(function () {
  /*---------------------
  ------- IMPORT --------
  ----------------------*/
  var Q = window.flatworld_libraries.Q;
  var Howl = window.flatworld_libraries.Howler;
  var log = window.flatworld.mapLayers;

  /*---------------------
  --------- API ---------
  ----------------------*/
  class Sound {
    constructor() {
      this._allSounds = {};
    }
    /**
     * Add a sound to be used.
     *
     * @namespace flatworld
     * @method add
     * @param {String} name               Name / identifier
     * @param {String} urls               An array of urls or one url
     * @param {Object} options            *OPTIONAL*
     * @param {Booleam} options.loop      Wether the sound will be looped or not
     * @param {Object} options.volume     The volume of the sound (0 - 1)
     * @return {Object}                   Created instance of sound
     */
    add(name, url, options = { loop: false, volume: 1 }) {
      const ERROR_STRING = 'The sound "' + name + '" was unable to load!';
      var { loop, volume } = options;

      this._allSounds[name] = {};
      this._allSounds[name] = new Howl({
        urls: [url],
        autoplay: false,
        loop,
        volume,
      });

      return this._allSounds[name];
    }
    /**
     * Remove the sound from usage and memory
     *
     * @method remove
     * @param {String} name     Name / identifier of the sound to be removed
     */
    remove(name) {
      delete this._allSounds[name];
    }
    /**
     * Start the sounds playback
     *
     * @method play
     * @param  {String} name      Name of the sound to play
     */
    play(name) {
      var promise = Q.defer();

      this._allSounds[name]._onend = () => {
        promise.resolve(true);
      };
      this._allSounds[name].play();
    }
    /**
     * stop sound playback
     *
     * @method stop
     * @param  {String} name      Name of the sound to stop playing
     */
    stop(name) {
      this._allSounds[name].stop();
    }
    /**
     * Fade the sound in or out
     *
     * @method  fade
     * @param  {String} name            Name / identifier of the sound
     * @param  {Object} from            Volume to fade from
     * @param  {Object} to              Volume to fade to
     * @param  {Object} duration        Time in milliseconds to fade
     * @return {Promise}                Promise that resolves after fade is complete
     */
    fade(name, from, to, duration) {
      var promise = Q.defer();
      var cb;
      cb = () => {
        promise.resolve(true);
      };

      this._allSounds[name].fade(from, to, duration, cb);

      return promise.promise;
    }
  }

  window.flatworld.Sound = Sound;
})();