const internals = {

  promisesSupported: !!(window.browser),
  port: null,
  currentUrl: null,

  icons: {
    call: {
      16: 'icons/action-16.png',
      32: 'icons/action-32.png'
    },

    hangUp: {
      16: 'icons/hang_up-16.png',
      32: 'icons/hang_up-32.png'
    }
  },

  onClick() {
    if (internals.isInCall()) {
      return internals.hangUp();
    }

    return internals.joinAudioCall();
  },

  onConnect(port) {

    internals.port = port;
    port.onDisconnect.addListener(internals.onDisconnect);
    port.onMessage.addListener(internals.onMessage);
    port.postMessage({
      action: 'joinAudioCall',
      data: {
        currentUrl: internals.currentUrl,
        tada: internals.getRoot().runtime.getURL('sounds/tada.wav')
      }
    });
    internals.getRoot().browserAction.enable();
    internals.setIcon('hangUp');
  },

  onMessage(message) {

    if (message.action === 'error') {
      internals.getRoot().browserAction.setBadgeText({ text: 'x' }, () => {});
    }
  },

  onDisconnect() {
    internals.getRoot().browserAction.setBadgeText({ text: '' }, () => {});
    internals.setIcon('call');
    internals.currentUrl = null;
    internals.port = null;
    internals.getRoot().browserAction.enable();
  },

  async joinAudioCall() {

    internals.getRoot().browserAction.disable();
    const activeTabs = await internals.getActiveTabs();

    internals.currentUrl = activeTabs[0].url;
    const execution = await internals.getRoot().tabs.executeScript(activeTabs[0].id, {
      file: '/build/content_script.js'
    }, () => {

      if (internals.getRoot().runtime.lastError) {
        internals.onDisconnect();
      }
    });

    if (execution && !execution[0]) {
      internals.onDisconnect();
    }
  }
  ,

  hangUp() {

    internals.getRoot().browserAction.disable();
    internals.port.postMessage({
      action: 'hangUp'
    });
  },

  isInCall() {

    return !!(internals.port);
  },

  setIcon(iconSet) {

    internals.getRoot().browserAction.setIcon({
      path: internals.icons[iconSet]
    });
  },

  getRoot() {

    return window.browser || window.chrome;
  },

  // Chrome doesn't yet implement the promise based tabs.query :'(

  getActiveTabs() {

    const query = {
      currentWindow: true,
      active: true
    };

    if (internals.promisesSupported) {
      return internals.getRoot().tabs.query(query);
    }

    return new Promise((resolve, reject) => {

      internals.getRoot().tabs.query(query, (tabs) => {

        return resolve(tabs);
      });
    });
  },
};

internals.getRoot().browserAction.onClicked.addListener(internals.onClick);
internals.getRoot().runtime.onConnect.addListener(internals.onConnect);