/**
 * @author Bruno Bornsztein <bruno@missingmethod.com>
 * @copyright 2007 Curbly LLC
 * @package Glider
 * @license MIT
 * @url http://www.missingmethod.com/projects/glider/
 * @version 0.0.4
 * @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)
	{
		this.scrolling  = false;
		this.wrapper    = $(wrapper);
		this.scroller   = this.wrapper.down('div.scroller');
		this.sections   = this.wrapper.getElementsBySelector('div.section');
		this.options    = Object.extend({ controlsEvent:'click', duration: 1.0, frequency: 3 }, options || {});

		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() 
	{
		this.controls = this.wrapper.getElementsBySelector('.controls a');
		this.controls.invoke('observe', this.options.controlsEvent, this.events.click);
	},

	click: function(event) 
	{
		var element = Event.findElement(event, 'a');

		Event.stop(event);

		this.stop();

		if (this.scrolling)
		{ this.scrolling.cancel();	}
		
		var sect = element.href.split("#")[1];
		switch(sect)
		{
			case 'previous':
				this.previous();
				break;

			case 'next':
				this.next();
				break;

			default:
				var mvT = this.wrapper.down('#' + sect);
				this.moveTo(mvT, this.scroller, { duration:this.options.duration });     
				break;
		}
	},

	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])}
		);

		var selId = this.current.id;
		this.controls.each(
			function(control)
			{
				if (control.href.split("#")[1] == selId)
				{	control.addClassName("active")	}
				else
				{	control.removeClassName("active")	}			
			}
		);

		return false;
	},

	next: function()
	{
		if (this.current)
		{
			var currentIndex = this.current._index;
			var nextIndex = (this.sections.length - 1 == currentIndex) ? 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);
			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;
	}
});