/**
 * @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[0].parentNode.appendChild(
//    this.scroller.appendChild(
      this.sections[0].cloneNode(true)
    );
    
    this.sections   = this.wrapper.getElementsBySelector('div.section');
    this.sections.each( function(section, index) {
			  section._index = index;
			  section.id = "section"+(index+1);
			});    
		    
    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 });     
    this.moveTo(this.sections[element.href.split("#section")[1]], this.scroller, { duration:this.options.duration });     
    Event.stop(event);
  },
		
  shift: function(){
    this.moveTo(this.sections[1], this.scroller, {duration: null});
  },

  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])});
//    console.log(element);
    return false;
  },

  next: function(){
    if (this.current) {
      var currentIndex = this.current._index;
      var nextIndex = (this.sections.length - 1 == currentIndex) ? 0 : currentIndex + 1;
      if(nextIndex==0){
	this.moveTo(this.sections[0], this.scroller, {duration: null});
	nextIndex = 1;
      }
    } else nextIndex = 1;
    
    this.moveTo(this.sections[nextIndex], this.scroller, {duration: this.options.duration});
  },
		      
  previous: function(){
    var prevIndex;
    if (this.current && this.current._index != 0) {
      var currentIndex = this.current._index;
	prevIndex = currentIndex - 1;
    }else{
      this.moveTo(this.sections[this.sections.length - 1], this.scroller, {duration: null});
      prevIndex = this.sections.length - 2;
    }// 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;
  }
});