/**
 * @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) {
		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.sections.each( function(section, index) {
			section._index = index;
		});	   

		this.events = {
			click: this.click.bind(this)
		};

		this.addObservers();
		if (this.options.initialSection) {
			// initialSection should be the id of the section you want to show up on load
			this.moveTo(this.options.initialSection, this.scroller, { duration:this.options.duration });
		}
		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) ? 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;
  }
});