Capture session configuration

captureSessionConfig.swift

    //  MARK: Session Managment
    
    // Call this on the session queue.
    /// - Tag: ConfigureSession
    private func configureSession() {
        if setupResult != .success {
            return
        }
        
        session.beginConfiguration()
        
        session.sessionPreset = .photo
        
        // Add video input.
        do {
            var defaultVideoDevice: AVCaptureDevice?
            
            if let backCameraDevice = AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: .back) {
                // If a rear dual camera is not available, default to the rear wide angle camera.
                defaultVideoDevice = backCameraDevice
            } else if let frontCameraDevice = AVCaptureDevice.default(.builtInWideAngleCamera, for: .video, position: .front) {
                // If the rear wide angle camera isn't available, default to the front wide angle camera.
                defaultVideoDevice = frontCameraDevice
            }
            
            guard let videoDevice = defaultVideoDevice else {
                print("Default video device is unavailable.")
                setupResult = .configurationFailed
                session.commitConfiguration()
                return
            }
            
            let videoDeviceInput = try AVCaptureDeviceInput(device: videoDevice)
            
            if session.canAddInput(videoDeviceInput) {
                session.addInput(videoDeviceInput)
                self.videoDeviceInput = videoDeviceInput
                
            } else {
                print("Couldn't add video device input to the session.")
                setupResult = .configurationFailed
                session.commitConfiguration()
                return
            }
        } catch {
            print("Couldn't create video device input: \(error)")
            setupResult = .configurationFailed
            session.commitConfiguration()
            return
        }
        
        // Add the photo output.
        if session.canAddOutput(photoOutput) {
            session.addOutput(photoOutput)
            
            photoOutput.isHighResolutionCaptureEnabled = true
            photoOutput.maxPhotoQualityPrioritization = .quality
            
        } else {
            print("Could not add photo output to the session")
            setupResult = .configurationFailed
            session.commitConfiguration()
            return
        }
        
        session.commitConfiguration()
        self.isConfigured = true
        
        self.start()
    }