// JavaScript Document
/**
 * Image src URLs
 */

var lastRan = -1;

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

  	var innerHTML = 
  		'<a id="dhtml-carousel-a-'+index+'" href="' + 
  		url + 
  		'"><img id="dhtml-carousel-img-' + index + '" src="' + 
  		imgUrl +
		'" width="' +
		75 +
		'" height="' +
		75+
		'"/>' + 
  		title + 
  		'<\/a>';
  
	return innerHTML;
};

var loadInitialItems = function(type, args) {

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

	load(this, start, last);	
};

 var loadNextItems = function(type, args) {	

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

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 handlePrevButtonState = function(type, args) {

	var enabling = args[0];
	var leftImage = args[1];
	if(enabling) {
		leftImage.src = "slideshow/latest_articles_leftarrow.gif";	
	} else {
		leftImage.src = "slideshow/latest_articles_leftarrow.gif";
	}
	
};

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

var pageLoad = function() 
{
	carousel = new YAHOO.extension.Carousel("dhtml-carousel", 
		{
			numVisible:        3,
			animationSpeed:   1.5,
			scrollInc:         1,
			navMargin:         30,
			prevElement:     "prev-arrow",
			nextElement:     "next-arrow",
			loadInitHandler:   loadInitialItems,
			loadNextHandler:   loadNextItems,
			loadPrevHandler:   loadPrevItems,
			prevButtonStateHandler:   handlePrevButtonState,
			autoPlay: 5000,
			size:12,
			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);