
+}

app/src/main/kotlin/net/syncthing/lite/dialogs/downloadfile/DownloadFileDialogFragment.kt

@@ -0,0 +1,114 @@
+package net.syncthing.lite.dialogs.downloadfile
+
+import android.app.Dialog
+import android.app.ProgressDialog
+import android.arch.lifecycle.Observer
+import android.arch.lifecycle.ViewModelProviders
+import android.content.ActivityNotFoundException
+import android.content.DialogInterface
+import android.content.Intent
+import android.os.Bundle
+import android.support.v4.app.DialogFragment
+import android.support.v4.app.FragmentManager
+import android.support.v4.content.FileProvider
+import android.util.Log
+import android.webkit.MimeTypeMap
+import net.syncthing.java.core.beans.FileInfo
+import net.syncthing.lite.BuildConfig
+import net.syncthing.lite.R
+import net.syncthing.lite.library.LibraryHandler
+import org.apache.commons.io.FilenameUtils
+import org.jetbrains.anko.newTask
+import org.jetbrains.anko.toast
+
+class DownloadFileDialogFragment : DialogFragment() {
+    companion object {
+        private const val ARG_FILE_SPEC = "file spec"
+        private const val TAG = "DownloadFileDialog"
+
+        fun newInstance(fileInfo: FileInfo) = newInstance(DownloadFileSpec(
+                folder = fileInfo.folder,
+                path = fileInfo.path,
+                fileName = fileInfo.fileName
+        ))
+
+        fun newInstance(fileSpec: DownloadFileSpec) = DownloadFileDialogFragment().apply {
+            arguments = Bundle().apply {
+                putSerializable(ARG_FILE_SPEC, fileSpec)
+            }
+        }
+    }
+
+    val model: DownloadFileDialogViewModel by lazy {
+        ViewModelProviders.of(this).get(DownloadFileDialogViewModel::class.java)
+    }
+
+    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
+        val fileSpec = arguments!!.getSerializable(ARG_FILE_SPEC) as DownloadFileSpec
+
+        model.init(
+                libraryHandler = LibraryHandler(context!!),
+                fileSpec = fileSpec,
+                externalCacheDir = context!!.externalCacheDir
+        )
+
+        val progressDialog = ProgressDialog(context).apply {
+            setMessage(context!!.getString(R.string.dialog_downloading_file, fileSpec.fileName))
+            setProgressStyle(ProgressDialog.STYLE_HORIZONTAL)
+            isCancelable = true
+            isIndeterminate = true
+            max = DownloadFileStatusRunning.MAX_PROGRESS
+        }
+
+        model.status.observe(this, Observer {
+            status ->
+
+            when (status) {
+                is DownloadFileStatusRunning -> {
+                    progressDialog.apply {
+                        isIndeterminate = false
+                        progress = status.progress
+                    }
+                }
+                is DownloadFileStatusDone -> {
+                    dismissAllowingStateLoss()
+
+                    try {
+                        context!!.startActivity(
+                                Intent(Intent.ACTION_VIEW)
+                                        .setDataAndType(
+                                                FileProvider.getUriForFile(context!!, "net.syncthing.lite.fileprovider", status.file),
+                                                MimeTypeMap.getSingleton().getMimeTypeFromExtension(FilenameUtils.getExtension(fileSpec.fileName))
+                                        )
+                                        .newTask()
+                                        .addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
+                        )
+                    } catch (e: ActivityNotFoundException) {
+                        if (BuildConfig.DEBUG) {
+                            Log.w(TAG, "No handler found for file " + status.file.name, e)
+                        }
+
+                        context!!.toast(R.string.toast_open_file_failed)
+                    }
+                }
+                is DownloadFileStatusFailed -> {
+                    dismissAllowingStateLoss()
+
+                    context!!.toast(R.string.toast_file_download_failed)
+                }
+            }
+        })
+
+        return progressDialog
+    }
+
+    override fun onCancel(dialog: DialogInterface?) {
+        super.onCancel(dialog)
+
+        model.cancel()
+    }
+
+    fun show(fragmentManager: FragmentManager?) {
+        show(fragmentManager, TAG)
+    }
+}

app/src/main/kotlin/net/syncthing/lite/dialogs/downloadfile/DownloadFileDialogViewModel.kt

@@ -0,0 +1,91 @@
+package net.syncthing.lite.dialogs.downloadfile
+
+import android.arch.lifecycle.LiveData
+import android.arch.lifecycle.MutableLiveData
+import android.arch.lifecycle.ViewModel;
+import android.support.v4.os.CancellationSignal
+import android.util.Log
+import net.syncthing.lite.BuildConfig
+import net.syncthing.lite.library.DownloadFileTask
+import net.syncthing.lite.library.LibraryHandler
+import java.io.File
+
+class DownloadFileDialogViewModel : ViewModel() {
+    companion object {
+        private const val TAG = "DownloadFileDialog"
+    }
+
+    private var isInitialized = false
+    private val statusInternal = MutableLiveData<DownloadFileStatus>()
+    private val cancellationSignal = CancellationSignal()
+    val status: LiveData<DownloadFileStatus> = statusInternal
+
+    fun init(libraryHandler: LibraryHandler, fileSpec: DownloadFileSpec, externalCacheDir: File) {
+        if (isInitialized) {
+            return
+        }
+
+        isInitialized = true
+
+        libraryHandler.start()
+
+        // this keeps the client only active as long as the block is running
+        // but the file downloading is not synchronous.
+        // Due to that, the start and stop calls are used.
+        libraryHandler.syncthingClient {
+            syncthingClient ->
+
+            try {
+                val fileInfo = syncthingClient.indexHandler.getFileInfoByPath(
+                        folder = fileSpec.folder,
+                        path = fileSpec.path
+                )!!
+
+                val task = DownloadFileTask(
+                        fileStorageDirectory = externalCacheDir,
+                        syncthingClient = syncthingClient,
+                        fileInfo = fileInfo,
+                        onProgress = { status ->
+                            val newProgress = (status.downloadedBytes * DownloadFileStatusRunning.MAX_PROGRESS / status.totalTransferSize).toInt()
+                            val currentStatus = statusInternal.value
+
+                            // only update if it changed
+                            if (!(currentStatus is DownloadFileStatusRunning) || currentStatus.progress != newProgress) {
+                                statusInternal.value = DownloadFileStatusRunning(newProgress)
+                            }
+                        },
+                        onComplete = {
+                            statusInternal.value = DownloadFileStatusDone(it)
+
+                            libraryHandler.stop()
+                        },
+                        onError = {
+                            statusInternal.value = DownloadFileStatusFailed
+
+                            libraryHandler.stop()
+                        }
+                )
+
+                cancellationSignal.setOnCancelListener {
+                    task.cancel()
+                }
+            } catch (ex: Exception) {
+                if (BuildConfig.DEBUG) {
+                    Log.w(TAG, "downloading file failed", ex)
+                }
+
+                statusInternal.postValue(DownloadFileStatusFailed)
+            }
+        }
+    }
+
+    override fun onCleared() {
+        super.onCleared()
+
+        cancel()
+    }
+
+    fun cancel() {
+        cancellationSignal.cancel()
+    }
+}

app/src/main/kotlin/net/syncthing/lite/dialogs/downloadfile/DownloadFileSpec.kt

@@ -0,0 +1,5 @@
+package net.syncthing.lite.dialogs.downloadfile
+
+import java.io.Serializable
+
+data class DownloadFileSpec(val folder: String, val path: String, val fileName: String): Serializable

app/src/main/kotlin/net/syncthing/lite/dialogs/downloadfile/DownloadFileStatus.kt

@@ -0,0 +1,12 @@
+package net.syncthing.lite.dialogs.downloadfile
+
+import java.io.File
+
+sealed class DownloadFileStatus
+object DownloadFileStatusFailed: DownloadFileStatus()
+data class DownloadFileStatusDone(val file: File): DownloadFileStatus()
+data class DownloadFileStatusRunning(val progress: Int): DownloadFileStatus() {
+    companion object {
+        const val MAX_PROGRESS = 100
+    }
+}

app/src/main/kotlin/net/syncthing/lite/fragments/DevicesFragment.kt

@@ -9,135 +9,117 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import android.view.inputmethod.InputMethodManager
-import android.widget.EditText
-import android.widget.Toast
 import com.google.zxing.integration.android.IntentIntegrator
 import kotlinx.coroutines.experimental.android.UI
 import kotlinx.coroutines.experimental.async
-import net.syncthing.java.core.beans.DeviceId
 import net.syncthing.java.core.beans.DeviceInfo
-import net.syncthing.java.core.beans.DeviceStats
 import net.syncthing.lite.R
+import net.syncthing.lite.adapters.DeviceAdapterListener
 import net.syncthing.lite.adapters.DevicesAdapter
 import net.syncthing.lite.databinding.FragmentDevicesBinding
-import net.syncthing.lite.library.UpdateIndexTask
+import net.syncthing.lite.databinding.ViewEnterDeviceIdBinding
 import net.syncthing.lite.utils.FragmentIntentIntegrator
-import org.apache.commons.lang3.StringUtils.isBlank
-import uk.co.markormesher.android_fab.SpeedDialMenuAdapter
-import uk.co.markormesher.android_fab.SpeedDialMenuItem
+import net.syncthing.lite.utils.Util
 import java.io.IOException
-import java.security.InvalidParameterException
 
 class DevicesFragment : SyncthingFragment() {
 
     private lateinit var binding: FragmentDevicesBinding
-    private lateinit var adapter: DevicesAdapter
+    private val adapter = DevicesAdapter()
+    private var addDeviceDialog: AlertDialog? = null
+    private var addDeviceDialogBinding: ViewEnterDeviceIdBinding? = null
 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
                               savedInstanceState: Bundle?): View? {
         binding = DataBindingUtil.inflate(layoutInflater, R.layout.fragment_devices, container, false)
-        binding.list.emptyView = binding.empty
-        binding.fab.speedDialMenuAdapter = FabMenuAdapter()
+        binding.addDevice.setOnClickListener { showDialog() }
         return binding.root
     }
 
+    override fun onResume() {
+        super.onResume()
+        libraryHandler?.syncthingClient { it.addOnConnectionChangedListener { _ -> updateDeviceList() } }
+    }
+
+    override fun onPause() {
+        super.onPause()
+        libraryHandler?.syncthingClient { it.removeOnConnectionChangedListener{ _ -> updateDeviceList() } }
+    }
+
     override fun onLibraryLoaded() {
         initDeviceList()
         updateDeviceList()
     }
 
     private fun initDeviceList() {
-        adapter = DevicesAdapter(context!!)
         binding.list.adapter = adapter
-        binding.list.setOnItemLongClickListener { _, _, position, _ ->
-            val device = (binding.list.getItemAtPosition(position) as DeviceStats)
-            AlertDialog.Builder(context)
-                    .setTitle(getString(R.string.remove_device_title, device.name))
-                    .setMessage(getString(R.string.remove_device_message, device.deviceId.deviceId.substring(0, 7)))
-                    .setPositiveButton(android.R.string.yes) { _, _ ->
-                        libraryHandler?.configuration { it.Editor().removePeer(device.deviceId).persistLater() }
-                    }
-                    .setNegativeButton(android.R.string.no, null)
-                    .show()
-            false
+
+        adapter.listener = object: DeviceAdapterListener {
+            override fun onDeviceLongClicked(deviceInfo: DeviceInfo): Boolean {
+                AlertDialog.Builder(context)
+                        .setTitle(getString(R.string.remove_device_title, deviceInfo.name))
+                        .setMessage(getString(R.string.remove_device_message, deviceInfo.deviceId.deviceId.substring(0, 7)))
+                        .setPositiveButton(android.R.string.yes) { _, _ ->
+                            libraryHandler?.configuration { config ->
+                                config.peers = config.peers.filterNot { it.deviceId == deviceInfo.deviceId }.toSet()
+                                config.persistLater()
+                                updateDeviceList()
+                            }
+                        }
+                        .setNegativeButton(android.R.string.no, null)
+                        .show()
+
+                return false
+            }
         }
     }
 
     private fun updateDeviceList() {
-        libraryHandler?.syncthingClient { syncthingClient ->
-            adapter.clear()
-            adapter.addAll(syncthingClient.devicesHandler.getDeviceStatsList())
-            adapter.notifyDataSetChanged()
+        libraryHandler.syncthingClient { syncthingClient ->
+            async(UI) {
+                adapter.data = syncthingClient.getPeerStatus()
+                binding.isEmpty = adapter.data.isEmpty()
+            }
         }
     }
 
     override fun onActivityResult(requestCode: Int, resultCode: Int, intent: Intent?) {
-        // Check if this was a QR code scan.
         val scanResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, intent)
-        if (scanResult != null) {
-            val deviceId = scanResult.contents
-            if (!isBlank(deviceId)) {
-                importDeviceId(deviceId)
-            }
+        if (scanResult?.contents != null && scanResult.contents.isNotBlank()) {
+            addDeviceDialogBinding?.deviceId?.setText(scanResult.contents)
         }
     }
 
-    private fun importDeviceId(deviceIdString: String) {
-        libraryHandler?.library { configuration, syncthingClient, _ ->
-            async(UI) {
-                val deviceId =
-                    try {
-                        DeviceId(deviceIdString)
-                    } catch (e: IOException) {
-                        Toast.makeText(this@DevicesFragment.context, R.string.invalid_device_id, Toast.LENGTH_SHORT).show()
-                        return@async
+    private fun showDialog() {
+        addDeviceDialogBinding = DataBindingUtil.inflate(LayoutInflater.from(context), R.layout.view_enter_device_id, null, false)
+        addDeviceDialogBinding?.let { binding ->
+            binding.scanQrCode.setOnClickListener {
+                FragmentIntentIntegrator(this@DevicesFragment).initiateScan()
+            }
+            binding.deviceId.post {
+                val imm = context!!.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
+                imm.showSoftInput(binding.deviceId, InputMethodManager.SHOW_IMPLICIT)
+            }
+
+            addDeviceDialog = AlertDialog.Builder(context)
+                    .setTitle(R.string.device_id_dialog_title)
+                    .setView(binding.root)
+                    .setPositiveButton(android.R.string.ok, null)
+                    .setNegativeButton(android.R.string.cancel, null)
+                    .show()
+
+            // Use different listener to keep dialog open after button click.
+            // https://stackoverflow.com/a/15619098
+            addDeviceDialog?.getButton(AlertDialog.BUTTON_POSITIVE)
+                    ?.setOnClickListener {
+                        try {
+                            val deviceId = binding.deviceId.text.toString()
+                            Util.importDeviceId(libraryHandler, context, deviceId, { updateDeviceList() })
+                            addDeviceDialog?.dismiss()
+                        } catch (e: IOException) {
+                            binding.deviceId.error = getString(R.string.invalid_device_id)
+                        }
                     }
-
-                val modified = configuration.Editor().addPeers(DeviceInfo(deviceId, null))
-                if (modified) {
-                    configuration.Editor().persistLater()
-                    Toast.makeText(this@DevicesFragment.context, getString(R.string.device_import_success, deviceId), Toast.LENGTH_SHORT).show()
-                    updateDeviceList()//TODO remove this if event triggered (and handler trigger update)
-                    UpdateIndexTask(this@DevicesFragment.context!!, syncthingClient).updateIndex()
-                } else {
-                    Toast.makeText(this@DevicesFragment.context, getString(R.string.device_already_known, deviceId), Toast.LENGTH_SHORT).show()
-                }
-            }
-        }
-    }
-
-    private inner class FabMenuAdapter : SpeedDialMenuAdapter() {
-        override fun getCount(): Int {
-            return 2
-        }
-
-        override fun getMenuItem(context: Context, position: Int): SpeedDialMenuItem {
-            when (position) {
-                0 -> return SpeedDialMenuItem(context, R.drawable.ic_qr_code_white_24dp, R.string.scan_qr_code)
-                1 -> return SpeedDialMenuItem(context, R.drawable.ic_edit_white_24dp, R.string.enter_device_id)
-            }
-            throw InvalidParameterException()
-        }
-
-        override fun onMenuItemClick(position: Int): Boolean {
-            when (position) {
-                0 -> FragmentIntentIntegrator(this@DevicesFragment).initiateScan()
-                1 -> {
-                    val editText = EditText(context)
-                    val dialog = AlertDialog.Builder(context)
-                            .setTitle(R.string.device_id_dialog_title)
-                            .setView(editText)
-                            .setPositiveButton(android.R.string.ok) { _, _ -> importDeviceId(editText.text.toString()) }
-                            .setNegativeButton(android.R.string.cancel, null)
-                            .create()
-                    dialog.setOnShowListener {
-                        val imm = context!!.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
-                        imm.showSoftInput(editText, InputMethodManager.SHOW_IMPLICIT)
-                    }
-                    dialog.show()
-                }
-            }
-            return true
         }
     }
 }

app/src/main/kotlin/net/syncthing/lite/fragments/FoldersFragment.kt

@@ -1,13 +1,17 @@
 package net.syncthing.lite.fragments
 
-import android.databinding.DataBindingUtil
+import android.arch.lifecycle.Observer
 import android.os.Bundle
 import android.util.Log
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
-import net.syncthing.lite.R
+import kotlinx.coroutines.experimental.android.UI
+import kotlinx.coroutines.experimental.async
+import net.syncthing.java.core.beans.FolderInfo
+import net.syncthing.java.core.beans.FolderStats
 import net.syncthing.lite.activities.FolderBrowserActivity
+import net.syncthing.lite.adapters.FolderListAdapterListener
 import net.syncthing.lite.adapters.FoldersListAdapter
 import net.syncthing.lite.databinding.FragmentFoldersBinding
 import org.jetbrains.anko.intentFor
@@ -20,8 +24,10 @@ class FoldersFragment : SyncthingFragment() {
 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
                               savedInstanceState: Bundle?): View? {
-        binding = DataBindingUtil.inflate(layoutInflater, R.layout.fragment_folders, container, false)
-        binding.list.emptyView = binding.empty
+        binding = FragmentFoldersBinding.inflate(layoutInflater, container, false)
+
+        libraryHandler.isListeningPortTaken.observe(this, Observer { binding.listeningPortTaken = it })
+
         return binding.root
     }
 
@@ -30,16 +36,30 @@ class FoldersFragment : SyncthingFragment() {
     }
 
     private fun showAllFoldersListView() {
-        libraryHandler?.folderBrowser { folderBrowser ->
-            val list = folderBrowser.folderInfoAndStatsList().sortedBy { it.left.label }
-            Log.i(TAG, "list folders = " + list + " (" + list.size + " records)")
-            val adapter = FoldersListAdapter(context, list)
-            binding.list.adapter = adapter
-            binding.list.setOnItemClickListener { _, _, position, _ ->
-                val folder = adapter.getItem(position)!!.left.folder
-                val intent = context?.intentFor<FolderBrowserActivity>(FolderBrowserActivity.EXTRA_FOLDER_NAME to folder)
-                startActivity(intent)
+        libraryHandler.folderBrowser { folderBrowser ->
+            val list = folderBrowser.folderInfoAndStatsList()
+
+            async (UI) {
+                Log.i(TAG, "list folders = " + list + " (" + list.size + " records)")
+                val adapter = FoldersListAdapter().apply { data = list }
+                binding.list.adapter = adapter
+                adapter.listener = object : FolderListAdapterListener {
+                    override fun onFolderClicked(folderInfo: FolderInfo, folderStats: FolderStats) {
+                        startActivity(
+                                activity!!.intentFor<FolderBrowserActivity>(
+                                        FolderBrowserActivity.EXTRA_FOLDER_NAME to folderInfo.folderId
+                                )
+                        )
+                    }
+                }
+
+                binding.isEmpty = list.isEmpty()
             }
         }
     }
+
+    override fun onIndexUpdateComplete(folderInfo: FolderInfo) {
+        super.onIndexUpdateComplete(folderInfo)
+        showAllFoldersListView()
+    }
 }

app/src/main/kotlin/net/syncthing/lite/fragments/SettingsFragment.kt

@@ -0,0 +1,31 @@
+package net.syncthing.lite.fragments
+
+import android.os.Bundle
+import android.support.v7.preference.EditTextPreference
+import android.support.v7.preference.PreferenceFragmentCompat
+import net.syncthing.lite.R
+import net.syncthing.lite.activities.SyncthingActivity
+
+class SettingsFragment : PreferenceFragmentCompat() {
+
+    override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
+        addPreferencesFromResource(R.xml.preferences)
+
+        val localDeviceName = findPreference("local_device_name") as EditTextPreference
+        val appVersion      = findPreference("app_version")
+
+        (activity as SyncthingActivity?)?.let { activity ->
+            val versionName = activity.packageManager.getPackageInfo(activity.packageName, 0)?.versionName
+            appVersion.summary = versionName
+
+            activity.libraryHandler?.configuration { localDeviceName.text = it.localDeviceName }
+            localDeviceName.setOnPreferenceChangeListener { _, _ ->
+                activity.libraryHandler?.configuration { conf ->
+                    conf.localDeviceName = localDeviceName.text
+                    conf.persistLater()
+                }
+                true
+            }
+        }
+    }
+}

app/src/main/kotlin/net/syncthing/lite/fragments/SyncthingDialogFragment.kt

@@ -0,0 +1,22 @@
+package net.syncthing.lite.fragments
+
+import android.support.v4.app.DialogFragment
+import net.syncthing.lite.library.LibraryHandler
+
+abstract class SyncthingDialogFragment : DialogFragment() {
+    val libraryHandler: LibraryHandler by lazy { LibraryHandler(
+            context = context!!
+    )}
+
+    override fun onStart() {
+        super.onStart()
+
+        libraryHandler.start()
+    }
+
+    override fun onStop() {
+        super.onStop()
+
+        libraryHandler.stop()
+    }
+}

app/src/main/kotlin/net/syncthing/lite/fragments/SyncthingFragment.kt

@@ -1,33 +1,34 @@
 package net.syncthing.lite.fragments
 
-import android.os.Bundle
 import android.support.v4.app.Fragment
+import net.syncthing.java.core.beans.FolderInfo
 import net.syncthing.lite.library.LibraryHandler
 
 abstract class SyncthingFragment : Fragment() {
+    val libraryHandler: LibraryHandler by lazy { LibraryHandler(
+            context = context!!,
+            onIndexUpdateProgressListener = this::onIndexUpdateProgress,
+            onIndexUpdateCompleteListener = this::onIndexUpdateComplete
+    )}
 
-    var libraryHandler: LibraryHandler? = null
-        private set
+    override fun onStart() {
+        super.onStart()
 
-    override fun onActivityCreated(savedInstanceState: Bundle?) {
-        super.onActivityCreated(savedInstanceState)
-        LibraryHandler(context!!, this::onLibraryLoadedInternal, this::onIndexUpdateProgress,
-                this::onIndexUpdateComplete)
+        libraryHandler.start {
+            // TODO: check if this is still useful
+            onLibraryLoaded()
+        }
     }
 
-    private fun onLibraryLoadedInternal(libraryHandler: LibraryHandler) {
-        this.libraryHandler = libraryHandler
-        onLibraryLoaded()
-    }
+    override fun onStop() {
+        super.onStop()
 
-    override fun onDestroy() {
-        super.onDestroy()
-        libraryHandler?.close()
+        libraryHandler.stop()
     }
 
     open fun onLibraryLoaded() {}
 
-    open fun onIndexUpdateProgress(folder: String, percentage: Int) {}
+    open fun onIndexUpdateProgress(folderInfo: FolderInfo, percentage: Int) {}
 
-    open fun onIndexUpdateComplete() {}
+    open fun onIndexUpdateComplete(folderInfo: FolderInfo) {}
 }

app/src/main/kotlin/net/syncthing/lite/library/DefaultLibraryManager.kt

@@ -0,0 +1,65 @@
+package net.syncthing.lite.library
+
+import android.content.Context
+import android.os.Handler
+import android.os.Looper
+import android.util.Log
+import net.syncthing.lite.BuildConfig
+import net.syncthing.lite.R
+import org.jetbrains.anko.defaultSharedPreferences
+
+object DefaultLibraryManager {
+    private const val LOG_TAG = "DefaultLibraryManager"
+
+    private var instance: LibraryManager? = null
+    private val lock = Object()
+    private val handler = Handler(Looper.getMainLooper())
+
+    fun with(context: Context) = withApplicationContext(context.applicationContext)
+
+    private fun withApplicationContext(context: Context): LibraryManager {
+        if (instance == null) {
+            synchronized(lock) {
+                if (instance == null) {
+                    val shutdownRunnable = Runnable {
+                        instance!!.shutdownIfThereAreZeroUsers()
+                    }
+
+                    fun scheduleShutdown() {
+                        val shutdownDelay = context.defaultSharedPreferences.getString(
+                                "shutdown_delay",
+                                context.getString(R.string.default_shutdown_delay)
+                        ).toLong()
+
+                        handler.postDelayed(shutdownRunnable, shutdownDelay)
+                    }
+
+                    fun cancelShutdown() {
+                        handler.removeCallbacks(shutdownRunnable)
+                    }
+
+                    instance = LibraryManager(
+                            synchronousInstanceCreator = { LibraryInstance(context) },
+                            userCounterListener = {
+                                newUserCounter ->
+
+                                if (BuildConfig.DEBUG) {
+                                    Log.d(LOG_TAG, "user counter updated to $newUserCounter")
+                                }
+
+                                val isUsed = newUserCounter > 0
+
+                                if (isUsed) {
+                                    cancelShutdown()
+                                } else {
+                                    scheduleShutdown()
+                                }
+                            }
+                    )
+                }
+            }
+        }
+
+        return instance!!
+    }
+}

app/src/main/kotlin/net/syncthing/lite/library/DownloadFilePath.kt

@@ -0,0 +1,9 @@
+package net.syncthing.lite.library
+
+import java.io.File
+
+data class DownloadFilePath (val baseDirectory: File, val fileHash: String) {
+    val filesDirectory = File(baseDirectory, fileHash.substring(0, 2))
+    val targetFile = File(filesDirectory, fileHash.substring(2))
+    val tempFile = File(filesDirectory, fileHash.substring(2) + "_temp")
+}

app/src/main/kotlin/net/syncthing/lite/library/DownloadFileTask.kt

@@ -1,106 +1,148 @@
 package net.syncthing.lite.library
 
-import android.app.ProgressDialog
-import android.content.ActivityNotFoundException
-import android.content.Context
-import android.content.Intent
-import android.support.annotation.StringRes
-import android.support.v4.content.FileProvider
+import android.os.Handler
+import android.os.Looper
+import android.support.v4.os.CancellationSignal
 import android.util.Log
-import android.webkit.MimeTypeMap
-import net.syncthing.java.bep.BlockPuller
+import kotlinx.coroutines.experimental.launch
+import kotlinx.coroutines.experimental.suspendCancellableCoroutine
+import net.syncthing.java.bep.BlockPullerStatus
 import net.syncthing.java.client.SyncthingClient
 import net.syncthing.java.core.beans.FileInfo
-import net.syncthing.lite.R
+import net.syncthing.lite.BuildConfig
 import org.apache.commons.io.FileUtils
-import org.apache.commons.io.FilenameUtils
-import org.jetbrains.anko.doAsync
-import org.jetbrains.anko.newTask
-import org.jetbrains.anko.toast
-import org.jetbrains.anko.uiThread
 import java.io.File
 import java.io.IOException
 
-class DownloadFileTask(private val mContext: Context, private val mSyncthingClient: SyncthingClient,
-                       private val mFileInfo: FileInfo) {
+class DownloadFileTask(private val fileStorageDirectory: File,
+                       syncthingClient: SyncthingClient,
+                       private val fileInfo: FileInfo,
+                       private val onProgress: (status: BlockPullerStatus) -> Unit,
+                       private val onComplete: (File) -> Unit,
+                       private val onError: (Exception) -> Unit) {
 
-    private val TAG = "DownloadFileTask"
-    private lateinit var progressDialog: ProgressDialog
-    private var cancelled = false
+    companion object {
+        private const val TAG = "DownloadFileTask"
+        private val handler = Handler(Looper.getMainLooper())
 
-    fun downloadFile() {
-        showDialog()
-        mSyncthingClient.pullFile(mFileInfo, { observer ->
-            onProgress(observer)
-            try {
-                while (!observer.isCompleted()) {
-                    if (cancelled)
-                        return@pullFile
+        suspend fun downloadFileCoroutine(
+                externalCacheDir: File,
+                syncthingClient: SyncthingClient,
+                fileInfo: FileInfo,
+                onProgress: (status: BlockPullerStatus) -> Unit
+        ) = suspendCancellableCoroutine<File> {
+            continuation ->
 
-                    observer.waitForProgressUpdate()
-                    Log.i("pullFile", "download progress = " + observer.progressMessage())
-                    onProgress(observer)
+            val task = DownloadFileTask(
+                    externalCacheDir,
+                    syncthingClient,
+                    fileInfo,
+                    onProgress,
+                    {
+                        continuation.resume(it)
+                    },
+                    {
+                        continuation.resumeWithException(it)
+                    }
+            )
+
+            continuation.invokeOnCancellation {
+                task.cancel()
+            }
+        }
+    }
+
+    private val cancellationSignal = CancellationSignal()
+    private var doneListenerCalled = false
+
+    init {
+        val file = DownloadFilePath(fileStorageDirectory, fileInfo.hash!!)
+
+        launch {
+            if (file.targetFile.exists()) {
+                if (BuildConfig.DEBUG) {
+                    Log.d(TAG, "there is already a file")
                 }
 
-                val outputFile = File("${mContext.externalCacheDir}/${mFileInfo.folder}/${mFileInfo.path}")
-                FileUtils.copyInputStreamToFile(observer.inputStream(), outputFile)
-                Log.i(TAG, "downloaded file = " + mFileInfo.path)
-                onComplete(outputFile)
-            } catch (e: IOException) {
-                onError(R.string.toast_file_download_failed)
-                Log.w(TAG, "Failed to download file " + mFileInfo, e)
-            } catch (e: InterruptedException) {
-                onError(R.string.toast_file_download_failed)
-                Log.w(TAG, "Failed to download file " + mFileInfo, e)
+                callComplete(file.targetFile)
+
+                return@launch
             }
-        }) { onError(R.string.toast_file_download_failed) }
+
+            syncthingClient.getBlockPuller(fileInfo.folder, { blockPuller ->
+                val job = launch {
+                    try {
+                        if (!file.filesDirectory.isDirectory) {
+                            if (!file.filesDirectory.mkdirs()) {
+                                throw IOException("could not create output directory")
+                            }
+                        }
+
+                        // download the file to a temp location
+                        val inputStream = blockPuller.pullFileCoroutine(fileInfo, this@DownloadFileTask::callProgress)
+
+                        try {
+                            FileUtils.copyInputStreamToFile(inputStream, file.tempFile)
+                            file.tempFile.renameTo(file.targetFile)
+                        } finally {
+                            file.tempFile.delete()
+                        }
+
+                        if (BuildConfig.DEBUG) {
+                            Log.i(TAG, "Downloaded file $fileInfo")
+                        }
+
+                        callComplete(file.targetFile)
+                    } catch (e: Exception) {
+                        callError(e)
+
+                        if (BuildConfig.DEBUG) {
+                            Log.w(TAG, "Failed to download file $fileInfo", e)
+                        }
+                    }
+                }
+
+                cancellationSignal.setOnCancelListener {
+                    job.cancel()
+                }
+            }, { callError(IOException("could not get block puller for file")) })
+        }
     }
 
-    private fun showDialog() {
-        progressDialog = ProgressDialog(mContext)
-        progressDialog.setMessage(mContext.getString(R.string.dialog_downloading_file, mFileInfo.fileName))
-        progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL)
-        progressDialog.setCancelable(true)
-        progressDialog.setOnCancelListener { cancelled = true }
-        progressDialog.isIndeterminate = true
-        progressDialog.show()
-    }
+    private fun callProgress(status: BlockPullerStatus) {
+        handler.post {
+            if (!doneListenerCalled) {
+                if (BuildConfig.DEBUG) {
+                    Log.i("pullFile", "download progress = $status")
+                }
 
-    private fun onProgress(fileDownloadObserver: BlockPuller.FileDownloadObserver) {
-        doAsync {
-            uiThread {
-                progressDialog.isIndeterminate = false
-                progressDialog.max = (mFileInfo.size as Long).toInt()
-                progressDialog.progress = (fileDownloadObserver.progress() * mFileInfo.size!!).toInt()
+                onProgress(status)
             }
         }
     }
 
-    private fun onComplete(file: File) {
-        progressDialog.dismiss()
-        if (cancelled)
-            return
+    private fun callComplete(file: File) {
+        handler.post {
+            if (!doneListenerCalled) {
+                doneListenerCalled = true
 
-        val mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(FilenameUtils.getExtension(file.name))
-        val intent = Intent(Intent.ACTION_VIEW)
-        val uri = FileProvider.getUriForFile(mContext, "net.syncthing.lite.fileprovider", file)
-        intent.setDataAndType(uri, mimeType)
-        intent.newTask()
-        intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
-        try {
-            mContext.startActivity(intent)
-        } catch (e: ActivityNotFoundException) {
-            onError(R.string.toast_open_file_failed)
-            Log.w(TAG, "No handler found for file " + file.name, e)
-        }
-    }
-
-    private fun onError(@StringRes error: Int) {
-        doAsync {
-            uiThread {
-                progressDialog.dismiss()
-                mContext.toast(error)
+                onComplete(file)
             }
         }
     }
-}
+
+    private fun callError(exception: Exception) {
+        handler.post {
+            if (!doneListenerCalled) {
+                doneListenerCalled = true
+
+                onError(exception)
+            }
+        }
+    }
+
+    fun cancel() {
+        cancellationSignal.cancel()
+        callError(InterruptedException())
+    }
+}

app/src/main/kotlin/net/syncthing/lite/library/LibraryHandler.kt

@@ -1,133 +1,118 @@
 package net.syncthing.lite.library
 
+import android.arch.lifecycle.LiveData
+import android.arch.lifecycle.MutableLiveData
 import android.content.Context
 import android.os.Handler
-import android.preference.PreferenceManager
+import android.os.Looper
 import android.util.Log
 import kotlinx.coroutines.experimental.android.UI
 import kotlinx.coroutines.experimental.async
 import net.syncthing.java.bep.FolderBrowser
 import net.syncthing.java.client.SyncthingClient
+import net.syncthing.java.core.beans.DeviceId
 import net.syncthing.java.core.beans.FileInfo
+import net.syncthing.java.core.beans.FolderInfo
 import net.syncthing.java.core.beans.IndexInfo
-import net.syncthing.java.core.configuration.ConfigurationService
-import net.syncthing.java.core.security.KeystoreHandler
-import net.syncthing.lite.utils.Util
-import org.apache.commons.io.FileUtils
+import net.syncthing.java.core.configuration.Configuration
 import org.jetbrains.anko.doAsync
-import org.jetbrains.anko.uiThread
-import java.io.File
-import java.io.IOException
-import java.util.*
+import java.util.concurrent.atomic.AtomicBoolean
 
-class LibraryHandler(context: Context, onLibraryLoaded: (LibraryHandler) -> Unit,
-                     private val onIndexUpdateProgressListener: (String, Int) -> Unit,
-                     private val onIndexUpdateCompleteListener: () -> Unit) {
+/**
+ * This class helps when using the library.
+ * It's required to start and stop it to make the callbacks fire (or stop to fire).
+ *
+ * It's possible to do multiple start and stop cycles with one instance of this class.
+ */
+class LibraryHandler(context: Context,
+                     private val onIndexUpdateProgressListener: (FolderInfo, Int) -> Unit = {_, _ -> },
+                     private val onIndexUpdateCompleteListener: (FolderInfo) -> Unit = {}) {
 
     companion object {
-        private var instanceCount = 0
-        private var configuration: ConfigurationService? = null
-        private var syncthingClient: SyncthingClient? = null
-        private var folderBrowser: FolderBrowser? = null
-        private val callbacks = ArrayList<(ConfigurationService, SyncthingClient, FolderBrowser) -> Unit>()
-        private var isLoading = false
+        private const val TAG = "LibraryHandler"
+        private val handler = Handler(Looper.getMainLooper())
     }
 
-    private val TAG = "LibConnectionHandler"
+    private val libraryManager = DefaultLibraryManager.with(context)
+    private val isStarted = AtomicBoolean(false)
+    private val isListeningPortTakenInternal = MutableLiveData<Boolean>().apply { value = false }
 
-    private val onIndexUpdateListener: Any
+    val isListeningPortTaken: LiveData<Boolean> = isListeningPortTakenInternal
 
-    init {
-        instanceCount++
-        if (configuration == null && !isLoading) {
-            doAsync {
-                init(context)
-                //trigger update if last was more than 10mins ago
-                val lastUpdateMillis = PreferenceManager.getDefaultSharedPreferences(context)
-                        .getLong(UpdateIndexTask.LAST_INDEX_UPDATE_TS_PREF, -1)
-                val lastUpdateTimeAgo = Date().time - lastUpdateMillis
-                if (lastUpdateMillis == -1L || lastUpdateTimeAgo > 10 * 60 * 1000) {
-                    Log.d(TAG, "trigger index update, last was " + Date(lastUpdateMillis))
-                    syncthingClient { UpdateIndexTask(context, it).updateIndex() }
-                }
-                uiThread {
-                    onLibraryLoaded(this@LibraryHandler)
-                }
-            }
-        } else {
+    private val messageFromUnknownDeviceListeners = HashSet<(DeviceId) -> Unit>()
+    private val internalMessageFromUnknownDeviceListener: (DeviceId) -> Unit = {
+        deviceId ->
+
+        handler.post {
+            messageFromUnknownDeviceListeners.forEach { listener -> listener(deviceId) }
+        }
+    }
+
+    fun start(onLibraryLoaded: (LibraryHandler) -> Unit = {}) {
+        if (isStarted.getAndSet(true) == true) {
+            throw IllegalStateException("already started")
+        }
+
+        libraryManager.startLibraryUsage {
+            libraryInstance ->
+
+            isListeningPortTakenInternal.value = libraryInstance.isListeningPortTaken
             onLibraryLoaded(this)
+
+            val client = libraryInstance.syncthingClient
+
+            client.indexHandler.registerOnIndexRecordAcquiredListener(this::onIndexRecordAcquired)
+            client.indexHandler.registerOnFullIndexAcquiredListenersListener(this::onRemoteIndexAcquired)
+            client.discoveryHandler.registerMessageFromUnknownDeviceListener(internalMessageFromUnknownDeviceListener)
+        }
+    }
+
+    fun stop() {
+        if (isStarted.getAndSet(false) == false) {
+            throw IllegalStateException("already stopped")
         }
 
-        onIndexUpdateListener = object : Any() {
-        }
         syncthingClient {
-            it.indexHandler.registerOnIndexRecordAcquiredListener(this::onIndexRecordAcquired)
-            it.indexHandler.registerOnFullIndexAcquiredListenersListener(this::onRemoteIndexAcquired)
+            try {
+                it.indexHandler.unregisterOnIndexRecordAcquiredListener(this::onIndexRecordAcquired)
+                it.indexHandler.unregisterOnFullIndexAcquiredListenersListener(this::onRemoteIndexAcquired)
+                it.discoveryHandler.unregisterMessageFromUnknownDeviceListener(internalMessageFromUnknownDeviceListener)
+            } catch (e: IllegalArgumentException) {
+                // ignored, no idea why this is thrown
+            }
         }
+
+        libraryManager.stopLibraryUsage()
     }
 
-    private fun onIndexRecordAcquired(folderId: String, newRecords: List<FileInfo>, indexInfo: IndexInfo) {
-        newRecords.size
+    private fun onIndexRecordAcquired(folderInfo: FolderInfo, newRecords: List<FileInfo>, indexInfo: IndexInfo) {
         Log.i(TAG, "handleIndexRecordEvent trigger folder list update from index record acquired")
-        onIndexUpdateProgressListener(folderId, (indexInfo.getCompleted() * 100).toInt())
-    }
-
-    private fun onRemoteIndexAcquired(folderId: String) {
-        Log.i(TAG, "handleIndexAcquiredEvent trigger folder list update from index acquired")
-        onIndexUpdateCompleteListener()
-    }
-
-    private fun init(context: Context) {
-        isLoading = true
-        val configuration = ConfigurationService.Loader()
-                .setCache(File(context.externalCacheDir, ".cache"))
-                .setDatabase(File(context.getExternalFilesDir(null), "database"))
-                .loadFrom(File(context.getExternalFilesDir(null), "config.properties"))
-        configuration.Editor().setDeviceName(Util.getDeviceName())
-        try {
-            FileUtils.cleanDirectory(configuration.temp)
-        } catch (e: IOException) {
-            Log.e(TAG, "Failed to delete temporary files", e)
-            close()
-        }
-
-        KeystoreHandler.Loader().loadAndStore(configuration)
-        configuration.Editor().persistLater()
-        Log.i(TAG, "loaded mConfiguration = " + configuration.Writer().dumpToString())
-        Log.i(TAG, "storage space = " + configuration.getStorageInfo().dumpAvailableSpace())
-        val syncthingClient = SyncthingClient(configuration)
-        //TODO listen for device events, update device list
-        val folderBrowser = syncthingClient.indexHandler.newFolderBrowser()
-
-        if (instanceCount == 0) {
-            Log.d(TAG, "All LibraryHandler instances were closed during init")
-            configuration.close()
-            syncthingClient.close()
-            folderBrowser.close()
-        }
 
         async(UI) {
-            callbacks.forEach { it(configuration, syncthingClient, folderBrowser) }
+            onIndexUpdateProgressListener(folderInfo, (indexInfo.getCompleted() * 100).toInt())
         }
-        LibraryHandler.configuration = configuration
-        LibraryHandler.syncthingClient = syncthingClient
-        LibraryHandler.folderBrowser = folderBrowser
-        isLoading = false
     }
 
-    fun library(callback: (ConfigurationService, SyncthingClient, FolderBrowser) -> Unit) {
-        val nullCount = listOf(configuration, syncthingClient, folderBrowser).count { it == null }
-        assert(nullCount == 0 || nullCount == 3, { "Inconsistent library state" })
+    private fun onRemoteIndexAcquired(folderInfo: FolderInfo) {
+        Log.i(TAG, "handleIndexAcquiredEvent trigger folder list update from index acquired")
 
-        // https://stackoverflow.com/a/35522422/1837158
-        fun <T1: Any, T2: Any, T3: Any, R: Any> safeLet(p1: T1?, p2: T2?, p3: T3?, block: (T1, T2, T3)->R?): R? {
-            return if (p1 != null && p2 != null && p3 != null) block(p1, p2, p3) else null
+        async(UI) {
+            onIndexUpdateCompleteListener(folderInfo)
         }
-        safeLet(configuration, syncthingClient, folderBrowser) { c, s, f ->
-            callback(c, s, f)
-        } ?: run {
-            if (isLoading) {
-                callbacks.add(callback)
+    }
+
+    /*
+     * The callback is executed asynchronously.
+     * As soon as it returns, there is no guarantee about the availability of the library
+     */
+    fun library(callback: (Configuration, SyncthingClient, FolderBrowser) -> Unit) {
+        libraryManager.startLibraryUsage {
+            doAsync {
+                try {
+                    callback(it.configuration, it.syncthingClient, it.folderBrowser)
+                } finally {
+                    libraryManager.stopLibraryUsage()
+                }
             }
         }
     }
@@ -136,7 +121,7 @@ class LibraryHandler(context: Context, onLibraryLoaded: (LibraryHandler) -> Unit
         library { _, s, _ -> callback(s) }
     }
 
-    fun configuration(callback: (ConfigurationService) -> Unit) {
+    fun configuration(callback: (Configuration) -> Unit) {
         library { c, _, _ -> callback(c) }
     }
 
@@ -144,35 +129,13 @@ class LibraryHandler(context: Context, onLibraryLoaded: (LibraryHandler) -> Unit
         library { _, _, f -> callback(f) }
     }
 
-    /**
-     * Unregisters index update listener and decreases instance count.
-     *
-     * We wait a bit before closing [[syncthingClient]] etc, in case LibraryHandler is opened again
-     * soon (eg in case of device rotation).
-     */
-    fun close() {
-        syncthingClient {
-            try {
-                it.indexHandler.unregisterOnIndexRecordAcquiredListener(this::onIndexRecordAcquired)
-                it.indexHandler.unregisterOnFullIndexAcquiredListenersListener(this::onRemoteIndexAcquired)
-            } catch (e: IllegalArgumentException) {
-                // ignored, no idea why this is thrown
-            }
-        }
-
-        instanceCount--
-        Handler().postDelayed({
-            Thread {
-                if (instanceCount == 0) {
-                    folderBrowser?.close()
-                    folderBrowser = null
-                    syncthingClient?.close()
-                    syncthingClient = null
-                    configuration?.close()
-                    configuration = null
-                }
-            }.start()
-        }, 1000)
+    // these listeners are called at the UI Thread
+    // there is no need to unregister because they removed from the library when close is called
+    fun registerMessageFromUnknownDeviceListener(listener: (DeviceId) -> Unit) {
+        messageFromUnknownDeviceListeners.add(listener)
+    }
 
+    fun unregisterMessageFromUnknownDeviceListener(listener: (DeviceId) -> Unit) {
+        messageFromUnknownDeviceListeners.remove(listener)
     }
 }

app/src/main/kotlin/net/syncthing/lite/library/LibraryInstance.kt

@@ -0,0 +1,65 @@
+package net.syncthing.lite.library
+
+import android.content.Context
+import android.util.Log
+import net.syncthing.java.client.SyncthingClient
+import net.syncthing.java.core.configuration.Configuration
+import net.syncthing.repository.android.SqliteIndexRepository
+import net.syncthing.repository.android.TempDirectoryLocalRepository
+import net.syncthing.repository.android.database.RepositoryDatabase
+import java.io.File
+import java.net.DatagramSocket
+import java.net.InetAddress
+import java.net.SocketException
+
+/**
+ * This class is used internally to access the syncthing-java library
+ * There should be never more than 1 instance of this class
+ *
+ * This class can not be recycled. This means that after doing a shutdown of it,
+ * a new instance must be created
+ *
+ * The creation and the shutdown are synchronous, so keep them out of the UI Thread
+ */
+class LibraryInstance (context: Context) {
+    companion object {
+        private const val LOG_TAG = "LibraryInstance"
+
+        /**
+         * Check if listening port for local discovery is taken by another app. Do this check here to
+         * avoid adding another callback.
+         */
+        private fun checkIsListeningPortTaken(): Boolean {
+            try {
+                DatagramSocket(21027, InetAddress.getByName("0.0.0.0")).close()
+
+                return false
+            } catch (e: SocketException) {
+                Log.w(LOG_TAG, e)
+
+                return true
+            }
+        }
+    }
+
+    private val tempRepository = TempDirectoryLocalRepository(File(context.filesDir, "temp_repository"))
+
+    val isListeningPortTaken = checkIsListeningPortTaken()  // this must come first to work correctly
+    val configuration = Configuration(configFolder = context.filesDir)
+    val syncthingClient = SyncthingClient(
+            configuration = configuration,
+            repository = SqliteIndexRepository(
+                    database = RepositoryDatabase.with(context),
+                    closeDatabaseOnClose = false,
+                    clearTempStorageHook = { tempRepository.deleteAllData() }
+            ),
+            tempRepository = tempRepository
+    )
+    val folderBrowser = syncthingClient.indexHandler.newFolderBrowser()
+
+    fun shutdown() {
+        folderBrowser.close()
+        syncthingClient.close()
+        configuration.persistNow()
+    }
+}

app/src/main/kotlin/net/syncthing/lite/library/LibraryManager.kt

@@ -0,0 +1,89 @@
+package net.syncthing.lite.library
+
+import android.os.Handler
+import android.os.Looper
+import java.util.concurrent.Executors
+import kotlin.coroutines.experimental.suspendCoroutine
+
+/**
+ * This class manages the access to an LibraryInstance
+ *
+ * Users can get an instance with startLibraryUsage()
+ * If they are done with it, the should call stopLibraryUsage()
+ * After this, it's NOT safe to continue using the received LibraryInstance
+ *
+ * Every call to startLibraryUsage should be followed by an call to stopLibraryUsage,
+ * even if the callback was not called yet. It can still be called, so users should watch out.
+ *
+ * All listeners are executed at the UI Thread (except the synchronousInstanceCreator)
+ *
+ * The userCounterListener is always called before the isRunningListener
+ *
+ * The listeners are called for all changes, nothing is skipped or batched
+ */
+class LibraryManager (
+        val synchronousInstanceCreator: () -> LibraryInstance,
+        val userCounterListener: (Int) -> Unit = {},
+        val isRunningListener: (isRunning: Boolean) -> Unit = {}
+) {
+    companion object {
+        private val handler = Handler(Looper.getMainLooper())
+    }
+
+    // this must be a SingleThreadExecutor to avoid race conditions
+    // only this Thread should access instance and userCounter
+    private val startStopExecutor = Executors.newSingleThreadExecutor()
+
+    private var instance: LibraryInstance? = null
+    private var userCounter = 0
+
+    fun startLibraryUsage(callback: (LibraryInstance) -> Unit) {
+        startStopExecutor.submit {
+            val newUserCounter = ++userCounter
+            handler.post { userCounterListener(newUserCounter) }
+
+            if (instance == null) {
+                instance = synchronousInstanceCreator()
+                handler.post { isRunningListener(true) }
+            }
+
+            handler.post { callback(instance!!) }
+        }
+    }
+
+    suspend fun startLibraryUsageCoroutine(): LibraryInstance {
+        return suspendCoroutine { continuation ->
+            startLibraryUsage { instance ->
+                continuation.resume(instance)
+            }
+        }
+    }
+
+    fun stopLibraryUsage() {
+        startStopExecutor.submit {
+            val newUserCounter = --userCounter
+
+            if (newUserCounter < 0) {
+                userCounter = 0
+
+                throw IllegalStateException("can not stop library usage if there are 0 users")
+            }
+
+            handler.post { userCounterListener(newUserCounter) }
+        }
+    }
+
+    fun shutdownIfThereAreZeroUsers(listener: (wasShutdownPerformed: Boolean) -> Unit = {}) {
+        startStopExecutor.submit {
+            if (userCounter == 0) {
+                instance?.shutdown()
+                instance = null
+
+                handler.post { isRunningListener(false) }
+                handler.post { listener(true) }
+            } else {
+                handler.post { listener(false) }
+            }
+        }
+    }
+}

app/src/main/kotlin/net/syncthing/lite/library/SyncthingProvider.kt

@@ -0,0 +1,158 @@
+package net.syncthing.lite.library
+
+import android.database.Cursor
+import android.database.MatrixCursor
+import android.os.CancellationSignal
+import android.os.ParcelFileDescriptor
+import android.provider.DocumentsContract.Document
+import android.provider.DocumentsContract.Root
+import android.provider.DocumentsProvider
+import android.util.Log
+import kotlinx.coroutines.experimental.cancel
+import kotlinx.coroutines.experimental.runBlocking
+import net.syncthing.java.bep.IndexBrowser
+import net.syncthing.java.core.beans.FileInfo
+import net.syncthing.java.core.beans.FolderInfo
+import net.syncthing.java.core.beans.FolderStats
+import net.syncthing.lite.R
+import java.io.FileNotFoundException
+import java.net.URLConnection
+import java.util.concurrent.CountDownLatch
+
+class SyncthingProvider : DocumentsProvider() {
+
+    companion object {
+        private const val Tag = "SyncthingProvider"
+        private val DefaultRootProjection = arrayOf(
+                Root.COLUMN_ROOT_ID,
+                Root.COLUMN_FLAGS,
+                Root.COLUMN_TITLE,
+                Root.COLUMN_SUMMARY,
+                Root.COLUMN_DOCUMENT_ID,
+                Root.COLUMN_ICON)
+        private val DefaultDocumentProjection = arrayOf(
+                Document.COLUMN_DOCUMENT_ID,
+                Document.COLUMN_DISPLAY_NAME,
+                Document.COLUMN_SIZE,
+                Document.COLUMN_MIME_TYPE,
+                Document.COLUMN_LAST_MODIFIED,
+                Document.COLUMN_FLAGS)
+    }
+
+    override fun onCreate(): Boolean {
+        Log.d(Tag, "onCreate()")
+        return true
+    }
+
+    // this instance is not started -> it connects and disconnects on demand
+    private val libraryHandler: LibraryHandler by lazy { LibraryHandler(context) }
+    private val libraryManager: LibraryManager by lazy { DefaultLibraryManager.with(context) }
+
+    override fun queryRoots(projection: Array<String>?): Cursor {
+        Log.d(Tag, "queryRoots($projection)")
+        val latch = CountDownLatch(1)
+        var folders: List<Pair<FolderInfo, FolderStats>>? = null
+        libraryHandler.folderBrowser { folderBrowser ->
+            folders = folderBrowser.folderInfoAndStatsList()
+            latch.countDown()
+        }
+        latch.await()
+
+        val result = MatrixCursor(projection ?: DefaultRootProjection)
+        folders!!.forEach { folder ->
+            val row = result.newRow()
+            row.add(Root.COLUMN_ROOT_ID, folder.first.folderId)
+            row.add(Root.COLUMN_SUMMARY, folder.first.label)
+            row.add(Root.COLUMN_FLAGS, 0)
+            row.add(Root.COLUMN_TITLE, context.getString(R.string.app_name))
+            row.add(Root.COLUMN_DOCUMENT_ID, getDocIdForFile(folder.first))
+            row.add(Root.COLUMN_ICON, R.mipmap.ic_launcher)
+        }
+        return result
+    }
+
+    override fun queryChildDocuments(parentDocumentId: String, projection: Array<String>?,
+                                     sortOrder: String?): Cursor {
+        Log.d(Tag, "queryChildDocuments($parentDocumentId, $projection, $sortOrder)")
+        val result = MatrixCursor(projection ?: DefaultDocumentProjection)
+        getIndexBrowser(getFolderIdForDocId(parentDocumentId))
+                .listFiles(getPathForDocId(parentDocumentId))
+                .forEach { fileInfo ->
+                    includeFile(result, fileInfo)
+                }
+        return result
+    }
+
+    override fun queryDocument(documentId: String, projection: Array<String>?): Cursor {
+        Log.d(Tag, "queryDocument($documentId, $projection)")
+        val result = MatrixCursor(projection ?: DefaultDocumentProjection)
+        val fileInfo = getIndexBrowser(getFolderIdForDocId(documentId))
+                .getFileInfoByAbsolutePath(getPathForDocId(documentId))
+        includeFile(result, fileInfo)
+        return result
+    }
+
+    @Throws(FileNotFoundException::class)
+    override fun openDocument(documentId: String, mode: String, signal: CancellationSignal?):
+            ParcelFileDescriptor {
+        Log.d(Tag, "openDocument($documentId, $mode, $signal)")
+        val fileInfo = getIndexBrowser(getFolderIdForDocId(documentId))
+                .getFileInfoByAbsolutePath(getPathForDocId(documentId))
+        val accessMode = ParcelFileDescriptor.parseMode(mode)
+        if (accessMode != ParcelFileDescriptor.MODE_READ_ONLY) {
+            throw NotImplementedError()
+        }
+
+        val outputFile = runBlocking {
+            signal?.setOnCancelListener {
+                this.coroutineContext.cancel()
+            }
+
+            val libraryInstance = libraryManager.startLibraryUsageCoroutine()
+
+            try {
+                DownloadFileTask.downloadFileCoroutine(
+                        externalCacheDir = context.externalCacheDir,
+                        syncthingClient = libraryInstance.syncthingClient,
+                        fileInfo = fileInfo,
+                        onProgress = { /* ignore the progress */ }
+                )
+            } finally {
+                libraryManager.stopLibraryUsage()
+            }
+        }
+
+        return ParcelFileDescriptor.open(outputFile, ParcelFileDescriptor.MODE_READ_ONLY)
+    }
+
+    private fun includeFile(result: MatrixCursor, fileInfo: FileInfo) {
+        val row = result.newRow()
+        row.add(Document.COLUMN_DOCUMENT_ID, getDocIdForFile(fileInfo))
+        row.add(Document.COLUMN_DISPLAY_NAME, fileInfo.fileName)
+        row.add(Document.COLUMN_SIZE, fileInfo.size)
+        val mime = if (fileInfo.isDirectory()) Document.MIME_TYPE_DIR
+        else URLConnection.guessContentTypeFromName(fileInfo.fileName)
+        row.add(Document.COLUMN_MIME_TYPE, mime)
+        row.add(Document.COLUMN_LAST_MODIFIED, fileInfo.lastModified)
+        row.add(Document.COLUMN_FLAGS, 0)
+    }
+
+    private fun getFolderIdForDocId(docId: String) = docId.split(":")[0]
+
+    private fun getPathForDocId(docId: String) = docId.split(":")[1]
+
+    private fun getDocIdForFile(folderInfo: FolderInfo) = folderInfo.folderId + ":"
+
+    private fun getDocIdForFile(fileInfo: FileInfo) = fileInfo.folder + ":" + fileInfo.path
+
+    private fun getIndexBrowser(folderId: String): IndexBrowser {
+        val latch = CountDownLatch(1)
+        var indexBrowser: IndexBrowser? = null
+        libraryHandler.syncthingClient {
+            indexBrowser = it.indexHandler.newIndexBrowser(folderId)
+            latch.countDown()
+        }
+        latch.await()
+        return indexBrowser!!
+    }
+}

app/src/main/kotlin/net/syncthing/lite/library/UpdateIndexTask.kt

@@ -1,47 +0,0 @@
-package net.syncthing.lite.library
-
-import android.content.Context
-import android.preference.PreferenceManager
-import net.syncthing.java.client.SyncthingClient
-import net.syncthing.lite.R
-import org.jetbrains.anko.doAsync
-import org.jetbrains.anko.toast
-import org.jetbrains.anko.uiThread
-import java.util.*
-
-class UpdateIndexTask(private val androidContext: Context, private val syncthingClient: SyncthingClient) {
-    private val mPreferences = PreferenceManager.getDefaultSharedPreferences(androidContext)
-
-    fun updateIndex() {
-        if (sIndexUpdateInProgress)
-            return
-
-        sIndexUpdateInProgress = true
-        syncthingClient.updateIndexFromPeers { _, failures ->
-            sIndexUpdateInProgress = false
-            if (failures.isEmpty()) {
-                showToast(androidContext.getString(R.string.toast_index_update_successful))
-            } else {
-                showToast(androidContext.getString(R.string.toast_index_update_failed, failures.size))
-            }
-            mPreferences.edit()
-                    .putLong(LAST_INDEX_UPDATE_TS_PREF, Date().time)
-                    .apply()
-        }
-    }
-
-    private fun showToast(message: String) {
-        doAsync {
-            uiThread {
-                androidContext.toast(message)
-            }
-        }
-    }
-
-    companion object {
-
-        val LAST_INDEX_UPDATE_TS_PREF = "LAST_INDEX_UPDATE_TS"
-
-        private var sIndexUpdateInProgress: Boolean = false
-    }
-}

app/src/main/kotlin/net/syncthing/lite/library/UploadFileTask.kt

@@ -1,97 +1,55 @@
 package net.syncthing.lite.library
 
-import android.app.ProgressDialog
 import android.content.Context
 import android.net.Uri
+import android.os.Handler
+import android.os.Looper
 import android.util.Log
-import kotlinx.coroutines.experimental.android.UI
-import kotlinx.coroutines.experimental.async
 import net.syncthing.java.bep.BlockPusher
 import net.syncthing.java.client.SyncthingClient
 import net.syncthing.java.core.utils.PathUtils
-import net.syncthing.lite.R
 import net.syncthing.lite.utils.Util
-import org.jetbrains.anko.toast
-import java.io.IOException
+import org.apache.commons.io.IOUtils
 
 // TODO: this should be an IntentService with notification
-class UploadFileTask(private val context: Context, private val syncthingClient: SyncthingClient,
-                     private val localFile: Uri, private val syncthingFolder: String,
+class UploadFileTask(context: Context, syncthingClient: SyncthingClient,
+                     localFile: Uri, private val syncthingFolder: String,
                      syncthingSubFolder: String,
-                     private val onUploadCompleteListener: () -> Unit) {
+                     private val onProgress: (BlockPusher.FileUploadObserver) -> Unit,
+                     private val onComplete: () -> Unit,
+                     private val onError: () -> Unit) {
 
     companion object {
-        private val TAG = "UploadFileTask"
+        private const val TAG = "UploadFileTask"
+        private val handler = Handler(Looper.getMainLooper())
     }
 
-    private val fileName = Util.getContentFileName(context, localFile)
-    private val syncthingPath = PathUtils.buildPath(syncthingSubFolder, fileName)
+    private val syncthingPath = PathUtils.buildPath(syncthingSubFolder, Util.getContentFileName(context, localFile))
+    private val uploadStream = context.contentResolver.openInputStream(localFile)
 
-    private lateinit var mProgressDialog: ProgressDialog
-    private var mCancelled = false
+    private var isCancelled = false
 
-    fun uploadFile() {
-        createDialog()
+    init {
         Log.i(TAG, "Uploading file $localFile to folder $syncthingFolder:$syncthingPath")
-        try {
-            val uploadStream = context.contentResolver.openInputStream(localFile)
-            syncthingClient.pushFile(uploadStream, syncthingFolder, syncthingPath, { observer ->
-                onProgress(observer)
-                try {
-                    while (!observer.isCompleted()) {
-                        if (mCancelled)
-                            return@pushFile
+        syncthingClient.getBlockPusher(syncthingFolder, { blockPusher ->
+            val observer = blockPusher.pushFile(uploadStream, syncthingFolder, syncthingPath)
 
-                        observer.waitForProgressUpdate()
-                        Log.i(TAG, "upload progress = " + observer.progressMessage())
-                        onProgress(observer)
-                    }
-                } catch (e: InterruptedException) {
-                    onError()
-                }
+            handler.post { onProgress(observer) }
 
-                onComplete()
-            }, { this.onError() })
-        } catch (e: IOException) {
-            onError()
-        }
+            while (!observer.isCompleted()) {
+                if (isCancelled)
+                    return@getBlockPusher
 
+                observer.waitForProgressUpdate()
+                Log.i(TAG, "upload progress = ${observer.progressPercentage()}%")
+                handler.post { onProgress(observer) }
+            }
+            IOUtils.closeQuietly(uploadStream)
+            handler.post { onComplete() }
+        }, { handler.post { onError() } })
     }
 
-    private fun createDialog() {
-        mProgressDialog = ProgressDialog(context)
-        mProgressDialog.setMessage(context.getString(R.string.dialog_uploading_file, fileName))
-        mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL)
-        mProgressDialog.setCancelable(true)
-        mProgressDialog.setOnCancelListener { mCancelled = true }
-        mProgressDialog.isIndeterminate = true
-        mProgressDialog.show()
-    }
-
-    private fun onProgress(observer: BlockPusher.FileUploadObserver) {
-        async(UI) {
-            mProgressDialog.isIndeterminate = false
-            mProgressDialog.max = observer.dataSource().getSize().toInt()
-            mProgressDialog.progress = (observer.progress() * observer.dataSource().getSize()).toInt()
-        }
-    }
-
-    private fun onComplete() {
-        if (mCancelled)
-            return
-
-        Log.i(TAG, "Uploaded file $fileName to folder $syncthingFolder:$syncthingPath")
-        async(UI) {
-            mProgressDialog.dismiss()
-            this@UploadFileTask.context.toast(R.string.toast_upload_complete)
-            onUploadCompleteListener()
-        }
-    }
-
-    private fun onError() {
-        async(UI) {
-            mProgressDialog.dismiss()
-            this@UploadFileTask.context.toast(R.string.toast_file_upload_failed)
-        }
+    fun cancel() {
+        isCancelled = true
     }
 }

app/src/main/kotlin/net/syncthing/lite/utils/Util.kt

@@ -3,15 +3,21 @@ package net.syncthing.lite.utils
 import android.content.Context
 import android.net.Uri
 import android.os.Build
-import android.provider.MediaStore
-import android.util.Log
+import android.provider.OpenableColumns
+import kotlinx.coroutines.experimental.android.UI
+import kotlinx.coroutines.experimental.async
+import net.syncthing.java.core.beans.DeviceId
+import net.syncthing.java.core.beans.DeviceInfo
+import net.syncthing.lite.R
+import net.syncthing.lite.library.LibraryHandler
 import org.apache.commons.lang3.StringUtils.capitalize
-import java.io.File
+import org.jetbrains.anko.toast
+import java.io.IOException
+import java.security.InvalidParameterException
+import java.util.*
 
 object Util {
 
-    private val Tag = "Util"
-
     fun getDeviceName(): String {
         val manufacturer = Build.MANUFACTURER ?: ""
         val model = Build.MODEL ?: ""
@@ -24,17 +30,32 @@ object Util {
         return deviceName ?: "android"
     }
 
-    fun getContentFileName(context: Context, contentUri: Uri): String {
-        var fileName = File(contentUri.lastPathSegment).name
-        if (contentUri.scheme == "content") {
-            context.contentResolver.query(contentUri, arrayOf(MediaStore.Images.Media.DATA), null, null, null)!!.use { cursor ->
-                val columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA)
-                cursor.moveToFirst()
-                val path = cursor.getString(columnIndex)
-                Log.d(Tag, "recovered 'content' uri real path = " + path)
-                fileName = File(Uri.parse(path).lastPathSegment).name
+    fun getContentFileName(context: Context, uri: Uri): String {
+        context.contentResolver.query(uri, null, null, null, null, null).use { cursor ->
+            if (cursor == null || !cursor.moveToFirst()) {
+                throw InvalidParameterException("Cursor is null or empty")
+            }
+            return cursor.getString(cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME))
+        }
+    }
+
+    @Throws(IOException::class)
+    fun importDeviceId(libraryHandler: LibraryHandler?, context: Context?, deviceId: String,
+                       onComplete: () -> Unit) {
+        val deviceId2 = DeviceId(deviceId.toUpperCase(Locale.US))
+        libraryHandler?.configuration { configuration ->
+            if (!configuration.peerIds.contains(deviceId2)) {
+                configuration.peers = configuration.peers + DeviceInfo(deviceId2, null)
+                configuration.persistLater()
+                async(UI) {
+                    context?.toast(context.getString(R.string.device_import_success, deviceId2.shortId))
+                    onComplete()
+                }
+            } else {
+                async(UI) {
+                    context?.toast(context.getString(R.string.device_already_known, deviceId2.shortId))
+                }
             }
         }
-        return fileName
     }
 }

app/src/main/res/drawable/ic_content_copy_black_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M16,1L4,1c-1.1,0 -2,0.9 -2,2v14h2L4,3h12L16,1zM19,5L8,5c-1.1,0 -2,0.9 -2,2v14c0,1.1 0.9,2 2,2h11c1.1,0 2,-0.9 2,-2L21,7c0,-1.1 -0.9,-2 -2,-2zM19,21L8,21L8,7h11v14z"/>
+</vector>

app/src/main/res/drawable/ic_edit_white_24dp.xml

@@ -1,9 +0,0 @@
-<vector xmlns:android="http://schemas.android.com/apk/res/android"
-        android:width="24dp"
-        android:height="24dp"
-        android:viewportWidth="24.0"
-        android:viewportHeight="24.0">
-    <path
-        android:fillColor="#FFFFFFFF"
-        android:pathData="M3,17.25V21h3.75L17.81,9.94l-3.75,-3.75L3,17.25zM20.71,7.04c0.39,-0.39 0.39,-1.02 0,-1.41l-2.34,-2.34c-0.39,-0.39 -1.02,-0.39 -1.41,0l-1.83,1.83 3.75,3.75 1.83,-1.83z"/>
-</vector>

app/src/main/res/drawable/ic_power_settings_new_black_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M13,3h-2v10h2L13,3zM17.83,5.17l-1.42,1.42C17.99,7.86 19,9.81 19,12c0,3.87 -3.13,7 -7,7s-7,-3.13 -7,-7c0,-2.19 1.01,-4.14 2.58,-5.42L6.17,5.17C4.23,6.82 3,9.26 3,12c0,4.97 4.03,9 9,9s9,-4.03 9,-9c0,-2.74 -1.23,-5.18 -3.17,-6.83z"/>
+</vector>

app/src/main/res/drawable/ic_qr_code_black_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M3,11H5V13H3V11M11,5H13V9H11V5M9,11H13V15H11V13H9V11M15,11H17V13H19V11H21V13H19V15H21V19H19V21H17V19H13V21H11V17H15V15H17V13H15V11M19,19V15H17V19H19M15,3H21V9H15V3M17,5V7H19V5H17M3,3H9V9H3V3M5,5V7H7V5H5M3,15H9V21H3V15M5,17V19H7V17H5Z"/>
+</vector>

app/src/main/res/drawable/ic_refresh_gray_24dp.xml

@@ -1,9 +0,0 @@
-<vector xmlns:android="http://schemas.android.com/apk/res/android"
-        android:width="24dp"
-        android:height="24dp"
-        android:viewportWidth="24.0"
-        android:viewportHeight="24.0">
-    <path
-        android:fillColor="#7D000000"
-        android:pathData="M17.65,6.35C16.2,4.9 14.21,4 12,4c-4.42,0 -7.99,3.58 -7.99,8s3.57,8 7.99,8c3.73,0 6.84,-2.55 7.73,-6h-2.08c-0.82,2.33 -3.04,4 -5.65,4 -3.31,0 -6,-2.69 -6,-6s2.69,-6 6,-6c1.66,0 3.14,0.69 4.22,1.78L13,11h7V4l-2.35,2.35z"/>
-</vector>

app/src/main/res/drawable/ic_settings_gray_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#7D000000"
+        android:pathData="M19.43,12.98c0.04,-0.32 0.07,-0.64 0.07,-0.98s-0.03,-0.66 -0.07,-0.98l2.11,-1.65c0.19,-0.15 0.24,-0.42 0.12,-0.64l-2,-3.46c-0.12,-0.22 -0.39,-0.3 -0.61,-0.22l-2.49,1c-0.52,-0.4 -1.08,-0.73 -1.69,-0.98l-0.38,-2.65C14.46,2.18 14.25,2 14,2h-4c-0.25,0 -0.46,0.18 -0.49,0.42l-0.38,2.65c-0.61,0.25 -1.17,0.59 -1.69,0.98l-2.49,-1c-0.23,-0.09 -0.49,0 -0.61,0.22l-2,3.46c-0.13,0.22 -0.07,0.49 0.12,0.64l2.11,1.65c-0.04,0.32 -0.07,0.65 -0.07,0.98s0.03,0.66 0.07,0.98l-2.11,1.65c-0.19,0.15 -0.24,0.42 -0.12,0.64l2,3.46c0.12,0.22 0.39,0.3 0.61,0.22l2.49,-1c0.52,0.4 1.08,0.73 1.69,0.98l0.38,2.65c0.03,0.24 0.24,0.42 0.49,0.42h4c0.25,0 0.46,-0.18 0.49,-0.42l0.38,-2.65c0.61,-0.25 1.17,-0.59 1.69,-0.98l2.49,1c0.23,0.09 0.49,0 0.61,-0.22l2,-3.46c0.12,-0.22 0.07,-0.49 -0.12,-0.64l-2.11,-1.65zM12,15.5c-1.93,0 -3.5,-1.57 -3.5,-3.5s1.57,-3.5 3.5,-3.5 3.5,1.57 3.5,3.5 -1.57,3.5 -3.5,3.5z"/>
+</vector>

app/src/main/res/drawable/ic_share_black_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M18,16.08c-0.76,0 -1.44,0.3 -1.96,0.77L8.91,12.7c0.05,-0.23 0.09,-0.46 0.09,-0.7s-0.04,-0.47 -0.09,-0.7l7.05,-4.11c0.54,0.5 1.25,0.81 2.04,0.81 1.66,0 3,-1.34 3,-3s-1.34,-3 -3,-3 -3,1.34 -3,3c0,0.24 0.04,0.47 0.09,0.7L8.04,9.81C7.5,9.31 6.79,9 6,9c-1.66,0 -3,1.34 -3,3s1.34,3 3,3c0.79,0 1.5,-0.31 2.04,-0.81l7.12,4.16c-0.05,0.21 -0.08,0.43 -0.08,0.65 0,1.61 1.31,2.92 2.92,2.92 1.61,0 2.92,-1.31 2.92,-2.92s-1.31,-2.92 -2.92,-2.92z"/>
+</vector>

app/src/main/res/layout/activity_folder_browser.xml

@@ -2,91 +2,43 @@
 <layout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto">
 
+    <data>
+        <variable
+            name="isLoading"
+            type="Boolean" />
+
+        <import type="android.view.View" />
+    </data>
+
     <RelativeLayout
         android:layout_width="match_parent"
         android:layout_height="match_parent">
 
-        <!--center content BEGIN-->
-            <LinearLayout
-                android:layout_width="match_parent"
-                android:layout_height="match_parent"
-                android:orientation="vertical"
-                android:divider="?android:listDivider"
-                android:showDividers="middle">
+        <android.support.v7.widget.RecyclerView
+            android:visibility="@{safeUnbox(isLoading) ? View.GONE : View.VISIBLE}"
+            app:layoutManager="android.support.v7.widget.LinearLayoutManager"
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            android:id="@+id/list_view" />
 
-                <!--index loading progress BEGIN-->
-                <LinearLayout
-                    android:layout_width="match_parent"
-                    android:layout_height="40dp"
-                    android:padding="8dp"
-                    android:id="@+id/index_update"
-                    android:orientation="horizontal"
-                    android:background="@color/primary"
-                    android:visibility="gone">
-                    <ProgressBar
-                        android:layout_width="wrap_content"
-                        android:layout_height="match_parent"
-                        android:indeterminate="true"
-                        android:paddingStart="12dp"
-                        android:paddingEnd="12dp"/>
-                    <TextView
-                        android:id="@+id/index_update_label"
-                        android:layout_width="0dp"
-                        android:layout_weight="1"
-                        android:layout_height="match_parent"
-                        android:textSize="18sp"
-                        android:textColor="@color/white_on_primary"
-                        android:text="@string/index_update_progress_message"
-                        android:layout_gravity="start"
-                        android:textAlignment="gravity"
-                        />
-                </LinearLayout>
-                <!--index loading progress END-->
+        <ProgressBar
+            android:visibility="@{safeUnbox(isLoading) ? View.VISIBLE : View.GONE}"
+            android:layout_centerInParent="true"
+            android:id="@+id/progress_bar"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content" />
 
-                <!--main list view BEGIN-->
-                <ListView
-                    android:layout_width="match_parent"
-                    android:layout_height="wrap_content"
-                    android:layout_weight="1"
-                    android:id="@+id/list_view"
-                    android:divider="@color/divider"
-                    android:dividerHeight="2dp">
-                </ListView>
-
-                <TextView
-                    android:id="@+id/empty_view"
-                    android:layout_width="match_parent"
-                    android:layout_height="wrap_content"
-                    android:layout_weight="1"
-                    android:textAlignment="center"
-                    android:text="@string/folder_list_empty_message"
-                    android:textSize="20sp"
-                    android:visibility="gone" />
-
-                <ProgressBar
-                    android:id="@+id/progress_bar"
-                    android:layout_width="wrap_content"
-                    android:layout_height="match_parent"
-                    android:layout_gravity="center"
-                    android:visibility="gone"/>
-                <!--main list view END-->
-
-            </LinearLayout>
-        <!--center content END-->
-
-        <!--upload here overlay button BEGIN-->
-            <android.support.design.widget.FloatingActionButton
-                android:id="@+id/main_list_view_upload_here_button"
-                android:layout_width="wrap_content"
-                android:layout_height="wrap_content"
-                android:layout_marginEnd="24dp"
-                android:layout_marginBottom="24dp"
-                android:layout_alignParentEnd="true"
-                android:layout_alignParentBottom="true"
-                app:elevation="6dp"
-                app:pressedTranslationZ="12dp"
-                android:src="@drawable/ic_file_upload_white_24dp"/>
-        <!--upload here overlay button END-->
+        <android.support.design.widget.FloatingActionButton
+            android:id="@+id/main_list_view_upload_here_button"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginEnd="24dp"
+            android:layout_marginBottom="24dp"
+            android:layout_alignParentEnd="true"
+            android:layout_alignParentBottom="true"
+            app:elevation="6dp"
+            app:pressedTranslationZ="12dp"
+            android:src="@drawable/ic_file_upload_white_24dp"/>
 
     </RelativeLayout>
 

app/src/main/res/layout/activity_folder_picker.xml

@@ -1,22 +0,0 @@
-<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    android:layout_width="match_parent"
-    android:layout_height="match_parent"
-    android:orientation="vertical">
-
-    <FrameLayout
-        android:layout_width="match_parent"
-        android:layout_height="match_parent">
-
-        <ListView
-            android:id="@android:id/list"
-            android:layout_width="match_parent"
-            android:layout_height="match_parent" />
-
-        <TextView
-            android:id="@android:id/empty"
-            android:layout_width="wrap_content"
-            android:layout_height="wrap_content"
-            android:layout_gravity="center"
-            android:text="@string/directory_empty" />
-    </FrameLayout>
-</LinearLayout>

app/src/main/res/layout/activity_main.xml

@@ -5,40 +5,12 @@
         android:id="@+id/drawer_layout"
         android:layout_width="match_parent"
         android:layout_height="match_parent">
-        <!-- The main content view -->
-
-        <LinearLayout
-            android:layout_width="match_parent"
-            android:layout_height="40dp"
-            android:padding="8dp"
-            android:id="@+id/index_update"
-            android:orientation="horizontal"
-            android:background="@color/primary"
-            android:visibility="gone">
-            <ProgressBar
-                android:layout_width="wrap_content"
-                android:layout_height="match_parent"
-                android:indeterminate="true"
-                android:paddingStart="12dp"
-                android:paddingEnd="12dp"/>
-            <TextView
-                android:id="@+id/index_update_label"
-                android:layout_width="0dp"
-                android:layout_weight="1"
-                android:layout_height="match_parent"
-                android:textSize="18sp"
-                android:textColor="@color/white_on_primary"
-                android:text="@string/index_update_progress_message"
-                android:layout_gravity="start"
-                android:textAlignment="gravity"
-                />
-        </LinearLayout>
 
         <FrameLayout
             android:id="@+id/content_frame"
             android:layout_width="match_parent"
             android:layout_height="match_parent" />
-        <!-- The navigation drawer -->
+
         <android.support.design.widget.NavigationView
             android:id="@+id/navigation"
             android:layout_width="wrap_content"
@@ -46,6 +18,7 @@
             android:layout_gravity="start"
             android:background="@android:color/white"
             app:menu="@menu/drawer_view" />
+
     </android.support.v4.widget.DrawerLayout>
 
 </layout>

app/src/main/res/layout/dialog_device_id.xml

@@ -0,0 +1,74 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
+
+    <ScrollView
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content">
+
+        <LinearLayout
+            android:orientation="vertical"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_margin="12dp">
+
+            <LinearLayout
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:orientation="horizontal">
+
+                <TextView
+                    android:id="@+id/device_id"
+                    android:layout_height="wrap_content"
+                    android:layout_width="0dp"
+                    android:layout_weight="1"
+                    android:padding="8dp"
+                    android:clickable="true"
+                    android:drawableEnd="@drawable/ic_content_copy_black_24dp"
+                    android:focusable="true"
+                    android:fontFamily="monospace"
+                    android:textAppearance="@style/TextAppearance.AppCompat.Caption"
+                    tools:text="ASD1ASD-ASD1ASD-ASD1ASD-ASD1ASD-ASD1ASD-ASD1ASD-ASD1ASD-ASD1ASD"/>
+
+                <TextView
+                    android:id="@+id/share"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:layout_gravity="center"
+                    android:padding="8dp"
+                    android:drawableEnd="@drawable/ic_share_black_24dp"
+                    android:clickable="true"
+                    android:focusable="true" />
+
+            </LinearLayout>
+
+            <ViewFlipper
+                android:id="@+id/flipper"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content">
+
+                <RelativeLayout
+                    android:layout_width="match_parent"
+                    android:layout_height="match_parent">
+
+                    <ProgressBar
+                        android:layout_centerInParent="true"
+                        android:layout_width="wrap_content"
+                        android:layout_height="wrap_content"/>
+
+                </RelativeLayout>
+
+                <ImageView
+                    android:id="@+id/qr_code"
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content"
+                    android:scaleType="fitCenter" />
+
+            </ViewFlipper>
+
+        </LinearLayout>
+
+    </ScrollView>
+
+</layout>

app/src/main/res/layout/dialog_loading.xml

@@ -4,27 +4,20 @@
     <LinearLayout
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:padding="@dimen/abc_action_bar_content_inset_material"
+        android:padding="24dp"
         android:theme="?alertDialogTheme"
-        android:orientation="vertical">
+        android:orientation="horizontal"
+        android:gravity="center">
 
-        <LinearLayout
-            android:layout_width="match_parent"
+        <ProgressBar
+            android:layout_width="wrap_content"
             android:layout_height="wrap_content"
-            android:orientation="horizontal"
-            android:gravity="center">
+            android:layout_marginEnd="24dp" />
 
-            <ProgressBar
-                android:layout_width="wrap_content"
-                android:layout_height="wrap_content"
-                android:layout_marginEnd="@dimen/abc_action_bar_content_inset_material" />
-
-            <TextView
-                android:id="@+id/loading_text"
-                android:layout_width="wrap_content"
-                android:layout_height="wrap_content"/>
-
-        </LinearLayout>
+        <TextView
+            android:id="@+id/loading_text"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"/>
 
     </LinearLayout>
 

app/src/main/res/layout/fragment_devices.xml

@@ -2,32 +2,44 @@
 <layout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto">
 
+    <data>
+        <variable
+            name="isEmpty"
+            type="Boolean" />
+
+        <import type="android.view.View" />
+    </data>
+
     <RelativeLayout
         android:layout_width="match_parent"
         android:layout_height="match_parent">
 
-            <ListView
-                android:layout_width="match_parent"
-                android:layout_height="match_parent"
-                android:id="@+id/list"
-                android:divider="@color/divider"
-                android:dividerHeight="2dp">
-            </ListView>
-            <TextView
-                android:id="@+id/empty"
-                android:layout_width="wrap_content"
-                android:layout_height="wrap_content"
-                android:layout_centerInParent="true"
-                android:text="@string/devices_list_view_empty_message"
-                android:textSize="20sp"
-                android:visibility="gone" />
-
-        <uk.co.markormesher.android_fab.FloatingActionButton
-            android:id="@+id/fab"
+        <android.support.v7.widget.RecyclerView
+            app:layoutManager="android.support.v7.widget.LinearLayoutManager"
             android:layout_width="match_parent"
             android:layout_height="match_parent"
-            app:buttonIcon="@drawable/ic_add_white_24dp"
-            app:buttonBackgroundColour="@color/accent"/>
+            android:id="@+id/list"
+            android:divider="@color/divider"
+            android:dividerHeight="2dp">
+        </android.support.v7.widget.RecyclerView>
+
+        <TextView
+            android:id="@+id/empty"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_centerInParent="true"
+            android:text="@string/devices_list_view_empty_message"
+            android:textSize="20sp"
+            android:visibility="@{safeUnbox(isEmpty) ? View.VISIBLE : View.GONE}" />
+
+        <android.support.design.widget.FloatingActionButton
+            android:id="@+id/add_device"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_alignParentBottom="true"
+            android:layout_alignParentEnd="true"
+            app:useCompatPadding="true"
+            android:src="@drawable/ic_add_white_24dp" />
 
     </RelativeLayout>
 

app/src/main/res/layout/fragment_folders.xml

@@ -2,26 +2,69 @@
 <layout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto">
 
-    <FrameLayout
+    <data>
+        <variable
+            name="isEmpty"
+            type="Boolean" />
+
+        <import type="android.view.View" />
+
+        <variable
+            name="listeningPortTaken"
+            type="Boolean" />
+    </data>
+
+    <LinearLayout
+        android:orientation="vertical"
         android:layout_width="match_parent"
         android:layout_height="match_parent">
 
-        <ListView
+        <FrameLayout
+            android:layout_weight="1"
             android:layout_width="match_parent"
-            android:layout_height="match_parent"
-            android:id="@+id/list"
-            android:divider="@color/divider"
-            android:dividerHeight="2dp">
-        </ListView>
-        <TextView
-            android:id="@+id/empty"
-            android:layout_width="wrap_content"
-            android:layout_height="wrap_content"
-            android:layout_gravity="center"
-            android:text="@string/folder_list_empty_message"
-            android:textSize="20sp"
-            android:visibility="gone" />
+            android:layout_height="0dp">
 
-    </FrameLayout>
+            <android.support.v7.widget.RecyclerView
+                app:layoutManager="android.support.v7.widget.LinearLayoutManager"
+                android:layout_width="match_parent"
+                android:layout_height="match_parent"
+                android:id="@+id/list"
+                android:visibility="@{safeUnbox(isEmpty) ? View.GONE : View.VISIBLE}" />
 
-</layout>
+            <TextView
+                android:id="@+id/empty"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_gravity="center"
+                android:text="@string/folder_list_empty_message"
+                android:textSize="20sp"
+                android:visibility="@{safeUnbox(isEmpty) ? View.VISIBLE : View.GONE}" />
+
+        </FrameLayout>
+
+        <LinearLayout
+            android:theme="@style/ThemeOverlay.AppCompat.Dark"
+            android:background="?colorPrimary"
+            android:visibility="@{safeUnbox(listeningPortTaken) ? View.VISIBLE : View.GONE}"
+            android:padding="8dp"
+            android:orientation="vertical"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content">
+
+            <TextView
+                android:textAppearance="?android:textAppearanceMedium"
+                android:text="@string/other_syncthing_instance_title"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content" />
+
+            <TextView
+                android:textAppearance="?android:textAppearanceSmall"
+                android:text="@string/other_syncthing_instance_message"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content" />
+
+        </LinearLayout>
+
+    </LinearLayout>
+
+</layout>

app/src/main/res/layout/fragment_intro_one.xml

@@ -0,0 +1,65 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <data>
+        <variable
+            name="listeningPortTaken"
+            type="Boolean" />
+
+        <import type="android.view.View" />
+    </data>
+
+    <LinearLayout
+        android:orientation="vertical"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:background="@color/intro_primary"
+        android:padding="28dp"
+        android:gravity="center_horizontal">
+
+            <TextView
+                android:id="@+id/title"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginBottom="24dp"
+                android:textColor="#eee"
+                android:textSize="24sp"
+                android:text="@string/intro_page_one_title"/>
+
+            <ImageView
+                android:layout_width="160dp"
+                android:layout_height="0dp"
+                android:layout_weight="1"
+                android:src="@mipmap/ic_launcher"/>
+
+            <TextView
+                android:id="@+id/description"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="24dp"
+                android:layout_marginBottom="@dimen/appIntroBottomBarHeight"
+                android:textSize="16sp"
+                android:textAlignment="center"
+                android:textColor="#eee"
+                android:text="@string/intro_page_one_description" />
+
+        <TextView
+            android:visibility="@{safeUnbox(listeningPortTaken) ? View.VISIBLE : View.GONE}"
+            android:textAppearance="?android:textAppearanceMedium"
+            android:textColor="#eee"
+            android:text="@string/other_syncthing_instance_title"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content" />
+
+        <TextView
+            android:layout_marginBottom="48dp"
+            android:visibility="@{safeUnbox(listeningPortTaken) ? View.VISIBLE : View.GONE}"
+            android:textAppearance="?android:textAppearanceSmall"
+            android:textColor="#eee"
+            android:text="@string/other_syncthing_instance_message"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content" />
+
+    </LinearLayout>
+
+</layout>

app/src/main/res/layout/fragment_intro_three.xml

@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
+
+    <LinearLayout
+        android:orientation="vertical"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:background="@color/intro_primary"
+        android:padding="28dp"
+        android:gravity="center_horizontal">
+
+            <TextView
+                android:id="@+id/title"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginBottom="24dp"
+                android:textColor="#eee"
+                android:textSize="24sp"
+                android:text="@string/intro_page_three_title"/>
+
+            <ProgressBar
+                android:layout_width="72dp"
+                android:layout_height="0dp"
+                android:layout_weight="1"/>
+
+            <TextView
+                android:id="@+id/description"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="24dp"
+                android:layout_marginBottom="@dimen/appIntroBottomBarHeight"
+                android:textSize="16sp"
+                android:textAlignment="center"
+                android:textColor="#eee"
+                tools:text="@string/intro_page_three_description" />
+
+    </LinearLayout>
+
+</layout>

app/src/main/res/layout/fragment_intro_two.xml

@@ -0,0 +1,73 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout xmlns:android="http://schemas.android.com/apk/res/android">
+    <LinearLayout
+        android:orientation="vertical"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:background="@color/intro_primary"
+        android:padding="28dp"
+        android:gravity="center_horizontal">
+
+        <TextView
+            android:id="@+id/title"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginBottom="24dp"
+            android:textColor="#eee"
+            android:textSize="24sp"
+            android:text="@string/intro_page_two_title"/>
+
+        <FrameLayout
+            android:layout_weight="1"
+            android:layout_width="match_parent"
+            android:layout_height="0dp">
+            <ScrollView
+                android:layout_gravity="center"
+                android:id="@+id/scroll"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content">
+                <LinearLayout
+                    android:orientation="vertical"
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content">
+
+                    <include
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content"
+                        android:layout_gravity="center"
+                        android:id="@+id/enter_device_id"
+                        layout="@layout/view_enter_device_id" />
+
+                    <LinearLayout
+                        android:id="@+id/found_devices"
+                        android:orientation="vertical"
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content">
+
+                        <!--
+                            Found device ids will be put here as buttons
+
+                            This does not use an ListView or RecyclerView because this allows using
+                            wrap_content as height and because it's expected to be an small list
+                        -->
+
+                    </LinearLayout>
+
+                </LinearLayout>
+            </ScrollView>
+        </FrameLayout>
+
+        <TextView
+            android:id="@+id/description"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="24dp"
+            android:layout_marginBottom="@dimen/appIntroBottomBarHeight"
+            android:textSize="16sp"
+            android:textAlignment="center"
+            android:textColor="#eee"
+            android:text="@string/intro_page_two_description" />
+
+    </LinearLayout>
+
+</layout>

app/src/main/res/layout/item_folder_picker.xml

@@ -1,13 +0,0 @@
-<layout xmlns:android="http://schemas.android.com/apk/res/android">
-
-    <TextView
-    android:id="@android:id/text1"
-    android:layout_width="match_parent"
-    android:layout_height="wrap_content"
-    android:textAppearance="@style/TextAppearance.AppCompat.Body1"
-    android:gravity="center_vertical"
-    android:paddingLeft="@dimen/abc_action_bar_content_inset_material"
-    android:paddingRight="@dimen/abc_action_bar_content_inset_material"
-    android:minHeight="48dp" />
-
-</layout>

app/src/main/res/layout/listview_device.xml

@@ -1,23 +1,38 @@
 <?xml version="1.0" encoding="utf-8"?>
-<layout xmlns:android="http://schemas.android.com/apk/res/android">
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
+
+    <data>
+        <variable
+            name="name"
+            type="String" />
+
+        <variable
+            name="isConnected"
+            type="Boolean" />
+    </data>
 
     <RelativeLayout
+        android:background="?selectableItemBackground"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:paddingBottom="12dp"
-        android:paddingLeft="@dimen/abc_action_bar_content_inset_material"
-        android:paddingRight="@dimen/abc_action_bar_content_inset_material"
+        android:paddingLeft="24dp"
+        android:paddingRight="24dp"
         android:paddingTop="12dp">
 
         <ImageView
             android:id="@+id/device_icon"
             android:layout_width="32dp"
             android:layout_height="32dp"
-            android:src="@drawable/ic_laptop_green_24dp"
+            tools:src="@drawable/ic_laptop_green_24dp"
+            android:src="@{safeUnbox(isConnected) ? @drawable/ic_laptop_green_24dp : @drawable/ic_laptop_red_24dp}"
             android:layout_alignParentStart="true"
             android:layout_alignParentTop="true"/>
 
         <TextView
+            tools:text="Computer"
+            android:text="@{name}"
             android:id="@+id/device_name"
             android:layout_width="match_parent"
             android:layout_alignParentEnd="true"

app/src/main/res/layout/listview_file.xml

@@ -2,7 +2,21 @@
 <layout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools">
 
+    <data>
+        <variable
+            name="fileName"
+            type="String" />
+
+        <variable
+            name="fileSize"
+            type="String" />
+
+        <import type="android.view.View" />
+        <import type="android.text.TextUtils" />
+    </data>
+
     <RelativeLayout
+        android:background="?selectableItemBackground"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:paddingTop="8dp"
@@ -19,6 +33,8 @@
             android:layout_alignParentTop="true" />
 
         <TextView
+            tools:text="Test Directory"
+            android:text="@{fileName}"
             android:id="@+id/file_label"
             android:maxLines="1"
             android:layout_width="wrap_content"
@@ -29,7 +45,9 @@
             android:textSize="22sp" />
 
         <TextView
-            android:id="@+id/file_size"
+            android:visibility="@{TextUtils.isEmpty(fileSize) ? View.GONE : View.VISIBLE}"
+            tools:text="250 MB"
+            android:text="@{fileSize}"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:ellipsize="end"

app/src/main/res/layout/listview_folder.xml

@@ -1,16 +1,33 @@
 <?xml version="1.0" encoding="utf-8"?>
-<layout xmlns:android="http://schemas.android.com/apk/res/android">
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
+    <data>
+        <variable
+            name="folderName"
+            type="String" />
+
+        <variable
+            name="lastModification"
+            type="String" />
+
+        <variable
+            name="info"
+            type="String" />
+    </data>
 
     <RelativeLayout
+        android:background="?selectableItemBackground"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:paddingBottom="12dp"
-        android:paddingLeft="@dimen/abc_action_bar_content_inset_material"
-        android:paddingRight="@dimen/abc_action_bar_content_inset_material"
+        android:paddingLeft="24dp"
+        android:paddingRight="24dp"
         android:paddingTop="12dp">
 
         <TextView
-            android:id="@+id/folder_name"
+            tools:text="Music"
+            android:text="@{folderName}"
+            android:id="@+id/folder_name_view"
             android:layout_width="match_parent"
             android:layout_alignParentEnd="true"
             android:layout_height="wrap_content"
@@ -23,16 +40,20 @@
             android:textStyle="bold"/>
 
         <TextView
+            tools:text="Last modified: two minutes ago"
+            android:text="@{lastModification}"
             android:id="@+id/folder_lastmod_info"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:ellipsize="end"
             android:maxLines="1"
-            android:layout_below="@id/folder_name"
+            android:layout_below="@id/folder_name_view"
             android:textSize="14sp"
             android:layout_alignParentStart="true" />
 
         <TextView
+            tools:text="Additional information"
+            android:text="@{info}"
             android:id="@+id/folder_content_info"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"

app/src/main/res/layout/view_enter_device_id.xml

@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+
+    <LinearLayout
+        android:orientation="horizontal"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:paddingStart="16dp"
+        android:paddingEnd="16dp">
+
+        <android.support.design.widget.TextInputLayout
+            android:id="@+id/device_id_holder"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            app:errorEnabled="true">
+
+            <android.support.design.widget.TextInputEditText
+                android:id="@+id/device_id"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:minLines="3"
+                android:inputType="textNoSuggestions|textMultiLine|textCapCharacters"
+                tools:text="VPNPKMK-VL2SOQN-SS5I2AB-G4BV7ZK-RO5ODEE-Y2G3CZ4-C4FUW4P-ZEMJOAF"/>
+
+        </android.support.design.widget.TextInputLayout>
+
+        <ImageButton
+            android:id="@+id/scan_qr_code"
+            android:layout_width="48dp"
+            android:layout_height="48dp"
+            android:layout_gravity="center"
+            android:padding="8dp"
+            android:layout_marginBottom="8dp"
+            android:scaleType="fitCenter"
+            android:src="@drawable/ic_qr_code_black_24dp"
+            android:background="?android:selectableItemBackgroundBorderless"/>
+
+    </LinearLayout>
+</layout>

app/src/main/res/menu/drawer_view.xml

@@ -14,10 +14,15 @@
             android:title="@string/devices_label" />
 
         <item
-            android:id="@+id/update_index"
-            android:icon="@drawable/ic_refresh_gray_24dp"
-            android:title="@string/update_remote_index_label"
-            android:checkable="false"/>
+            android:id="@+id/settings"
+            android:icon="@drawable/ic_settings_gray_24dp"
+            android:title="@string/settings" />
+
+        <item
+            android:id="@+id/device_id"
+            android:icon="@drawable/ic_qr_code_black_24dp"
+            android:title="@string/show_device_id"
+            android:checkable="false" />
 
         <item
             android:id="@+id/clear_index"

app/src/main/res/values-de/strings.xml

@@ -1,32 +1,19 @@
 <resources>
     <string name="app_name">Syncthing Lite</string>
-    <string name="index_update_progress_message">Index wird aktualisiert…</string>
     <string name="folder_list_empty_message">Keine Ordner verfügbar</string>
     <string name="clear_local_cache_index_label">Lokalen Index und Cache löschen</string>
-    <string name="update_remote_index_label">Index aktualisieren</string>
     <string name="devices_list_view_empty_message">Keine Geräte verfügbar</string>
-    <string name="toast_write_storage_permission_required">Schreibrechte werden für diese Funktion benötigt</string>
-    <string name="scan_qr_code">QR code scannen</string>
-    <string name="enter_device_id">Geräte ID eingeben</string>
-    <string name="invalid_device_id">Ungültige Geräte ID</string>
     <string name="device_id_dialog_title">Geräte ID eingeben</string>
-    <string name="toast_index_update_successful">Index erfolgreich aktualisiert</string>
-    <string name="toast_index_update_failed">Index update für %1$d Geräte fehlgeschlagen</string>
     <string name="dialog_downloading_file">Datei %1$s wird heruntergeladen</string>
     <string name="toast_file_download_failed">Datei konnte nicht heruntergeladen werden</string>
     <string name="toast_open_file_failed">Keine kompatible app gefunden</string>
     <string name="toast_file_upload_failed">Hochladen gescheitert</string>
     <string name="toast_upload_complete">Hochladen erfolgreich</string>
     <string name="dialog_uploading_file">Datei %1$s wird hochgeladen</string>
-    <string name="directory_empty">Ordner ist leer</string>
     <string name="clear_cache_and_index_title">Lokalen Cache und Index löschen?</string>
     <string name="clear_cache_and_index_body">Gesamten lokalen Cache und Index löschen?</string>
-    <string name="index_update_progress_label">Index aktualisierung für Ordner %1$s, %2$d\\% synchronisiert</string>
-    <string name="loading_config_starting_syncthing_client">Konfiguartion wird geladen, Syncthing wird gestartet</string>
-    <string name="last_modified_unknown">zuletzt modifiziert: unbekannt</string>
     <string name="last_modified_time">Zuletzt modifiziert: %1$s</string>
-    <string name="remove_device_title">Gerät entfernen:</string>
-    <string name="remove_device_message">Gerät %1$s entfernen?</string>
+    <string name="remove_device_title">Gerät entfernen: %1$s</string>
     <string name="device_import_success">Gerät %1$s erfolgreich importiert</string>
     <string name="device_already_known">Gerät ist bereits bekannt $1%s</string>
     <string name="folders_label">Ordner</string>
@@ -34,4 +21,4 @@
     <string name="folder_label_format">%1$s (%2$s)</string>
     <string name="folder_content_info">%1$s, %2$d Dateien, %3$d Ordner</string>
     <string name="file_info">%1$s, zuletzt modifiziert %2$s</string>
-</resources>
+    </resources>

app/src/main/res/values-fr/strings.xml

@@ -0,0 +1,24 @@
+<resources>
+    <string name="app_name">Syncthing Lite</string>
+    <string name="folder_list_empty_message">Aucun dossier disponible</string>
+    <string name="clear_local_cache_index_label">Effacer le cache et l\'index local</string>
+    <string name="devices_list_view_empty_message">Aucun appareil disponible</string>
+    <string name="device_id_dialog_title">Entrer l\'ID de l\'appareil</string>
+    <string name="dialog_downloading_file">Téléchargement du fichier %1$s</string>
+    <string name="toast_file_download_failed">Le téléchargement du fichier a échoué</string>
+    <string name="toast_open_file_failed">Aucune appli compatible trouvée</string>
+    <string name="toast_file_upload_failed">Échec de l\'upload</string>
+    <string name="toast_upload_complete">Upload du fichier terminé</string>
+    <string name="dialog_uploading_file">Upload du fichier %1$s</string>
+    <string name="clear_cache_and_index_title">Effacer le cache local et l\'index?</string>
+    <string name="clear_cache_and_index_body">Effacer toutes les données du cache local et de l\'index ?</string>
+    <string name="last_modified_time">Dernière modification : %1$s</string>
+    <string name="remove_device_title">Supprimer l\'appareil %1$s\?</string>
+    <string name="device_import_success">Appareil %1$s importé avec succès</string>
+    <string name="device_already_known">Appareil déjà connu %1$s</string>
+    <string name="folders_label">Dossiers</string>
+    <string name="devices_label">Appareils</string>
+    <string name="folder_label_format">%1$s (%2$s)</string>
+    <string name="folder_content_info">%1$s, %2$d fichiers, %3$d dossiers</string>
+    <string name="file_info">%1$s, dernière modification %2$s</string>
+    </resources>

app/src/main/res/values-it/strings.xml

@@ -0,0 +1,25 @@
+<resources>
+    <string name="app_name">Syncthing Lite</string>
+    <string name="folder_list_empty_message">Nessuna cartella disponibile</string>
+    <string name="clear_local_cache_index_label">Cancella cache/indice</string>
+    <string name="devices_list_view_empty_message">Nessun dispositivo disponibile</string>
+    <string name="device_id_dialog_title">Inserisci ID Dispositivo</string>
+    <string name="dialog_downloading_file">Download del file %1$s</string>
+    <string name="toast_file_download_failed">Impossibile scaricare il file</string>
+    <string name="toast_open_file_failed">Nessuna applicazione compatibile trovata</string>
+    <string name="toast_file_upload_failed">Caricamento file fallito</string>
+    <string name="toast_upload_complete">Caricamento file completato</string>
+    <string name="dialog_uploading_file">Caricamento del file %1$s</string>
+    <string name="clear_cache_and_index_title">Cancellare la cache locale e l\'indice?</string>
+    <string name="clear_cache_and_index_body">Cancellare tutti i dati della cache locale e i dati dell\'indice?</string>
+    <string name="index_update_progress_label">Aggiornamento dell\'indice per la cartella %1$s, %2$d%% sincronizzato</string>
+    <string name="last_modified_time">Ultima modifica: %1$s</string>
+    <string name="remove_device_title">Rimuovere il dispositivo %1$s\?</string>
+    <string name="device_import_success">Dispositivo %1$s importato con successo</string>
+    <string name="device_already_known">Dispositivo %1$s già presente</string>
+    <string name="folders_label">Cartelle</string>
+    <string name="devices_label">Dispositivi</string>
+    <string name="folder_label_format">%1$s (%2$s)</string>
+    <string name="folder_content_info">%1$s, %2$d file, %3$d cartelle</string>
+    <string name="file_info">%1$s, ultima modifica %2$s</string>
+    </resources>

app/src/main/res/values-ja/strings.xml

@@ -0,0 +1,25 @@
+<resources>
+    <string name="app_name">Syncthing Lite</string>
+    <string name="folder_list_empty_message">フォルダーがありません</string>
+    <string name="clear_local_cache_index_label">ローカルキャッシュ/索引をクリア</string>
+    <string name="devices_list_view_empty_message">デバイスがありません</string>
+    <string name="device_id_dialog_title">デバイス ID を入力</string>
+    <string name="dialog_downloading_file">ファイル %1$s のダウンロード中</string>
+    <string name="toast_file_download_failed">ファイルのダウンロードに失敗しました</string>
+    <string name="toast_open_file_failed">利用できるアプリが見つかりません</string>
+    <string name="toast_file_upload_failed">ファイルのアップロードに失敗しました</string>
+    <string name="toast_upload_complete">ファイルのアップロードが完了しました</string>
+    <string name="dialog_uploading_file">ファイル %1$s のアップロード中</string>
+    <string name="clear_cache_and_index_title">ローカルキャッシュと索引をクリアしますか?</string>
+    <string name="clear_cache_and_index_body">すべてのローカルキャッシュデータと索引データをクリアしますか?</string>
+    <string name="index_update_progress_label">フォルダー %1$s の索引を更新しました。 %2$d%% 同期しました</string>
+    <string name="last_modified_time">最終更新: %1$s</string>
+    <string name="remove_device_title">デバイス %1$sを削除しますか?</string>
+    <string name="device_import_success">デバイス %1$s のインポートに成功しました</string>
+    <string name="device_already_known">デバイスは既に存在します %1$s</string>
+    <string name="folders_label">フォルダー</string>
+    <string name="devices_label">デバイス</string>
+    <string name="folder_label_format">%1$s (%2$s)</string>
+    <string name="folder_content_info">%1$s, %2$d ファイル, %3$d ディレクトリー</string>
+    <string name="file_info">%1$s, 最終更新 %2$s</string>
+    </resources>

app/src/main/res/values-ro/strings.xml

@@ -0,0 +1,24 @@
+<resources>
+    <string name="app_name">Syncthing Lite</string>
+    <string name="folder_list_empty_message">Nici un director disponibil</string>
+    <string name="clear_local_cache_index_label">Curăță indexul/memoria locală</string>
+    <string name="devices_list_view_empty_message">Nici un dispozitiv disponibil</string>
+    <string name="device_id_dialog_title">Introduceți ID dispozitiv</string>
+    <string name="dialog_downloading_file">Se descarcă fișierul %1$s</string>
+    <string name="toast_file_download_failed">Descărcarea fișierului a eșuat</string>
+    <string name="toast_open_file_failed">Nu a fost găsită nici o aplicație compatibilă</string>
+    <string name="toast_file_upload_failed">Încărcarea fișierului a eșuat</string>
+    <string name="toast_upload_complete">Încărcarea fișierelor finalizată</string>
+    <string name="dialog_uploading_file">Se încarcă fișierul %1$s</string>
+    <string name="clear_cache_and_index_title">Se curăță memoria locală și indexul?</string>
+    <string name="clear_cache_and_index_body">Se curăță datele din memoria locală și datele indexului?</string>
+    <string name="last_modified_time">Modificat ultima dată pe: %1$s</string>
+    <string name="remove_device_title">Ștergere dispozitiv %1$s\?</string>
+    <string name="device_import_success">Dispozitiv importat cu succes %1$s</string>
+    <string name="device_already_known">Dispozitiv deja prezent %1$s</string>
+    <string name="folders_label">Directoare</string>
+    <string name="devices_label">Dispozitive</string>
+    <string name="folder_label_format">%1$s (%2$s)</string>
+    <string name="folder_content_info">%1$s, %2$d fișier(e), %3$d director(oare)</string>
+    <string name="file_info">%1$s, modificat ultima dată pe %2$s</string>
+    </resources>

app/src/main/res/values/colors.xml

@@ -1,9 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <color name="primary">#f43703</color>
-    <color name="primary_dark">#d13602</color>
-    <color name="white_on_primary">#fefefe</color>
+    <color name="primary_dark">#b90000</color>
     <color name="accent">#FFC107</color>
     <color name="divider">#1F000000</color>
-
+    <color name="intro_primary">#ff5252</color>
+    <color name="intro_primary_dark">#c50e29</color>
 </resources>

app/src/main/res/values/settings.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string-array name="shutdown_delay_labels">
+        <item>@string/settings_shutdown_delay_10_seconds</item>
+        <item>@string/settings_shutdown_delay_30_seconds</item>
+        <item>@string/settings_shutdown_delay_1_minute</item>
+        <item>@string/settings_shutdown_delay_5_minutes</item>
+    </string-array>
+
+    <string-array name="shutdown_delay_values">
+        <item>10000</item>
+        <item>30000</item>
+        <item>60000</item>
+        <item>300000</item>
+    </string-array>
+
+    <string translatable="false" name="default_shutdown_delay">60000</string>
+</resources>

app/src/main/res/values/strings.xml

@@ -1,32 +1,22 @@
 <resources>
     <string name="app_name">Syncthing Lite</string>
-    <string name="index_update_progress_message">Index update…</string>
     <string name="folder_list_empty_message">No folder available</string>
     <string name="clear_local_cache_index_label">Clear local cache/index</string>
-    <string name="update_remote_index_label">Update remote index</string>
     <string name="devices_list_view_empty_message">No devices available</string>
-    <string name="toast_write_storage_permission_required">Write storage permission is required for this functionality</string>
-    <string name="scan_qr_code">Scan QR code</string>
-    <string name="enter_device_id">Enter device ID</string>
-    <string name="invalid_device_id">Invalid device ID</string>
-    <string name="device_id_dialog_title">Enter Device ID</string>
-    <string name="toast_index_update_successful">Index update successful</string>
-    <string name="toast_index_update_failed">Index update failed for %1$d devices</string>
+    <string name="invalid_device_id">Error: Invalid device ID</string>
     <string name="dialog_downloading_file">Downloading file %1$s</string>
     <string name="toast_file_download_failed">Failed to download file</string>
     <string name="toast_open_file_failed">No compatible app found</string>
     <string name="toast_file_upload_failed">File upload failed</string>
     <string name="toast_upload_complete">File upload complete</string>
     <string name="dialog_uploading_file">Uploading file %1$s</string>
-    <string name="directory_empty">Directory is empty</string>
     <string name="clear_cache_and_index_title">Clear local cache and index?</string>
     <string name="clear_cache_and_index_body">Clear all local cache data and index data?</string>
-    <string name="index_update_progress_label">Index update for folder %1$s, %2$d% synchronized</string>
-    <string name="loading_config_starting_syncthing_client">Loading config, starting syncthing client</string>
-    <string name="last_modified_unknown">Last modified: unknown</string>
+    <string name="index_update_progress_label">Index update for folder %1$s, %2$d%% synchronized</string>
+    <string name="loading_config_starting_syncthing_client">Loading config, starting syncthing client…</string>
     <string name="last_modified_time">Last modified: %1$s</string>
     <string name="remove_device_title">Remove device %1$s\?</string>
-    <string name="remove_device_message">Remove device %1$s from list of known devices?</string>
+    <string name="remove_device_message">Remove %1$s from the list of known devices?</string>
     <string name="device_import_success">Successfully imported device %1$s</string>
     <string name="device_already_known">Device already present %1$s</string>
     <string name="folders_label">Folders</string>
@@ -34,4 +24,33 @@
     <string name="folder_label_format">%1$s (%2$s)</string>
     <string name="folder_content_info">%1$s, %2$d files, %3$d directories</string>
     <string name="file_info">%1$s, last modified %2$s</string>
+    <string name="show_device_id">Show device ID</string>
+    <string name="device_id">Device ID</string>
+    <string name="device_id_copied">Device ID copied to clipboard</string>
+    <string name="share_device_id_chooser">Share device ID with</string>
+    <string name="other_syncthing_instance_title">Another Syncthing instance is running</string>
+    <string name="other_syncthing_instance_message">Local discovery will not work. Stop the other Syncthing instance to enable local discovery.</string>
+    <string name="intro_page_one_title">Welcome to Syncthing Lite</string>
+    <string name="intro_page_one_description">Syncthing replaces proprietary sync and cloud services with something open, trustworthy and decentralized. Your data is your data alone and you deserve to choose where it is stored, if it is shared with some third party and how it\'s transmitted over the Internet.</string>
+    <string name="intro_page_two_title">Add a device</string>
+    <string name="intro_page_three_title">Share your folders</string>
+    <string name="intro_page_two_description">Enter a Syncthing device ID, or scan a device ID from a QR code</string>
+    <string name="intro_page_three_description">Now accept the device with ID %1$s, and share a folder with it. It may take a few minutes until the devices connect.</string>
+    <string name="settings">Settings</string>
+    <string name="settings_app_version_title">App version</string>
+    <string name="settings_local_device_name">Local device name</string>
+    <string name="settings_local_device_summary">The name that other devices will see for this device</string>
+    <string name="settings_shutdown_delay_title">Shutdown delay</string>
+    <string name="settings_shutdown_delay_summary">Time before shuting down the Syncthing client after its last usage</string>
+    <string name="device_id_dialog_title">Enter Device ID</string>
+    <string name="settings_shutdown_delay_10_seconds">10 seconds</string>
+    <string name="settings_shutdown_delay_30_seconds">30 seconds</string>
+    <string name="settings_shutdown_delay_1_minute">1 minute</string>
+    <string name="settings_shutdown_delay_5_minutes">5 minutes</string>
+    <string name="dialog_warning_reconnect_problem">
+        Due to the behaviour of this App and the behaviour of the Syncthing Server,
+        you can\'t reconnct for some minutes if the App was killed (due to removing from the recent App list)
+        or the connection was interrupted.
+        This does not apply to local discovery connections.
+    </string>
 </resources>

app/src/main/res/values/themes.xml

@@ -4,6 +4,15 @@
         <item name="colorPrimary">@color/primary</item>
         <item name="colorPrimaryDark">@color/primary_dark</item>
         <item name="colorAccent">@color/accent</item>
+        <item name="preferenceTheme">@style/PreferenceThemeOverlay.v14.Material</item>
+    </style>
+
+    <style name="Theme.Syncthing.NoActionBar" parent="@style/Theme.AppCompat">
+        <item name="colorPrimary">@color/intro_primary</item>
+        <item name="colorPrimaryDark">@color/intro_primary_dark</item>
+        <item name="colorAccent">@color/accent</item>
+        <item name="windowActionBar">false</item>
+        <item name="windowNoTitle">true</item>
     </style>
 
 </resources>

app/src/main/res/xml/preferences.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <PreferenceCategory
+        android:title="@string/settings">
+
+        <EditTextPreference
+            android:key="local_device_name"
+            android:title="@string/settings_local_device_name"
+            android:summary="@string/settings_local_device_summary"
+            android:persistent="false"/>
+
+        <!--
+
+        This is something for the advanced preferences (later), but it still has got an effect
+
+        <ListPreference
+            android:key="shutdown_delay"
+            android:title="@string/settings_shutdown_delay_title"
+            android:summary="@string/settings_shutdown_delay_summary"
+            android:entries="@array/shutdown_delay_labels"
+            android:entryValues="@array/shutdown_delay_values"
+            android:defaultValue="@string/default_shutdown_delay" />
+
+        -->
+
+        <Preference
+            android:key="app_version"
+            android:title="@string/settings_app_version_title"/>
+
+    </PreferenceCategory>
+
+</PreferenceScreen>

build.gradle

@@ -1,10 +1,11 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 
 buildscript {
-    ext.kotlin_version = '1.2.20'
+    ext.kotlin_version = '1.2.61'
     ext.support_version = '27.0.2'
-    ext.build_tools_version = '3.0.1'
-    ext.anko_version = '0.10.4'
+    ext.build_tools_version = '3.2.0'
+    ext.anko_version = '0.10.7'
+    ext.protobuf_lite_version = '3.0.1'
     repositories {
         mavenLocal()
         jcenter()
@@ -15,16 +16,16 @@ buildscript {
         classpath "com.android.tools.build:gradle:$build_tools_version"
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
         classpath 'com.github.ben-manes:gradle-versions-plugin:0.17.0'
+        classpath 'com.google.protobuf:protobuf-gradle-plugin:0.8.6'
     }
 }
 
 allprojects {
     repositories {
-        mavenLocal()
+        google()
         jcenter()
         maven {
             url "https://jitpack.io"
         }
-        google()
     }
 }

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Mon Dec 28 10:00:20 PST 2015
+#Fri Sep 14 08:50:38 CEST 2018
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.3.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.6-all.zip

settings.gradle

@@ -1 +1 @@
-include ':app'
+include ':app', ':syncthing-repository-android', ':syncthing-repository-default', ':syncthing-relay-client', ':syncthing-bep', ':syncthing-core', ':syncthing-client', ':syncthing-discovery', ':syncthing-client-cli', ':syncthing-http-relay-client'

syncthing-bep/build.gradle

@@ -0,0 +1,42 @@
+apply plugin: 'java-library'
+apply plugin: 'kotlin'
+apply plugin: 'com.google.protobuf'
+
+dependencies {
+    compile fileTree(dir: 'libs', include: ['*.jar'])
+    compile project(':syncthing-core')
+    compile project(':syncthing-relay-client')
+    compile project(':syncthing-http-relay-client')
+    compile "net.jpountz.lz4:lz4:1.3.0"
+    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:0.30.2'
+    implementation "com.google.protobuf:protobuf-lite:$protobuf_lite_version"
+}
+
+protobuf {
+    protoc {
+        artifact = "com.google.protobuf:protoc:3.5.1-1"
+    }
+    plugins {
+        javalite {
+            // The codegen for lite comes as a separate artifact
+            artifact = "com.google.protobuf:protoc-gen-javalite:3.0.0"
+        }
+    }
+    generateProtoTasks {
+        all().each { task ->
+            task.builtins {
+                // In most cases you don't need the full Java output
+                // if you use the lite output.
+                remove java
+            }
+            task.plugins {
+                javalite { }
+            }
+        }
+    }
+}
+
+// Workaround for https://github.com/google/protobuf-gradle-plugin/issues/100
+compileKotlin.dependsOn('generateProto')
+sourceSets.main.kotlin.srcDirs += file("${protobuf.generatedFilesBaseDir}/main/javalite")

syncthing-bep/src/main/kotlin/net/syncthing/java/bep/BlockPuller.kt

@@ -0,0 +1,198 @@
+/*
+ * Copyright (C) 2016 Davide Imbriaco
+ * Copyright (C) 2018 Jonas Lochmann
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.bep
+
+import com.google.protobuf.ByteString
+import kotlinx.coroutines.experimental.*
+import kotlinx.coroutines.experimental.channels.Channel
+import net.syncthing.java.bep.BlockExchangeProtos.ErrorCode
+import net.syncthing.java.bep.BlockExchangeProtos.Request
+import net.syncthing.java.bep.utils.longSumBy
+import net.syncthing.java.core.beans.BlockInfo
+import net.syncthing.java.core.beans.FileBlocks
+import net.syncthing.java.core.beans.FileInfo
+import net.syncthing.java.core.interfaces.TempRepository
+import net.syncthing.java.core.utils.NetworkUtils
+import org.apache.commons.io.FileUtils
+import org.bouncycastle.util.encoders.Hex
+import org.slf4j.LoggerFactory
+import java.io.*
+import java.lang.Exception
+import java.security.MessageDigest
+import java.util.*
+import kotlin.collections.HashMap
+
+class BlockPuller internal constructor(private val connectionHandler: ConnectionHandler,
+                                       private val indexHandler: IndexHandler,
+                                       private val responseHandler: ResponseHandler,
+                                       private val tempRepository: TempRepository) {
+
+    private val logger = LoggerFactory.getLogger(javaClass)
+
+    fun pullFileSync(
+            fileInfo: FileInfo,
+            progressListener: (status: BlockPullerStatus) -> Unit = {  }
+    ): InputStream {
+        return runBlocking {
+            pullFileCoroutine(fileInfo, progressListener)
+        }
+    }
+
+    suspend fun pullFileCoroutine(
+            fileInfo: FileInfo,
+            progressListener: (status: BlockPullerStatus) -> Unit = {  }
+    ): InputStream {
+        val fileBlocks = indexHandler.waitForRemoteIndexAcquired(connectionHandler)
+                .getFileInfoAndBlocksByPath(fileInfo.folder, fileInfo.path)
+                ?.value
+                ?: throw IOException("file not found in local index for folder = ${fileInfo.folder} path = ${fileInfo.path}")
+        logger.info("pulling file = {}", fileBlocks)
+        NetworkUtils.assertProtocol(connectionHandler.hasFolder(fileBlocks.folder), { "supplied connection handler $connectionHandler will not share folder ${fileBlocks.folder}" })
+
+        // the file could have changed since the caller read it
+        // this would save the file using a wrong name, so throw here
+        if (fileBlocks.hash != fileInfo.hash) {
+            throw IllegalStateException("the current file entry hash does not match the hash of the provided one")
+        }
+
+        val blockTempIdByHash = Collections.synchronizedMap(HashMap<String, String>())
+
+        var status = BlockPullerStatus(
+                downloadedBytes = 0,
+                totalTransferSize = fileBlocks.blocks.distinctBy { it.hash }.longSumBy { it.size.toLong() },
+                totalFileSize = fileBlocks.size
+        )
+
+        try {
+            val reportProgressLock = Object()
+
+            fun updateProgress(additionalDownloadedBytes: Long) {
+                synchronized(reportProgressLock) {
+                    status = status.copy(
+                            downloadedBytes = status.downloadedBytes + additionalDownloadedBytes
+                    )
+
+                    progressListener(status)
+                }
+            }
+
+            coroutineScope {
+                val pipe = Channel<BlockInfo>()
+
+                repeat(4 /* 4 blocks per time */) { workerNumber ->
+                    async {
+                        for (block in pipe) {
+                            logger.debug("request block with hash = {} from worker {}", block.hash, workerNumber)
+
+                            val blockContent = pullBlock(fileBlocks, block, 1000 * 60 /* 60 seconds timeout per block */)
+
+                            blockTempIdByHash[block.hash] = tempRepository.pushTempData(blockContent)
+
+                            updateProgress(blockContent.size.toLong())
+                        }
+                    }
+                }
+
+                fileBlocks.blocks.distinctBy { it.hash }.forEach { block ->
+                    pipe.send(block)
+                }
+
+                pipe.close()
+            }
+
+            // the sequence is evaluated lazy -> only one block per time is loaded
+            val fileBlocksIterator = fileBlocks.blocks
+                    .asSequence()
+                    .map { tempRepository.popTempData(blockTempIdByHash[it.hash]!!) }
+                    .map { ByteArrayInputStream(it) }
+                    .iterator()
+
+            return object : SequenceInputStream(object : Enumeration<InputStream> {
+                override fun hasMoreElements() = fileBlocksIterator.hasNext()
+                override fun nextElement() = fileBlocksIterator.next()
+            }) {
+                override fun close() {
+                    super.close()
+
+                    // delete all temp blocks now
+                    // they are deleted after reading, but the consumer could stop before reading the whole stream
+                    tempRepository.deleteTempData(blockTempIdByHash.values.toList())
+                }
+            }
+        } catch (ex: Exception) {
+            // delete all temp blocks now
+            tempRepository.deleteTempData(blockTempIdByHash.values.toList())
+
+            throw ex
+        }
+    }
+
+    private suspend fun pullBlock(fileBlocks: FileBlocks, block: BlockInfo, timeoutInMillis: Long): ByteArray {
+        logger.debug("sent request for block, hash = {}", block.hash)
+
+        val response =
+                withTimeout(timeoutInMillis) {
+                    try {
+                        doRequest(
+                                Request.newBuilder()
+                                        .setFolder(fileBlocks.folder)
+                                        .setName(fileBlocks.path)
+                                        .setOffset(block.offset)
+                                        .setSize(block.size)
+                                        .setHash(ByteString.copyFrom(Hex.decode(block.hash)))
+                        )
+                    } catch (ex: TimeoutCancellationException) {
+                        // It seems like the TimeoutCancellationException
+                        // is handled differently so that the timeout is ignored.
+                        // Due to that, it's converted to an IOException.
+
+                        throw IOException("timeout during requesting block")
+                    }
+                }
+
+        NetworkUtils.assertProtocol(response.code == ErrorCode.NO_ERROR) {
+            "received error response, code = ${response.code}"
+        }
+
+        val data = response.data.toByteArray()
+        val hash = Hex.toHexString(MessageDigest.getInstance("SHA-256").digest(data))
+
+        if (hash != block.hash) {
+            throw IllegalStateException("expected block with hash ${block.hash}, but got block with hash $hash")
+        }
+
+        return data
+    }
+
+    private suspend fun doRequest(request: Request.Builder): BlockExchangeProtos.Response {
+        return suspendCancellableCoroutine { continuation ->
+            val requestId = responseHandler.registerListener { response ->
+                continuation.resume(response)
+            }
+
+            connectionHandler.sendMessage(
+                    request
+                            .setId(requestId)
+                            .build()
+            )
+        }
+    }
+}
+
+data class BlockPullerStatus(
+        val downloadedBytes: Long,
+        val totalTransferSize: Long,
+        val totalFileSize: Long
+)

syncthing-bep/src/main/kotlin/net/syncthing/java/bep/BlockPusher.kt

@@ -0,0 +1,308 @@
+/* 
+ * Copyright (C) 2016 Davide Imbriaco
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.bep
+
+import com.google.protobuf.ByteString
+import net.syncthing.java.bep.BlockExchangeProtos.Vector
+import net.syncthing.java.core.beans.*
+import net.syncthing.java.core.beans.FileInfo.Version
+import net.syncthing.java.core.configuration.Configuration
+import net.syncthing.java.core.utils.BlockUtils
+import net.syncthing.java.core.utils.NetworkUtils
+import net.syncthing.java.core.utils.submitLogging
+import org.apache.commons.io.IOUtils
+import org.apache.commons.lang3.tuple.Pair
+import org.bouncycastle.util.encoders.Hex
+import org.slf4j.LoggerFactory
+import java.io.Closeable
+import java.io.IOException
+import java.io.InputStream
+import java.nio.ByteBuffer
+import java.security.MessageDigest
+import java.util.*
+import java.util.concurrent.ConcurrentHashMap
+import java.util.concurrent.ExecutionException
+import java.util.concurrent.Executors
+import java.util.concurrent.Future
+import java.util.concurrent.atomic.AtomicBoolean
+import java.util.concurrent.atomic.AtomicReference
+
+class BlockPusher internal constructor(private val localDeviceId: DeviceId,
+                                       private val connectionHandler: ConnectionHandler,
+                                       private val indexHandler: IndexHandler) {
+
+    private val logger = LoggerFactory.getLogger(javaClass)
+
+
+    fun pushDelete(folderId: String, targetPath: String): IndexEditObserver {
+        val fileInfo = indexHandler.waitForRemoteIndexAcquired(connectionHandler).getFileInfoByPath(folderId, targetPath)!!
+        NetworkUtils.assertProtocol(connectionHandler.hasFolder(fileInfo.folder), {"supplied connection handler $connectionHandler will not share folder ${fileInfo.folder}"})
+        return IndexEditObserver(sendIndexUpdate(folderId, BlockExchangeProtos.FileInfo.newBuilder()
+                .setName(targetPath)
+                .setType(BlockExchangeProtos.FileInfoType.valueOf(fileInfo.type.name))
+                .setDeleted(true), fileInfo.versionList))
+    }
+
+    fun pushDir(folder: String, path: String): IndexEditObserver {
+        NetworkUtils.assertProtocol(connectionHandler.hasFolder(folder), {"supplied connection handler $connectionHandler will not share folder $folder"})
+        return IndexEditObserver(sendIndexUpdate(folder, BlockExchangeProtos.FileInfo.newBuilder()
+                .setName(path)
+                .setType(BlockExchangeProtos.FileInfoType.DIRECTORY), null))
+    }
+
+    fun pushFile(inputStream: InputStream, folderId: String, targetPath: String): FileUploadObserver {
+        val fileInfo = indexHandler.waitForRemoteIndexAcquired(connectionHandler).getFileInfoByPath(folderId, targetPath)
+        NetworkUtils.assertProtocol(connectionHandler.hasFolder(folderId), {"supplied connection handler $connectionHandler will not share folder $folderId"})
+        assert(fileInfo == null || fileInfo.folder == folderId)
+        assert(fileInfo == null || fileInfo.path == targetPath)
+        val monitoringProcessExecutorService = Executors.newCachedThreadPool()
+        val dataSource = DataSource(inputStream)
+        val fileSize = dataSource.size
+        val sentBlocks = Collections.newSetFromMap(ConcurrentHashMap<String, Boolean>())
+        val uploadError = AtomicReference<Exception>()
+        val isCompleted = AtomicBoolean(false)
+        val updateLock = Object()
+        val listener = {request: BlockExchangeProtos.Request ->
+            if (request.folder == folderId && request.name == targetPath) {
+                val hash = Hex.toHexString(request.hash.toByteArray())
+                logger.debug("handling block request = {}:{}-{} ({})", request.name, request.offset, request.size, hash)
+                val data = dataSource.getBlock(request.offset, request.size, hash)
+                val future = connectionHandler.sendMessage(BlockExchangeProtos.Response.newBuilder()
+                        .setCode(BlockExchangeProtos.ErrorCode.NO_ERROR)
+                        .setData(ByteString.copyFrom(data))
+                        .setId(request.id)
+                        .build())
+                monitoringProcessExecutorService.submitLogging {
+                    try {
+                        future.get()
+                        sentBlocks.add(hash)
+                        synchronized(updateLock) {
+                            updateLock.notifyAll()
+                        }
+                        //TODO retry on error, register error and throw on watcher
+                    } catch (ex: InterruptedException) {
+                        //return and do nothing
+                    } catch (ex: ExecutionException) {
+                        uploadError.set(ex)
+                        synchronized(updateLock) {
+                            updateLock.notifyAll()
+                        }
+                    }
+                }
+            }
+        }
+        connectionHandler.registerOnRequestMessageReceivedListeners(listener)
+        logger.debug("send index update for file = {}", targetPath)
+        val indexListener = { folderInfo: FolderInfo, newRecords: List<FileInfo>, indexInfo: IndexInfo ->
+            if (folderInfo.folderId == folderId) {
+                for (fileInfo2 in newRecords) {
+                    if (fileInfo2.path == targetPath && fileInfo2.hash == dataSource.getHash()) { //TODO check not invalid
+                        //                                sentBlocks.addAll(dataSource.getHashes());
+                        isCompleted.set(true)
+                        synchronized(updateLock) {
+                            updateLock.notifyAll()
+                        }
+                    }
+                }
+            }
+        }
+        indexHandler.registerOnIndexRecordAcquiredListener(indexListener)
+        val indexUpdate = sendIndexUpdate(folderId, BlockExchangeProtos.FileInfo.newBuilder()
+                .setName(targetPath)
+                .setSize(fileSize)
+                .setType(BlockExchangeProtos.FileInfoType.FILE)
+                .addAllBlocks(dataSource.blocks), fileInfo?.versionList).right
+        return object : FileUploadObserver() {
+
+            override fun progressPercentage() = if (isCompleted.get()) 100 else (sentBlocks.size.toFloat() / dataSource.getHashes().size).toInt()
+
+            // return sentBlocks.size() == dataSource.getHashes().size();
+            override fun isCompleted() = isCompleted.get()
+
+            override fun close() {
+                logger.debug("closing upload process")
+                monitoringProcessExecutorService.shutdown()
+                indexHandler.unregisterOnIndexRecordAcquiredListener(indexListener)
+                connectionHandler.unregisterOnRequestMessageReceivedListeners(listener)
+                val fileInfo1 = indexHandler.pushRecord(indexUpdate.folder, indexUpdate.filesList.single())
+                logger.info("sent file info record = {}", fileInfo1)
+            }
+
+            @Throws(InterruptedException::class, IOException::class)
+            override fun waitForProgressUpdate(): Int {
+                synchronized(updateLock) {
+                    updateLock.wait()
+                }
+                if (uploadError.get() != null) {
+                    throw IOException(uploadError.get())
+                }
+                return progressPercentage()
+            }
+
+        }
+    }
+
+    private fun sendIndexUpdate(folderId: String, fileInfoBuilder: BlockExchangeProtos.FileInfo.Builder,
+                                oldVersions: Iterable<Version>?): Pair<Future<*>, BlockExchangeProtos.IndexUpdate> {
+        run {
+            val nextSequence = indexHandler.sequencer().nextSequence()
+            val list = oldVersions ?: emptyList()
+            logger.debug("version list = {}", list)
+            val id = ByteBuffer.wrap(localDeviceId.toHashData()).long
+            val version = BlockExchangeProtos.Counter.newBuilder()
+                    .setId(id)
+                    .setValue(nextSequence)
+                    .build()
+            logger.debug("append new version = {}", version)
+            fileInfoBuilder
+                    .setSequence(nextSequence)
+                    .setVersion(Vector.newBuilder().addAllCounters(list.map { record ->
+                        BlockExchangeProtos.Counter.newBuilder().setId(record.id).setValue(record.value).build()
+                    })
+                            .addCounters(version))
+        }
+        val lastModified = Date()
+        val fileInfo = fileInfoBuilder
+                .setModifiedS(lastModified.time / 1000)
+                .setModifiedNs((lastModified.time % 1000 * 1000000).toInt())
+                .setNoPermissions(true)
+                .build()
+        val indexUpdate = BlockExchangeProtos.IndexUpdate.newBuilder()
+                .setFolder(folderId)
+                .addFiles(fileInfo)
+                .build()
+        logger.debug("index update = {}", fileInfo)
+        return Pair.of(connectionHandler.sendMessage(indexUpdate), indexUpdate)
+    }
+
+    abstract inner class FileUploadObserver : Closeable {
+
+        abstract fun progressPercentage(): Int
+
+        abstract fun isCompleted(): Boolean
+
+        @Throws(InterruptedException::class)
+        abstract fun waitForProgressUpdate(): Int
+
+        @Throws(InterruptedException::class)
+        fun waitForComplete(): FileUploadObserver {
+            while (!isCompleted()) {
+                waitForProgressUpdate()
+            }
+            return this
+        }
+    }
+
+    inner class IndexEditObserver(private val future: Future<*>, private val indexUpdate: BlockExchangeProtos.IndexUpdate) : Closeable {
+
+        //throw exception if job has errors
+        @Throws(InterruptedException::class, ExecutionException::class)
+        fun isCompleted(): Boolean {
+            return if (future.isDone) {
+                future.get()
+                true
+            } else {
+                false
+            }
+        }
+
+        constructor(pair: Pair<Future<*>, BlockExchangeProtos.IndexUpdate>) : this(pair.left, pair.right)
+
+        @Throws(InterruptedException::class, ExecutionException::class)
+        fun waitForComplete() {
+            future.get()
+        }
+
+        @Throws(IOException::class)
+        override fun close() {
+            indexHandler.pushRecord(indexUpdate.folder, indexUpdate.filesList.single())
+        }
+
+    }
+
+    private class DataSource @Throws(IOException::class) constructor(private val inputStream: InputStream) {
+
+        var size: Long = 0
+            private set
+        lateinit var blocks: List<BlockExchangeProtos.BlockInfo>
+            private set
+        private var hashes: Set<String>? = null
+
+        private var hash: String? = null
+
+        init {
+            inputStream.use { it ->
+                val list = mutableListOf<BlockExchangeProtos.BlockInfo>()
+                var offset: Long = 0
+                while (true) {
+                    var block = ByteArray(BLOCK_SIZE)
+                    val blockSize = it.read(block)
+                    if (blockSize <= 0) {
+                        break
+                    }
+                    if (blockSize < block.size) {
+                        block = Arrays.copyOf(block, blockSize)
+                    }
+
+                    val hash = MessageDigest.getInstance("SHA-256").digest(block)
+                    list.add(BlockExchangeProtos.BlockInfo.newBuilder()
+                            .setHash(ByteString.copyFrom(hash))
+                            .setOffset(offset)
+                            .setSize(blockSize)
+                            .build())
+                    offset += blockSize.toLong()
+                }
+                size = offset
+                blocks = list
+            }
+        }
+
+        @Throws(IOException::class)
+        fun getBlock(offset: Long, size: Int, hash: String): ByteArray {
+            val buffer = ByteArray(size)
+            inputStream.use { it ->
+                IOUtils.skipFully(it, offset)
+                IOUtils.readFully(it, buffer)
+                NetworkUtils.assertProtocol(Hex.toHexString(MessageDigest.getInstance("SHA-256").digest(buffer)) == hash, {"block hash mismatch!"})
+                return buffer
+            }
+        }
+
+
+        fun getHashes(): Set<String> {
+            return hashes ?: let {
+                val hashes2 = blocks.map { input -> Hex.toHexString(input.hash.toByteArray()) }.toSet()
+                hashes = hashes2
+                return hashes2
+            }
+        }
+
+        fun getHash(): String {
+            return hash ?: let {
+                val blockInfo = blocks.map { input ->
+                    BlockInfo(input.offset, input.size, Hex.toHexString(input.hash.toByteArray()))
+                }
+                val hash2 = BlockUtils.hashBlocks(blockInfo)
+                hash = hash2
+                hash2
+            }
+        }
+    }
+
+    companion object {
+
+        const val BLOCK_SIZE = 128 * 1024
+    }
+
+}

syncthing-bep/src/main/kotlin/net/syncthing/java/bep/ClusterConfigFolderInfo.kt

@@ -0,0 +1,23 @@
+/* 
+ * Copyright (C) 2016 Davide Imbriaco
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.bep
+
+internal data class ClusterConfigFolderInfo(val folderId: String, var label: String = folderId,
+                                            var isAnnounced: Boolean = false, var isShared: Boolean = false) {
+
+    init {
+        assert(folderId.isNotEmpty())
+    }
+
+}

syncthing-bep/src/main/kotlin/net/syncthing/java/bep/ConnectionHandler.kt

@@ -0,0 +1,517 @@
+/* 
+ * Copyright (C) 2016 Davide Imbriaco
+ * Copyright (C) 2018 Jonas Lochmann
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.bep
+
+import com.google.protobuf.ByteString
+import com.google.protobuf.MessageLite
+import net.jpountz.lz4.LZ4Factory
+import net.syncthing.java.bep.BlockExchangeProtos.*
+import net.syncthing.java.client.protocol.rp.RelayClient
+import net.syncthing.java.core.beans.DeviceAddress
+import net.syncthing.java.core.beans.DeviceId
+import net.syncthing.java.core.beans.DeviceInfo
+import net.syncthing.java.core.beans.FolderInfo
+import net.syncthing.java.core.configuration.Configuration
+import net.syncthing.java.core.interfaces.TempRepository
+import net.syncthing.java.core.security.KeystoreHandler
+import net.syncthing.java.core.utils.NetworkUtils
+import net.syncthing.java.core.utils.submitLogging
+import net.syncthing.java.httprelay.HttpRelayClient
+import org.apache.commons.io.IOUtils
+import org.apache.commons.lang3.tuple.Pair
+import org.slf4j.LoggerFactory
+import java.io.Closeable
+import java.io.DataInputStream
+import java.io.DataOutputStream
+import java.io.IOException
+import java.lang.reflect.InvocationTargetException
+import java.nio.ByteBuffer
+import java.security.cert.CertificateException
+import java.util.concurrent.ConcurrentHashMap
+import java.util.concurrent.Executors
+import java.util.concurrent.Future
+import java.util.concurrent.TimeUnit
+import javax.net.ssl.SSLSocket
+
+class ConnectionHandler(private val configuration: Configuration, val address: DeviceAddress,
+                        private val indexHandler: IndexHandler,
+                        private val tempRepository: TempRepository,
+                        private val onNewFolderSharedListener: (ConnectionHandler, FolderInfo) -> Unit,
+                        private val onConnectionChangedListener: (ConnectionHandler) -> Unit) : Closeable {
+
+    private val logger = LoggerFactory.getLogger(javaClass)
+
+    private val outExecutorService = Executors.newSingleThreadExecutor()
+    private val inExecutorService = Executors.newSingleThreadExecutor()
+    private val messageProcessingService = Executors.newCachedThreadPool()
+    private val periodicExecutorService = Executors.newSingleThreadScheduledExecutor()
+    private lateinit var socket: SSLSocket
+    private var inputStream: DataInputStream? = null
+    private var outputStream: DataOutputStream? = null
+    private var lastActive = Long.MIN_VALUE
+    internal var clusterConfigInfo: ClusterConfigInfo? = null
+        private set
+    private val clusterConfigWaitingLock = Object()
+    private val responseHandler = ResponseHandler()
+    private val blockPuller = BlockPuller(this, indexHandler, responseHandler, tempRepository)
+    private val blockPusher = BlockPusher(configuration.localDeviceId, this, indexHandler)
+    private val onRequestMessageReceivedListeners = mutableSetOf<(Request) -> Unit>()
+    private var isClosed = false
+    var isConnected = false
+        private set
+
+    fun deviceId(): DeviceId = address.deviceId()
+
+    private fun checkNotClosed() {
+        NetworkUtils.assertProtocol(!isClosed, {"connection $this closed"})
+    }
+
+    internal fun registerOnRequestMessageReceivedListeners(listener: (Request) -> Unit) {
+        onRequestMessageReceivedListeners.add(listener)
+    }
+
+    internal fun unregisterOnRequestMessageReceivedListeners(listener: (Request) -> Unit) {
+        assert(onRequestMessageReceivedListeners.contains(listener))
+        onRequestMessageReceivedListeners.remove(listener)
+    }
+
+    @Throws(IOException::class, KeystoreHandler.CryptoException::class)
+    fun connect(): ConnectionHandler {
+        checkNotClosed()
+        assert(!isConnected, {"already connected!"})
+        logger.info("connecting to {}", address.address)
+
+        val keystoreHandler = KeystoreHandler.Loader().loadKeystore(configuration)
+
+        socket = when (address.getType()) {
+            DeviceAddress.AddressType.TCP -> {
+                logger.debug("opening tcp ssl connection")
+                keystoreHandler.createSocket(address.getSocketAddress(), KeystoreHandler.BEP)
+            }
+            DeviceAddress.AddressType.RELAY -> {
+                logger.debug("opening relay connection")
+                keystoreHandler.wrapSocket(RelayClient(configuration).openRelayConnection(address), KeystoreHandler.BEP)
+            }
+            DeviceAddress.AddressType.HTTP_RELAY, DeviceAddress.AddressType.HTTPS_RELAY -> {
+                logger.debug("opening http relay connection")
+                keystoreHandler.wrapSocket(HttpRelayClient().openRelayConnection(address), KeystoreHandler.BEP)
+            }
+            else -> throw UnsupportedOperationException("unsupported address type = " + address.getType())
+        }
+        inputStream = DataInputStream(socket.inputStream)
+        outputStream = DataOutputStream(socket.outputStream)
+
+        sendHelloMessage(BlockExchangeProtos.Hello.newBuilder()
+                .setClientName(configuration.clientName)
+                .setClientVersion(configuration.clientVersion)
+                .setDeviceName(configuration.localDeviceName)
+                .build().toByteArray())
+        markActivityOnSocket()
+
+        receiveHelloMessage()
+        try {
+            keystoreHandler.checkSocketCertificate(socket, address.deviceId())
+        } catch (e: CertificateException) {
+            throw IOException(e)
+        }
+
+        run {
+            val clusterConfigBuilder = ClusterConfig.newBuilder()
+            for (folder in configuration.folders) {
+                val folderBuilder = Folder.newBuilder()
+                        .setId(folder.folderId)
+                        .setLabel(folder.label)
+                run {
+                    //our device
+                    val deviceBuilder = Device.newBuilder()
+                            .setId(ByteString.copyFrom(configuration.localDeviceId.toHashData()))
+                            .setIndexId(indexHandler.sequencer().indexId())
+                            .setMaxSequence(indexHandler.sequencer().currentSequence())
+                    folderBuilder.addDevices(deviceBuilder)
+                }
+                run {
+                    //other device
+                    val deviceBuilder = Device.newBuilder()
+                            .setId(ByteString.copyFrom(DeviceId(address.deviceId).toHashData()))
+                    val indexSequenceInfo = indexHandler.indexRepository.findIndexInfoByDeviceAndFolder(address.deviceId(), folder.folderId)
+                    indexSequenceInfo?.let {
+                        deviceBuilder
+                                .setIndexId(indexSequenceInfo.indexId)
+                                .setMaxSequence(indexSequenceInfo.localSequence)
+                        logger.info("send delta index info device = {} index = {} max (local) sequence = {}",
+                                indexSequenceInfo.deviceId,
+                                indexSequenceInfo.indexId,
+                                indexSequenceInfo.localSequence)
+                    }
+                    folderBuilder.addDevices(deviceBuilder)
+                }
+                clusterConfigBuilder.addFolders(folderBuilder)
+                //TODO other devices??
+            }
+            sendMessage(clusterConfigBuilder.build())
+        }
+        synchronized(clusterConfigWaitingLock) {
+            startMessageListenerService()
+            while (clusterConfigInfo == null && !isClosed) {
+                logger.debug("wait for cluster config")
+                try {
+                    clusterConfigWaitingLock.wait()
+                } catch (e: InterruptedException) {
+                    throw IOException(e)
+                }
+            }
+            if (clusterConfigInfo == null) {
+                throw IOException("unable to retrieve cluster config from peer!")
+            }
+        }
+        for (folder in configuration.folders) {
+            if (hasFolder(folder.folderId)) {
+                sendIndexMessage(folder.folderId)
+            }
+        }
+        periodicExecutorService.scheduleWithFixedDelay({ this.sendPing() }, 90, 90, TimeUnit.SECONDS)
+        isConnected = true
+        onConnectionChangedListener(this)
+        return this
+    }
+
+    fun getBlockPuller(): BlockPuller {
+        return blockPuller
+    }
+
+    fun getBlockPusher(): BlockPusher {
+        return blockPusher
+    }
+
+    private fun sendIndexMessage(folderId: String) {
+        sendMessage(Index.newBuilder()
+                .setFolder(folderId)
+                .build())
+    }
+
+    fun closeBg() {
+        Thread { close() }.start()
+    }
+
+    /**
+     * Receive hello message and save device name to configuration.
+     */
+    @Throws(IOException::class)
+    private fun receiveHelloMessage() {
+        val magic = inputStream!!.readInt()
+        NetworkUtils.assertProtocol(magic == MAGIC, {"magic mismatch, expected $MAGIC, got $magic"})
+        val length = inputStream!!.readShort().toInt()
+        NetworkUtils.assertProtocol(length > 0, {"invalid lenght, must be >0, got $length"})
+        val buffer = ByteArray(length)
+        inputStream!!.readFully(buffer)
+        val hello = BlockExchangeProtos.Hello.parseFrom(buffer)
+        logger.info("Received hello message, deviceName=${hello.deviceName}, clientName=${hello.clientName}, clientVersion=${hello.clientVersion}")
+        configuration.peers = configuration.peers.map { peer ->
+                if (peer.deviceId == deviceId()) {
+                    DeviceInfo(deviceId(), hello.deviceName)
+                } else {
+                    peer
+                }
+            }.toSet()
+        configuration.persistLater()
+    }
+
+    private fun sendHelloMessage(payload: ByteArray): Future<*> {
+        return outExecutorService.submitLogging {
+            try {
+                logger.debug("Sending hello message")
+                val header = ByteBuffer.allocate(6)
+                header.putInt(MAGIC)
+                header.putShort(payload.size.toShort())
+                outputStream!!.write(header.array())
+                outputStream!!.write(payload)
+                outputStream!!.flush()
+            } catch (ex: IOException) {
+                if (outExecutorService.isShutdown) {
+                    return@submitLogging
+                }
+                logger.error("error writing to output stream", ex)
+                closeBg()
+            }
+        }
+    }
+
+    private fun sendPing(): Future<*> {
+        return sendMessage(Ping.newBuilder().build())
+    }
+
+    private fun markActivityOnSocket() {
+        lastActive = System.currentTimeMillis()
+    }
+
+    @Throws(IOException::class)
+    private fun receiveMessage(): Pair<BlockExchangeProtos.MessageType, MessageLite> {
+        var headerLength = inputStream!!.readShort().toInt()
+        while (headerLength == 0) {
+            logger.warn("got headerLength == 0, skipping short")
+            headerLength = inputStream!!.readShort().toInt()
+        }
+        markActivityOnSocket()
+        NetworkUtils.assertProtocol(headerLength > 0, {"invalid lenght, must be >0, got $headerLength"})
+        val headerBuffer = ByteArray(headerLength)
+        inputStream!!.readFully(headerBuffer)
+        val header = BlockExchangeProtos.Header.parseFrom(headerBuffer)
+        var messageLength = 0
+        while (messageLength == 0) {
+            logger.warn("received readInt() == 0, expecting 'bep message header length' (int >0), ignoring (keepalive?)")
+            messageLength = inputStream!!.readInt()
+        }
+        NetworkUtils.assertProtocol(messageLength >= 0, {"invalid lenght, must be >=0, got $messageLength"})
+        var messageBuffer = ByteArray(messageLength)
+        inputStream!!.readFully(messageBuffer)
+        markActivityOnSocket()
+        if (header.compression == BlockExchangeProtos.MessageCompression.LZ4) {
+            val uncompressedLength = ByteBuffer.wrap(messageBuffer).int
+            messageBuffer = LZ4Factory.fastestInstance().fastDecompressor().decompress(messageBuffer, 4, uncompressedLength)
+        }
+        val messageTypeInfo = messageTypesByProtoMessageType[header.type]
+        NetworkUtils.assertProtocol(messageTypeInfo != null, {"unsupported message type = ${header.type}"})
+        try {
+            val message = messageTypeInfo!!.parseFrom(messageBuffer)
+            return Pair.of(header.type, message)
+        } catch (e: Exception) {
+            when (e) {
+                is IllegalAccessException, is IllegalArgumentException, is InvocationTargetException, is NoSuchMethodException, is SecurityException ->
+                    throw IOException(e)
+                else -> throw e
+            }
+        }
+    }
+
+    internal fun sendMessage(message: MessageLite): Future<*> {
+        checkNotClosed()
+        val messageTypeInfo = messageTypesByJavaClass[message.javaClass]
+        messageTypeInfo!!
+        val header = BlockExchangeProtos.Header.newBuilder()
+                .setCompression(BlockExchangeProtos.MessageCompression.NONE)
+                // invert map
+                .setType(messageTypeInfo.protoMessageType)
+                .build()
+        val headerData = header.toByteArray()
+        val messageData = message.toByteArray() //TODO compression
+        return outExecutorService.submit<Any> {
+            try {
+                logger.debug("sending message type = {} {}", header.type, getIdForMessage(message))
+                markActivityOnSocket()
+                outputStream!!.writeShort(headerData.size)
+                outputStream!!.write(headerData)
+                outputStream!!.writeInt(messageData.size)//with compression, check this
+                outputStream!!.write(messageData)
+                outputStream!!.flush()
+                markActivityOnSocket()
+            } catch (ex: IOException) {
+                if (!outExecutorService.isShutdown) {
+                    logger.error("error writing to output stream", ex)
+                    closeBg()
+                }
+                throw ex
+            }
+
+            null
+        }
+    }
+
+    override fun close() {
+        if (!isClosed) {
+            sendMessage(Close.getDefaultInstance())
+            isClosed = true
+            isConnected = false
+            periodicExecutorService.shutdown()
+            outExecutorService.shutdown()
+            inExecutorService.shutdown()
+            messageProcessingService.shutdown()
+            assert(onRequestMessageReceivedListeners.isEmpty())
+            if (outputStream != null) {
+                IOUtils.closeQuietly(outputStream)
+                outputStream = null
+            }
+            if (inputStream != null) {
+                IOUtils.closeQuietly(inputStream)
+                inputStream = null
+            }
+            try {
+              IOUtils.closeQuietly(socket)
+            } catch (ex: Exception) {
+              // ignore this
+              // this can throw an exception if socket was not yet initialized/ set
+              // as Kotlin does an check about this, the closeQuietly does not catch it
+            }
+            logger.info("closed connection {}", address)
+            synchronized(clusterConfigWaitingLock) {
+                clusterConfigWaitingLock.notifyAll()
+            }
+            onConnectionChangedListener(this)
+            try {
+                periodicExecutorService.awaitTermination(2, TimeUnit.SECONDS)
+                outExecutorService.awaitTermination(2, TimeUnit.SECONDS)
+                inExecutorService.awaitTermination(2, TimeUnit.SECONDS)
+                messageProcessingService.awaitTermination(2, TimeUnit.SECONDS)
+            } catch (ex: InterruptedException) {
+                logger.warn("", ex)
+            }
+
+        }
+    }
+
+    /**
+     * return time elapsed since last activity on socket, inputStream millis
+     *
+     * @return
+     */
+    fun getLastActive(): Long {
+        return System.currentTimeMillis() - lastActive
+    }
+
+    private fun startMessageListenerService() {
+        inExecutorService.submitLogging {
+            try {
+                while (!Thread.interrupted()) {
+                    val message = receiveMessage()
+                    messageProcessingService.submitLogging {
+                        logger.debug("received message type = {} {}", message.left, getIdForMessage(message.right))
+                        when (message.left) {
+                            BlockExchangeProtos.MessageType.INDEX -> {
+                                val index = message.value as Index
+                                indexHandler.handleIndexMessageReceivedEvent(index.folder, index.filesList, this)
+                            }
+                            BlockExchangeProtos.MessageType.INDEX_UPDATE -> {
+                                val update = message.value as IndexUpdate
+                                indexHandler.handleIndexMessageReceivedEvent(update.folder, update.filesList, this)
+                            }
+                            BlockExchangeProtos.MessageType.REQUEST -> {
+                                onRequestMessageReceivedListeners.forEach { it(message.value as Request) }
+                            }
+                            BlockExchangeProtos.MessageType.RESPONSE -> {
+                                responseHandler.handleResponse(message.value as Response)
+                            }
+                            BlockExchangeProtos.MessageType.PING -> logger.debug("ping message received")
+                            BlockExchangeProtos.MessageType.CLOSE -> {
+                                val close = message.value as BlockExchangeProtos.Close
+                                logger.info("received close message, reason=${close.reason}")
+                                closeBg()
+                            }
+                            BlockExchangeProtos.MessageType.CLUSTER_CONFIG -> {
+                                NetworkUtils.assertProtocol(clusterConfigInfo == null, {"received cluster config message twice!"})
+                                clusterConfigInfo = ClusterConfigInfo()
+                                val clusterConfig = message.value as ClusterConfig
+                                for (folder in clusterConfig.foldersList ?: emptyList()) {
+                                    val folderInfo = ClusterConfigFolderInfo(folder.id, folder.label)
+                                    val devicesById = (folder.devicesList ?: emptyList())
+                                            .associateBy { input ->
+                                                DeviceId.fromHashData(input.id!!.toByteArray())
+                                            }
+                                    val otherDevice = devicesById[address.deviceId()]
+                                    val ourDevice = devicesById[configuration.localDeviceId]
+                                    if (otherDevice != null) {
+                                        folderInfo.isAnnounced = true
+                                    }
+                                    if (ourDevice != null) {
+                                        folderInfo.isShared = true
+                                        logger.info("folder shared from device = {} folder = {}", address.deviceId, folderInfo)
+                                        val folderIds = configuration.folders.map { it.folderId }
+                                        if (!folderIds.contains(folderInfo.folderId)) {
+                                            val fi = FolderInfo(folderInfo.folderId, folderInfo.label)
+                                            configuration.folders = configuration.folders + fi
+                                            onNewFolderSharedListener(this, fi)
+                                            logger.info("new folder shared = {}", folderInfo)
+                                        }
+                                    } else {
+                                        logger.info("folder not shared from device = {} folder = {}", address.deviceId, folderInfo)
+                                    }
+                                    clusterConfigInfo!!.putFolderInfo(folderInfo)
+                                }
+                                configuration.persistLater()
+                                indexHandler.handleClusterConfigMessageProcessedEvent(clusterConfig)
+                                synchronized(clusterConfigWaitingLock) {
+                                    clusterConfigWaitingLock.notifyAll()
+                                }
+                            }
+                        }
+                    }
+                }
+            } catch (ex: IOException) {
+                if (inExecutorService.isShutdown) {
+                    return@submitLogging
+                }
+                logger.error("error receiving message", ex)
+                closeBg()
+            }
+        }
+    }
+
+    override fun toString(): String {
+        return "ConnectionHandler{" + "address=" + address + ", lastActive=" + getLastActive() / 1000.0 + "secs ago}"
+    }
+
+    internal inner class ClusterConfigInfo {
+
+        private val folderInfoById = ConcurrentHashMap<String, ClusterConfigFolderInfo>()
+
+        fun getSharedFolders(): Set<String> = folderInfoById.values.filter { it.isShared }.map { it.folderId }.toSet()
+
+        fun putFolderInfo(folderInfo: ClusterConfigFolderInfo) {
+            folderInfoById[folderInfo.folderId] = folderInfo
+        }
+
+    }
+
+    fun hasFolder(folder: String): Boolean {
+        return clusterConfigInfo!!.getSharedFolders().contains(folder)
+    }
+
+    companion object {
+
+        private const val MAGIC = 0x2EA7D90B
+
+        private val messageTypes = listOf(
+                MessageTypeInfo(MessageType.CLOSE, Close::class.java) { Close.parseFrom(it) },
+                MessageTypeInfo(MessageType.CLUSTER_CONFIG, ClusterConfig::class.java) { ClusterConfig.parseFrom(it) },
+                MessageTypeInfo(MessageType.DOWNLOAD_PROGRESS, DownloadProgress::class.java) { DownloadProgress.parseFrom(it) },
+                MessageTypeInfo(MessageType.INDEX, Index::class.java) { Index.parseFrom(it) },
+                MessageTypeInfo(MessageType.INDEX_UPDATE, IndexUpdate::class.java) { IndexUpdate.parseFrom(it) },
+                MessageTypeInfo(MessageType.PING, Ping::class.java) { Ping.parseFrom(it) },
+                MessageTypeInfo(MessageType.REQUEST, Request::class.java) { Request.parseFrom(it) },
+                MessageTypeInfo(MessageType.RESPONSE, Response::class.java) { Response.parseFrom(it) }
+        )
+
+        private val messageTypesByProtoMessageType = messageTypes.map { it.protoMessageType to it }.toMap()
+        private val messageTypesByJavaClass = messageTypes.map { it.javaClass to it }.toMap()
+
+        /**
+         * get id for message bean/instance, for log tracking
+         *
+         * @param message
+         * @return id for message bean
+         */
+        private fun getIdForMessage(message: MessageLite): String {
+            return when (message) {
+                is Request -> Integer.toString(message.id)
+                is Response -> Integer.toString(message.id)
+                else -> Integer.toString(Math.abs(message.hashCode()))
+            }
+        }
+    }
+
+    data class MessageTypeInfo(
+            val protoMessageType: MessageType,
+            val javaClass: Class<out MessageLite>,
+            val parseFrom: (data: ByteArray) -> MessageLite
+    )
+}

syncthing-bep/src/main/kotlin/net/syncthing/java/bep/FolderBrowser.kt

@@ -0,0 +1,58 @@
+/* 
+ * Copyright (C) 2016 Davide Imbriaco
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.bep
+
+import net.syncthing.java.core.beans.FolderInfo
+import net.syncthing.java.core.beans.FolderStats
+import net.syncthing.java.core.interfaces.IndexRepository
+import java.io.Closeable
+
+class FolderBrowser internal constructor(private val indexHandler: IndexHandler) : Closeable {
+    private val folderStatsCache = mutableMapOf<String, FolderStats>()
+    private val indexRepositoryEventListener = { event: IndexRepository.FolderStatsUpdatedEvent ->
+        addFolderStats(event.getFolderStats())
+    }
+
+    fun folderInfoAndStatsList(): List<Pair<FolderInfo, FolderStats>> =
+            indexHandler.folderInfoList()
+                    .map { folderInfo -> Pair(folderInfo, getFolderStats(folderInfo.folderId)) }
+                    .sortedBy { it.first.label }
+
+    init {
+        indexHandler.indexRepository.setOnFolderStatsUpdatedListener(indexRepositoryEventListener)
+        addFolderStats(indexHandler.indexRepository.findAllFolderStats())
+    }
+
+    private fun addFolderStats(folderStatsList: List<FolderStats>) {
+        for (folderStats in folderStatsList) {
+            folderStatsCache.put(folderStats.folderId, folderStats)
+        }
+    }
+
+    fun getFolderStats(folder: String): FolderStats {
+        return folderStatsCache[folder] ?: let {
+            FolderStats.Builder()
+                    .setFolder(folder)
+                    .build()
+        }
+    }
+
+    fun getFolderInfo(folder: String): FolderInfo? {
+        return indexHandler.getFolderInfo(folder)
+    }
+
+    override fun close() {
+        indexHandler.indexRepository.setOnFolderStatsUpdatedListener(null)
+    }
+}

syncthing-bep/src/main/kotlin/net/syncthing/java/bep/IndexBrowser.kt

@@ -0,0 +1,184 @@
+/* 
+ * Copyright (C) 2016 Davide Imbriaco
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.bep
+
+import net.syncthing.java.core.beans.FileInfo
+import net.syncthing.java.core.interfaces.IndexRepository
+import net.syncthing.java.core.utils.PathUtils
+import net.syncthing.java.core.utils.awaitTerminationSafe
+import net.syncthing.java.core.utils.submitLogging
+import org.apache.commons.lang3.StringUtils
+import org.slf4j.LoggerFactory
+import java.io.Closeable
+import java.util.*
+import java.util.concurrent.Executors
+
+class IndexBrowser internal constructor(private val indexRepository: IndexRepository, private val indexHandler: IndexHandler,
+                                       val folder: String, private val includeParentInList: Boolean = false,
+                                       private val allowParentInRoot: Boolean = false, ordering: Comparator<FileInfo>?) : Closeable {
+
+    private fun isParent(fileInfo: FileInfo) = PathUtils.isParent(fileInfo.path)
+
+    val ALPHA_ASC_DIR_FIRST: Comparator<FileInfo> =
+            compareBy<FileInfo>({!isParent(it)}, {!it.isDirectory()})
+                    .thenBy { it.fileName.toLowerCase() }
+    val LAST_MOD_DESC: Comparator<FileInfo> =
+            compareBy<FileInfo>({!isParent(it)}, {it.lastModified})
+                    .thenBy { it.fileName.toLowerCase() }
+
+    private val ordering = ordering ?: ALPHA_ASC_DIR_FIRST
+    private val logger = LoggerFactory.getLogger(javaClass)
+
+    var currentPath: String = PathUtils.ROOT_PATH
+        private set
+    private val PARENT_FILE_INFO: FileInfo
+    private val ROOT_FILE_INFO: FileInfo
+    private val executorService = Executors.newSingleThreadScheduledExecutor()
+    private val preloadJobs = mutableSetOf<String>()
+    private val preloadJobsLock = Any()
+    private var mOnPathChangedListener: (() -> Unit)? = null
+
+    private fun isCacheReady(): Boolean {
+        synchronized(preloadJobsLock) {
+            return preloadJobs.isEmpty()
+        }
+    }
+
+    internal fun onIndexChangedevent(folder: String, newRecord: FileInfo) {
+        if (folder == this.folder) {
+            preloadFileInfoForCurrentPath()
+        }
+    }
+
+    fun currentPathInfo(): FileInfo = getFileInfoByAbsolutePath(currentPath)
+
+    fun currentPathFileName(): String? = PathUtils.getFileName(currentPath)
+
+    fun isRoot(): Boolean = PathUtils.isRoot(currentPath)
+
+    init {
+        assert(folder.isNotEmpty())
+        PARENT_FILE_INFO = FileInfo(folder = folder, type = FileInfo.FileType.DIRECTORY, path = PathUtils.PARENT_PATH)
+        ROOT_FILE_INFO = FileInfo(folder = folder, type = FileInfo.FileType.DIRECTORY, path = PathUtils.ROOT_PATH)
+        navigateToAbsolutePath(PathUtils.ROOT_PATH)
+    }
+
+    fun setOnFolderChangedListener(onPathChangedListener: (() -> Unit)?) {
+        mOnPathChangedListener = onPathChangedListener
+    }
+
+    private fun preloadFileInfoForCurrentPath() {
+        logger.debug("trigger preload for folder = '{}'", folder)
+        synchronized(preloadJobsLock) {
+            currentPath.let<String, Any> { currentPath ->
+                if (preloadJobs.contains(currentPath)) {
+                    preloadJobs.remove(currentPath)
+                    preloadJobs.add(currentPath) ///add last
+                } else {
+                    preloadJobs.add(currentPath)
+                    executorService.submitLogging(object : Runnable {
+
+                        override fun run() {
+
+                            val preloadPath =
+                                    synchronized(preloadJobsLock) {
+                                        assert(!preloadJobs.isEmpty())
+                                        preloadJobs.last() //pop last job
+                                    }
+
+                            logger.info("folder preload BEGIN for folder = '{}' path = '{}'", folder, preloadPath)
+                            getFileInfoByAbsolutePath(preloadPath)
+                            if (!PathUtils.isRoot(preloadPath)) {
+                                val parent = PathUtils.getParentPath(preloadPath)
+                                getFileInfoByAbsolutePath(parent)
+                                listFiles(parent)
+                            }
+                            for (record in listFiles(preloadPath)) {
+                                if (record.path == PARENT_FILE_INFO.path && record.isDirectory()) {
+                                    listFiles(record.path)
+                                }
+                            }
+                            logger.info("folder preload END for folder = '{}' path = '{}'", folder, preloadPath)
+                            synchronized(preloadJobsLock) {
+                                preloadJobs.remove(preloadPath)
+                                if (isCacheReady()) {
+                                    logger.info("cache ready, notify listeners")
+                                    mOnPathChangedListener?.invoke()
+                                } else {
+                                    logger.info("still {} job[s] left in cache loader", preloadJobs.size)
+                                    executorService.submitLogging(this)
+                                }
+                            }
+                        }
+                    })
+                }
+            }
+        }
+    }
+
+    fun listFiles(path: String = currentPath): List<FileInfo> {
+        logger.debug("doListFiles for path = '{}' BEGIN", path)
+        val list = ArrayList(indexRepository.findNotDeletedFilesByFolderAndParent(folder, path))
+        logger.debug("doListFiles for path = '{}' : {} records loaded)", path, list.size)
+        if (includeParentInList && (!PathUtils.isRoot(path) || allowParentInRoot)) {
+            list.add(0, PARENT_FILE_INFO)
+        }
+        return list.sortedWith(ordering)
+    }
+
+    fun getFileInfoByAbsolutePath(path: String): FileInfo {
+        return if (PathUtils.isRoot(path)) {
+            ROOT_FILE_INFO
+        } else {
+            logger.debug("doGetFileInfoByAbsolutePath for path = '{}' BEGIN", path)
+            val fileInfo = indexRepository.findNotDeletedFileInfo(folder, path) ?: error("file not found for path = $path")
+            logger.debug("doGetFileInfoByAbsolutePath for path = '{}' END", path)
+            fileInfo
+        }
+    }
+
+    fun navigateTo(fileInfo: FileInfo) {
+        assert(fileInfo.isDirectory())
+        assert(fileInfo.folder == folder)
+        return if (fileInfo.path == PARENT_FILE_INFO.path)
+            navigateToAbsolutePath(PathUtils.getParentPath(currentPath))
+        else
+            navigateToAbsolutePath(fileInfo.path)
+    }
+
+    fun navigateToNearestPath(oldPath: String) {
+        if (!StringUtils.isBlank(oldPath)) {
+            navigateToAbsolutePath(oldPath)
+        }
+    }
+
+    private fun navigateToAbsolutePath(newPath: String) {
+        if (PathUtils.isRoot(newPath)) {
+            currentPath = PathUtils.ROOT_PATH
+        } else {
+            val fileInfo = getFileInfoByAbsolutePath(newPath)
+            assert(fileInfo.isDirectory(), {"cannot navigate to path ${fileInfo.path}: not a directory"})
+            currentPath = fileInfo.path
+        }
+        logger.info("navigate to path = '{}'", currentPath)
+        preloadFileInfoForCurrentPath()
+    }
+
+    override fun close() {
+        logger.info("closing")
+        indexHandler.unregisterIndexBrowser(this)
+        executorService.shutdown()
+        executorService.awaitTerminationSafe()
+    }
+}

syncthing-bep/src/main/kotlin/net/syncthing/java/bep/IndexHandler.kt

@@ -0,0 +1,453 @@
+/* 
+ * Copyright (C) 2016 Davide Imbriaco
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.bep
+
+import net.syncthing.java.core.beans.*
+import net.syncthing.java.core.beans.FileInfo.Version
+import net.syncthing.java.core.configuration.Configuration
+import net.syncthing.java.core.interfaces.IndexRepository
+import net.syncthing.java.core.interfaces.Sequencer
+import net.syncthing.java.core.interfaces.TempRepository
+import net.syncthing.java.core.utils.BlockUtils
+import net.syncthing.java.core.utils.NetworkUtils
+import net.syncthing.java.core.utils.awaitTerminationSafe
+import net.syncthing.java.core.utils.submitLogging
+import org.apache.commons.lang3.tuple.Pair
+import org.apache.http.util.TextUtils
+import org.bouncycastle.util.encoders.Hex
+import org.slf4j.LoggerFactory
+import java.io.Closeable
+import java.io.IOException
+import java.util.*
+import java.util.concurrent.Executors
+
+class IndexHandler(private val configuration: Configuration, val indexRepository: IndexRepository,
+                   private val tempRepository: TempRepository) : Closeable {
+    private val logger = LoggerFactory.getLogger(javaClass)
+    private val folderInfoByFolder = mutableMapOf<String, FolderInfo>()
+    private val indexMessageProcessor = IndexMessageProcessor()
+    private var lastIndexActivity: Long = 0
+    private val writeAccessLock = Object()
+    private val indexWaitLock = Object()
+    private val indexBrowsers = mutableSetOf<IndexBrowser>()
+    private val onIndexRecordAcquiredListeners = mutableSetOf<(FolderInfo, List<FileInfo>, IndexInfo) -> Unit>()
+    private val onFullIndexAcquiredListeners = mutableSetOf<(FolderInfo) -> Unit>()
+
+    private fun lastActive(): Long = System.currentTimeMillis() - lastIndexActivity
+
+    fun sequencer(): Sequencer = indexRepository.getSequencer()
+
+    fun folderList(): List<String> = folderInfoByFolder.keys.toList()
+
+    fun folderInfoList(): List<FolderInfo> = folderInfoByFolder.values.toList()
+
+    private fun markActive() {
+        lastIndexActivity = System.currentTimeMillis()
+    }
+
+    fun registerOnIndexRecordAcquiredListener(listener: (FolderInfo, List<FileInfo>, IndexInfo) -> Unit) {
+        onIndexRecordAcquiredListeners.add(listener)
+    }
+
+    fun unregisterOnIndexRecordAcquiredListener(listener: (FolderInfo, List<FileInfo>, IndexInfo) -> Unit) {
+        assert(onIndexRecordAcquiredListeners.contains(listener))
+        onIndexRecordAcquiredListeners.remove(listener)
+    }
+
+    fun registerOnFullIndexAcquiredListenersListener(listener: (FolderInfo) -> Unit) {
+        onFullIndexAcquiredListeners.add(listener)
+    }
+
+    fun unregisterOnFullIndexAcquiredListenersListener(listener: (FolderInfo) -> Unit) {
+        assert(onFullIndexAcquiredListeners.contains(listener))
+        onFullIndexAcquiredListeners.remove(listener)
+    }
+
+    init {
+        loadFolderInfoFromConfig()
+    }
+
+    private fun loadFolderInfoFromConfig() {
+        synchronized(writeAccessLock) {
+            for (folderInfo in configuration.folders) {
+                folderInfoByFolder.put(folderInfo.folderId, folderInfo) //TODO reference 'folder info' repository
+            }
+        }
+    }
+
+    @Synchronized
+    fun clearIndex() {
+        synchronized(writeAccessLock) {
+            indexRepository.clearIndex()
+            folderInfoByFolder.clear()
+            loadFolderInfoFromConfig()
+        }
+    }
+
+    internal fun isRemoteIndexAcquired(clusterConfigInfo: ConnectionHandler.ClusterConfigInfo, peerDeviceId: DeviceId): Boolean {
+        var ready = true
+        for (folder in clusterConfigInfo.getSharedFolders()) {
+            val indexSequenceInfo = indexRepository.findIndexInfoByDeviceAndFolder(peerDeviceId, folder)
+            if (indexSequenceInfo == null || indexSequenceInfo.localSequence < indexSequenceInfo.maxSequence) {
+                logger.debug("waiting for index on folder = {} sequenceInfo = {}", folder, indexSequenceInfo)
+                ready = false
+            }
+        }
+        return ready
+    }
+
+    @Throws(InterruptedException::class)
+    fun waitForRemoteIndexAcquired(connectionHandler: ConnectionHandler, timeoutSecs: Long? = null): IndexHandler {
+        val timeoutMillis = (timeoutSecs ?: DEFAULT_INDEX_TIMEOUT) * 1000
+        synchronized(indexWaitLock) {
+            while (!isRemoteIndexAcquired(connectionHandler.clusterConfigInfo!!, connectionHandler.deviceId())) {
+                indexWaitLock.wait(timeoutMillis)
+                NetworkUtils.assertProtocol(connectionHandler.getLastActive() < timeoutMillis || lastActive() < timeoutMillis,
+                        {"unable to acquire index from connection $connectionHandler, timeout reached!"})
+            }
+        }
+        logger.debug("acquired all indexes on connection {}", connectionHandler)
+        return this
+    }
+
+    fun handleClusterConfigMessageProcessedEvent(clusterConfig: BlockExchangeProtos.ClusterConfig) {
+        synchronized(writeAccessLock) {
+            for (folderRecord in clusterConfig.foldersList) {
+                val folder = folderRecord.id
+                val folderInfo = updateFolderInfo(folder, folderRecord.label)
+                logger.debug("acquired folder info from cluster config = {}", folderInfo)
+                for (deviceRecord in folderRecord.devicesList) {
+                    val deviceId = DeviceId.fromHashData(deviceRecord.id.toByteArray())
+                    if (deviceRecord.hasIndexId() && deviceRecord.hasMaxSequence()) {
+                        val folderIndexInfo = updateIndexInfo(folder, deviceId, deviceRecord.indexId, deviceRecord.maxSequence, null)
+                        logger.debug("acquired folder index info from cluster config = {}", folderIndexInfo)
+                    }
+                }
+            }
+        }
+    }
+
+    fun handleIndexMessageReceivedEvent(folderId: String, filesList: List<BlockExchangeProtos.FileInfo>, connectionHandler: ConnectionHandler) {
+        indexMessageProcessor.handleIndexMessageReceivedEvent(folderId, filesList, connectionHandler)
+    }
+
+    fun pushRecord(folder: String, bepFileInfo: BlockExchangeProtos.FileInfo): FileInfo? {
+        var fileBlocks: FileBlocks? = null
+        val builder = FileInfo.Builder()
+                .setFolder(folder)
+                .setPath(bepFileInfo.name)
+                .setLastModified(Date(bepFileInfo.modifiedS * 1000 + bepFileInfo.modifiedNs / 1000000))
+                .setVersionList((if (bepFileInfo.hasVersion()) bepFileInfo.version.countersList else null ?: emptyList()).map { record -> Version(record.id, record.value) })
+                .setDeleted(bepFileInfo.deleted)
+        when (bepFileInfo.type) {
+            BlockExchangeProtos.FileInfoType.FILE -> {
+                fileBlocks = FileBlocks(folder, builder.getPath()!!, ((bepFileInfo.blocksList ?: emptyList())).map { record ->
+                    BlockInfo(record.offset, record.size, Hex.toHexString(record.hash.toByteArray()))
+                })
+                builder
+                        .setTypeFile()
+                        .setHash(fileBlocks.hash)
+                        .setSize(bepFileInfo.size)
+            }
+            BlockExchangeProtos.FileInfoType.DIRECTORY -> builder.setTypeDir()
+            else -> {
+                logger.warn("unsupported file type = {}, discarding file info", bepFileInfo.type)
+                return null
+            }
+        }
+        return addRecord(builder.build(), fileBlocks)
+    }
+
+    private fun updateIndexInfo(folder: String, deviceId: DeviceId, indexId: Long?, maxSequence: Long?, localSequence: Long?): IndexInfo {
+        synchronized(writeAccessLock) {
+            var indexSequenceInfo = indexRepository.findIndexInfoByDeviceAndFolder(deviceId, folder)
+            var shouldUpdate = false
+            val builder: IndexInfo.Builder
+            if (indexSequenceInfo == null) {
+                shouldUpdate = true
+                assert(indexId != null, {"index sequence info not found, and supplied null index id (folder = $folder, device = $deviceId)"})
+                builder = IndexInfo.newBuilder()
+                        .setFolder(folder)
+                        .setDeviceId(deviceId.deviceId)
+                        .setIndexId(indexId!!)
+                        .setLocalSequence(0)
+                        .setMaxSequence(-1)
+            } else {
+                builder = indexSequenceInfo.copyBuilder()
+            }
+            if (indexId != null && indexId != builder.getIndexId()) {
+                shouldUpdate = true
+                builder.setIndexId(indexId)
+            }
+            if (maxSequence != null && maxSequence > builder.getMaxSequence()) {
+                shouldUpdate = true
+                builder.setMaxSequence(maxSequence)
+            }
+            if (localSequence != null && localSequence > builder.getLocalSequence()) {
+                shouldUpdate = true
+                builder.setLocalSequence(localSequence)
+            }
+            if (shouldUpdate) {
+                indexSequenceInfo = builder.build()
+                indexRepository.updateIndexInfo(indexSequenceInfo)
+            }
+            return indexSequenceInfo!!
+        }
+    }
+
+    private fun addRecord(record: FileInfo, fileBlocks: FileBlocks?): FileInfo? {
+        synchronized(writeAccessLock) {
+            val lastModified = indexRepository.findFileInfoLastModified(record.folder, record.path)
+            return if (lastModified != null && !record.lastModified.after(lastModified)) {
+                logger.trace("discarding record = {}, modified before local record", record)
+                null
+            } else {
+                indexRepository.updateFileInfo(record, fileBlocks)
+                logger.trace("loaded new record = {}", record)
+                indexBrowsers.forEach {
+                    it.onIndexChangedevent(record.folder, record)
+                }
+                record
+            }
+        }
+    }
+
+    fun getFileInfoByPath(folder: String, path: String): FileInfo? {
+        return indexRepository.findFileInfo(folder, path)
+    }
+
+    fun getFileInfoAndBlocksByPath(folder: String, path: String): Pair<FileInfo, FileBlocks>? {
+        val fileInfo = getFileInfoByPath(folder, path)
+        return if (fileInfo == null) {
+            null
+        } else {
+            assert(fileInfo.isFile())
+            val fileBlocks = indexRepository.findFileBlocks(folder, path)
+            checkNotNull(fileBlocks, {"file blocks not found for file info = $fileInfo"})
+
+            FileInfo.checkBlocks(fileInfo, fileBlocks!!)
+
+            Pair.of(fileInfo, fileBlocks)
+        }
+    }
+
+    private fun updateFolderInfo(folder: String, label: String?): FolderInfo {
+        var folderInfo: FolderInfo? = folderInfoByFolder[folder]
+        if (folderInfo == null || !TextUtils.isEmpty(label)) {
+            folderInfo = FolderInfo(folder, label)
+            folderInfoByFolder.put(folderInfo.folderId, folderInfo)
+        }
+        return folderInfo
+    }
+
+    fun getFolderInfo(folder: String): FolderInfo? {
+        return folderInfoByFolder[folder]
+    }
+
+    fun getIndexInfo(device: DeviceId, folder: String): IndexInfo? {
+        return indexRepository.findIndexInfoByDeviceAndFolder(device, folder)
+    }
+
+    fun newFolderBrowser(): FolderBrowser {
+        return FolderBrowser(this)
+    }
+
+    fun newIndexBrowser(folder: String, includeParentInList: Boolean = false, allowParentInRoot: Boolean = false,
+                        ordering: Comparator<FileInfo>? = null): IndexBrowser {
+        val indexBrowser = IndexBrowser(indexRepository, this, folder, includeParentInList, allowParentInRoot, ordering)
+        indexBrowsers.add(indexBrowser)
+        return indexBrowser
+    }
+
+    internal fun unregisterIndexBrowser(indexBrowser: IndexBrowser) {
+        assert(indexBrowsers.contains(indexBrowser))
+        indexBrowsers.remove(indexBrowser)
+    }
+
+    override fun close() {
+        assert(indexBrowsers.isEmpty())
+        assert(onIndexRecordAcquiredListeners.isEmpty())
+        assert(onFullIndexAcquiredListeners.isEmpty())
+        indexMessageProcessor.stop()
+    }
+
+    private inner class IndexMessageProcessor {
+
+        private val executorService = Executors.newSingleThreadExecutor()
+        private var queuedMessages = 0
+        private var queuedRecords: Long = 0
+        //        private long lastRecordProcessingTime = 0;
+        //        , delay = 0;
+        //        private boolean addProcessingDelayForInterface = true;
+        //        private final int MIN_DELAY = 0, MAX_DELAY = 5000, MAX_RECORD_PER_PROCESS = 16, DELAY_FACTOR = 1;
+        private var startTime: Long? = null
+
+        fun handleIndexMessageReceivedEvent(folderId: String, filesList: List<BlockExchangeProtos.FileInfo>, connectionHandler: ConnectionHandler) {
+            logger.info("received index message event, preparing (queued records = {} event record count = {})", queuedRecords, filesList.size)
+            markActive()
+            val clusterConfigInfo = connectionHandler.clusterConfigInfo
+            val peerDeviceId = connectionHandler.deviceId()
+            //            List<BlockExchangeProtos.FileInfo> fileList = event.getFilesList();
+            //            for (int index = 0; index < fileList.size(); index += MAX_RECORD_PER_PROCESS) {
+            //                BlockExchangeProtos.IndexUpdate data = BlockExchangeProtos.IndexUpdate.newBuilder()
+            //                    .addAllFiles(Iterables.limit(Iterables.skip(fileList, index), MAX_RECORD_PER_PROCESS))
+            //                    .setFolder(event.getFolder())
+            //                    .build();
+            //                if (queuedMessages > 0) {
+            //                    storeAndProcessBg(data, clusterConfigInfo, peerDeviceId);
+            //                } else {
+            //                    processBg(data, clusterConfigInfo, peerDeviceId);
+            //                }
+            //            }
+            val data = BlockExchangeProtos.IndexUpdate.newBuilder()
+                    .addAllFiles(filesList)
+                    .setFolder(folderId)
+                    .build()
+            if (queuedMessages > 0) {
+                storeAndProcessBg(data, clusterConfigInfo, peerDeviceId)
+            } else {
+                processBg(data, clusterConfigInfo, peerDeviceId)
+            }
+        }
+
+        private fun processBg(data: BlockExchangeProtos.IndexUpdate, clusterConfigInfo: ConnectionHandler.ClusterConfigInfo?, peerDeviceId: DeviceId) {
+            logger.debug("received index message event, queuing for processing")
+            queuedMessages++
+            queuedRecords += data.filesCount.toLong()
+            executorService.submitLogging(object : ProcessingRunnable() {
+                override fun runProcess() {
+                    doHandleIndexMessageReceivedEvent(data, clusterConfigInfo, peerDeviceId)
+                }
+            })
+        }
+
+        private fun storeAndProcessBg(data: BlockExchangeProtos.IndexUpdate, clusterConfigInfo: ConnectionHandler.ClusterConfigInfo?, peerDeviceId: DeviceId) {
+            val key = tempRepository.pushTempData(data.toByteArray())
+            logger.debug("received index message event, stored to temp record {}, queuing for processing", key)
+            queuedMessages++
+            queuedRecords += data.filesCount.toLong()
+            executorService.submitLogging(object : ProcessingRunnable() {
+                override fun runProcess() {
+                    try {
+                        doHandleIndexMessageReceivedEvent(key, clusterConfigInfo, peerDeviceId)
+                    } catch (ex: IOException) {
+                        logger.error("error processing index message", ex)
+                    }
+
+                }
+
+            })
+        }
+
+        private abstract inner class ProcessingRunnable : Runnable {
+
+            override fun run() {
+                startTime = System.currentTimeMillis()
+                runProcess()
+                queuedMessages--
+                //                lastRecordProcessingTime = stopwatch.elapsed(TimeUnit.MILLISECONDS) - delay;
+                //                logger.info("processed a bunch of records, {}*{} remaining", queuedMessages, MAX_RECORD_PER_PROCESS);
+                //                logger.debug("processed index message in {} secs", lastRecordProcessingTime / 1000d);
+                startTime = null
+            }
+
+            protected abstract fun runProcess()
+
+            //        private boolean isVersionOlderThanSequence(BlockExchangeProtos.FileInfo fileInfo, long localSequence) {
+            //            long fileSequence = fileInfo.getSequence();
+            //            //TODO should we check last version instead of sequence? verify
+            //            return fileSequence < localSequence;
+            //        }
+            @Throws(IOException::class)
+            protected fun doHandleIndexMessageReceivedEvent(key: String, clusterConfigInfo: ConnectionHandler.ClusterConfigInfo?, peerDeviceId: DeviceId) {
+                logger.debug("processing index message event from temp record {}", key)
+                markActive()
+                val data = tempRepository.popTempData(key)
+                val message = BlockExchangeProtos.IndexUpdate.parseFrom(data)
+                doHandleIndexMessageReceivedEvent(message, clusterConfigInfo, peerDeviceId)
+            }
+
+            protected fun doHandleIndexMessageReceivedEvent(message: BlockExchangeProtos.IndexUpdate, clusterConfigInfo: ConnectionHandler.ClusterConfigInfo?, peerDeviceId: DeviceId) {
+                //            synchronized (writeAccessLock) {
+                //                if (addProcessingDelayForInterface) {
+                //                    delay = Math.min(MAX_DELAY, Math.max(MIN_DELAY, lastRecordProcessingTime * DELAY_FACTOR));
+                //                    logger.info("add delay of {} secs before processing index message (to allow UI to process)", delay / 1000d);
+                //                    try {
+                //                        Thread.sleep(delay);
+                //                    } catch (InterruptedException ex) {
+                //                        logger.warn("interrupted", ex);
+                //                    }
+                //                } else {
+                //                    delay = 0;
+                //                }
+                logger.info("processing index message with {} records (queue size: messages = {} records = {})", message.filesCount, queuedMessages, queuedRecords)
+                //            String deviceId = connectionHandler.getDeviceId();
+                val folderId = message.folder
+                var sequence: Long = -1
+                val newRecords = mutableListOf<FileInfo>()
+                //                IndexInfo oldIndexInfo = indexRepository.findIndexInfoByDeviceAndFolder(deviceId, folder);
+                //            Stopwatch stopwatch = Stopwatch.createStarted();
+                logger.debug("processing {} index records for folder {}", message.filesList.size, folderId)
+                for (fileInfo in message.filesList) {
+                    markActive()
+                    //                    if (oldIndexInfo != null && isVersionOlderThanSequence(fileInfo, oldIndexInfo.getLocalSequence())) {
+                    //                        logger.trace("skipping file {}, version older than sequence {}", fileInfo, oldIndexInfo.getLocalSequence());
+                    //                    } else {
+                    val newRecord = pushRecord(folderId, fileInfo)
+                    if (newRecord != null) {
+                        newRecords.add(newRecord)
+                    }
+                    sequence = Math.max(fileInfo.sequence, sequence)
+                    markActive()
+                    //                    }
+                }
+                val newIndexInfo = updateIndexInfo(folderId, peerDeviceId, null, null, sequence)
+                val elap = System.currentTimeMillis() - startTime!!
+                queuedRecords -= message.filesCount.toLong()
+                logger.info("processed {} index records, acquired {} ({} secs, {} record/sec)", message.filesCount, newRecords.size, elap / 1000.0, Math.round(message.filesCount / (elap / 1000.0) * 100) / 100.0)
+                if (logger.isInfoEnabled && newRecords.size <= 10) {
+                    for (fileInfo in newRecords) {
+                        logger.info("acquired record = {}", fileInfo)
+                    }
+                }
+                val folderInfo = folderInfoByFolder[folderId]
+                if (!newRecords.isEmpty()) {
+                    onIndexRecordAcquiredListeners.forEach { it(folderInfo!!, newRecords, newIndexInfo) }
+                }
+                logger.debug("index info = {}", newIndexInfo)
+                if (isRemoteIndexAcquired(clusterConfigInfo!!, peerDeviceId)) {
+                    logger.debug("index acquired")
+                    onFullIndexAcquiredListeners.forEach { it(folderInfo!!)}
+                }
+                //                IndexHandler.this.notifyAll();
+                markActive()
+                synchronized(indexWaitLock) {
+                    indexWaitLock.notifyAll()
+                }
+            }
+        }
+
+        fun stop() {
+            logger.info("stopping index record processor")
+            executorService.shutdown()
+            executorService.awaitTerminationSafe()
+        }
+
+    }
+
+    companion object {
+
+        private const val DEFAULT_INDEX_TIMEOUT: Long = 30
+    }
+}

syncthing-bep/src/main/kotlin/net/syncthing/java/bep/ResponseHandler.kt

@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2018 Jonas Lochmann
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.bep
+
+import org.slf4j.LoggerFactory
+import java.util.*
+import java.util.concurrent.atomic.AtomicInteger
+import kotlin.collections.HashMap
+
+class ResponseHandler {
+    companion object {
+        private val logger = LoggerFactory.getLogger(ResponseHandler::class.java)
+    }
+
+    private val responseListeners = Collections.synchronizedMap(HashMap<Int, (BlockExchangeProtos.Response) -> Unit>())
+    private val nextRequestId = AtomicInteger(0)
+
+    fun registerListener(listener: (BlockExchangeProtos.Response) -> Unit): Int {
+        val requestId = nextRequestId.getAndIncrement()
+
+        responseListeners[requestId] = listener
+
+        return requestId
+    }
+
+    fun unregisterListener(requestId: Int) {
+        responseListeners.remove(requestId)
+    }
+
+    fun handleResponse(response: BlockExchangeProtos.Response) {
+        val listener = responseListeners.remove(response.id)
+
+        if (listener != null) {
+            listener(response)
+        } else {
+            logger.warn("received response for {} without associated handler", response.id)
+        }
+    }
+}

syncthing-bep/src/main/kotlin/net/syncthing/java/bep/utils/SumBy.kt

@@ -0,0 +1,11 @@
+package net.syncthing.java.bep.utils
+
+inline fun <T> Iterable<T>.longSumBy(selector: (T) -> Long): Long {
+    var sum = 0L
+
+    this.forEach {
+        sum += selector(it)
+    }
+
+    return sum
+}

syncthing-bep/src/main/proto/blockExchangeExtraProtos.proto

@@ -0,0 +1,9 @@
+package net.syncthing.java.bep;
+
+option optimize_for = LITE_RUNTIME;
+
+import "blockExchangeProtos.proto";
+
+message Blocks {
+    repeated BlockInfo blocks = 1;
+}

syncthing-bep/src/main/proto/blockExchangeProtos.proto

@@ -0,0 +1,161 @@
+package net.syncthing.java.bep;
+
+option optimize_for = LITE_RUNTIME;
+
+message Hello {
+    optional string device_name    = 1;
+    optional string client_name    = 2;
+    optional string client_version = 3;
+}
+
+message Header {
+    optional MessageType        type        = 1;
+    optional MessageCompression compression = 2;
+}
+
+enum MessageType {
+    CLUSTER_CONFIG    = 0;
+    INDEX             = 1;
+    INDEX_UPDATE      = 2;
+    REQUEST           = 3;
+    RESPONSE          = 4;
+    DOWNLOAD_PROGRESS = 5;
+    PING              = 6;
+    CLOSE             = 7;
+}
+
+enum MessageCompression {
+    NONE = 0;
+    LZ4  = 1;
+}
+
+message ClusterConfig {
+    repeated Folder folders = 1;
+}
+
+message Folder {
+    optional string id                   = 1;
+    optional string label                = 2;
+    optional bool   read_only            = 3;
+    optional bool   ignore_permissions   = 4;
+    optional bool   ignore_delete        = 5;
+    optional bool   disable_temp_indexes = 6;
+
+    repeated Device devices = 16;
+}
+
+message Device {
+    optional bytes       id           = 1;
+    optional string      name         = 2;
+    repeated string      addresses    = 3;
+    optional Compression compression  = 4;
+    optional string      cert_name    = 5;
+    optional int64       max_sequence = 6;
+    optional bool        introducer   = 7;
+    optional uint64      index_id     = 8;
+}
+
+enum Compression {
+    METADATA = 0;
+    NEVER    = 1;
+    ALWAYS   = 2;
+}
+
+message Index {
+    optional string   folder = 1;
+    repeated FileInfo files  = 2;
+}
+
+message IndexUpdate {
+    optional string   folder = 1;
+    repeated FileInfo files  = 2;
+}
+
+message FileInfo {
+    optional string       name           = 1;
+    optional FileInfoType type           = 2;
+    optional int64        size           = 3;
+    optional uint32       permissions    = 4;
+    optional int64        modified_s     = 5;
+    optional int32        modified_ns    = 11;
+    optional uint64       modified_by    = 12;
+    optional bool         deleted        = 6;
+    optional bool         invalid        = 7;
+    optional bool         no_permissions = 8;
+    optional Vector       version        = 9;
+    optional int64        sequence       = 10;
+
+    repeated BlockInfo Blocks         = 16;
+    optional string    symlink_target = 17;
+}
+
+enum FileInfoType {
+    FILE              = 0;
+    DIRECTORY         = 1;
+    SYMLINK_FILE      = 2;
+    SYMLINK_DIRECTORY = 3;
+    SYMLINK           = 4;
+}
+
+message BlockInfo {
+    optional  int64  offset    = 1;
+    optional  int32  size      = 2;
+    optional  bytes  hash      = 3;
+    optional  uint32 weak_hash = 4;
+}
+
+message Vector {
+    repeated Counter counters = 1;
+}
+
+message Counter {
+    optional uint64 id    = 1;
+    optional uint64 value = 2;
+}
+
+message Request {
+    optional int32  id             = 1;
+    optional string folder         = 2;
+    optional string name           = 3;
+    optional int64  offset         = 4;
+    optional int32  size           = 5;
+    optional bytes  hash           = 6;
+    optional bool   from_temporary = 7;
+}
+
+message Response {
+    optional int32     id   = 1;
+    optional bytes     data = 2;
+    optional ErrorCode code = 3;
+}
+
+enum ErrorCode {
+    NO_ERROR     = 0;
+    GENERIC      = 1;
+    NO_SUCH_FILE = 2;
+    INVALID_FILE = 3;
+}
+
+message DownloadProgress {
+    optional string                     folder  = 1;
+    repeated FileDownloadProgressUpdate updates = 2;
+}
+
+message FileDownloadProgressUpdate {
+    optional FileDownloadProgressUpdateType update_type   = 1;
+    optional string                         name          = 2;
+    optional Vector                         version       = 3;
+    repeated int32                          block_indexes = 4;
+}
+
+enum FileDownloadProgressUpdateType {
+    APPEND = 0;
+    FORGET = 1;
+}
+
+message Ping {
+}
+
+message Close {
+    optional string reason = 1;
+}

syncthing-client-cli/build.gradle

@@ -0,0 +1,16 @@
+apply plugin: 'application'
+apply plugin: 'kotlin'
+mainClassName = 'net.syncthing.java.client.cli.Main'
+
+dependencies {
+    compile project(':syncthing-client')
+    compile project(':syncthing-repository-default')
+    compile "commons-cli:commons-cli:1.4"
+    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+}
+
+run {
+    if (project.hasProperty('args')) {
+        args project.args.split('\\s+')
+    }
+}

syncthing-client-cli/src/main/kotlin/net/syncthing/java/client/cli/Main.kt

@@ -0,0 +1,227 @@
+/* 
+ * Copyright (C) 2016 Davide Imbriaco
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.client.cli
+
+import net.syncthing.java.core.beans.DeviceId
+import net.syncthing.java.core.beans.DeviceInfo
+import net.syncthing.java.core.beans.FileInfo
+import net.syncthing.java.core.configuration.Configuration
+import net.syncthing.java.repository.repo.SqlRepository
+import net.syncthing.java.client.SyncthingClient
+import org.apache.commons.cli.*
+import org.apache.commons.io.FileUtils
+import org.slf4j.LoggerFactory
+import java.io.File
+import java.io.FileInputStream
+import java.io.IOException
+import java.util.concurrent.CountDownLatch
+
+class Main(private val commandLine: CommandLine) {
+
+    companion object {
+        @JvmStatic
+        fun main(args: Array<String>) {
+            val options = generateOptions()
+            val parser = DefaultParser()
+            val cmd = parser.parse(options, args)
+            if (cmd.hasOption("h")) {
+                val formatter = HelpFormatter()
+                formatter.printHelp("s-client", options)
+                return
+            }
+            val configuration = if (cmd.hasOption("C")) Configuration(File(cmd.getOptionValue("C")))
+            else                                        Configuration()
+
+            val repository = SqlRepository(configuration.databaseFolder)
+
+            SyncthingClient(configuration, repository, repository).use { syncthingClient ->
+                val main = Main(cmd)
+                cmd.options.forEach { main.handleOption(it, configuration, syncthingClient) }
+            }
+        }
+
+        private fun generateOptions(): Options {
+            val options = Options()
+            options.addOption("C", "set-config", true, "set config file for s-client")
+            options.addOption("c", "config", false, "dump config")
+            options.addOption("S", "set-peers", true, "set peer, or comma-separated list of peers")
+            options.addOption("p", "pull", true, "pull file from network")
+            options.addOption("P", "push", true, "push file to network")
+            options.addOption("o", "output", true, "set output file/directory")
+            options.addOption("i", "input", true, "set input file/directory")
+            options.addOption("a", "list-peers", false, "list peer addresses")
+            options.addOption("a", "address", true, "use this peer addresses")
+            options.addOption("L", "list-remote", false, "list folder (root) content from network")
+            options.addOption("I", "list-info", false, "dump folder info from network")
+            options.addOption("l", "list-info", false, "list folder info from local db")
+            options.addOption("D", "delete", true, "push delete to network")
+            options.addOption("M", "mkdir", true, "push directory create to network")
+            options.addOption("h", "help", false, "print help")
+            return options
+        }
+    }
+
+    private val logger = LoggerFactory.getLogger(Main::class.java)
+
+    private fun handleOption(option: Option, configuration: Configuration, syncthingClient: SyncthingClient) {
+        when (option.opt) {
+            "S" -> {
+                val peers = option.value
+                        .split(",")
+                        .filterNot { it.isEmpty() }
+                        .map { DeviceId(it.trim()) }
+                        .toList()
+                System.out.println("set peers = $peers")
+                configuration.peers = peers.map { DeviceInfo(it, null) }.toSet()
+                configuration.persistNow()
+            }
+            "p" -> {
+                val folderAndPath = option.value
+                System.out.println("file path = $folderAndPath")
+                val folder = folderAndPath.split(":".toRegex()).dropLastWhile({ it.isEmpty() }).toTypedArray()[0]
+                val path = folderAndPath.split(":".toRegex()).dropLastWhile({ it.isEmpty() }).toTypedArray()[1]
+                val latch = CountDownLatch(1)
+                val fileInfo = FileInfo(folder = folder, path = path, type = FileInfo.FileType.FILE)
+                syncthingClient.getBlockPuller(folder, { blockPuller ->
+                    try {
+                        val inputStream = blockPuller.pullFileSync(fileInfo)
+                        val fileName = syncthingClient.indexHandler.getFileInfoByPath(folder, path)!!.fileName
+                        val file  =
+                                if (commandLine.hasOption("o")) {
+                                    val param = File(commandLine.getOptionValue("o"))
+                                    if (param.isDirectory) File(param, fileName) else param
+                                } else {
+                                    File(fileName)
+                                }
+                        FileUtils.copyInputStreamToFile(inputStream, file)
+                        System.out.println("saved file to = $file.absolutePath")
+                    } catch (e: InterruptedException) {
+                        logger.warn("", e)
+                    } catch (e: IOException) {
+                        logger.warn("", e)
+                    }
+                }, { logger.warn("Failed to pull file") })
+                latch.await()
+            }
+            "P" -> {
+                var path = option.value
+                val file = File(commandLine.getOptionValue("i"))
+                assert(!path.startsWith("/")) //TODO check path syntax
+                System.out.println("file path = $path")
+                val folder = path.split(":".toRegex()).dropLastWhile({ it.isEmpty() }).toTypedArray()[0]
+                path = path.split(":".toRegex()).dropLastWhile({ it.isEmpty() }).toTypedArray()[1]
+                val latch = CountDownLatch(1)
+                syncthingClient.getBlockPusher(folder, { blockPusher ->
+                    val observer = blockPusher.pushFile(FileInputStream(file), folder, path)
+                    while (!observer.isCompleted()) {
+                        try {
+                            observer.waitForProgressUpdate()
+                        } catch (e: InterruptedException) {
+                            logger.warn("", e)
+                        }
+
+                        System.out.println("upload progress ${observer.progressPercentage()}%")
+                    }
+                    latch.countDown()
+                }, { logger.warn("Failed to upload file") })
+                latch.await()
+                System.out.println("uploaded file to network")
+            }
+            "D" -> {
+                var path = option.value
+                val folder = path.split(":".toRegex()).dropLastWhile({ it.isEmpty() }).toTypedArray()[0]
+                path = path.split(":".toRegex()).dropLastWhile({ it.isEmpty() }).toTypedArray()[1]
+                System.out.println("delete path = $path")
+                val latch = CountDownLatch(1)
+                syncthingClient.getBlockPusher(folder, { blockPusher ->
+                    try {
+                        blockPusher.pushDelete(folder, path).waitForComplete()
+                    } catch (e: InterruptedException) {
+                        logger.warn("", e)
+                    }
+
+                    latch.countDown()
+                }, { System.out.println("Failed to delete path") })
+                latch.await()
+                System.out.println("deleted path")
+            }
+            "M" -> {
+                var path = option.value
+                val folder = path.split(":".toRegex()).dropLastWhile({ it.isEmpty() }).toTypedArray()[0]
+                path = path.split(":".toRegex()).dropLastWhile({ it.isEmpty() }).toTypedArray()[1]
+                System.out.println("dir path = $path")
+                val latch = CountDownLatch(1)
+                syncthingClient.getBlockPusher(folder, { blockPusher ->
+                    try {
+                        blockPusher.pushDir(folder, path).waitForComplete()
+                    } catch (e: InterruptedException) {
+                        logger.warn("", e)
+                    }
+
+                    latch.countDown()
+                }, { System.out.println("Failed to push directory") })
+                latch.await()
+                System.out.println("uploaded dir to network")
+            }
+            "L" -> {
+                waitForIndexUpdate(syncthingClient, configuration)
+                for (folder in syncthingClient.indexHandler.folderList()) {
+                    syncthingClient.indexHandler.newIndexBrowser(folder).use { indexBrowser ->
+                        System.out.println("list folder = ${indexBrowser.folder}")
+                        for (fileInfo in indexBrowser.listFiles()) {
+                            System.out.println("${fileInfo.type.name.substring(0, 1)}\t${fileInfo.describeSize()}\t${fileInfo.path}")
+                        }
+                    }
+                }
+            }
+            "I" -> {
+                waitForIndexUpdate(syncthingClient, configuration)
+                val folderInfo = StringBuilder()
+                for (folder in syncthingClient.indexHandler.folderList()) {
+                    folderInfo.append("\nfolder info: ")
+                            .append(syncthingClient.indexHandler.getFolderInfo(folder))
+                    folderInfo.append("\nfolder stats: ")
+                            .append(syncthingClient.indexHandler.newFolderBrowser().getFolderStats(folder).dumpInfo())
+                            .append("\n")
+                }
+                System.out.println("folders:\n$folderInfo\n")
+            }
+            "l" -> {
+                var folderInfo = ""
+                for (folder in syncthingClient.indexHandler.folderList()) {
+                    folderInfo += "\nfolder info: " + syncthingClient.indexHandler.getFolderInfo(folder)
+                    folderInfo += "\nfolder stats: " + syncthingClient.indexHandler.newFolderBrowser().getFolderStats(folder).dumpInfo() + "\n"
+                }
+                System.out.println("folders:\n$folderInfo\n")
+            }
+            "a" -> {
+                val deviceAddressSupplier = syncthingClient.discoveryHandler.newDeviceAddressSupplier()
+                var deviceAddressesStr = ""
+                for (deviceAddress in deviceAddressSupplier.toList()) {
+                    deviceAddressesStr += "\n" + deviceAddress?.deviceId + " : " + deviceAddress?.address
+                }
+                System.out.println("device addresses:\n$deviceAddressesStr\n")
+            }
+        }
+    }
+
+    @Throws(InterruptedException::class)
+    private fun waitForIndexUpdate(client: SyncthingClient, configuration: Configuration) {
+        val latch = CountDownLatch(configuration.peers.size)
+        client.indexHandler.registerOnFullIndexAcquiredListenersListener {
+            latch.countDown()
+        }
+        latch.await()
+    }
+}

syncthing-client/build.gradle

@@ -0,0 +1,9 @@
+apply plugin: 'java-library'
+apply plugin: 'kotlin'
+
+dependencies {
+    compile project(':syncthing-core')
+    compile project(':syncthing-bep')
+    compile project(':syncthing-discovery')
+    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+}

syncthing-client/src/main/kotlin/net/syncthing/java/client/SyncthingClient.kt

@@ -0,0 +1,231 @@
+/* 
+ * Copyright (C) 2016 Davide Imbriaco
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.client
+
+import net.syncthing.java.bep.BlockPuller
+import net.syncthing.java.bep.BlockPusher
+import net.syncthing.java.bep.ConnectionHandler
+import net.syncthing.java.bep.IndexHandler
+import net.syncthing.java.core.beans.DeviceAddress
+import net.syncthing.java.core.beans.DeviceId
+import net.syncthing.java.core.beans.DeviceInfo
+import net.syncthing.java.core.configuration.Configuration
+import net.syncthing.java.core.interfaces.IndexRepository
+import net.syncthing.java.core.interfaces.TempRepository
+import net.syncthing.java.core.security.KeystoreHandler
+import net.syncthing.java.core.utils.awaitTerminationSafe
+import net.syncthing.java.discovery.DiscoveryHandler
+import org.slf4j.LoggerFactory
+import java.io.Closeable
+import java.io.IOException
+import java.util.Collections
+import java.util.TreeSet
+import java.util.concurrent.Executors
+import java.util.concurrent.TimeUnit
+import java.util.concurrent.atomic.AtomicBoolean
+import kotlin.collections.ArrayList
+
+class SyncthingClient(
+        private val configuration: Configuration,
+        private val repository: IndexRepository,
+        private val tempRepository: TempRepository
+) : Closeable {
+
+    private val logger = LoggerFactory.getLogger(javaClass)
+    val discoveryHandler: DiscoveryHandler
+    val indexHandler: IndexHandler
+    private val connections = Collections.synchronizedSet(createConnectionsSet())
+    private val connectByDeviceIdLocks = Collections.synchronizedMap(HashMap<DeviceId, Object>())
+    private val onConnectionChangedListeners = Collections.synchronizedList(mutableListOf<(DeviceId) -> Unit>())
+    private var connectDevicesScheduler = Executors.newSingleThreadScheduledExecutor()
+
+    private fun createConnectionsSet() = TreeSet<ConnectionHandler>(compareBy { it.address.score })
+
+    init {
+        indexHandler = IndexHandler(configuration, repository, tempRepository)
+        discoveryHandler = DiscoveryHandler(configuration)
+        connectDevicesScheduler.scheduleAtFixedRate(this::updateIndexFromPeers, 0, 15, TimeUnit.SECONDS)
+    }
+
+    fun clearCacheAndIndex() {
+        indexHandler.clearIndex()
+        configuration.folders = emptySet()
+        configuration.persistLater()
+        updateIndexFromPeers()
+    }
+
+    fun addOnConnectionChangedListener(listener: (DeviceId) -> Unit) {
+        onConnectionChangedListeners.add(listener)
+    }
+
+    fun removeOnConnectionChangedListener(listener: (DeviceId) -> Unit) {
+        assert(onConnectionChangedListeners.contains(listener))
+        onConnectionChangedListeners.remove(listener)
+    }
+
+    @Throws(IOException::class, KeystoreHandler.CryptoException::class)
+    private fun openConnection(deviceAddress: DeviceAddress): ConnectionHandler {
+        logger.debug("Connecting to ${deviceAddress.deviceId}, active connections: ${connections.map { it.deviceId().deviceId }}")
+        val connectionHandler = ConnectionHandler(
+                configuration, deviceAddress, indexHandler, tempRepository, { connectionHandler, _ ->
+                    connectionHandler.close()
+                    openConnection(deviceAddress)
+                },
+                {connection ->
+                    if (!connection.isConnected) {
+                        connections.remove(connection)
+                    }
+                    onConnectionChangedListeners.forEach { it(connection.deviceId()) }
+                })
+
+        try {
+          connectionHandler.connect()
+        } catch (ex: Exception) {
+          connectionHandler.closeBg()
+
+          throw ex
+        }
+
+        connections.add(connectionHandler)
+
+        return connectionHandler
+    }
+
+    /**
+     * Takes discovered addresses from [[DiscoveryHandler]] and connects to devices.
+     *
+     * We need to make sure that we are only connecting once to each device.
+     */
+    private fun getPeerConnections(listener: (connection: ConnectionHandler) -> Unit, completeListener: () -> Unit) {
+        // create an copy to prevent dispatching an action two times
+        val connectionsWhichWereDispatched = createConnectionsSet()
+
+        synchronized (connections) {
+          connectionsWhichWereDispatched.addAll(connections)
+        }
+
+        connectionsWhichWereDispatched.forEach { listener(it) }
+
+        discoveryHandler.newDeviceAddressSupplier()
+                .takeWhile { it != null }
+                .filterNotNull()
+                .groupBy { it.deviceId() }
+                .filterNot { it.value.isEmpty() }
+                .forEach { (deviceId, addresses) ->
+                    // create an lock per device id to prevent multiple connections to one device
+
+                    synchronized (connectByDeviceIdLocks) {
+                      if (connectByDeviceIdLocks[deviceId] == null) {
+                        connectByDeviceIdLocks[deviceId] = Object()
+                      }
+                    }
+
+                    synchronized (connectByDeviceIdLocks[deviceId]!!) {
+                      val existingConnection = connections.find { it.deviceId() == deviceId && it.isConnected }
+
+                      if (existingConnection != null) {
+                        connectionsWhichWereDispatched.add(existingConnection)
+                        listener(existingConnection)
+
+                        return@synchronized
+                      }
+
+                      // try to use all addresses
+                      for (address in addresses.distinctBy { it.address }) {
+                        try {
+                          val newConnection = openConnection(address)
+
+                          connectionsWhichWereDispatched.add(newConnection)
+                          listener(newConnection)
+
+                          break  // it worked, no need to try more
+                        } catch (e: IOException) {
+                          logger.warn("error connecting to device = $address", e)
+                        } catch (e: KeystoreHandler.CryptoException) {
+                          logger.warn("error connecting to device = $address", e)
+                        }
+                      }
+                    }
+                }
+
+        // use all connections which were added in the time between and were not added by this function call
+        val newConnectionsBackup = createConnectionsSet()
+
+        synchronized (connections) {
+          newConnectionsBackup.addAll(connections)
+        }
+
+        connectionsWhichWereDispatched.forEach { newConnectionsBackup.remove(it) }
+
+        newConnectionsBackup.forEach { listener(it) }
+
+        completeListener()
+    }
+
+    private fun updateIndexFromPeers() {
+        getPeerConnections({ connection ->
+            try {
+                indexHandler.waitForRemoteIndexAcquired(connection)
+            } catch (ex: InterruptedException) {
+                logger.warn("exception while waiting for index", ex)
+            }
+        }, {})
+    }
+
+    private fun getConnectionForFolder(folder: String, listener: (connection: ConnectionHandler) -> Unit,
+                                       errorListener: () -> Unit) {
+        val isConnected = AtomicBoolean(false)
+        getPeerConnections({ connection ->
+            if (connection.hasFolder(folder) && !isConnected.get()) {
+                listener(connection)
+                isConnected.set(true)
+            }
+        }, {
+            if (!isConnected.get()) {
+                errorListener()
+            }
+        })
+    }
+
+    fun getBlockPuller(folderId: String, listener: (BlockPuller) -> Unit, errorListener: () -> Unit) {
+        getConnectionForFolder(folderId, { connection ->
+            listener(connection.getBlockPuller())
+        }, errorListener)
+    }
+
+    fun getBlockPusher(folderId: String, listener: (BlockPusher) -> Unit, errorListener: () -> Unit) {
+        getConnectionForFolder(folderId, { connection ->
+            listener(connection.getBlockPusher())
+        }, errorListener)
+    }
+
+    fun getPeerStatus(): List<DeviceInfo> {
+        return configuration.peers.map { device ->
+            val isConnected = connections.find { it.deviceId() == device.deviceId }?.isConnected ?: false
+            device.copy(isConnected = isConnected)
+        }
+    }
+
+    override fun close() {
+        connectDevicesScheduler.awaitTerminationSafe()
+        discoveryHandler.close()
+        // Create copy of list, because it will be modified by handleConnectionClosedEvent(), causing ConcurrentModificationException.
+        ArrayList(connections).forEach{it.close()}
+        indexHandler.close()
+        repository.close()
+        tempRepository.close()
+        assert(onConnectionChangedListeners.isEmpty())
+    }
+
+}

syncthing-core/build.gradle

@@ -0,0 +1,15 @@
+apply plugin: 'java-library'
+apply plugin: 'kotlin'
+
+dependencies {
+    compile "org.apache.commons:commons-lang3:3.7"
+    compile 'commons-codec:commons-codec:1.11'
+    // Can't upgrade to 2.6 because it crashes on Android
+    compile "commons-io:commons-io:2.5"
+    compile "org.slf4j:slf4j-api:1.7.25"
+    compile "ch.qos.logback:logback-classic:1.2.3"
+    compile "com.google.code.gson:gson:2.8.2"
+    compile "org.apache.httpcomponents:httpclient:4.5.4"
+    compile "org.bouncycastle:bcmail-jdk15on:1.59"
+    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+}

syncthing-core/src/main/kotlin/net/syncthing/java/core/beans/BlockInfo.kt

@@ -0,0 +1,16 @@
+/* 
+ * Copyright (C) 2016 Davide Imbriaco
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.core.beans
+
+data class BlockInfo(val offset: Long, val size: Int, val hash: String)

syncthing-core/src/main/kotlin/net/syncthing/java/core/beans/DeviceAddress.kt

@@ -0,0 +1,205 @@
+/* 
+ * Copyright (C) 2016 Davide Imbriaco
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.core.beans
+
+import org.slf4j.LoggerFactory
+import java.net.InetAddress
+import java.net.InetSocketAddress
+import java.net.UnknownHostException
+import java.util.*
+
+/**
+ *
+ * TODO: this class cant use [[DeviceId]] because [[GlobalDiscoveryHandler.pickAnnounceServers]] uses that field for discovery server URLs.
+ */
+class DeviceAddress private constructor(val deviceId: String, private val instanceId: Long?, val address: String, producer: AddressProducer?, score: Int?, lastModified: Date?) {
+    private val producer = producer ?: AddressProducer.UNKNOWN
+    val score = score ?: Integer.MAX_VALUE
+    private val lastModified = lastModified ?: Date()
+
+    fun deviceId() = DeviceId(deviceId)
+
+    @Throws(UnknownHostException::class)
+    private fun getInetAddress(): InetAddress = InetAddress.getByName(address.replaceFirst("^[^:]+://".toRegex(), "").replaceFirst("(:[0-9]+)?(/.*)?$".toRegex(), ""))
+
+    private fun getPort(): Int = if (address.matches("^[a-z]+://[^:]+:([0-9]+).*".toRegex())) {
+            Integer.parseInt(address.replaceFirst("^[a-z]+://[^:]+:([0-9]+).*".toRegex(), "$1"))
+        } else {
+            DEFAULT_PORT_BY_PROTOCOL[getType()]!!
+        }
+
+    fun getType(): AddressType = when {
+        address.isEmpty() -> AddressType.NULL
+        address.startsWith("tcp://") -> AddressType.TCP
+        address.startsWith("relay://") -> AddressType.RELAY
+        address.startsWith("relay-http://") -> AddressType.HTTP_RELAY
+        address.startsWith("relay-https://") -> AddressType.HTTPS_RELAY
+        else -> AddressType.OTHER
+    }
+
+    @Throws(UnknownHostException::class)
+    fun getSocketAddress(): InetSocketAddress = InetSocketAddress(getInetAddress(), getPort())
+
+    fun isWorking(): Boolean = score < Integer.MAX_VALUE
+
+    constructor(deviceId: String, address: String) : this(deviceId, null, address, null, null, null)
+
+    fun containsUriParamValue(key: String): Boolean {
+        return !getUriParam(key).isNullOrEmpty()
+    }
+
+    /**
+     * Returns value for the specified URL parameter key.
+     *
+     * We need to parse the URL manually, as it is not URL encoded and may contain invalid key/values
+     * like "key=a b" (with an unencoded space).
+     */
+    fun getUriParam(key: String): String? {
+        assert(!key.isEmpty())
+        return address
+                .split("?", limit = 2).first()
+                .splitToSequence("&")
+                .map { it.split("=", limit = 2) }
+                .map { it[0] to (it.getOrNull(1) ?: "") }
+                .find { it.first == key }
+                ?.second
+    }
+
+    enum class AddressType {
+        TCP, RELAY, OTHER, NULL, HTTP_RELAY, HTTPS_RELAY
+    }
+
+    enum class AddressProducer {
+        LOCAL_DISCOVERY, GLOBAL_DISCOVERY, UNKNOWN
+    }
+
+    override fun toString(): String {
+        return "DeviceAddress(deviceId=$deviceId, instanceId=$instanceId, address=$address, producer=$producer, score=$score, lastModified=$lastModified)"
+    }
+
+    override fun hashCode(): Int {
+        var hash = 3
+        hash = 29 * hash + Objects.hashCode(this.deviceId)
+        hash = 29 * hash + Objects.hashCode(this.address)
+        return hash
+    }
+
+    override fun equals(obj: Any?): Boolean {
+        if (this === obj) {
+            return true
+        }
+        if (obj == null) {
+            return false
+        }
+        if (javaClass != obj.javaClass) {
+            return false
+        }
+        val other = obj as DeviceAddress?
+        if (this.deviceId != other!!.deviceId) {
+            return false
+        }
+        return this.address == other.address
+    }
+
+    fun copyBuilder(): Builder {
+        return Builder(deviceId, instanceId, address, producer, score, lastModified)
+    }
+
+    class Builder {
+
+        private var deviceId: String? = null
+        private var instanceId: Long? = null
+        private var address: String? = null
+        private var producer: AddressProducer? = null
+        private var score: Int? = null
+        private var lastModified: Date? = null
+
+        constructor()
+
+        internal constructor(deviceId: String, instanceId: Long?, address: String, producer: AddressProducer, score: Int?, lastModified: Date) {
+            this.deviceId = deviceId
+            this.instanceId = instanceId
+            this.address = address
+            this.producer = producer
+            this.score = score
+            this.lastModified = lastModified
+        }
+
+        fun getLastModified(): Date? {
+            return lastModified
+        }
+
+        fun setLastModified(lastModified: Date): Builder {
+            this.lastModified = lastModified
+            return this
+        }
+
+        fun getDeviceId(): String? {
+            return deviceId
+        }
+
+        fun setDeviceId(deviceId: String): Builder {
+            this.deviceId = deviceId
+            return this
+        }
+
+        fun getInstanceId(): Long? {
+            return instanceId
+        }
+
+        fun setInstanceId(instanceId: Long?): Builder {
+            this.instanceId = instanceId
+            return this
+        }
+
+        fun getAddress(): String? {
+            return address
+        }
+
+        fun setAddress(address: String): Builder {
+            this.address = address
+            return this
+        }
+
+        fun getProducer(): AddressProducer? {
+            return producer
+        }
+
+        fun setProducer(producer: AddressProducer): Builder {
+            this.producer = producer
+            return this
+        }
+
+        fun getScore(): Int? {
+            return score
+        }
+
+        fun setScore(score: Int?): Builder {
+            this.score = score
+            return this
+        }
+
+        fun build(): DeviceAddress {
+            return DeviceAddress(deviceId!!, instanceId, address!!, producer, score, lastModified)
+        }
+    }
+
+    companion object {
+        private val DEFAULT_PORT_BY_PROTOCOL = mapOf(
+                AddressType.TCP to 22000,
+                AddressType.RELAY to 22067,
+                AddressType.HTTP_RELAY to 80,
+                AddressType.HTTPS_RELAY to 443)
+    }
+}

syncthing-core/src/main/kotlin/net/syncthing/java/core/beans/DeviceId.kt

@@ -0,0 +1,83 @@
+package net.syncthing.java.core.beans
+
+import com.google.gson.stream.JsonReader
+import com.google.gson.stream.JsonWriter
+import net.syncthing.java.core.utils.NetworkUtils
+import org.apache.commons.codec.binary.Base32
+import org.slf4j.LoggerFactory
+import java.io.IOException
+
+data class DeviceId @Throws(IOException::class) constructor(val deviceId: String) {
+
+    init {
+        val withoutDashes = this.deviceId.replace("-", "")
+        NetworkUtils.assertProtocol(DeviceId.fromHashDataToString(toHashData()) == withoutDashes)
+    }
+
+    val shortId
+        get() = deviceId.substring(0, 7)
+
+    fun toHashData(): ByteArray {
+        NetworkUtils.assertProtocol(deviceId.matches("^[A-Z0-9]{7}-[A-Z0-9]{7}-[A-Z0-9]{7}-[A-Z0-9]{7}-[A-Z0-9]{7}-[A-Z0-9]{7}-[A-Z0-9]{7}-[A-Z0-9]{7}$".toRegex()), {"device id syntax error for deviceId = $deviceId"})
+        val base32data = deviceId.replaceFirst("(.{7})-(.{6}).-(.{7})-(.{6}).-(.{7})-(.{6}).-(.{7})-(.{6}).".toRegex(), "$1$2$3$4$5$6$7$8") + "==="
+        val binaryData = Base32().decode(base32data)
+        NetworkUtils.assertProtocol(binaryData.size == SHA256_BYTES)
+        return binaryData
+    }
+
+    companion object {
+
+        private const val DEVICE_ID = "deviceId"
+
+        private const val SHA256_BYTES = 256 / 8
+
+        private fun fromHashDataToString(hashData: ByteArray): String {
+            NetworkUtils.assertProtocol(hashData.size == SHA256_BYTES)
+            val string = Base32().encodeAsString(hashData).replace("=", "")
+            return string.chunked(13).joinToString("") { part -> part + generateLuhn32Checksum(part) }
+        }
+
+        fun fromHashData(hashData: ByteArray): DeviceId {
+            return DeviceId(fromHashDataToString(hashData).chunked(7).joinToString("-"))
+        }
+
+        private fun generateLuhn32Checksum(string: String): Char {
+            val alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567"
+            var factor = 1
+            var sum = 0
+            val n = alphabet.length
+            for (character in string.toCharArray()) {
+                val index = alphabet.indexOf(character)
+                NetworkUtils.assertProtocol(index >= 0)
+                var add = factor * index
+                factor = if (factor == 2) 1 else 2
+                add = add / n + add % n
+                sum += add
+            }
+            val remainder = sum % n
+            val check = (n - remainder) % n
+            return alphabet[check]
+        }
+
+        fun parse(reader: JsonReader): DeviceId {
+            var deviceId: String? = null
+
+            reader.beginObject()
+            while (reader.hasNext()) {
+                when (reader.nextName()) {
+                    DEVICE_ID -> deviceId = reader.nextString()
+                    else -> reader.skipValue()
+                }
+            }
+            reader.endObject()
+
+            return DeviceId(deviceId!!)
+        }
+    }
+
+    fun serialize(writer: JsonWriter) {
+        writer.beginObject()
+        writer.name(DEVICE_ID).value(deviceId)
+        writer.endObject()
+    }
+}

syncthing-core/src/main/kotlin/net/syncthing/java/core/beans/DeviceInfo.kt

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2016 Davide Imbriaco <davide.imbriaco@gmail.com>
+ * Copyright 2018 Jonas Lochmann
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.core.beans
+
+import com.google.gson.stream.JsonReader
+import com.google.gson.stream.JsonWriter
+
+data class DeviceInfo(val deviceId: DeviceId, val name: String, val isConnected: Boolean? = null) {
+
+    companion object {
+        private const val DEVICE_ID = "deviceId"
+        private const val NAME = "name"
+
+        fun parse(reader: JsonReader): DeviceInfo {
+            var deviceId: DeviceId? = null
+            var name: String? = null
+
+            reader.beginObject()
+            while (reader.hasNext()) {
+                when (reader.nextName()) {
+                    DEVICE_ID -> deviceId = DeviceId.parse(reader)
+                    NAME -> name = reader.nextString()
+                    else -> reader.skipValue()
+                }
+            }
+            reader.endObject()
+
+            return DeviceInfo(
+                    deviceId = deviceId!!,
+                    name = name!!
+            )
+        }
+    }
+
+    constructor(deviceId: DeviceId, name: String?) :
+            this(deviceId, if (name != null && !name.isBlank()) name else deviceId.shortId, null)
+
+    fun serialize(writer: JsonWriter) {
+        writer.beginObject()
+
+        writer.name(DEVICE_ID)
+        deviceId.serialize(writer)
+
+        writer.name(NAME).value(name)
+
+        writer.endObject()
+    }
+}

syncthing-core/src/main/kotlin/net/syncthing/java/core/beans/FileBlocks.kt

@@ -0,0 +1,40 @@
+/* 
+ * Copyright (C) 2016 Davide Imbriaco
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.core.beans
+
+import net.syncthing.java.core.utils.BlockUtils
+
+class FileBlocks(val folder: String, val path: String, blocks: List<BlockInfo>) {
+
+    val blocks: List<BlockInfo>
+    val hash: String
+    val size: Long
+
+    init {
+        assert(!folder.isEmpty())
+        assert(!path.isEmpty())
+        this.blocks = blocks.toList()
+        var num: Long = 0
+        for (block in blocks) {
+            num += block.size.toLong()
+        }
+        this.size = num
+        this.hash = BlockUtils.hashBlocks(this.blocks)
+    }
+
+    override fun toString(): String {
+        return "FileBlocks(" + "blocks=" + blocks.size + ", hash=" + hash + ", folder=" + folder + ", path=" + path + ", size=" + size + ")"
+    }
+
+}

syncthing-core/src/main/kotlin/net/syncthing/java/core/beans/FileInfo.kt

@@ -0,0 +1,179 @@
+/* 
+ * Copyright (C) 2016 Davide Imbriaco
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.core.beans
+
+import net.syncthing.java.core.utils.PathUtils
+import org.apache.commons.io.FileUtils
+import java.util.*
+
+class FileInfo(val folder: String, val type: FileType, val path: String, size: Long? = null,
+               lastModified: Date? = Date(0), hash: String? = null, versionList: List<Version>? = null,
+               val isDeleted: Boolean = false) {
+    val fileName: String
+    val parent: String
+    val hash: String?
+    val size: Long?
+    val lastModified: Date
+    val versionList: List<Version>
+
+    fun isDirectory(): Boolean = type == FileType.DIRECTORY
+
+    fun isFile(): Boolean = type == FileType.FILE
+
+    init {
+        assert(!folder.isEmpty())
+        if (PathUtils.isParent(path)) {
+            this.fileName = PathUtils.PARENT_PATH
+            this.parent = PathUtils.ROOT_PATH
+        } else {
+            this.fileName = PathUtils.getFileName(path)
+            this.parent = if (PathUtils.isRoot(path)) PathUtils.ROOT_PATH else PathUtils.getParentPath(path)
+        }
+        this.lastModified = lastModified ?: Date(0)
+        if (type == FileType.DIRECTORY) {
+            this.size = null
+            this.hash = null
+        } else {
+            assert(size != null)
+            assert(!hash.isNullOrEmpty())
+            this.size = size
+            this.hash = hash
+        }
+        this.versionList = versionList ?: emptyList()
+    }
+
+    enum class FileType {
+        FILE, DIRECTORY
+    }
+
+    fun describeSize(): String = if (isFile()) FileUtils.byteCountToDisplaySize(size!!) else ""
+
+    override fun toString(): String {
+        return "FileRecord{" + "folder=" + folder + ", path=" + path + ", size=" + size + ", lastModified=" + lastModified + ", type=" + type + ", last version = " + versionList.lastOrNull() + '}'
+    }
+
+    class Version(val id: Long, val value: Long) {
+
+        override fun toString(): String {
+            return "Version{id=$id, value=$value}"
+        }
+
+    }
+
+    class Builder {
+
+        private var folder: String? = null
+        private var path: String? = null
+        private var hash: String? = null
+        private var size: Long? = null
+        private var lastModified = Date(0)
+        private var type: FileType? = null
+        var versionList: List<Version>? = null
+            private set
+        private var deleted = false
+
+        fun getFolder(): String? {
+            return folder
+        }
+
+        fun setFolder(folder: String): Builder {
+            this.folder = folder
+            return this
+        }
+
+        fun getPath(): String? {
+            return path
+        }
+
+        fun setPath(path: String): Builder {
+            this.path = path
+            return this
+        }
+
+        fun getSize(): Long? {
+            return size
+        }
+
+        fun setSize(size: Long?): Builder {
+            this.size = size
+            return this
+        }
+
+        fun getLastModified(): Date {
+            return lastModified
+        }
+
+        fun setLastModified(lastModified: Date): Builder {
+            this.lastModified = lastModified
+            return this
+        }
+
+        fun getType(): FileType? {
+            return type
+        }
+
+        fun setType(type: FileType): Builder {
+            this.type = type
+            return this
+        }
+
+        fun setTypeFile(): Builder {
+            return setType(FileType.FILE)
+        }
+
+        fun setTypeDir(): Builder {
+            return setType(FileType.DIRECTORY)
+        }
+
+        fun setVersionList(versionList: Iterable<Version>?): Builder {
+            this.versionList = versionList?.toList()
+            return this
+        }
+
+        fun isDeleted(): Boolean {
+            return deleted
+        }
+
+        fun setDeleted(deleted: Boolean): Builder {
+            this.deleted = deleted
+            return this
+        }
+
+        fun getHash(): String? {
+            return hash
+        }
+
+        fun setHash(hash: String): Builder {
+            this.hash = hash
+            return this
+        }
+
+        fun build(): FileInfo {
+            return FileInfo(folder!!, type!!, path!!, size, lastModified, hash, versionList, deleted)
+        }
+
+    }
+
+    companion object {
+
+        fun checkBlocks(fileInfo: FileInfo, fileBlocks: FileBlocks) {
+            assert(fileBlocks.folder == fileInfo.folder, {"file info folder not match file block folder"})
+            assert(fileBlocks.path == fileInfo.path, {"file info path does not match file block path"})
+            assert(fileInfo.isFile(), {"file info must be of type 'FILE' to have blocks"})
+            assert(fileBlocks.size == fileInfo.size, {"file info size does not match file block size"})
+            assert(fileBlocks.hash == fileInfo.hash, {"file info hash does not match file block hash"})
+        }
+    }
+
+}

syncthing-core/src/main/kotlin/net/syncthing/java/core/beans/FolderInfo.kt

@@ -0,0 +1,66 @@
+/* 
+ * Copyright (C) 2016 Davide Imbriaco
+ * Copyright (C) 2018 Jonas Lochmann
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.core.beans
+
+import com.google.gson.stream.JsonReader
+import com.google.gson.stream.JsonWriter
+
+open class FolderInfo(val folderId: String, label: String? = null) {
+    companion object {
+        private const val FOLDER_ID = "folderId"
+        private const val LABEL = "label"
+
+        fun parse(reader: JsonReader): FolderInfo {
+            var folderId: String? = null
+            var label: String? = null
+
+            reader.beginObject()
+            while (reader.hasNext()) {
+                when (reader.nextName()) {
+                    FOLDER_ID -> folderId = reader.nextString()
+                    LABEL -> label = reader.nextString()
+                    else -> reader.skipValue()
+                }
+            }
+            reader.endObject()
+
+            return FolderInfo(
+                    folderId = folderId!!,
+                    label = label!!
+            )
+        }
+    }
+
+    val label: String
+
+    init {
+        assert(!folderId.isEmpty())
+        this.label = if (label != null && !label.isEmpty()) label else folderId
+    }
+
+    override fun toString(): String {
+        return "FolderInfo(folderId=$folderId, label=$label)"
+    }
+
+    fun serialize(writer: JsonWriter) {
+        writer.beginObject()
+
+        writer.name(FOLDER_ID).value(folderId)
+        writer.name(LABEL).value(label)
+
+        writer.endObject()
+    }
+
+}

syncthing-core/src/main/kotlin/net/syncthing/java/core/beans/FolderStats.kt

@@ -0,0 +1,103 @@
+/* 
+ * Copyright (C) 2016 Davide Imbriaco
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.core.beans
+
+import org.apache.commons.io.FileUtils
+
+import java.util.Date
+
+class FolderStats private constructor(val fileCount: Long, val dirCount: Long, val size: Long, val lastUpdate: Date, folder: String, label: String?) : FolderInfo(folder, label) {
+
+    fun getRecordCount(): Long = dirCount + fileCount
+
+    fun describeSize(): String = FileUtils.byteCountToDisplaySize(size)
+
+    fun dumpInfo(): String {
+        return ("folder " + label + " (" + folderId + ") file count = " + fileCount
+                + " dir count = " + dirCount + " folder size = " + describeSize() + " last update = " + lastUpdate)
+    }
+
+    override fun toString(): String {
+        return "FolderStats{folder=$folderId, fileCount=$fileCount, dirCount=$dirCount, size=$size, lastUpdate=$lastUpdate}"
+    }
+
+    fun copyBuilder(): Builder = Builder(fileCount, dirCount, size, folderId, label)
+
+    class Builder {
+
+        private var fileCount: Long = 0
+        private var dirCount: Long = 0
+        private var size: Long = 0
+        private var lastUpdate = Date(0)
+        private var folder: String? = null
+        private var label: String? = null
+
+        constructor()
+
+        constructor(fileCount: Long, dirCount: Long, size: Long, folder: String, label: String) {
+            this.fileCount = fileCount
+            this.dirCount = dirCount
+            this.size = size
+            this.folder = folder
+            this.label = label
+        }
+
+        fun getFileCount(): Long = fileCount
+
+        fun setFileCount(fileCount: Long): Builder {
+            this.fileCount = fileCount
+            return this
+        }
+
+        fun getDirCount(): Long = dirCount
+
+        fun setDirCount(dirCount: Long): Builder {
+            this.dirCount = dirCount
+            return this
+        }
+
+        fun getSize(): Long = size
+
+        fun setSize(size: Long): Builder {
+            this.size = size
+            return this
+        }
+
+        fun getLastUpdate(): Date = lastUpdate
+
+        fun setLastUpdate(lastUpdate: Date): Builder {
+            this.lastUpdate = lastUpdate
+            return this
+        }
+
+        fun getFolder(): String? = folder
+
+        fun setFolder(folder: String): Builder {
+            this.folder = folder
+            return this
+        }
+
+        fun getLabel(): String? = label
+
+        fun setLabel(label: String): Builder {
+            this.label = label
+            return this
+        }
+
+        fun build(): FolderStats {
+            return FolderStats(fileCount, dirCount, size, lastUpdate, folder!!, label)
+        }
+
+    }
+}

syncthing-core/src/main/kotlin/net/syncthing/java/core/beans/IndexInfo.kt

@@ -0,0 +1,111 @@
+/* 
+ * Copyright (C) 2016 Davide Imbriaco
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.core.beans
+
+
+class IndexInfo private constructor(folder: String, val deviceId: String, val indexId: Long, val localSequence: Long, val maxSequence: Long) : FolderInfo(folder) {
+
+    fun getCompleted(): Double = if (maxSequence > 0) localSequence.toDouble() / maxSequence else 0.0
+
+    init {
+        assert(!deviceId.isEmpty())
+    }
+
+    fun copyBuilder(): Builder {
+        return Builder(folderId, indexId, deviceId, localSequence, maxSequence)
+    }
+
+    override fun toString(): String {
+        return "FolderIndexInfo{indexId=$indexId, folder=$folderId, deviceId=$deviceId, localSequence=$localSequence, maxSequence=$maxSequence}"
+    }
+
+    class Builder {
+
+        private var indexId: Long = 0
+        private var deviceId: String? = null
+        private var folder: String? = null
+        private var localSequence: Long = 0
+        private var maxSequence: Long = 0
+
+        internal constructor()
+
+        internal constructor(folder: String, indexId: Long, deviceId: String, localSequence: Long, maxSequence: Long) {
+            assert(!folder.isEmpty())
+            assert(!deviceId.isEmpty())
+            this.folder = folder
+            this.indexId = indexId
+            this.deviceId = deviceId
+            this.localSequence = localSequence
+            this.maxSequence = maxSequence
+        }
+
+        fun getIndexId(): Long {
+            return indexId
+        }
+
+        fun getDeviceId(): String? {
+            return deviceId
+        }
+
+        fun getFolder(): String? {
+            return folder
+        }
+
+        fun getLocalSequence(): Long {
+            return localSequence
+        }
+
+        fun getMaxSequence(): Long {
+            return maxSequence
+        }
+
+        fun setIndexId(indexId: Long): Builder {
+            this.indexId = indexId
+            return this
+        }
+
+        fun setDeviceId(deviceId: String): Builder {
+            this.deviceId = deviceId
+            return this
+        }
+
+        fun setFolder(folder: String): Builder {
+            this.folder = folder
+            return this
+        }
+
+        fun setLocalSequence(localSequence: Long): Builder {
+            this.localSequence = localSequence
+            return this
+        }
+
+        fun setMaxSequence(maxSequence: Long): Builder {
+            this.maxSequence = maxSequence
+            return this
+        }
+
+        fun build(): IndexInfo {
+            return IndexInfo(folder!!, deviceId!!, indexId, localSequence, maxSequence)
+        }
+
+    }
+
+    companion object {
+
+        fun newBuilder(): Builder {
+            return Builder()
+        }
+    }
+
+}

syncthing-core/src/main/kotlin/net/syncthing/java/core/configuration/Config.kt

@@ -0,0 +1,121 @@
+package net.syncthing.java.core.configuration
+
+import com.google.gson.stream.JsonReader
+import com.google.gson.stream.JsonWriter
+import net.syncthing.java.core.beans.DeviceInfo
+import net.syncthing.java.core.beans.FolderInfo
+import java.util.*
+import kotlin.collections.HashSet
+
+data class Config(
+        val peers: Set<DeviceInfo>,
+        val folders: Set<FolderInfo>,
+        val localDeviceName: String,
+        val localDeviceId: String,
+        val discoveryServers: Set<String>,
+        val keystoreAlgorithm: String,
+        val keystoreData: String
+) {
+    companion object {
+        private const val PEERS = "peers"
+        private const val FOLDERS = "folders"
+        private const val LOCAL_DEVICE_NAME = "localDeviceName"
+        private const val LOCAL_DEVICE_ID = "localDeviceId"
+        private const val DISCOVERY_SERVERS = "discoveryServers"
+        private const val KEYSTORE_ALGORITHM = "keystoreAlgorithm"
+        private const val KEYSTORE_DATA = "keystoreData"
+
+        fun parse(reader: JsonReader): Config {
+            var peers: Set<DeviceInfo>? = null
+            var folders: Set<FolderInfo>? = null
+            var localDeviceName: String? = null
+            var localDeviceId: String? = null
+            var discoveryServers: Set<String>? = null
+            var keystoreAlgorithm: String? = null
+            var keystoreData: String? = null
+
+            reader.beginObject()
+            while (reader.hasNext()) {
+                when (reader.nextName()) {
+                    PEERS -> {
+                        val newPeers = HashSet<DeviceInfo>()
+
+                        reader.beginArray()
+                        while (reader.hasNext()) {
+                            newPeers.add(DeviceInfo.parse(reader))
+                        }
+                        reader.endArray()
+
+                        peers = Collections.unmodifiableSet(newPeers)
+                    }
+                    FOLDERS -> {
+                        val newFolders = HashSet<FolderInfo>()
+
+                        reader.beginArray()
+                        while (reader.hasNext()) {
+                            newFolders.add(FolderInfo.parse(reader))
+                        }
+                        reader.endArray()
+
+                        folders = Collections.unmodifiableSet(newFolders)
+                    }
+                    LOCAL_DEVICE_NAME -> localDeviceName = reader.nextString()
+                    LOCAL_DEVICE_ID -> localDeviceId = reader.nextString()
+                    DISCOVERY_SERVERS -> {
+                        val newDiscoveryServers = HashSet<String>()
+
+                        reader.beginArray()
+                        while (reader.hasNext()) {
+                            newDiscoveryServers.add(reader.nextString())
+                        }
+                        reader.endArray()
+
+                        discoveryServers = Collections.unmodifiableSet(newDiscoveryServers)
+                    }
+                    KEYSTORE_ALGORITHM -> keystoreAlgorithm = reader.nextString()
+                    KEYSTORE_DATA -> keystoreData = reader.nextString()
+                    else -> reader.skipValue()
+                }
+            }
+            reader.endObject()
+
+            return Config(
+                    peers = peers!!,
+                    folders = folders!!,
+                    localDeviceName = localDeviceName!!,
+                    localDeviceId = localDeviceId!!,
+                    discoveryServers = discoveryServers!!,
+                    keystoreAlgorithm = keystoreAlgorithm!!,
+                    keystoreData = keystoreData!!
+            )
+        }
+    }
+
+    fun serialize(writer: JsonWriter) {
+        writer.beginObject()
+
+        writer.name(PEERS).beginArray()
+        peers.forEach { it.serialize(writer) }
+        writer.endArray()
+
+        writer.name(FOLDERS).beginArray()
+        folders.forEach { it.serialize(writer) }
+        writer.endArray()
+
+        writer.name(LOCAL_DEVICE_NAME).value(localDeviceName)
+        writer.name(LOCAL_DEVICE_ID).value(localDeviceId)
+
+        writer.name(DISCOVERY_SERVERS).beginArray()
+        discoveryServers.forEach { writer.value(it) }
+        writer.endArray()
+
+        writer.name(KEYSTORE_ALGORITHM).value(keystoreAlgorithm)
+        writer.name(KEYSTORE_DATA).value(keystoreData)
+
+        writer.endObject()
+    }
+
+    // Exclude keystoreData from toString()
+    override fun toString() = "Config(peers=$peers, folders=$folders, localDeviceName=$localDeviceName, " +
+            "localDeviceId=$localDeviceId, discoveryServers=$discoveryServers, keystoreAlgorithm=$keystoreAlgorithm)"
+}

syncthing-core/src/main/kotlin/net/syncthing/java/core/configuration/Configuration.kt

@@ -0,0 +1,148 @@
+package net.syncthing.java.core.configuration
+
+import com.google.gson.stream.JsonReader
+import com.google.gson.stream.JsonWriter
+import net.syncthing.java.core.beans.DeviceId
+import net.syncthing.java.core.beans.DeviceInfo
+import net.syncthing.java.core.beans.FolderInfo
+import net.syncthing.java.core.security.KeystoreHandler
+import org.bouncycastle.util.encoders.Base64
+import org.slf4j.LoggerFactory
+import java.io.File
+import java.io.StringReader
+import java.io.StringWriter
+import java.net.InetAddress
+import java.util.*
+
+class Configuration(configFolder: File = DefaultConfigFolder) {
+
+    private val logger = LoggerFactory.getLogger(javaClass)
+
+    private val configFile = File(configFolder, ConfigFileName)
+    val databaseFolder = File(configFolder, DatabaseFolderName)
+
+    private var isSaved = true
+    private var config: Config
+
+    init {
+        configFolder.mkdirs()
+        databaseFolder.mkdirs()
+        assert(configFolder.isDirectory && configFile.canWrite(), { "Invalid config folder $configFolder" })
+
+        if (!configFile.exists()) {
+            var localDeviceName = InetAddress.getLocalHost().hostName
+            if (localDeviceName.isEmpty() || localDeviceName == "localhost") {
+                localDeviceName = "syncthing-lite"
+            }
+            val keystoreData = KeystoreHandler.Loader().generateKeystore()
+            isSaved = false
+            config = Config(peers = setOf(), folders = setOf(),
+                    localDeviceName = localDeviceName,
+                    discoveryServers = Companion.DiscoveryServers,
+                    localDeviceId = keystoreData.first.deviceId,
+                    keystoreData = Base64.toBase64String(keystoreData.second),
+                    keystoreAlgorithm = keystoreData.third)
+            persistNow()
+        } else {
+            config = Config.parse(JsonReader(StringReader(configFile.readText())))
+
+            // automatic migration if the old config was used
+            if (config.discoveryServers == OldDiscoveryServers) {
+                config = Config(
+                    peers = config.peers,
+                    folders = config.folders,
+                    localDeviceName = config.localDeviceName,
+                    localDeviceId = config.localDeviceId,
+                    discoveryServers = Companion.DiscoveryServers,
+                    keystoreAlgorithm = config.keystoreAlgorithm,
+                    keystoreData = config.keystoreData
+                )
+            }
+        }
+        logger.debug("Loaded config = $config")
+    }
+
+    companion object {
+        private val DefaultConfigFolder = File(System.getProperty("user.home"), ".config/syncthing-java/")
+        private const val ConfigFileName = "config.json"
+        private const val DatabaseFolderName = "database"
+        private val DiscoveryServers = setOf(
+                "discovery.syncthing.net", "discovery-v4.syncthing.net", "discovery-v6.syncthing.net")
+        private val OldDiscoveryServers = setOf(
+                "discovery-v4-1.syncthing.net", "discovery-v4-2.syncthing.net", "discovery-v4-3.syncthing.net",
+                "discovery-v6-1.syncthing.net", "discovery-v6-2.syncthing.net", "discovery-v6-3.syncthing.net")
+    }
+
+    val instanceId = Math.abs(Random().nextLong())
+
+    val localDeviceId: DeviceId
+        get() = DeviceId(config.localDeviceId)
+
+    val discoveryServers: Set<String>
+        get() = config.discoveryServers
+
+    val keystoreData: ByteArray
+        get() = Base64.decode(config.keystoreData)
+
+    val keystoreAlgorithm: String
+        get() = config.keystoreAlgorithm
+
+    val clientName = "syncthing-java"
+
+    val clientVersion = javaClass.`package`.implementationVersion ?: "0.0.0"
+
+    val peerIds: Set<DeviceId>
+        get() = config.peers.map { it.deviceId }.toSet()
+
+    var localDeviceName: String
+        get() = config.localDeviceName
+        set(localDeviceName) {
+            config = config.copy(localDeviceName = localDeviceName)
+            isSaved = false
+        }
+
+    var folders: Set<FolderInfo>
+        get() = config.folders
+        set(folders) {
+            config = config.copy(folders = folders)
+            isSaved = false
+        }
+
+    var peers: Set<DeviceInfo>
+        get() = config.peers
+        set(peers) {
+            config = config.copy(peers = peers)
+            isSaved = false
+        }
+
+    fun persistNow() {
+        persist()
+    }
+
+    fun persistLater() {
+        Thread { persist() }.start()
+    }
+
+    private fun persist() {
+        if (isSaved)
+            return
+
+        config.let {
+            System.out.println("writing config to $configFile")
+            configFile.writeText(
+                    StringWriter().apply {
+                        JsonWriter(this).apply {
+                            setIndent("  ")
+
+                            config.serialize(this)
+                        }
+                    }.toString()
+            )
+            isSaved = true
+        }
+    }
+
+    override fun toString() = "Configuration(peers=$peers, folders=$folders, localDeviceName=$localDeviceName, " +
+            "localDeviceId=${localDeviceId.deviceId}, discoveryServers=$discoveryServers, instanceId=$instanceId, " +
+            "configFile=$configFile, databaseFolder=$databaseFolder)"
+}