/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 */

#include "ags/shared/core/assetmanager.h"
#include "ags/shared/util/misc.h" // ci_fopen
#include "ags/shared/util/multifilelib.h"
#include "ags/shared/util/path.h"
#include "ags/shared/util/string_utils.h"

namespace AGS3 {
namespace AGS {
namespace Shared {

AssetLocation::AssetLocation()
	: Offset(0)
	, Size(0) {
}


AssetManager *AssetManager::_theAssetManager = nullptr;

/* static */ bool AssetManager::CreateInstance() {
	// Issue a warning - recreating asset manager is not a normal behavior
	assert(_theAssetManager == NULL);
	delete _theAssetManager;
	_theAssetManager = new AssetManager();
	_theAssetManager->SetSearchPriority(kAssetPriorityDir);
	return _theAssetManager != nullptr; // well, we should return _something_
}

/* static */ void AssetManager::DestroyInstance() {
	delete _theAssetManager;
	_theAssetManager = nullptr;
}

AssetManager::~AssetManager() {
	delete &_assetLib;
}

/* static */ bool AssetManager::SetSearchPriority(AssetSearchPriority priority) {
	assert(_theAssetManager != NULL);
	return _theAssetManager ? _theAssetManager->_SetSearchPriority(priority) : false;
}

/* static */ AssetSearchPriority AssetManager::GetSearchPriority() {
	assert(_theAssetManager != NULL);
	return _theAssetManager ? _theAssetManager->_GetSearchPriority() : kAssetPriorityUndefined;
}

/* static */ bool AssetManager::IsDataFile(const String &data_file) {
	Stream *in = ci_fopen(data_file, Shared::kFile_Open, Shared::kFile_Read);
	if (in) {
		MFLUtil::MFLError err = MFLUtil::TestIsMFL(in, true);
		delete in;
		return err == MFLUtil::kMFLNoError;
	}
	return false;
}

AssetError AssetManager::ReadDataFileTOC(const String &data_file, AssetLibInfo &lib) {
	Stream *in = ci_fopen(data_file, Shared::kFile_Open, Shared::kFile_Read);
	return ReadDataFileTOC(in, lib);
}

AssetError AssetManager::ReadDataFileTOC(Stream *in, AssetLibInfo &lib) {
	if (in) {
		MFLUtil::MFLError err = MFLUtil::ReadHeader(lib, in);
		delete in;
		return (err != MFLUtil::kMFLNoError) ? kAssetErrLibParse : kAssetNoError;
	}

	return kAssetErrNoLibFile;
}

/* static */ AssetError AssetManager::SetDataFile(const String &data_file) {
	assert(_theAssetManager != NULL);
	return _theAssetManager ? _theAssetManager->_SetDataFile(data_file) : kAssetErrNoManager;
}

/* static */ String AssetManager::GetLibraryForAsset(const String &asset_name) {
	assert(_theAssetManager != NULL);
	return _theAssetManager ? _theAssetManager->_GetLibraryForAsset(asset_name) : "";
}

/* static */ soff_t AssetManager::GetAssetOffset(const String &asset_name) {
	assert(_theAssetManager != NULL);
	return _theAssetManager ? _theAssetManager->_GetAssetOffset(asset_name) : 0;
}

/* static */ soff_t AssetManager::GetAssetSize(const String &asset_name) {
	assert(_theAssetManager != NULL);
	return _theAssetManager ? _theAssetManager->_GetAssetSize(asset_name) : 0;
}

/* static */ soff_t AssetManager::GetLastAssetSize() {
	assert(_theAssetManager != NULL);
	return _theAssetManager ? _theAssetManager->_GetLastAssetSize() : 0;
}

/* static */ int AssetManager::GetAssetCount() {
	assert(_theAssetManager != NULL);
	return _theAssetManager ? _theAssetManager->_GetAssetCount() : 0;
}

/* static */ String AssetManager::GetAssetFileByIndex(int index) {
	assert(_theAssetManager != NULL);
	return _theAssetManager ? _theAssetManager->_GetAssetFileByIndex(index) : "";
}

/* static */ String AssetManager::GetLibraryBaseFile() {
	assert(_theAssetManager != NULL);
	return _theAssetManager ? _theAssetManager->_GetLibraryBaseFile() : "";
}

/* static */ const AssetLibInfo *AssetManager::GetLibraryTOC() {
	assert(_theAssetManager != NULL);
	return _theAssetManager ? &_theAssetManager->_GetLibraryTOC() : nullptr;
}

/* static */ bool AssetManager::GetAssetLocation(const String &asset_name, AssetLocation &loc) {
	assert(_theAssetManager != NULL);
	return _theAssetManager ? _theAssetManager->GetAssetByPriority(asset_name, loc, kFile_Open, kFile_Read) : false;
}

/* static */ bool AssetManager::DoesAssetExist(const String &asset_name) {
	assert(_theAssetManager != NULL);
	if (!_theAssetManager) {
		return false;
	}
	return _theAssetManager->_DoesAssetExist(asset_name);
}

/* static */ Stream *AssetManager::OpenAsset(const String &asset_name,
	FileOpenMode open_mode,
	FileWorkMode work_mode) {
	assert(_theAssetManager != NULL);
	if (!_theAssetManager) {
		return nullptr;
	}
	return _theAssetManager->OpenAssetAsStream(asset_name, open_mode, work_mode);
}

AssetManager::AssetManager()
	: _assetLib(*new AssetLibInfo())
	, _searchPriority(kAssetPriorityDir)
	, _lastAssetSize(0) {
}

bool AssetManager::_SetSearchPriority(AssetSearchPriority priority) {
	_searchPriority = priority;
	return true;
}

AssetSearchPriority AssetManager::_GetSearchPriority() {
	return _searchPriority;
}

AssetError AssetManager::_SetDataFile(const String &data_file) {
	if (data_file.IsEmpty()) {
		return kAssetErrNoLibFile;
	}
	if (Path::ComparePaths(_assetLib.BaseFilePath, data_file) == 0) {
		return kAssetNoError;
	}
	AssetError err = RegisterAssetLib(data_file, "");
	return err;
}

String AssetManager::_GetLibraryForAsset(const String &asset_name) {
	if (asset_name.IsEmpty()) {
		return "";
	}
	AssetInfo *asset = FindAssetByFileName(asset_name);
	if (!asset) {
		// asset not found
		return "";
	}

	return MakeLibraryFileNameForAsset(asset);
}

soff_t AssetManager::_GetAssetOffset(const String &asset_name) {
	if (asset_name.IsEmpty()) {
		return -1;
	}
	AssetInfo *asset = FindAssetByFileName(asset_name);
	if (asset) {
		return asset->Offset;
	}
	return -1;
}

soff_t AssetManager::_GetAssetSize(const String &asset_name) {
	if (asset_name.IsEmpty()) {
		return -1;
	}
	AssetInfo *asset = FindAssetByFileName(asset_name);
	if (asset) {
		return asset->Size;
	}
	return -1;
}

soff_t AssetManager::_GetLastAssetSize() {
	return _lastAssetSize;
}

int AssetManager::_GetAssetCount() {
	return _assetLib.AssetInfos.size();
}

String AssetManager::_GetAssetFileByIndex(int index) {
	if ((index < 0) || ((size_t)index >= _assetLib.AssetInfos.size()))
		return nullptr;

	return _assetLib.AssetInfos[index].FileName;
}

String AssetManager::_GetLibraryBaseFile() {
	return _assetLib.BaseFileName;
}

const AssetLibInfo &AssetManager::_GetLibraryTOC() const {
	return _assetLib;
}

bool AssetManager::_DoesAssetExist(const String &asset_name) {
	return FindAssetByFileName(asset_name) != nullptr ||
		File::TestReadFile(asset_name);
}

AssetError AssetManager::RegisterAssetLib(const String &data_file, const String &password) {
	// base path is current directory
	_basePath = ".";

	// open data library
	Stream *in = ci_fopen(data_file, Shared::kFile_Open, Shared::kFile_Read);
	if (!in)
		return kAssetErrNoLibFile; // can't be opened, return error code

	// read MultiFileLibrary header (CLIB)
	// PSP: allocate struct on the heap to avoid overflowing the stack.
	MFLUtil::MFLError mfl_err = MFLUtil::ReadHeader(_assetLib, in);
	delete in;

	if (mfl_err != MFLUtil::kMFLNoError) {
		_assetLib.Unload();
		return kAssetErrLibParse;
	}

	// fixup base library filename
	String nammwas = data_file;
	String data_file_fixed = data_file;
	// TODO: this algorythm should be in path/string utils
	data_file_fixed.TruncateToRightSection('\\');
	data_file_fixed.TruncateToRightSection('/');
	if (data_file_fixed.Compare(nammwas) != 0) {
		// store complete path
		_basePath = nammwas;
		_basePath.TruncateToLeft(nammwas.GetLength() - data_file_fixed.GetLength());
		_basePath.TrimRight('\\');
		_basePath.TrimRight('/');
	}

	// set library filename
	_assetLib.LibFileNames[0] = data_file_fixed;
	// make a lowercase backup of the original file name
	_assetLib.BaseFileName = data_file_fixed;
	_assetLib.BaseFileName.MakeLower();
	_assetLib.BaseFilePath = Path::MakeAbsolutePath(data_file);
	return kAssetNoError;
}

AssetInfo *AssetManager::FindAssetByFileName(const String &asset_name) {
	for (size_t i = 0; i < _assetLib.AssetInfos.size(); ++i) {
		if (_assetLib.AssetInfos[i].FileName.CompareNoCase(asset_name) == 0) {
			return &_assetLib.AssetInfos[i];
		}
	}
	return nullptr;
}

String AssetManager::MakeLibraryFileNameForAsset(const AssetInfo *asset) {
	// deduce asset library file containing this asset
	return String::FromFormat("%s/%s", _basePath.GetCStr(), _assetLib.LibFileNames[asset->LibUid].GetCStr());
}

bool AssetManager::GetAssetFromLib(const String &asset_name, AssetLocation &loc, FileOpenMode open_mode, FileWorkMode work_mode) {
	if (open_mode != Shared::kFile_Open || work_mode != Shared::kFile_Read)
		return false; // creating/writing is allowed only for common files on disk

	AssetInfo *asset = FindAssetByFileName(asset_name);
	if (!asset)
		return false; // asset not found

	String libfile = cbuf_to_string_and_free(ci_find_file(nullptr, MakeLibraryFileNameForAsset(asset)));
	if (libfile.IsEmpty())
		return false;
	loc.FileName = libfile;
	loc.Offset = asset->Offset;
	loc.Size = asset->Size;
	return true;
}

bool AssetManager::GetAssetFromDir(const String &file_name, AssetLocation &loc, FileOpenMode open_mode, FileWorkMode work_mode) {
	String exfile = cbuf_to_string_and_free(ci_find_file(nullptr, file_name));
	if (exfile.IsEmpty() || !Path::IsFile(exfile))
		return false;
	loc.FileName = exfile;
	loc.Offset = 0;
	loc.Size = File::GetFileSize(exfile);
	return true;
}

bool AssetManager::GetAssetByPriority(const String &asset_name, AssetLocation &loc, FileOpenMode open_mode, FileWorkMode work_mode) {
	if (_searchPriority == kAssetPriorityDir) {
		// check for disk, otherwise use datafile
		return GetAssetFromDir(asset_name, loc, open_mode, work_mode) ||
			GetAssetFromLib(asset_name, loc, open_mode, work_mode);
	} else if (_searchPriority == kAssetPriorityLib) {
		// check datafile first, then scan directory
		return GetAssetFromLib(asset_name, loc, open_mode, work_mode) ||
			GetAssetFromDir(asset_name, loc, open_mode, work_mode);
	}
	return false;
}

Stream *AssetManager::OpenAssetAsStream(const String &asset_name, FileOpenMode open_mode, FileWorkMode work_mode) {
	AssetLocation loc;
	if (GetAssetByPriority(asset_name, loc, open_mode, work_mode)) {
		Stream *s = File::OpenFile(loc.FileName, open_mode, work_mode);
		if (s) {
			s->Seek(loc.Offset, kSeekBegin);
			_lastAssetSize = loc.Size;
		}
		return s;
	}
	return nullptr;
}


String GetAssetErrorText(AssetError err) {
	switch (err) {
	case kAssetNoError:
		return "No error.";
	case kAssetErrNoLibFile:
		return "Asset library file not found or could not be opened.";
	case kAssetErrLibParse:
		return "Not an asset library or unsupported format.";
	case kAssetErrNoManager:
		return "Asset manager is not initialized.";
	}
	return "Unknown error.";
}

} // namespace Shared
} // namespace AGS
} // namespace AGS3