/**
 * @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/  */

var glider = null;
function containsDOM (container, containee) {
  var isParent = false;
  do {
    if ((isParent = container == containee))
      break;
    containee = containee.parentNode;
  }
  while (containee != null);
  return isParent;
}

function checkMouseEnter (element, evt) {
  if (element.contains && evt.fromElement) {
    return !element.contains(evt.fromElement);
  }
  else if (evt.relatedTarget) {
    return !containsDOM(element, evt.relatedTarget);
  }
}

function checkMouseLeave (element, evt) {
  if (element.contains && evt.toElement) {
    return !element.contains(evt.toElement);
  }
  else if (evt.relatedTarget) {
    return !containsDOM(element, evt.relatedTarget);
  }
}

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.timer      = null;

	    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) 
        {
            gl = this;
            this.start();
            /*this.wrapper.onmouseover = this.mouseover;
            this.wrapper.onmouseout = this.mouseout;*/
        }
	  },
	
    addObservers: function() {
    var controls = this.wrapper.getElementsBySelector('div.controls a');
    controls.invoke('observe', 'click', this.events.click);
    },	

    mouseover: function(e, o) 
    {
        if (!checkMouseEnter(o, e))
            return;
        
        clearTimeout(gl.timer);
    },
    
    mouseout: function(e, o) 
    {
        if (!checkMouseLeave(o, e))
            return;
	    
        if (gl.options.autoGlide) gl.start();
    },
    
    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) {
			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;
  }
});