var lastRan = -1;

var fmtItem = function(imgUrl, url, title, index) {

  	var innerHTML = 
  		'<a id="dhtml-carousel-a-'+index+'" href="' + 
  		url + 
  		'"><img class="imgcarousel" id="dhtml-carousel-img-' + index + '" src="' + 
  		imgUrl +
		'" width="' +
		69 +
		'" height="' +
		90+
		'"/>' + 
  		title + 
  		'<\/a>';
  
	return innerHTML;
};


/**
 * Custom inital load handler. Called when the carousel loads the initial
 * set of data items. Specified to the carousel as the configuration
 * parameter: loadInitHandler
 **/
var loadInitialItems = function(type, args) {

	var start = args[0];
	var last = args[1]; 

	load(this, start, last);	
};

/**
 * Custom load next handler. Called when the carousel loads the next
 * set of data items. Specified to the carousel as the configuration
 * parameter: loadNextHandler
 **/
 var loadNextItems = function(type, args) {	

	var start = args[0];
	var last = args[1]; 
	var alreadyCached = args[2];
	
	if(!alreadyCached) {
		load(this, start, last);
	}
};

/**
 * Custom load previous handler. Called when the carousel loads the previous
 * set of data items. Specified to the carousel as the configuration
 * parameter: loadPrevHandler
 **/
var loadPrevItems = function(type, args) {
	var start = args[0];
	var last = args[1]; 
	var alreadyCached = args[2];
	
	if(!alreadyCached) {
		load(this, start, last);
	}
};

/*var load = function(carousel, start, last) {
	for(var i=start;i<=last;i++) {
		var liItem = carousel.addItem(i, fmtItem(imageList[i], "#", "Number " + i, i));
	}
}*/
var load = function(carousel, start, last) {
	for(var i=start;i<=last;i++) {
		//var liItem = carousel.addItem(i, fmtItem(imageList[i], "#", "Number " + i, i));
		var liItem = carousel.addItem(i, fmtItem(imageList[i], linkList[i], descList[i], i));
	}
}
/**
 * Custom button state handler for enabling/disabling button state. 
 * Called when the carousel has determined that the previous button
 * state should be changed.
 * Specified to the carousel as the configuration
 * parameter: prevButtonStateHandler
 **/
var handlePrevButtonState = function(type, args) {

	var enabling = args[0];
	var leftImage = args[1];
	if(enabling) {
		leftImage.src = "scroller/btn_previous.png";	
	} else {
		leftImage.src = "scroller/btn_previous.png";
	}
	
};

var carousel; // for ease of debugging; globals generally not a good idea

/**
 * You must create the carousel after the page is loaded since it is
 * dependent on an HTML element (in this case 'dhtml-carousel'.) See the
 * HTML code below.
 */
var pageLoad = function() 
{
	carousel = new YAHOO.extension.Carousel("dhtml-carousel", 
		{
			numVisible:        4,
			animationSpeed:   0.7,
			scrollInc:         3,
			navMargin:         20,
			prevElement:     "prev-arrow",
			nextElement:     "next-arrow",
			loadInitHandler:   loadInitialItems,
			loadNextHandler:   loadNextItems,
			loadPrevHandler:   loadPrevItems,
			prevButtonStateHandler:   handlePrevButtonState,
			autoPlay: 3000,
			size:24,
			wrap:true
		}
	);
	

};


/**
 * Illustrates stop autoplay
 */
var stopAutoPlay = function(e) {
	YAHOO.util.Dom.get("status").innerHTML = "Auto Play Stopped!";
	carousel.stopAutoPlay();
};

/**
 * Illustrates start autoplay
 */
var startAutoPlay = function(e) {
	YAHOO.util.Dom.get("status").innerHTML = "Auto Play Started!";
	carousel.startAutoPlay(2000);
};

YAHOO.util.Event.addListener(window, 'load', pageLoad);
YAHOO.util.Event.addListener("stop-button", 'click', stopAutoPlay);
YAHOO.util.Event.addListener("start-button", 'click', startAutoPlay);