/**********************************************************
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,
	userId:null,
	
	makeListContainer : function(list, group, loginUserId) {
		userId = loginUserId;
		// each container becomes a linked list node

		if (this.firstContainer == null) {
			this.firstContainer = this.lastContainer = list;
			list.previousContainer = null;
			list.nextContainer = null;
		} else {
			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++) {

			DragDrop.makeItemDragable(items[i]);
		}
	},

	makeItemDragable : function(item) {
		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

			if(container.id=="center" || container.id=="right_col"){
				if(container.getElementsByTagName( "li" ).length==0){
					container.onDragOver();
					this.isOutside = false;
					var tempParent = this.parentNode;					
						tempParent.removeChild( this );
						container.appendChild( this );
						tempParent.parentNode.removeChild( tempParent );
				}
			}
			else if(container.id=="user_col"){
					if(container.getElementsByTagName( "li" ).length==0){
						
						if(this.id==userId){
							container.onDragOver();
						this.isOutside = false;
						this.parentNode.removeChild( this );
						container.appendChild( this );

						}

					}

				}
				else if(container.id=="left_col"){
					if(this.id!=userId){
						container.onDragOver();
				this.isOutside = false;
				var tempParent = this.parentNode;
				tempParent.removeChild( this );
				container.appendChild( this );
				tempParent.parentNode.removeChild( tempParent );

					}

				
				}

			// 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;
		}//if
		container = container.nextContainer;
	}//while
	// we're still not inside the bounds of any container

	if (this.isOutside)
	return;

	// check if we're outside our parent's bounds
	}//closing if
	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) {
				
				if(container.id=="center" || container.id=="right_col"){	
					
					if(container.getElementsByTagName( "li" ).length==0){
						// we're inside this one
						container.onDragOver();
						this.isOutside = false;
						this.parentNode.removeChild( this );
						container.appendChild( this );
					}
				}
				else if(container.id=="user_col"){
					if(container.getElementsByTagName( "li" ).length==0){
						if(this.id==userId){
							container.onDragOver();
						this.isOutside = false;
						this.parentNode.removeChild( this );
						container.appendChild( this );

						}

					}

				}else if(container.id=="left_col"){
					if(this.id!=userId){
						container.onDragOver();
					this.isOutside = false;
					this.parentNode.removeChild( this );
					container.appendChild( this );

					}

					
				}
				break;
			}//closing if
			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

// check each container to see if in its bounds
	var container = DragDrop.firstContainer;
    var last	= DragDrop.lastContainer
	

	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

				if(container.id=="center" || container.id=="right_col"){
					var ele=container.getElementsByTagName( "li" )[0];
					if(ele.id==userId){
						DragDrop.lastContainer.appendChild( ele );										
					this.isOutside = false;
					container.appendChild( this );
					this.style["top"] = "0px";
					this.style["left"] = "0px";
					return;

					}
					else{
						DragDrop.firstContainer.appendChild( ele );										
					this.isOutside = false;
					container.appendChild( this );
					this.style["top"] = "0px";
					this.style["left"] = "0px";
					return;

					}
					
					
					
					
				}//closing if
				else if(container.id=="user_col"){
					
					var ele=container.getElementsByTagName( "li" )[0];
					if(this.id==userId){
						
						this.isOutside = false;
					container.appendChild( this );
					this.style["top"] = "0px";
					this.style["left"] = "0px";
					return;

					}					

				}
				break;
		}//closing if
	container = container.nextContainer;
	}//closing while
	
	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";
		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;
	}
};