SecondViewController.swift

//
//  ViewController.swift
//  QRCodeScanner
//
//  Created by Jeffrey Paulraj on 4/1/19.
//  Copyright © 2019 Jeffrey Paulraj. All rights reserved.
//

import UIKit
import AVFoundation

class SecondViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
    @IBOutlet weak var ArrowButton: UIButton!
    
    public static var count = 0;
    
    var video = AVCaptureVideoPreviewLayer()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        
        let session = AVCaptureSession()
        
        guard let captureDevice = AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: .back) else { return  }
        
        do
        {
            let input = try AVCaptureDeviceInput(device: captureDevice)
            session.addInput(input)
        }
        catch{
            print("Error")
        }
        
        let output = AVCaptureMetadataOutput()
        session.addOutput(output)
        
        output.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
        
        output.metadataObjectTypes = [AVMetadataObject.ObjectType.qr]
        
        video = AVCaptureVideoPreviewLayer(session: session)
        video.frame = view.layer.bounds
        view.layer.addSublayer(video)
        
        view.bringSubviewToFront(ArrowButton)
        session.startRunning()
    
    }
    
    func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) {
        if metadataObjects.count != 0
        {
            if let object = metadataObjects[0] as? AVMetadataMachineReadableCodeObject
            {
                if object.type == AVMetadataObject.ObjectType.qr
                {
                    count += 1
                    
                    let alert = UIAlertController(title: "QR Code", message: object.stringValue, preferredStyle: .alert)
                    alert.addAction(UIAlertAction(title: "Retake", style: .default, handler: nil))
                    alert.addAction(UIAlertAction(title: "Copy to Clipboard", style: .default, handler: { (nil) in
                        UIPasteboard.general.string = object.stringValue
                    }))
                    
                    present(alert, animated: true, completion: nil)
                }
            }
        }
    }
    
}