window.addEvent('domready', function() {
	var SCROLL_TIME = 5000;  // in ms
	if (initSlideshow()) {
	  setInterval('advanceSlideShow()', SCROLL_TIME);
        }
});

function initSlideshow() {
	var IMG_WIDTH = 320;
	var el = $('slideshow_preview_inner');
        if (el == null) { return false; }
        var size = el.getChildren().length;
        // We assume very last image is a repeat for wrap-around

        var rndIndex = Math.floor(Math.random()* (size - 1));
        el.style.left = "" + (-1 * rndIndex * IMG_WIDTH) + "px";
        return true;
}

function advanceSlideShow() {

	var SCROLL_SPEED = 800; // ms per scroll
	var IMG_WIDTH = 322;
	var el = $('slideshow_preview_inner');
        var myFx = new Fx.Styles(el, {duration: SCROLL_SPEED, wait: false});
        var newTop = parseInt(el.style.left) - IMG_WIDTH;
        if (-newTop >= el.offsetWidth) {
                el.style.left = "0px";
		newTop = -IMG_WIDTH;
	}
	myFx.start({'left': newTop});
};