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

import AVFoundation
import UIKit

class ScannerViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
    
    private let session = AVCaptureSession()
    private var previewLayer: AVCaptureVideoPreviewLayer!

    var didCapture: ((String) -> Void)?

    override func viewDidLoad() {
        super.viewDidLoad()

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

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

        let output = AVCaptureMetadataOutput()

        if (session.canAddOutput(output)) {
            session.addOutput(output)
            output.setMetadataObjectsDelegate(self, queue: .main)
            output.metadataObjectTypes = [.qr]
        } else {
            failed()
            return
        }

        previewLayer = AVCaptureVideoPreviewLayer(session: session)
        previewLayer.frame = view.layer.bounds
        previewLayer.videoGravity = .resizeAspectFill
        view.layer.addSublayer(previewLayer)

        session.startRunning()
    }

    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)
        if !session.isRunning {
            session.startRunning()
        }
    }

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

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

    func found(code: String) {
        DispatchQueue.main.async {
            self.didCapture?(code)
        }
    }

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