/**
 * Image src URLs
 */
var imageList = [
                 "images/common/carousel/pic01.jpg",
                 "images/common/carousel/pic02.jpg",
                 "images/common/carousel/pic03.jpg",
                 "images/common/carousel/pic04.jpg",
                 "images/common/carousel/pic05.jpg",
                 "images/common/carousel/pic06.jpg",
                 "images/common/carousel/pic07.jpg",
                 "images/common/carousel/pic08.jpg",
                 "images/common/carousel/pic09.jpg",
                 "images/common/carousel/pic10.jpg",
                 "images/common/carousel/pic11.jpg",
                 "images/common/carousel/pic12.jpg",
                 "images/common/carousel/pic13.jpg",
                 "images/common/carousel/pic14.jpg",
                 "images/common/carousel/pic15.jpg",
                 "images/common/carousel/pic16.jpg",
                 "images/common/carousel/pic17.jpg",
                 "images/common/carousel/pic18.jpg"
                 ];

var lastRan = -1;

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

      var innerHTML = 
          '<a href="' + 
          url + 
          '"><img src="' + 
          imgUrl +
        '" width="' +
        75 +
        '" height="' +
        75+
        '"/>' + 
          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[i-1], "images.aspx", ""));
    }
}

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 leftImage = args[1];
    if(enabling) {
        leftImage.src = "images/left-enabled.gif";    
    } else {
        leftImage.src = "images/left-disabled.gif";
    }
    
};

var carousel;

/**
 * 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:        6,
            animationSpeed:    0.9,
            scrollInc:         5,
            navMargin:         5,
            prevElementID:     "prev-arrow",
            nextElementID:     "next-arrow",
            loadInitHandler:   loadInitialItems,
            loadNextHandler:   loadNextItems,
            loadPrevHandler:   loadPrevItems,
          //  prevButtonStateHandler:   handlePrevButtonState,
            autoPlay: 8000,
            size:18,
            wrap:true
        }
    );
    carousel.startAutoPlay(8000);
};

/**
 * 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(6000);
};