/**
 * @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) 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) ? 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});
  },

  direct: function(toSection) {
	this.moveTo(toSection, 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;
  }
});