/*
 * Copyright 2016 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var Util = require('../util');

/**
 * A proxy class for working around the fact that as soon as a video is play()ed
 * on iOS, Safari auto-fullscreens the video.
 *
 * TODO(smus): The entire raison d'etre for this class is to work around this
 * issue. Once Safari implements some way to suppress this fullscreen player, we
 * can remove this code.
 */
function VideoProxy(videoElement) {
  this.videoElement = videoElement;
  // True if we're currently manually advancing the playhead (only on iOS).
  this.isFakePlayback = false;

  // When the video started playing.
  this.startTime = null;
}

VideoProxy.prototype.play = function() {
  if (Util.isIOS9OrLess()) {
    this.startTime = performance.now();
    this.isFakePlayback = true;

    // Make an audio element to playback just the audio part.
    this.audioElement = new Audio();
    this.audioElement.src = this.videoElement.src;
    this.audioElement.play();
  } else {
    this.videoElement.play().then(function(e) {
      console.log('Playing video.', e);
    });
  }
};

VideoProxy.prototype.pause = function() {
  if (Util.isIOS9OrLess() && this.isFakePlayback) {
    this.isFakePlayback = true;

    this.audioElement.pause();
  } else {
    this.videoElement.pause();
  }
};

VideoProxy.prototype.setVolume = function(volumeLevel) {
  if (this.videoElement) {
    // On iOS 10, the VideoElement.volume property is read-only. So we special
    // case muting and unmuting.
    if (Util.isIOS()) {
      this.videoElement.muted = (volumeLevel === 0);
    } else {
      this.videoElement.volume = volumeLevel;
    }
  }
  if (this.audioElement) {
    this.audioElement.volume = volumeLevel;
  }
};

/**
 * Set the attribute mute of the elements according with the muteState param.
 *
 * @param bool muteState
 */
VideoProxy.prototype.mute = function(muteState) {
  if (this.videoElement) {
    this.videoElement.muted = muteState;
  }
  if (this.audioElement) {
    this.audioElement.muted = muteState;
  }
};

VideoProxy.prototype.getCurrentTime = function() {
  return Util.isIOS9OrLess() ? this.audioElement.currentTime : this.videoElement.currentTime;
};

/**
 *
 * @param {Object} time
 */
VideoProxy.prototype.setCurrentTime = function(time) {
  if (this.videoElement) {
    this.videoElement.currentTime = time.currentTime;
  }
  if (this.audioElement) {
    this.audioElement.currentTime = time.currentTime;
  }
};

/**
 * Called on RAF to progress playback.
 */
VideoProxy.prototype.update = function() {
  // Fakes playback for iOS only.
  if (!this.isFakePlayback) {
    return;
  }
  var duration = this.videoElement.duration;
  var now = performance.now();
  var delta = now - this.startTime;
  var deltaS = delta / 1000;
  this.videoElement.currentTime = deltaS;

  // Loop through the video
  if (deltaS > duration) {
    this.startTime = now;
    this.videoElement.currentTime = 0;
    // Also restart the audio.
    this.audioElement.currentTime = 0;
  }
};

module.exports = VideoProxy;