CameraVC-PartOne.swift

class ViewController: UIViewController, HandSwiperDelegate{    
    
    //MARK: - Properties
    var modelData = [DataModel(bgColor: .systemYellow),
                         DataModel(bgColor: .systemBlue),
                         DataModel(bgColor: .systemRed),
                         DataModel(bgColor: .systemTeal),
                         DataModel(bgColor: .systemOrange),
                         DataModel(bgColor: .brown)]
    
    var stackContainer : StackContainerView!
    
    
    var buttonStackView: UIStackView!
    var leftButton : UIButton!, rightButton : UIButton!
    var cameraView : CameraView!
    
    //MARK: - Init
    override func loadView() {
        view = UIView()
        stackContainer = StackContainerView()
        view.addSubview(stackContainer)
        configureStackContainer()
        stackContainer.translatesAutoresizingMaskIntoConstraints = false
        
        addButtons()
        configureNavigationBarButtonItem()
        addCameraView()
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        title = "HandPoseSwipe"
        stackContainer.dataSource = self
    }
    
    private let videoDataOutputQueue = DispatchQueue(label: "CameraFeedDataOutput", qos: .userInteractive)
    private var cameraFeedSession: AVCaptureSession?
    private var handPoseRequest = VNDetectHumanHandPoseRequest()
    let message = UILabel()
    var handDelegate : HandSwiperDelegate?
    
    func addCameraView()
    {
        cameraView = CameraView()
        self.handDelegate = self
        view.addSubview(cameraView)
        
        cameraView.translatesAutoresizingMaskIntoConstraints = false
        cameraView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
        cameraView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        cameraView.widthAnchor.constraint(equalToConstant: 150).isActive = true
        cameraView.heightAnchor.constraint(equalToConstant: 150).isActive = true
    }
    
    //MARK: - Configurations
    func configureStackContainer() {
        stackContainer.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        stackContainer.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: -60).isActive = true
        stackContainer.widthAnchor.constraint(equalToConstant: 300).isActive = true
        stackContainer.heightAnchor.constraint(equalToConstant: 400).isActive = true
    }
    
    func addButtons()
    {
        //full source of UI setup at the end of this article
    }

    @objc func onButtonPress(sender: UIButton){
        
        
        UIView.animate(withDuration: 2.0,
                                   delay: 0,
                                   usingSpringWithDamping: CGFloat(0.20),
                                   initialSpringVelocity: CGFloat(6.0),
                                   options: UIView.AnimationOptions.allowUserInteraction,
                                   animations: {
                                    sender.transform = CGAffineTransform.identity
                                   },
                                   completion: { Void in()  })
        
        if let firstView = stackContainer.subviews.last as? TinderCardView{
            if sender.tag == 0{
                firstView.leftSwipeClicked(stackContainerView: stackContainer)
            }
            else{
                firstView.rightSwipeClicked(stackContainerView: stackContainer)
            }
        }
    }
    
    func configureNavigationBarButtonItem() {
        navigationItem.rightBarButtonItem = UIBarButtonItem(title: "Reset", style: .plain, target: self, action: #selector(resetTapped))
    }
    
    @objc func resetTapped() {
        stackContainer.reloadData()
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        do {
            if cameraFeedSession == nil {
                cameraView.previewLayer.videoGravity = .resizeAspectFill
                try setupAVSession()
                cameraView.previewLayer.session = cameraFeedSession
            }
            cameraFeedSession?.startRunning()
        } catch {
            AppError.display(error, inViewController: self)
        }
    }
    
    override func viewWillDisappear(_ animated: Bool) {
        cameraFeedSession?.stopRunning()
        super.viewWillDisappear(animated)
    }
    
    func setupAVSession() throws {
        // Select a front facing camera, make an input.
        guard let videoDevice = AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: .front) else {
            throw AppError.captureSessionSetup(reason: "Could not find a front facing camera.")
        }
        
        guard let deviceInput = try? AVCaptureDeviceInput(device: videoDevice) else {
            throw AppError.captureSessionSetup(reason: "Could not create video device input.")
        }
        
        let session = AVCaptureSession()
        session.beginConfiguration()
        session.sessionPreset = AVCaptureSession.Preset.high
        
        // Add a video input.
        guard session.canAddInput(deviceInput) else {
            throw AppError.captureSessionSetup(reason: "Could not add video device input to the session")
        }
        session.addInput(deviceInput)
        
        let dataOutput = AVCaptureVideoDataOutput()
        if session.canAddOutput(dataOutput) {
            session.addOutput(dataOutput)
            // Add a video data output.
            dataOutput.alwaysDiscardsLateVideoFrames = true
            dataOutput.videoSettings = [kCVPixelBufferPixelFormatTypeKey as String: Int(kCVPixelFormatType_420YpCbCr8BiPlanarFullRange)]
            dataOutput.setSampleBufferDelegate(self, queue: videoDataOutputQueue)
        } else {
            throw AppError.captureSessionSetup(reason: "Could not add video data output to the session")
        }
        session.commitConfiguration()
        cameraFeedSession = session
    }
    
}