MarshallOfSound/Google-Play-Music-Desktop-Player-UNOFFICIAL-

const GOOGLE_MINI_PLAYER_EXT_ID = 'fahmaaghhglfmonjliepjlchgpgfmobi';
const PING = 206;
const PONG = 207;
const TRIGGER_CONNECT = 21;
const CONNECTED = 111;
const SYNC = 211;
const SYNC_RESPOND = 305;
const STATUS_UPDATE = 15;

/**
 * This is effectively voodoo, basically we fake being the official Google Play Music
 * Mini Player and receive a whole bunch of handy events.  Would love to rewrite gmusic.js
 * to use this but really don't have the time.
 */
global.chrome.runtime = {
  connect: (extensionId) => {
    const createChannel = (label) => { // eslint-disable-line
      const fns = [];
      return {
        addListener: (...args) => {
          // console.info(extensionId, label, 'addL', args);
          fns.push(args[0]);
        },
        removeListener: () => {
          // console.info(extensionId, label, 'removeL', args);
        },
        call: (...args) => fns.forEach(fn => fn(...args)),
      };
    };
    // console.info('Connect:', extensionId, opts);

    const onDisconnect = createChannel('onDisconnect');
    const onMessage = createChannel('onMessage');

    // Immediately disconnect if it isn't the connection we're looking for
    if (extensionId !== GOOGLE_MINI_PLAYER_EXT_ID) {
      setTimeout(() => {
        // console.info('Disconnecting');
        onDisconnect.call();
      }, 0);
    }

    return {
      postMessage: (obj) => {
        if (extensionId === GOOGLE_MINI_PLAYER_EXT_ID) {
          if (obj.type === PING) {
            onMessage.call({ type: PONG, sentFrom: 'bg' });
          } else if (obj.type === TRIGGER_CONNECT) {
            onMessage.call({ type: CONNECTED, message: [true, null, false], sentFrom: 'bg' });
          } else if (obj.type === SYNC) {
            onMessage.call({ type: SYNC_RESPOND, message: [true, false, 3], sentFrom: 'bg' });
          } else if (obj.type === STATUS_UPDATE) {
            const rawMessage = obj.message[0];
            // descontruct
            const rawSongInfo = rawMessage[1];
            const songInfo = {
              id: rawSongInfo[0],
              title: rawSongInfo[1],
              artist: rawSongInfo[2],
              album: rawSongInfo[3],
              duration: rawSongInfo[9],
              albumArt: rawSongInfo[10],
            };
            const currentTime = rawMessage[2];
            const isPlaying = !rawMessage[5]; // eslint-disable-line

            window.GPM.emit('change:playback-time-internal', {
              current: currentTime,
              total: songInfo.duration,
            });
          }
        }
      },
      onMessage,
      onDisconnect,
    };
  },
};