/**
 * @author Bruno Bornsztein <bruno@missingmethod.com>
 * @copyright 2007 Curbly LLC
 * @package Glider
 * @license MIT
 * @url http://www.missingmethod.com/projects/glider/
 * @version 0.0.3
 * @dependencies prototype.js 1.5.1+, effects.js
 */

/*  Thanks to Andrew Dupont for refactoring help and code cleanup - http://andrewdupont.net/  */

Glider = Class.create();
Object.extend(Object.extend(Glider.prototype, Abstract.prototype), 
{
	initialize: function(wrapper, options, rewind, nbvisible)
	{
	    this.scrolling  = false;
	    this.wrapper    = $(wrapper);
	    this.scroller   = this.wrapper.down('div.scroller');
	    this.sections   = this.wrapper.getElementsBySelector('div.section');
	    this.options    = Object.extend({ duration: 1.0, frequency: 3 }, options || {});
	    this.sens   	= 'right';
	    this.rewind   	= rewind;
	    this.nbvisible 	= nbvisible;
	
	    this.sections.each( function(section, index) {
	      section._index = index;
	    });    
	
	    this.events = {
	      click: this.click.bind(this)
	    };
	
	    this.addObservers();
			if(this.options.initialSection) this.moveTo(this.options.initialSection, this.scroller, { duration:this.options.duration });  // initialSection should be the id of the section you want to show up on load
			if(this.options.autoGlide) this.start();
	},
	
	addObservers: function() 
	{
		var controls = this.wrapper.getElementsBySelector('div.controls a');
		controls.invoke('observe', 'click', this.events.click);
	},	

	click: function(event) 
	{
		this.stop();
		var element = Event.findElement(event, 'a');
		if (this.scrolling) this.scrolling.cancel();
		
		this.moveTo(element.href.split("#")[1], this.scroller, { duration:this.options.duration });     
		Event.stop(event);
	},

	moveTo: function(element, container, options)
	{
		this.current = $(element);

		Position.prepare();
	    var containerOffset = Position.cumulativeOffset(container),
	    elementOffset = Position.cumulativeOffset($(element));

		this.scrolling 	= new Effect.SmoothScroll(container, {duration:options.duration, x:(elementOffset[0]-containerOffset[0]), y:(elementOffset[1]-containerOffset[1])});
		return false;
	},
		
	next: function()
	{
		if (this.current) 
		{
			var currentIndex = this.current._index;
			var nextIndex = (this.sections.length - 1 == currentIndex + this.nbvisible - 1) ? 0 : currentIndex + 1;      
		} 
		else 
			var nextIndex = 1;
	
		this.moveTo(this.sections[nextIndex], this.scroller, { duration: this.options.duration});
	},
	
	previous: function()
	{
		if (this.current) 
		{
			var currentIndex = this.current._index;
			var prevIndex = (currentIndex == 0) ? this.sections.length - 1 : 
			currentIndex - 1;
		} 
		else 
			var prevIndex = this.sections.length - 1;
		
		this.moveTo(this.sections[prevIndex], this.scroller, 
		{ 
		  duration: this.options.duration
		});
	},

	
	stop: function()
	{
		clearTimeout(this.timer);
	},
	
	
	start: function()
	{
		this.periodicallyUpdate();
	},
		
	
	periodicallyUpdate: function()
	{ 
		if (this.timer != null) 
		{
			clearTimeout(this.timer);
			
			var currentIndex = this.current._index;
			var nMax = this.sections.length - 1;
			
			if (!this.rewind)
			{
				if(currentIndex + this.nbvisible - 1 >= nMax)
					this.sens = 'left';
					
				if(currentIndex == 0)
					this.sens = 'right';
			
				/* On passe en previous plutot que de tout rembobiner */
				if(this.sens == 'right')
					this.next();
				else
					this.previous();
			}
			else
				this.next();
			
		}
		
		
			this.timer = setTimeout(this.periodicallyUpdate.bind(this), this.options.frequency*1000);
	}

});



Effect.SmoothScroll = Class.create();
Object.extend(Object.extend(Effect.SmoothScroll.prototype, Effect.Base.prototype), 
{
	initialize: function(element) 
	{
		this.element = $(element);
		var options = Object.extend({
		  x:    0,
		  y:    0,
		  mode: 'absolute'
		} , arguments[1] || {}  );
		this.start(options);
	},
	
	setup: function() 
	{
		if (this.options.continuous && !this.element._ext ) 
		{
			this.element.cleanWhitespace();
			this.element._ext=true;
			this.element.appendChild(this.element.firstChild);
		}
   
		this.originalLeft=this.element.scrollLeft;
		this.originalTop=this.element.scrollTop;
   
    	if(this.options.mode == 'absolute') 
    	{
			this.options.x -= this.originalLeft;
			this.options.y -= this.originalTop;
    	} 
	},
  
	update: function(position) 
	{   
		this.element.scrollLeft = this.options.x * position + this.originalLeft;
		this.element.scrollTop  = this.options.y * position + this.originalTop;
	}
});