var autoplayDelay = 4000;

var imageList = PicSlides;
var lastRan = -1;
var fmtItem = function(imgUrl, url, title, alt, index) {
      var innerHTML = 
          '<a target="_blank" id="aImageSlide'+index+'" href="' + 
          url + 
          '"><img id="imgImageSlide' + index + '" src="' + 
          imgUrl +
        '" width="' +
        215 +
        '" height="' +
        150 +
        '" title="' + title +
        '" alt="' + alt +
        '" onclick="startAutoPlay()"/><\/a>';
  
    return innerHTML;
};

var loadInitialItems = function(type, args) {

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

    load(this, start, last);    
    brightenOrDim(this);
};

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

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

    brightenOrDim(this);
};

var load = function(carousel, start, last) {
    for(var i=start;i<=last;i++) {
        var liItem = carousel.addItem(i, fmtItem(imageList[i-1], PicLinks[i-1], PicTitles[i-1], PicAlts[i-1], i));
    }
}

var handlePrevButtonState = function(type, args) {
    var enabling = args[0];
    var leftImage = args[1];
    if(enabling) {
        leftImage.className = "arrow_enabled";    
    } else {
        leftImage.className = "arrow_disabled";
    }
    
};

var brightenOrDim = function(carousel) {
    var firstItemRevealed=carousel.getFirstItemRevealed();
    var lastItemRevealed=carousel.getLastItemRevealed();
    var firstVisible = carousel.getProperty("firstVisible");
    var lastVisible = carousel.getLastVisible();
        
    var first = (firstItemRevealed == -1) ? firstVisible : firstItemRevealed;
    var last = (lastItemRevealed == -1) ? lastVisible : lastItemRevealed;
    
    for(var i=first; i<=last; i++) {
        var li = carousel.getItem(i);
        if(li) {
            if(i == firstItemRevealed || i==lastItemRevealed) {
                YAHOO.util.Dom.replaceClass(li, "bright", "dim");
            } else {
                YAHOO.util.Dom.replaceClass(li, "dim", "bright");
            }
        }
    }
    
};

var carousel;
var pageLoad = function() 
{
	if (imageList.length == 0)
	{
		carousel = null;
	}
	else
	{
		carousel = new YAHOO.extension.Carousel("dhtml-carousel", 
			{
				numVisible:        scrollVisible,
				animationSpeed:   0.7,
				scrollInc:         2,
				navMargin:         40,
				prevElement:     "prev-arrow",
				nextElement:     "next-arrow",
				loadInitHandler:   loadInitialItems,
				loadNextHandler:   loadNextItems,
				loadPrevHandler:   loadPrevItems,
				prevButtonStateHandler:   handlePrevButtonState,
				autoPlay: autoplayDelay,
				size:imageList.length,
				wrap:true
			}
		);
	    
	    if (imageList.length < scrollVisible)
	    {
			var rArrow = document.getElementById("next-arrow")
			if (rArrow != null)
				rArrow.className = "arrow_disabled";
	    
			carousel.setProperty("nextElement", "");
			carousel.stopAutoPlay();
	    }
	    else {
			startAutoPlay();
	    }
    }
};

var startAutoPlay = function(e) {
    carousel.startAutoPlay(autoplayDelay);
};

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