import {setup} from './auto-advance.js';

/**
 * Removes all remote text tracks from a player.
 *
 * @param  {Player} player
 *         The player to clear tracks on
 */
const clearTracks = (player) => {
  const tracks = player.remoteTextTracks();
  let i = tracks && tracks.length || 0;

  // This uses a `while` loop rather than `forEach` because the
  // `TextTrackList` object is a live DOM list (not an array).
  while (i--) {
    player.removeRemoteTextTrack(tracks[i]);
  }
};

/**
 * Plays an item on a player's playlist.
 *
 * @param  {Player} player
 *         The player to play the item on
 *
 * @param  {Object} item
 *         A source from the playlist.
 *
 * @return {Player}
 *         The player that is now playing the item
 */
const playItem = (player, item) => {
  const replay = !player.paused() || player.ended();

  player.trigger('beforeplaylistitem', item);
  player.poster(item.poster || '');
  player.src(item.sources);
  clearTracks(player);

  player.ready(() => {
    (item.textTracks || []).forEach(player.addRemoteTextTrack.bind(player));
    player.trigger('playlistitem', item);

    if (replay) {
      const playPromise = player.play();

      // silence error when a pause interrupts a play request
      // on browsers which return a promise
      if (typeof playPromise !== 'undefined' && typeof playPromise.then === 'function') {
        playPromise.then(null, (e) => {});
      }
    }

    setup(player, player.playlist.autoadvance_.delay);
  });

  return player;
};

export default playItem;
export {clearTracks};