// Copyright (c) 2006 Sebastien Gruhier (http://xilinus.com, http://itseb.com)
// 
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
// VERSION 0.26

var Carousel = Class.create();
Carousel.prototype = {

initialize: function(carouselElemID) {
this.carouselElemID = carouselElemID;

this.options = Object.extend({
	numVisible:					 4,
	scrollInc:						4,
	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;
// Init data
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)
{

	document.getElementById("next-arrow").style.display="block";
	return;
}
var inc = this.options.scrollInc;

if (this.currentIndex - inc < 0)
{
	inc = this.currentIndex;
	if (document.getElementById("prev-arrow").style.display != "none")
	{

	}
}
if (this.currentIndex - inc == 0){
	document.getElementById("prev-arrow").style.display="none";
} else {
	document.getElementById("prev-arrow").style.display="block";
}
document.getElementById("next-arrow").style.display="block";
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){

			if (this.currentIndex + (this.options.numVisible*2) >=this.options.size){
				document.getElementById("next-arrow").style.display= "none";
			}
			this._scroll(-this.nbInCache);
			document.getElementById("prev-arrow").style.display = "block";
		} else {

		}
	}
}
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);

	if (document.getElementById("next-arrow").style.display != "none")
	{

	}
},

_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"));
}
}