//
//  CommonControllerQR.swift
//  Wallet
//
//  Created by Igor Danich on 03.08.2020.
//  Copyright © 2020 List. All rights reserved.
//

import AVFoundation
import UIKit
import WalletFoundation

final class ScannerViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
    
    typealias OnCaptureClosure = (String) -> Void
    
    private let session = AVCaptureSession()
    private var previewLayer: AVCaptureVideoPreviewLayer!

    var didCapture: OnCaptureClosure?

    override func viewDidLoad() {
        super.viewDidLoad()

        self.view.backgroundColor = Asset.snow.color
        
        guard let videoCaptureDevice = AVCaptureDevice.default(for: .video) else { return }
        let videoInput: AVCaptureDeviceInput
        do {
            videoInput = try AVCaptureDeviceInput(device: videoCaptureDevice)
        } catch {
            self.failed()
            return
        }

        if self.session.canAddInput(videoInput) {
            self.session.addInput(videoInput)
        } else {
            self.failed()
            return
        }

        let output = AVCaptureMetadataOutput()

        if self.session.canAddOutput(output) {
            self.session.addOutput(output)
            output.setMetadataObjectsDelegate(self, queue: .main)
            output.metadataObjectTypes = [.qr]
        } else {
            self.failed()
            return
        }
        
        self.previewLayer = AVCaptureVideoPreviewLayer(session: self.session)
        self.previewLayer.frame = self.view.bounds
        self.previewLayer.videoGravity = .resizeAspectFill
        self.view.layer.addSublayer(self.previewLayer)
        
        DispatchQueue.global(qos: .background).async { [weak self] in
            self?.session.startRunning()
        }
    }

    private func failed() {
        Alert.system(
            title: "Scanning not supported",
            text: "Your device does not support scanning a code from an item. Please use a device with a camera."
        )
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        
        self.navigationController >>- {
            $0.navigationBar.backgroundColor = .clear
            $0.navigationBar.isTranslucent = true
        }
        
        if !self.session.isRunning {
            self.session.startRunning()
        }
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        if self.session.isRunning {
            self.session.stopRunning()
        }
    }

    func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) {
        self.session.stopRunning()
        guard let string = (metadataObjects.first as? AVMetadataMachineReadableCodeObject)?.stringValue else { return }
        AudioServicesPlaySystemSound(SystemSoundID(kSystemSoundID_Vibrate))
        self.found(code: string)
    }

    private func found(code: String) {
        DispatchQueue.main.async { [weak self] in
            self?.didCapture?(code)
        }
    }

    override var prefersStatusBarHidden: Bool { true }
    override var supportedInterfaceOrientations: UIInterfaceOrientationMask { .portrait }
}