import ReplayKit
import os.log

// MARK: - Protocol

/// Protocol to add Replay Kit Screen Recording to any UIViewController
/// Example:
/// ~~~
/// class MainViewController: UIViewController, ReplayKitScreenRecorder {
///
/// // MARK: - ReplayKitScreenRecorder Properties
///
/// internal let recorder = RPScreenRecorder.shared()
///
/// ...
///
/// if recordVideoOfSession.isOn {
///     startRecording()
/// }
///
/// ...
///
/// if self.recordVideoOfSession.isOn {
///     stopRecording()
/// }
/// ~~~

public protocol ReplayKitScreenRecorder: UIViewController, RPPreviewViewControllerDelegate {

    var recorder: RPScreenRecorder { get }

    func startRecording()
    func stopRecording()
}

// MARK: - Default Implementation

extension ReplayKitScreenRecorder {

    /// Default implementation for starting screen recording
    /// Example:
    ///         if recordVideoOfSession.isOn {
    ///             startRecording()
    ///         }
    public func startRecording() {

        guard recorder.isAvailable else {
            os_log(.info, log: .recorder, "ReplayKit Recorder is not available")
            return
        }

        recorder.isMicrophoneEnabled = false

        recorder.startRecording { error in

            guard error == nil else {
                os_log(.error, log: .recorder, "Error starting the recording: '%@'",
                       error?.localizedDescription ?? "")
                return
            }

            os_log(.info, log: .recorder, "Started recording")
        }

    }

    /// Default implementation for stopping screen recording and saving / editing or deleting the video
    /// Example:
    ///         if self.recordVideoOfSession.isOn {
    ///             stopRecording()
    ///         }
    public func stopRecording() {

        recorder.stopRecording { viewController, error in
            os_log(.info, log: .recorder, "Stopped recording")

            if error != nil {
                os_log(.error, log: .recorder, "Error: stopping the recording: '%@'",
                       error?.localizedDescription ?? "")
            }

            guard let preview = viewController else {
                os_log(.error, log: .recorder, "Preview controller is not available")
                return
            }

            let alert = UIAlertController(title: Localized.alertTitle,
                                          message: Localized.alertMessage,
                                          preferredStyle: .actionSheet)

            let deleteAction = UIAlertAction(title: Localized.deleteTitle, style: .destructive) { _ in
                self.recorder.discardRecording  {
                    os_log(.info, log: .recorder, "Recording deleted")
                }
            }

            let editAction = UIAlertAction(title: Localized.editTitle, style: .default) { _ in
                os_log(.info, log: .recorder, "Will present Recording edit and save view controller")

                preview.previewControllerDelegate = self
                self.present(preview, animated: true, completion: nil)
            }

            alert.addAction(editAction)
            alert.addAction(deleteAction)
            os_log(.info, log: .recorder, "Will present Recording edit or delete action sheet")
            self.present(alert, animated: true, completion: nil)
        }
    }

    private typealias Localized = ScreenRecorderLocalizedString
}

// MARK: - Localized Strings

enum ScreenRecorderLocalizedString {

    static let alertTitle = NSLocalizedString("ddsu_recording_action_sheet_title",
        value: "Recording Finished",
      comment: "The title for screen recorder finished recording action sheet")

    static let alertMessage = NSLocalizedString("ddsu_recording_action_sheet_message",
        value: "Would you like to edit or delete your recording?",
      comment: "The title for screen recorder finished recording action sheet")

    static let editTitle  = NSLocalizedString("ddsu_recording_action_sheet_edit",
        value: "Save or Edit",
      comment: "The title for edit/save button in screen recorder finished recording action sheet")

    static let deleteTitle = NSLocalizedString("ddsu_recording_action_sheet_delete",
        value: "Delete",
      comment: "The title for delete button in screen recorder finished recording action sheet")

}

// MARK: - RPPreviewViewControllerDelegate Support

extension UIViewController {

    @nonobjc func previewControllerDidFinish(_ previewController: RPPreviewViewController) {
        os_log(.info, log: .recorder, "Recording preview controller finished")
        dismiss(animated: true)
     }
}

extension OSLog {
    /// Custom Log object to use when logging **Screen Recorder Lifecycle events**.
    fileprivate static let recorder = OSLog(subsystem: subsystem, category: "Screen Recorder")
}