// How to use this script:
// (1) Create a new AR Studio project
// (2) Add a plane, assign it a material
// (3) Attach an ExternalTexture to the newly created material
// (4) Add an audio source
// (5) Add ExternalVideo capability and whitelist the video domain
// (6) Add a script, paste this code
// (7) Create a new video: var video = new Video('url', texture, audio);
// (8) Call video.play() / video.stop() somewhere in the script

var S = require('Scene');
var D = require('Diagnostics');
var T = require('Textures');
var Time = require('Time');

/**
 * A Video entity that enables you to play a video with some sounds.
 * 
 * @param {!string} videoUrl - url of video (require TLS)
 * @param {!ExternalTexture} videoTexture - the external texture object from the scene
 * @param {AudioSource=} audioSource - the audio source object from the scene
 * @param {boolean=} autoPlay - whether to play the video right after it's created
 */
function Video(videoUrl, videoTexture, audioSource, autoPlay) {
  this.id = Video.id++;

  this.videoTexture = videoTexture;
  this.videoUrl = videoUrl;
  this.audioSource = audioSource;
  this.deferAudioPlaying = false;
  this.audioTimer = null;
  this.playing = false;

  this.mode = Video.mode.PLAY_AUDIO_RIGHT_AFTER_AVAIL_EVENT;
  this.delayAudioMs = 1000;
  // ^ Change those parameters to experiment:
  // Use PLAY_AUDIO_AFTER_CUSTOM_DELAY to call setTimeout with "delayAudioMs"

  var that = this;
  this.videoTexture.state.monitor().subscribe(function (event) {
    D.log('Video' + that.id + ': received texture event "' + event.newValue + '"');

    if (event.newValue === T.ExternalTexture.State.AVAILABLE) {
      if (that.deferAudioPlaying) {
        that.deferAudioPlaying = false;

        // At this point there are 3 things I noted:
        // (1) the video will actually play after a delay (about 1s)
        // (2) *sometimes*, the audio will play after a long delay after we do audioSource.play() (about 10s)
        // (3) if the audio is delayed once, then it won't be delayed the next time you play it!

        if (that.mode === Video.mode.PLAY_AUDIO_RIGHT_AFTER_AVAIL_EVENT) {
          D.log('Video' + that.id + ': now play the sound');
          that.audioSource.play();

        } else if (that.mode === Video.mode.PLAY_AUDIO_AFTER_CUSTOM_DELAY) {
          var startDate = Date.now();

          that.audioTimer = Time.setTimeout(function () {
            that.audioSource.play();
            var delay = Date.now() - startDate;
            D.log('Video' + that.id + ': audio.play() was called after a ' + delay + 'ms delay');
          }, that.delayAudioMs);
        }
      }
    } else if (event.newValue === T.ExternalTexture.State.PENDING) {
      // Pause sound (in theory)
    }
  });

  if (autoPlay) this.play();
}

Video.id = 0;

Video.mode = {
  PLAY_AUDIO_RIGHT_AFTER_AVAIL_EVENT: 1,
  PLAY_AUDIO_AFTER_CUSTOM_DELAY: 2
};

/** Play the video object with audio */
Video.prototype.play = function () {
  if (this.playing) return;
  this.videoTexture.url = this.videoUrl;

  if (this.audioSource) this.deferAudioPlaying = true;

  this.playing = true;
};

/** Stop the video and the audio. */
Video.prototype.stop = function () {
  if (!this.playing) return;
  this.videoTexture.url = '';

  if (this.audioSource) this.audioSource.stopAll();
  if (this.audioTimer) {
    Time.clearInterval(this.audioTimer);
    this.audioTimer = null;
  }
  this.deferAudioPlaying = false;

  this.playing = false;
};

Video.prototype.pause = function () {
  D.log('There is no way to pause a video right now.');
};