/**
 * Since carousel.addItem uses an HTML string to create the interface
 * for each carousel item, this method formats the HTML for an LI.
 **/
var fmtItem = function(imgUrl, url, title) {

  	var innerHTML =
  		'<a href="' +
  		url +
  		'"><img src="' +
  		imgUrl +
		'" width="' +
		75 +
		'" height="' +
		75+
		'" border=0/>' +
  		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 randomIndex = getRandom(18, lastRan);
		lastRan = randomIndex;
		carousel.addItem(i, fmtItem(imageList[randomIndex], "#", "Number " + i));
		*/
		var liItem = carousel.addItem(i, fmtItem(imageList[i], srcList[i], nomList[i], i));
	}
};

var getRandom = function(max, last) {
	var randomIndex;
	do {
		randomIndex = Math.floor(Math.random()*max);
	} while(randomIndex == last);

	return randomIndex;
};

/**
 * 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 upImage = args[1];

	if(enabling) {
		upImage.src = "images/up-enabled.gif";
	} else {
		upImage.src = "images/up-disabled.gif";
	}

};
var carousel; // for ease of debugging; globals generally not a good idea
var pageLoad = function()
{
	carousel = new YAHOO.extension.Carousel("dhtml-carousel",
		{
			numVisible:        4,
			animationSpeed:    3.7,
			scrollInc:         3,
			orientation:       "vertical",
			navMargin:         0,
			prevElement:     "up-arrow",
			nextElement:     "down-arrow",
			loadInitHandler:   loadInitialItems,
			loadNextHandler:   loadNextItems,
			loadPrevHandler:   loadPrevItems,
			prevButtonStateHandler:   handlePrevButtonState,
			autoPlay: 10000,
			size:10,
			wrap:true
		}
	);
};

YAHOO.util.Event.addListener(window, 'load', pageLoad);