var Carousel = Class.create();
Carousel.prototype = {
initialize: function(carouselElemID) {
this.carouselElemID = carouselElemID;
this.options = Object.extend({
numVisible:           4,
scrollInc:            3,
animParameters:      {},
buttonStateHandler:  null,
animHandler:         null,
ajaxHandler:         null,
initDoneHandler:     null,
queue:               "carousel",
size:                0,
prevElementID:       "prev-arrow",
nextElementID:       "next-arrow",
ajaxParameters:      null,
url:                 null
}, arguments[1] || {});
this.initDone = false;
this.animRunning = "none";
this.requestIsRunning = false;
this.animAfterFinish = this.options.animParameters.afterFinish;
Object.extend(this.options.animParameters, {afterFinish:  this._animDone.bind(this), queue: { position:'end', scope: this.options.queue }});
this.prevScroll = this._prevScroll.bindAsEventListener(this);
this.nextScroll = this._nextScroll.bindAsEventListener(this);
this.onComplete = this._onComplete.bindAsEventListener(this);
this.onFailure  = this._onFailure.bindAsEventListener(this);
Event.observe(this.options.prevElementID, "click", this.prevScroll);
Event.observe(this.options.nextElementID, "click", this.nextScroll);
var carouselListClass = "carousel-list";
this.carouselList = document.getElementsByClassName(carouselListClass, $(carouselElemID))[0]
this.options.size =  $(this.carouselList.getElementsByTagName("li")).length;
this._init();},
destroy: function() {
Event.stopObserving(this.options.prevElementID, "click", this.prevScroll);
Event.stopObserving(this.options.nextElementID, "click", this.nextScroll);},
scrollTo: function(newStart) {
var old_inc = this.options.scrollInc;
this.ignoreNoMoreImages = true;
if(newStart > this.currentIndex) {
this.options.scrollInc = newStart - this.currentIndex;
this._nextScroll(this);} else {
this.options.scrollInc = this.currentIndex - newStart;
this._prevScroll(this);}
this.options.scrollInc = old_inc;},_init: function() {
this.currentIndex = 0;
if (this.options.url)
this._request(this.currentIndex, this.options.numVisible);
else {
this._getLiElementSize();
this._updateButtonStateHandler(this.options.prevElementID, false);
this._updateButtonStateHandler(this.options.nextElementID, this.options.size > this.options.numVisible);}},_prevScroll: function(event) {
if (this.animRunning != "none" || this.currentIndex == 0)return;
var inc = this.options.scrollInc;
if (this.currentIndex - inc < 0)
inc = this.currentIndex;
this._scroll(inc)		  
return false;},
_nextScroll: function(event) {    
if (this.animRunning != "none")
return false;
if (this.currentIndex + this.options.numVisible + this.options.scrollInc <= this.options.size) 
this._scroll(-this.options.scrollInc);else {
this.nbInCache = this.options.size - (this.currentIndex + this.options.numVisible);
if (this.options.url && this.noMoreImages == false) 
this._request(this.currentIndex + this.options.numVisible + this.nbInCache, this.options.scrollInc - this.nbInCache);else  {
if (this.nbInCache > 0)
this._scroll(-this.nbInCache);}}
return false;},
_request: function(start, nb) {
if (this.options.url && ! this.requestIsRunning) {
this.requestIsRunning = true;
if (this.options.ajaxHandler)
this.options.ajaxHandler(this, "before");
var params = "start=" + start + "&nb=" + nb;
if (this.options.ajaxParameters != null)
params += "&" + this.options.ajaxParameters
new Ajax.Request(this.options.url, {parameters: params, onComplete: this.onComplete, onFailure: this.onFailure});}},
_onComplete: function(originalRequest){
this.requestIsRunning = false;
this.carouselList.innerHTML += originalRequest.responseText;
var size = this.options.size;
this.options.size = this.carouselList.getElementsByTagName("li").length;
var inc = this.options.size - size;
if (this.initDone == false) {
this._getLiElementSize()
this.currentIndex = 0;
this.initDone = true;
if (this.options.initDoneHandler) 
this.options.initDoneHandler(this);
this._updateButtonStateHandler(this.options.prevElementID, false);
this._updateButtonStateHandler(this.options.nextElementID, this.options.size == this.options.numVisible);
this.noMoreImages = this.options.size < this.options.numVisible}else {
if (!this.ignoreNoMoreImages)
this.noMoreImages = inc != this.options.scrollInc;else
this.ignoreNoMoreImages = false;
if (inc > 0) {
this._scroll(-inc, this.noMoreImages)}else {
if (this.nbInCache >0)
this._scroll(-this.nbInCache, true);
this._updateButtonStateHandler(this.options.nextElementID, false);}}
if (this.options.ajaxHandler)
this.options.ajaxHandler(this, "after");},
_onFailure: function(originalRequest){    
this.requestIsRunning = false;},
_animDone: function(event){   
if (this.options.animHandler)
this.options.animHandler(this.carouselElemID, "after", this.animRunning);
this.animRunning = "none";
if (this.animAfterFinish)
this.animAfterFinish(event);},
_updateButtonStateHandler: function(button, state) {
if (this.options.buttonStateHandler) 
this.options.buttonStateHandler(button, state)},
_scroll: function(delta, forceDisableNext) {      
this.animRunning = delta > 0 ? "prev" : "next";
if (this.options.animHandler)
this.options.animHandler(this.carouselElemID, "before", this.animRunning);
new Effect.MoveBy(this.carouselList, 0, delta * this.elementSize, this.options.animParameters);
this.currentIndex -= delta;
this._updateButtonStateHandler(this.options.prevElementID, this.currentIndex != 0);
if (this.options.url && this.noMoreImages == false)
enable = true;else
enable = (this.currentIndex + this.options.numVisible < this.options.size);
this._updateButtonStateHandler(this.options.nextElementID, (forceDisableNext ? false : enable));},
_getLiElementSize: function() {
var li = $(this.carouselList.getElementsByTagName("li")[0]);
this.elementSize = li.getDimensions().width + parseFloat(li.getStyle("margin-left")) + parseFloat(li.getStyle("margin-right"));}}