/**
 * @author Bruno Bornsztein <bruno@missingmethod.com> and annso
 * @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
 */

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#photos-wrapper');
	    this.sections   = this.wrapper.getElementsBySelector('img.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
		});
		
		this.displayPage(nextIndex+1);
	},

	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
		});
		
		this.displayPage(prevIndex+1);
	},

	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);
	},

	displayPage: function(index){
		document.getElementById("num_page").innerHTML = index+"/"+this.sections.length; 
	}
});

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;
	}
});