/**********************************************************
 Adapted from the sortable lists example by Tim Taylor
 http://tool-man.org/examples/sorting.html
 Modified by Tom Westcott : http://www.cyberdummy.co.uk 
 **********************************************************/

var DragDrop = {

	firstContainer 	: null,
	lastContainer 	: null,
	parent_id	 			: null,
	parent_group 		: null,
	
	makeListContainer : function( list, group ) {
		// each container becomes a linked list node
		
		
		
//		if( this.firstContainer == null ) {
			this.firstContainer 		= this.lastContainer = list;
			list.previousContainer 	= null;
			list.nextContainer 			= null;
//		} else {  //remove all this so adding a rating works, this was for multiple lists that interact
//			list.previousContainer = this.lastContainer;
//			list.nextContainer = null;
//			this.lastContainer.nextContainer = list;
//			this.lastContainer = list;
//		}
		
		// these functions are called when an item is draged over a container or out of a container bounds.  
		// onDragOut is also called when the drag ends with an item having been added to the container
		list.onDragOver 	= new Function();
		list.onDragOut 		= new Function();
		list.onDragDrop 	= new Function();
		list.group 				= group;
		
		var items = list.getElementsByTagName( "li" );
    	
		for (var i = 0; i < items.length; i++) {
//==========================================================================================
			if( items[i].threshold == undefined )
				DragDrop.makeItemDragable(items[i]);
		}
	},

	serData : function( group, theid ) {

		var container = DragDrop.firstContainer;
		var j 				= 0;
		var string 		= "";
                
		while (container != null) {
                
			if(theid != null && container.id != theid) {
				container = container.nextContainer;
				continue;
			}

			if(group != null && container.group != group) {
				container = container.nextContainer;
				continue;
			}
                
			j++;
			
			if( j > 1 ) {
				string += ":";
			}

			string += container.id;
                        
			var items = container.getElementsByTagName( "li" );
			string += "(";
		  
			for( var i = 0; i < items.length; i++ ) {
				if(i > 0) {
					string += ",";
				}
				string += items[i].id;
			}

			string += ")";
                        
			container = container.nextContainer;
		}
		
		return string;
	},

	makeItemDragable : function( item ) {
	
		if( item.onmousedown == undefined ) {
		Drag.makeDraggable( item );
		item.setDragThreshold( 5 );
		
		// tracks if the item is currently outside all containers
		item.isOutside 		= false;
		
		item.onDragStart 	= DragDrop.onDragStart;
		item.onDrag 			= DragDrop.onDrag;
		item.onDragEnd 		= DragDrop.onDragEnd;
		}
	},

	onDragStart : function(nwPosition, sePosition, nwOffset, seOffset) {
		// update all container bounds, since they may have changed
		// on a previous drag
		//
		// could be more smart about when to do this
		var container = DragDrop.firstContainer;


		while (container != null) {
			container.northwest = Coordinates.northwestOffset( container, true );
			container.southeast = Coordinates.southeastOffset( container, true );
			container = container.nextContainer;
		}
		
		// item starts out over current parent
		this.parentNode.onDragOver();
		parent_id = this.parentNode.id;
		parent_group = this.parentNode.group;
	},

	onDrag : function(nwPosition, sePosition, nwOffset, seOffset) {
		// check if we were nowhere
		if (this.isOutside) {
			// check each container to see if in its bounds
			var container = DragDrop.firstContainer;
			while( container != null ) {

				if( ( nwOffset.inside( container.northwest, container.southeast )	||
							seOffset.inside( container.northwest, container.southeast ) ) && 
							container.group == parent_group ) {
					// we're inside this one
					container.onDragOver();
					this.isOutside = false;
					
					// since isOutside was true, the current parent is a
					// temporary clone of some previous container node and
					// it needs to be removed from the document
					var tempParent = this.parentNode;
					tempParent.removeChild( this );
					container.appendChild( this );
					tempParent.parentNode.removeChild( tempParent );
					break;
				}
				container = container.nextContainer;
			}
			// we're still not inside the bounds of any container
			if (this.isOutside)
				return;
		
		// check if we're outside our parent's bounds
		} else if (!(nwOffset.inside( this.parentNode.northwest, this.parentNode.southeast ) ||
			seOffset.inside( this.parentNode.northwest, this.parentNode.southeast ))) {
			
			this.parentNode.onDragOut();
			this.isOutside = true;
			
			// check if we're inside a new container's bounds
			var container = DragDrop.firstContainer;
			while (container != null) {
				if ((nwOffset.inside( container.northwest, container.southeast ) ||
					seOffset.inside( container.northwest, container.southeast )) && container.group == parent_group) {
					// we're inside this one
					container.onDragOver();
					this.isOutside = false;
					this.parentNode.removeChild( this );
					container.appendChild( this );
					break;
				}
				container = container.nextContainer;
			}
			// if we're not in any container now, make a temporary clone of
			// the previous container node and add it to the document
			if (this.isOutside) {
				var tempParent = this.parentNode.cloneNode( false );
				this.parentNode.removeChild( this );
				tempParent.appendChild( this );
				// body puts a border or item at bottom of page if do not have this
                                tempParent.style.border = 0;
				document.getElementsByTagName( "body" ).item(0).appendChild( tempParent );
				return;
			}
		}
		
		// if we get here, we're inside some container bounds, so we do
		// everything the original dragsort script did to swap us into the
		// correct position
		
		var parent = this.parentNode;
				
		var item = this;
		var next = DragUtils.nextItem(item);
		while (next != null && this.offsetTop >= next.offsetTop - 2) {
			var item = next;
			var next = DragUtils.nextItem(item);
		}
		if (this != item) {
			DragUtils.swap(this, next);
			return;
		}

		var item = this;
		var previous = DragUtils.previousItem(item);
		while (previous != null && this.offsetTop <= previous.offsetTop + 2) {
			var item = previous;
			var previous = DragUtils.previousItem(item);
		}
		if (this != item) {
			DragUtils.swap(this, item);
			return;
		}
	},

	onDragEnd : function(nwPosition, sePosition, nwOffset, seOffset) {
		// if the drag ends and we're still outside all containers
		// it's time to remove ourselves from the document or add 
                // to the trash bin
		if (this.isOutside) {
			var container = DragDrop.firstContainer;
			
			while (container != null) {
				if(container.id == parent_id) {
					break;
				}
				container = container.nextContainer;
			}
			
			this.isOutside = false;
			this.parentNode.removeChild( this );
			container.appendChild( this );
			this.style["top"] = "0px";
			this.style["left"] = "0px";
			//var container = DragDrop.firstContainer;
			//container.appendChild( this );
			return;
		}
		this.parentNode.onDragOut();
		this.parentNode.onDragDrop();
		this.style["top"] = "0px";
		this.style["left"] = "0px";
	}
};


var DragUtils = {
	swap : function(item1, item2) {
		var parent = item1.parentNode;
		parent.removeChild(item1);
		parent.insertBefore(item1, item2);

		item1.style["top"] = "0px";
		item1.style["left"] = "0px";
	},

	nextItem : function( item ) {
		var sibling = item.nextSibling;
		while( sibling != null ) {
			if( sibling.nodeName == item.nodeName ) 
				return sibling;
			sibling = sibling.nextSibling;
		}
		return null;
	},

	previousItem : function(item) {
		var sibling = item.previousSibling;
		while( sibling != null ) {
			if( sibling.nodeName == item.nodeName ) 
				return sibling;
			sibling = sibling.previousSibling;
		}
		return null;
	}		
};