(function() {
    var NUMBER_OF_SLIDES = 5;
    var URL_PREFIX = 'http://hifi-content.s3.amazonaws.com/thoys/dev/2018/starDomainsPresentation/';
    var URL_POSTFIX = '.png';
    var PRESENTATION_CHANNEL = 'presentationChannel';

    var currentSlide = 0;
    var _entityID = null;

    function setSlide() {
        Entities.editEntity(_entityID, {
            sourceUrl: URL_PREFIX + currentSlide + URL_POSTFIX
        });
    }

    function next() {
        currentSlide = (currentSlide + 1) % NUMBER_OF_SLIDES;
        setSlide();
    }

    function previous() {
        currentSlide = (currentSlide + NUMBER_OF_SLIDES - 1) % NUMBER_OF_SLIDES;
        setSlide();
    }

    function onMessage(channel, message, sender) {
        if (channel === PRESENTATION_CHANNEL) {
            if (message === 'next') {
                next();
            } else if (message === 'previous') {
                previous();
            }
        }
    }

    this.preload = function(entityID) {
        _entityID = entityID;
        Messages.messageReceived.connect(onMessage);
        Messages.subscribe(PRESENTATION_CHANNEL);
        setSlide();
        print('initialized presentation');
    };
})