Function to check the appropriate camera permissions have been provided.

checkCameraPermissions.swift

    //        MARK: Checks for permisions, setup obeservers and starts running session
    public func checkForPermissions() {
        /*
         Check the video authorization status. Video access is required and audio
         access is optional. If the user denies audio access, CameraService won't
         record audio during movie recording.
         */
        switch AVCaptureDevice.authorizationStatus(for: .video) {
        case .authorized:
            // The user has previously granted access to the camera.
            break
        case .notDetermined:
            /*
             The user has not yet been presented with the option to grant
             video access. Suspend the session queue to delay session
             setup until the access request has completed.
             
             Note that audio access will be implicitly requested when we
             create an AVCaptureDeviceInput for audio during session setup.
             */
            sessionQueue.suspend()
            AVCaptureDevice.requestAccess(for: .video, completionHandler: { granted in
                if !granted {
                    self.setupResult = .notAuthorized
                }
                self.sessionQueue.resume()
            })
            
        default:
            // The user has previously denied access.
            setupResult = .notAuthorized
            
            DispatchQueue.main.async {
                self.alertError = AlertError(title: "Camera Access", message: "SwiftCamera does not have permissions to use the camera, please update your settings", primaryButtonTitle: "Configuración", secondaryButtonTitle: nil, primaryAction: {
                        UIApplication.shared.open(URL(string: UIApplication.openSettingsURLString)!,
                                                  options: [:], completionHandler: nil)
                    
                }, secondaryAction: nil)
                self.shouldShowAlertView = true
                self.isCameraUnavailable = true
                self.isCameraButtonDisabled = true
            }
        }
    }