Hangouts/Backbone.js integration bit

hangouts_backbone.js

// Fired off by the gadget manager, starts up our app by hooking it into the hangout loading process.
function init() {
    gapi.hangout.onApiReady.add(

    function (eventObj) {
        if (eventObj.isApiReady) {

            // Are we the admin?
            var currentParticipants = gapi.hangout.getParticipants();
            if (currentParticipants.length == 1) {
                isAdmin = true;
            }

            // If we're the admin, clear the state going forward.
            if (isAdmin) {
                gapi.hangout.data.clearValue('status');
                gapi.hangout.data.clearValue('buzzedByUserId');
                gapi.hangout.data.clearValue('currentVideoIndex');
                gapi.hangout.data.clearValue('participantData');
            }

            gapi.hangout.data.onStateChanged.add(onHangoutsStatusChanged);
            gapi.hangout.onParticipantsChanged.add(onParticipantsChanged);

            setupApp(); // Fire off the Backbone.js app here.

            // When a user first joins build out the local participant structures.
            App.initializeLocalParticipants(currentParticipants);

        }
    });
}

// Here's where we catch the updated data from Hangouts and hand it off to the Backbone app to process.
// These various App.* methods break apart the received data and perform the usual Backbone model object.set(key, value)
// bits, so everyone's in line with updates that get sent over from other people.
function onHangoutsStatusChanged(addedKeys, metadata, removedKeys, state) {
    App.updateGameStateStatus(addedKeys.state.status);
    App.updateGameStateBuzzedByUserId(addedKeys.state.buzzedByUserId);
    App.updateGameStateCurrentVideoIndex(addedKeys.state.currentVideoIndex);

    if (!isAdmin) {
        if (!_.isUndefined(addedKeys.state.participantData)) {
            var newParticipants = JSON.parse(addedKeys.state.participantData);
            App.updateScoresForParticipants(newParticipants); // Find each in the local participants and tweak their scores.
        }
    }
}