var Dialog = {};
Dialog.Box = Class.create();
Object.extend(Dialog.Box.prototype, {
	initialize: function(id) {
	    this.createOverlay();
       
	    this.dialog_box = $(id);
	    this.dialog_box.show = this.show.bind(this);
	    this.dialog_box.persistent_show = this.persistent_show.bind(this);
	    this.dialog_box.hide = this.hide.bind(this);
      
	    this.parent_element = this.dialog_box.parentNode;
      
	    this.dialog_box.style.position = "absolute";
      
	    var e_dims = Element.getDimensions(this.dialog_box);
	    var b_dims = Element.getDimensions(this.overlay);
      
	    this.dialog_box.style.left = ((b_dims.width/2) - (e_dims.width/2)) + 'px';
	    this.dialog_box.style.top = this.getScrollTop() + ((this.winHeight() - (e_dims.width/2))/2) + 'px';
	    this.dialog_box.style.zIndex = this.overlay.style.zIndex + 1;
        },
      
	    createOverlay: function() {
	    if($('dialog_overlay')) {
		this.overlay = $('dialog_overlay');
	    } else {
		this.overlay = document.createElement('div');
		this.overlay.id = 'dialog_overlay';
		Object.extend(this.overlay.style, {
			position: 'absolute',
			    top: 0,
			    left: 0,
			    zIndex: 90,
			    width: '100%',
			    backgroundColor: '#000',
			    display: 'none'
			    });
		document.body.insertBefore(this.overlay, document.body.childNodes[0]);
	    }
        },
      
	    moveDialogBox: function(where) {
	    Element.remove(this.dialog_box);
	    if(where == 'back')
		this.dialog_box = this.parent_element.appendChild(this.dialog_box);
	    else
		this.dialog_box = this.overlay.parentNode.insertBefore(this.dialog_box, this.overlay);
        },
      
	    show: function() {
	    this.overlay.style.height = this.bodyHeight()+'px';
	    this.moveDialogBox('out');
          
	    this.overlay.onclick = this.hide.bind(this);
          	
	    this.selectBoxes('hide');
	    new Effect.Appear(this.overlay, {duration: 0.1, from: 0.0, to: 0.3});
	    this.dialog_box.style.display = '';
      
	    this.dialog_box.style.left = '0px';
       
	    var e_dims = Element.getDimensions(this.dialog_box);
        	
	    this.dialog_box.style.left = ((this.winWidth()/2) - (e_dims.width)/2) + 'px';
        	
	    this.dialog_box.style.top = this.getScrollTop() + ((this.winHeight() - (e_dims.width/2))/2) + 'px';
        	
        },
        
	    getScrollTop: function() {
	    return (window.pageYOffset)?window.pageYOffset:(document.documentElement && document.documentElement.scrollTop)?document.documentElement.scrollTop:document.body.scrollTop;
        },
        
	    persistent_show: function() {
	    this.overlay.style.height = this.bodyHeight()+'px';
	    this.moveDialogBox('out');
       
	    this.selectBoxes('hide');
	    new Effect.Appear(this.overlay, {duration: 0.1, from: 0.0, to: 0.3});
         
	    this.dialog_box.style.display = '';
	    this.dialog_box.style.left = '0px';
	    var e_dims = Element.getDimensions(this.dialog_box);
	    this.dialog_box.style.left = ((this.winWidth()/2) - (e_dims.width)/2) + 'px';
        	
        },
      
	    hide: function() {
	    this.selectBoxes('show');
	    new Effect.Fade(this.overlay, {duration: 0.1});
	    this.dialog_box.style.display = 'none';
	    this.moveDialogBox('back');
	    $A(this.dialog_box.getElementsByTagName('input')).each(function(e){if(e.type!='submit')e.value=''});
        },
      
	    selectBoxes: function(what) {
	    $A(document.getElementsByTagName('select')).each(function(select) {
		    Element[what](select);
		});
     
	    if(what == 'hide')
		$A(this.dialog_box.getElementsByTagName('select')).each(function(select){Element.show(select)})
		    },
       
	    bodyWidth: function() { return document.body.offsetWidth || window.innerWidth || document.documentElement.clientWidth || 0; },
	    bodyHeight: function() { return document.body.offsetHeight || window.innerHeight || document.documentElement.clientHeight || 0; },
     
	    winWidth: function() {
	    var viewportwidth;
   		 
	    // the more standards compliant browsers (mozilla/netscape/opera/IE7) use window.innerWidth and window.innerHeight
   		 
	    if (typeof window.innerWidth != 'undefined')
		{
		    viewportwidth = window.innerWidth;
		}
   		 
	    // IE6 in standards compliant mode (i.e. with a valid doctype as the first line in the document)
   		
	    else if (typeof document.documentElement != 'undefined' && typeof document.documentElement.clientWidth != 'undefined' && document.documentElement.clientWidth != 0)
		{
		    viewportwidth = document.documentElement.clientWidth;
		}
   		 
	    // older versions of IE
  		 
	    else
		{
		    viewportwidth = document.getElementsByTagName('body')[0].clientWidth
			}
	    return viewportwidth;
      
        },
	    winHeight: function() { 
	    var viewportheight;
  		 
	    // the more standards compliant browsers (mozilla/netscape/opera/IE7) use window.innerWidth and window.innerHeight
   		 
	    if (typeof window.innerHeight != 'undefined')
		{
		    viewportheight = window.innerHeight
			}
   		 
	    // IE6 in standards compliant mode (i.e. with a valid doctype as the first line in the document)
   		
	    else if (typeof document.documentElement != 'undefined' && typeof document.documentElement.clientHeight != 'undefined' && document.documentElement.clientHeight != 0)
		{
		    viewportheight = document.documentElement.clientHeight;
		}
   		 
	    // older versions of IE
   		 
	    else
		{
		    viewportheight = document.getElementsByTagName('body')[0].clientHeight;
		}
	    return viewportheight;
   	
	}
     
    });