/*

    Copyright (C) 2016 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    View controller class to handle video playback.

*/

import UIKit

import AVFoundation

/// View controller that manages the video view and the playback controls for a given AVPlayer.

class PlaybackViewController: UIViewController {

    // MARK: Properties

    @IBOutlet weak var playerView: PlayerView!

    @IBOutlet weak var waitingIndicatorView: UIView!

    @IBOutlet weak var pauseButton: UIButton!

    @IBOutlet weak var playButton: UIButton!

    @IBOutlet weak var playImmediatelyButton: UIButton!

    @IBOutlet weak var automaticWaitingSwitch: UISwitch!

    private var observerContext = 0

    var player : AVPlayer? {

        didSet {

            playerView?.player = player

            // Make sure the players automaticallyWaitsToMinimizeStalling follows the switch in the UI.

            if let player = player, isViewLoaded {

                automaticWaitingSwitch.isOn = player.automaticallyWaitsToMinimizeStalling

            }

        }

    }

    // MARK: UIViewController

    override func viewDidLoad() {

        super.viewDidLoad()

        // Load value for the automatic waiting switch from user defaults.

        automaticWaitingSwitch.isOn = !UserDefaults.standard.bool(forKey: "disableAutomaticWaiting")

        player?.automaticallyWaitsToMinimizeStalling = automaticWaitingSwitch.isOn

        playerView?.player = player

        // We will use this to toggle our waiting indicator view.

        addObserver(self, forKeyPath: #keyPath(PlaybackViewController.player.reasonForWaitingToPlay), options: [.new, .initial], context: &observerContext)

    }

    deinit {

        removeObserver(self, forKeyPath: #keyPath(PlaybackViewController.player.reasonForWaitingToPlay), context: &observerContext)

    }

    // MARK: User Actions

    @IBAction func toggleAutomaticWaiting(_ sender: UISwitch) {

        // Check for the new value of the switch and update AVPlayer property and user defaults

        player?.automaticallyWaitsToMinimizeStalling = automaticWaitingSwitch.isOn

        UserDefaults.standard.set(!automaticWaitingSwitch.isOn, forKey: "disableAutomaticWaiting")

    }

    @IBAction func pause(_ sender: AnyObject?) {

        player?.pause()

    }

    @IBAction func play(_ sender: AnyObject?) {

        player?.play()

    }

    @IBAction func playImmediately(_ sender: AnyObject?) {

        player?.playImmediately(atRate: 1.0)

    }

    // MARK: KVO

    override func observeValue(forKeyPath keyPath: String?, of object: AnyObject?, change: [NSKeyValueChangeKey : AnyObject]?, context: UnsafeMutablePointer<Void>?) {

        guard context == &observerContext else {

            super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)

            return

        }

        if keyPath == #keyPath(AVPlayer.reasonForWaitingToPlay) {

            // Hide the indicator view if we are not waiting to minimize stalls.

            waitingIndicatorView.isHidden = (player?.reasonForWaitingToPlay != AVPlayerWaitingToMinimizeStallsReason)

        }

    }

}