/** @namespace H5P */
H5P.VideoHtml5 = (function ($) {

  /**
   * HTML5 video player for H5P.
   *
   * @class
   * @param {Array} sources Video files to use
   * @param {Object} options Settings for the player
   * @param {Object} l10n Localization strings
   */
  function Html5(sources, options, l10n) {
    var self = this;

    /**
     * Small helper to ensure all video sources get the same cache buster.
     *
     * @private
     * @param {Object} source
     * @return {string}
     */
    const getCrossOriginPath = function (source) {
      let path = H5P.getPath(source.path, self.contentId);
      if (video.crossOrigin !== null && H5P.addQueryParameter && H5PIntegration.crossoriginCacheBuster) {
        path = H5P.addQueryParameter(path, H5PIntegration.crossoriginCacheBuster);
      }
      return path
    };


    /**
     * Register track to video
     *
     * @param {Object} trackData Track object
     * @param {string} trackData.kind Kind of track
     * @param {Object} trackData.track Source path
     * @param {string} [trackData.label] Label of track
     * @param {string} [trackData.srcLang] Language code
     */
    const addTrack = function (trackData) {
      // Skip invalid tracks
      if (!trackData.kind || !trackData.track.path) {
        return;
      }

      var track = document.createElement('track');
      track.kind = trackData.kind;
      track.src = getCrossOriginPath(trackData.track); // Uses same crossOrigin as parent. You cannot mix.
      if (trackData.label) {
        track.label = trackData.label;
      }

      if (trackData.srcLang) {
        track.srcLang = trackData.srcLang;
      }

      return track;
    };

    /**
     * Small helper to set the inital video source.
     * Useful if some of the loading happens asynchronously.
     * NOTE: Setting the crossOrigin must happen before any of the
     * sources(poster, tracks etc.) are loaded
     *
     * @private
     */
    const setInitialSource = function () {
      if (qualities[currentQuality] === undefined) {
        return;
      }

      if (H5P.setSource !== undefined) {
        H5P.setSource(video, qualities[currentQuality].source, self.contentId)
      }
      else {
        // Backwards compatibility (H5P < v1.22)
        const srcPath = H5P.getPath(qualities[currentQuality].source.path, self.contentId);
        if (H5P.getCrossOrigin !== undefined) {
          var crossOrigin = H5P.getCrossOrigin(srcPath);
          video.setAttribute('crossorigin', crossOrigin !== null ? crossOrigin : 'anonymous');
        }
        video.src = srcPath;
      }

      // Add poster if provided
      if (options.poster) {
        video.poster = getCrossOriginPath(options.poster); // Uses same crossOrigin as parent. You cannot mix.
      }

      // Register tracks
      options.tracks.forEach(function (track, i) {
        var trackElement = addTrack(track);
        if (i === 0) {
          trackElement.default = true;
        }
        if (trackElement) {
          video.appendChild(trackElement);
        }
      });
    };

    /**
     * Displayed when the video is buffering
     * @private
     */
    var $throbber = $('<div/>', {
      'class': 'h5p-video-loading'
    });

    /**
     * Used to display error messages
     * @private
     */
    var $error = $('<div/>', {
      'class': 'h5p-video-error'
    });

    /**
     * Keep track of current state when changing quality.
     * @private
     */
    var stateBeforeChangingQuality;
    var currentTimeBeforeChangingQuality;

    /**
     * Avoids firing the same event twice.
     * @private
     */
    var lastState;

    /**
     * Keeps track whether or not the video has been loaded.
     * @private
     */
    var isLoaded = false;

    /**
     *
     * @private
     */
    var playbackRate = 1;
    var skipRateChange = false;

    // Create player
    var video = document.createElement('video');

    // Sort sources into qualities
    var qualities = getQualities(sources, video);
    var currentQuality;

    numQualities = 0;
    for (let quality in qualities) {
      numQualities++;
    }

    if (numQualities > 1 && H5P.VideoHtml5.getExternalQuality !== undefined) {
      H5P.VideoHtml5.getExternalQuality(sources, function (chosenQuality) {
        if (qualities[chosenQuality] !== undefined) {
          currentQuality = chosenQuality;
        }
        setInitialSource();
      });
    }
    else {
      // Select quality and source
      currentQuality = getPreferredQuality();
      if (currentQuality === undefined || qualities[currentQuality] === undefined) {
        // No preferred quality, pick the first.
        for (currentQuality in qualities) {
          if (qualities.hasOwnProperty(currentQuality)) {
            break;
          }
        }
      }
      setInitialSource();
    }

    // Setting webkit-playsinline, which makes iOS 10 beeing able to play video
    // inside browser.
    video.setAttribute('webkit-playsinline', '');
    video.setAttribute('playsinline', '');
    video.setAttribute('preload', 'metadata');

    // Remove buttons in Chrome's video player:
    let controlsList = 'nodownload';
    if (options.disableFullscreen) {
      controlsList += ' nofullscreen';
    }
    if (options.disableRemotePlayback) {
      controlsList += ' noremoteplayback';
    }
    video.setAttribute('controlsList', controlsList);

    // Remove picture in picture as it interfers with other video players
    video.disablePictureInPicture = true;

    // Set options
    video.disableRemotePlayback = (options.disableRemotePlayback ? true : false);
    video.controls = (options.controls ? true : false);
    // Hardcoded autoplay to false to avoid playing videos on init
    video.autoplay = false;
    video.loop = (options.loop ? true : false);
    video.className = 'h5p-video';
    video.style.display = 'block';

    if (options.fit) {
      // Style is used since attributes with relative sizes aren't supported by IE9.
      video.style.width = '100%';
      video.style.height = '100%';
    }

    /**
     * Helps registering events.
     *
     * @private
     * @param {String} native Event name
     * @param {String} h5p Event name
     * @param {String} [arg] Optional argument
     */
    var mapEvent = function (native, h5p, arg) {
      video.addEventListener(native, function () {
        switch (h5p) {
          case 'stateChange':
            if (lastState === arg) {
              return; // Avoid firing event twice.
            }

            var validStartTime = options.startAt && options.startAt > 0;
            if (arg === H5P.Video.PLAYING && validStartTime) {
              video.currentTime = options.startAt;
              delete options.startAt;
            }

            break;

          case 'loaded':
            isLoaded = true;

            if (stateBeforeChangingQuality !== undefined) {
              return; // Avoid loaded event when changing quality.
            }

            // Remove any errors
            if ($error.is(':visible')) {
              $error.remove();
            }

            if (OLD_ANDROID_FIX) {
              var andLoaded = function () {
                video.removeEventListener('durationchange', andLoaded, false);
                // On Android seeking isn't ready until after play.
                self.trigger(h5p);
              };
              video.addEventListener('durationchange', andLoaded, false);
              return;
            }
            break;

          case 'error':
            // Handle error and get message.
            arg = error(arguments[0], arguments[1]);
            break;

          case 'playbackRateChange':

            // Fix for keeping playback rate in IE11
            if (skipRateChange) {
              skipRateChange = false;
              return; // Avoid firing event when changing back
            }
            if (H5P.Video.IE11_PLAYBACK_RATE_FIX && playbackRate != video.playbackRate) { // Intentional
              // Prevent change in playback rate not triggered by the user
              video.playbackRate = playbackRate;
              skipRateChange = true;
              return;
            }
            // End IE11 fix

            arg = self.getPlaybackRate();
            break;
        }
        self.trigger(h5p, arg);
      }, false);
    };

    /**
     * Handle errors from the video player.
     *
     * @private
     * @param {Object} code Error
     * @param {String} [message]
     * @returns {String} Human readable error message.
     */
    var error = function (code, message) {
      if (code instanceof Event) {

        // No error code
        if (!code.target.error) {
          return '';
        }

        switch (code.target.error.code) {
          case MediaError.MEDIA_ERR_ABORTED:
            message = l10n.aborted;
            break;
          case MediaError.MEDIA_ERR_NETWORK:
            message = l10n.networkFailure;
            break;
          case MediaError.MEDIA_ERR_DECODE:
            message = l10n.cannotDecode;
            break;
          case MediaError.MEDIA_ERR_SRC_NOT_SUPPORTED:
            message = l10n.formatNotSupported;
            break;
          case MediaError.MEDIA_ERR_ENCRYPTED:
            message = l10n.mediaEncrypted;
            break;
        }
      }
      if (!message) {
        message = l10n.unknownError;
      }

      // Hide throbber
      $throbber.remove();

      // Display error message to user
      $error.text(message).insertAfter(video);

      // Pass message to our error event
      return message;
    };

    /**
     * Appends the video player to the DOM.
     *
     * @public
     * @param {jQuery} $container
     */
    self.appendTo = function ($container) {
      $container.append(video);
    };

    /**
     * Get list of available qualities. Not available until after play.
     *
     * @public
     * @returns {Array}
     */
    self.getQualities = function () {
      // Create reverse list
      var options = [];
      for (var q in qualities) {
        if (qualities.hasOwnProperty(q)) {
          options.splice(0, 0, {
            name: q,
            label: qualities[q].label
          });
        }
      }

      if (options.length < 2) {
        // Do not return if only one quality.
        return;
      }

      return options;
    };

    /**
     * Get current playback quality. Not available until after play.
     *
     * @public
     * @returns {String}
     */
    self.getQuality = function () {
      return currentQuality;
    };

    /**
     * Set current playback quality. Not available until after play.
     * Listen to event "qualityChange" to check if successful.
     *
     * @public
     * @params {String} [quality]
     */
    self.setQuality = function (quality) {
      if (qualities[quality] === undefined || quality === currentQuality) {
        return; // Invalid quality
      }

      // Keep track of last choice
      setPreferredQuality(quality);

      // Avoid multiple loaded events if changing quality multiple times.
      if (!stateBeforeChangingQuality) {
        // Keep track of last state
        stateBeforeChangingQuality = lastState;

        // Keep track of current time
        currentTimeBeforeChangingQuality = video.currentTime;

        // Seek and start video again after loading.
        var loaded = function () {
          video.removeEventListener('loadedmetadata', loaded, false);
          if (OLD_ANDROID_FIX) {
            var andLoaded = function () {
              video.removeEventListener('durationchange', andLoaded, false);
              // On Android seeking isn't ready until after play.
              self.seek(currentTimeBeforeChangingQuality);
            };
            video.addEventListener('durationchange', andLoaded, false);
          }
          else {
            // Seek to current time.
            self.seek(currentTimeBeforeChangingQuality);
          }

          // Always play to get image.
          video.play();

          if (stateBeforeChangingQuality !== H5P.Video.PLAYING) {
            // Do not resume playing
            video.pause();
          }

          // Done changing quality
          stateBeforeChangingQuality = undefined;

          // Remove any errors
          if ($error.is(':visible')) {
            $error.remove();
          }
        };
        video.addEventListener('loadedmetadata', loaded, false);
      }

      // Keep track of current quality
      currentQuality = quality;
      self.trigger('qualityChange', currentQuality);

      // Display throbber
      self.trigger('stateChange', H5P.Video.BUFFERING);

      // Change source
      video.src = getCrossOriginPath(qualities[quality].source); // (iPad does not support #t=).
      // Note: Optional tracks use same crossOrigin as the original. You cannot mix.

      // Remove poster so it will not show during quality change
      video.removeAttribute('poster');
    };

    /**
     * Starts the video.
     *
     * @public
     * @return {Promise|undefined} May return a Promise that resolves when
     * play has been processed.
     */
    self.play = function () {
      if ($error.is(':visible')) {
        return;
      }

      if (!isLoaded) {
        // Make sure video is loaded before playing
        video.load();
      }

      return video.play();
    };

    /**
     * Pauses the video.
     *
     * @public
     */
    self.pause = function () {
      video.pause();
    };

    /**
     * Seek video to given time.
     *
     * @public
     * @param {Number} time
     */
    self.seek = function (time) {
      if (lastState === undefined) {
        // Make sure we always play before we seek to get an image.
        // If not iOS devices will reset currentTime when pressing play.
        video.play();
        video.pause();
      }

      video.currentTime = time;
    };

    /**
     * Get elapsed time since video beginning.
     *
     * @public
     * @returns {Number}
     */
    self.getCurrentTime = function () {
      return video.currentTime;
    };

    /**
     * Get total video duration time.
     *
     * @public
     * @returns {Number}
     */
    self.getDuration = function () {
      if (isNaN(video.duration)) {
        return;
      }

      return video.duration;
    };

    /**
     * Get percentage of video that is buffered.
     *
     * @public
     * @returns {Number} Between 0 and 100
     */
    self.getBuffered = function () {
      // Find buffer currently playing from
      var buffered = 0;
      for (var i = 0; i < video.buffered.length; i++) {
        var from = video.buffered.start(i);
        var to = video.buffered.end(i);

        if (video.currentTime > from && video.currentTime < to) {
          buffered = to;
          break;
        }
      }

      // To percentage
      return buffered ? (buffered / video.duration) * 100 : 0;
    };

    /**
     * Turn off video sound.
     *
     * @public
     */
    self.mute = function () {
      video.muted = true;
    };

    /**
     * Turn on video sound.
     *
     * @public
     */
    self.unMute = function () {
      video.muted = false;
    };

    /**
     * Check if video sound is turned on or off.
     *
     * @public
     * @returns {Boolean}
     */
    self.isMuted = function () {
      return video.muted;
    };

    /**
     * Returns the video sound level.
     *
     * @public
     * @returns {Number} Between 0 and 100.
     */
    self.getVolume = function () {
      return video.volume * 100;
    };

    /**
     * Set video sound level.
     *
     * @public
     * @param {Number} level Between 0 and 100.
     */
    self.setVolume = function (level) {
      video.volume = level / 100;
    };

    /**
     * Get list of available playback rates.
     *
     * @public
     * @returns {Array} available playback rates
     */
    self.getPlaybackRates = function () {
      /*
       * not sure if there's a common rule about determining good speeds
       * using Google's standard options via a constant for setting
       */
      var playbackRates = PLAYBACK_RATES;

      return playbackRates;
    };

    /**
     * Get current playback rate.
     *
     * @public
     * @returns {Number} such as 0.25, 0.5, 1, 1.25, 1.5 and 2
     */
    self.getPlaybackRate = function () {
      return video.playbackRate;
    };

    /**
     * Set current playback rate.
     * Listen to event "playbackRateChange" to check if successful.
     *
     * @public
     * @params {Number} suggested rate that may be rounded to supported values
     */
    self.setPlaybackRate = function (newPlaybackRate) {
      playbackRate = newPlaybackRate;
      video.playbackRate = newPlaybackRate;
    };

    /**
     * Set current captions track.
     *
     * @param {H5P.Video.LabelValue} Captions track to show during playback
     */
    self.setCaptionsTrack = function (track) {
      for (var i = 0; i < video.textTracks.length; i++) {
        video.textTracks[i].mode = (track && track.value === i ? 'showing' : 'disabled');
      }
    };

    /**
     * Figure out which captions track is currently used.
     *
     * @return {H5P.Video.LabelValue} Captions track
     */
    self.getCaptionsTrack = function () {
      for (var i = 0; i < video.textTracks.length; i++) {
        if (video.textTracks[i].mode === 'showing') {
          return new H5P.Video.LabelValue(video.textTracks[i].label, i);
        }
      }

      return null;
    };

    // Register event listeners
    mapEvent('ended', 'stateChange', H5P.Video.ENDED);
    mapEvent('playing', 'stateChange', H5P.Video.PLAYING);
    mapEvent('pause', 'stateChange', H5P.Video.PAUSED);
    mapEvent('waiting', 'stateChange', H5P.Video.BUFFERING);
    mapEvent('loadedmetadata', 'loaded');
    mapEvent('canplay', 'canplay');
    mapEvent('error', 'error');
    mapEvent('ratechange', 'playbackRateChange');

    if (!video.controls) {
      // Disable context menu(right click) to prevent controls.
      video.addEventListener('contextmenu', function (event) {
        event.preventDefault();
      }, false);
    }

    // Display throbber when buffering/loading video.
    self.on('stateChange', function (event) {
      var state = event.data;
      lastState = state;
      if (state === H5P.Video.BUFFERING) {
        $throbber.insertAfter(video);
      }
      else {
        $throbber.remove();
      }
    });

    // Load captions after the video is loaded
    self.on('loaded', function () {
      nextTick(function () {
        var textTracks = [];
        for (var i = 0; i < video.textTracks.length; i++) {
          textTracks.push(new H5P.Video.LabelValue(video.textTracks[i].label, i));
        }
        if (textTracks.length) {
          self.trigger('captions', textTracks);
        }
      });
    });

    // Alternative to 'canplay' event
    /*self.on('resize', function () {
      if (video.offsetParent === null) {
        return;
      }

      video.style.width = '100%';
      video.style.height = '100%';

      var width = video.clientWidth;
      var height = options.fit ? video.clientHeight : (width * (video.videoHeight / video.videoWidth));

      video.style.width = width + 'px';
      video.style.height = height + 'px';
    });*/

    // Video controls are ready
    nextTick(function () {
      self.trigger('ready');
    });

    /**
     * Check video is loaded and ready play.
     *
     * @public
     * @param {Boolean}
     */
    self.isLoaded = function () {
      return isLoaded;
    };
  }

  /**
   * Check to see if we can play any of the given sources.
   *
   * @public
   * @static
   * @param {Array} sources
   * @returns {Boolean}
   */
  Html5.canPlay = function (sources) {
    var video = document.createElement('video');
    if (video.canPlayType === undefined) {
      return false; // Not supported
    }

    // Cycle through sources
    for (var i = 0; i < sources.length; i++) {
      var type = getType(sources[i]);
      if (type && video.canPlayType(type) !== '') {
        // We should be able to play this
        return true;
      }
    }

    return false;
  };

  /**
   * Find source type.
   *
   * @private
   * @param {Object} source
   * @returns {String}
   */
  var getType = function (source) {
    var type = source.mime;
    if (!type) {
      // Try to get type from URL
      var matches = source.path.match(/\.(\w+)$/);
      if (matches && matches[1]) {
        type = 'video/' + matches[1];
      }
    }

    if (type && source.codecs) {
      // Add codecs
      type += '; codecs="' + source.codecs + '"';
    }

    return type;
  };

  /**
   * Sort sources into qualities.
   *
   * @private
   * @static
   * @param {Array} sources
   * @param {Object} video
   * @returns {Object} Quality mapping
   */
  var getQualities = function (sources, video) {
    var qualities = {};
    var qualityIndex = 1;
    var lastQuality;

    // Cycle through sources
    for (var i = 0; i < sources.length; i++) {
      var source = sources[i];

      // Find and update type.
      var type = source.type = getType(source);

      // Check if we support this type
      var isPlayable = type && (type === 'video/unknown' || video.canPlayType(type) !== '');
      if (!isPlayable) {
        continue; // We cannot play this source
      }

      if (source.quality === undefined) {
        /**
         * No quality metadata. Create a quality tag to separate multiple sources of the same type,
         * e.g. if two mp4 files with different quality has been uploaded
         */

        if (lastQuality === undefined || qualities[lastQuality].source.type === type) {
          // Create a new quality tag
          source.quality = {
            name: 'q' + qualityIndex,
            label: (source.metadata && source.metadata.qualityName) ? source.metadata.qualityName : 'Quality ' + qualityIndex // TODO: l10n
          };
          qualityIndex++;
        }
        else {
          /**
           * Assumes quality already exists in a different format.
           * Uses existing label for this quality.
           */
          source.quality = qualities[lastQuality].source.quality;
        }
      }

      // Log last quality
      lastQuality = source.quality.name;

      // Look to see if quality exists
      var quality = qualities[lastQuality];
      if (quality) {
        // We have a source with this quality. Check if we have a better format.
        if (source.mime.split('/')[1] === PREFERRED_FORMAT) {
          quality.source = source;
        }
      }
      else {
        // Add new source with quality.
        qualities[source.quality.name] = {
          label: source.quality.label,
          source: source
        };
      }
    }

    return qualities;
  };

  /**
   * Set preferred video quality.
   *
   * @private
   * @static
   * @param {String} quality Index of preferred quality
   */
  var setPreferredQuality = function (quality) {
    try {
      localStorage.setItem('h5pVideoQuality', quality);
    }
    catch (err) {
      console.warn('Unable to set preferred video quality, localStorage is not available.');
    }
  };

  /**
   * Get preferred video quality.
   *
   * @private
   * @static
   * @returns {String} Index of preferred quality
   */
  var getPreferredQuality = function () {
    // First check localStorage
    let quality;
    try {
      quality = localStorage.getItem('h5pVideoQuality');
    }
    catch (err) {
      console.warn('Unable to retrieve preferred video quality from localStorage.');
    }
    if (!quality) {
      try {
        // The fallback to old cookie solution
        var settings = document.cookie.split(';');
        for (var i = 0; i < settings.length; i++) {
          var setting = settings[i].split('=');
          if (setting[0] === 'H5PVideoQuality') {
            quality = setting[1];
            break;
          }
        }
      }
      catch (err) {
        console.warn('Unable to retrieve preferred video quality from cookie.');
      }
    }
    return quality;
  };

  /**
   * Helps schedule a task for the next tick.
   * @param {function} task
   */
  var nextTick = function (task) {
    setTimeout(task, 0);
  };

  /** @constant {Boolean} */
  var OLD_ANDROID_FIX = false;

  /** @constant {Boolean} */
  var PREFERRED_FORMAT = 'mp4';

  /** @constant {Object} */
  var PLAYBACK_RATES = [0.25, 0.5, 1, 1.25, 1.5, 2];

  if (navigator.userAgent.indexOf('Android') !== -1) {
    // We have Android, check version.
    var version = navigator.userAgent.match(/AppleWebKit\/(\d+\.?\d*)/);
    if (version && version[1] && Number(version[1]) <= 534.30) {
      // Include fix for devices running the native Android browser.
      // (We don't know when video was fixed, so the number is just the lastest
      // native android browser we found.)
      OLD_ANDROID_FIX = true;
    }
  }
  else {
    if (navigator.userAgent.indexOf('Chrome') !== -1) {
      // If we're using chrome on a device that isn't Android, prefer the webm
      // format. This is because Chrome has trouble with some mp4 codecs.
      PREFERRED_FORMAT = 'webm';
    }
  }

  return Html5;
})(H5P.jQuery);

// Register video handler
H5P.videoHandlers = H5P.videoHandlers || [];
H5P.videoHandlers.push(H5P.VideoHtml5);
