dojo.provide("dijit.Tree");

dojo.require("dojo.fx");

dojo.require("dijit._Widget");
dojo.require("dijit._Templated");
dojo.require("dijit._Container");
dojo.require("dojo.cookie");

dojo.declare(
	"dijit._TreeNode",
	[dijit._Widget, dijit._Templated, dijit._Container, dijit._Contained],
{
	// summary:
	//		Single node within a tree

	// item: dojo.data.Item
	//		the dojo.data entry this tree represents
	item: null,	

	isTreeNode: true,

	// label: String
	//		Text of this tree node
	label: "",
	
	isExpandable: null, // show expando node
	
	isExpanded: false,

	// state: String
	//		dynamic loading-related stuff.
	//		When an empty folder node appears, it is "UNCHECKED" first,
	//		then after dojo.data query it becomes "LOADING" and, finally "LOADED"	
	state: "UNCHECKED",
	
	templatePath: dojo.moduleUrl("dijit", "_tree/Node.html"),		

	postCreate: function(){
		// set label, escaping special characters
		this.setLabelNode(this.label);

		// set expand icon for leaf
		this._setExpando();

		// set icon and label class based on item
		this._updateItemClasses(this.item);

		if(this.isExpandable){
			dijit.setWaiState(this.labelNode, "expanded", this.isExpanded);
		}
	},

	markProcessing: function(){
		// summary: visually denote that tree is loading data, etc.
		this.state = "LOADING";
		this._setExpando(true);	
	},

	unmarkProcessing: function(){
		// summary: clear markup from markProcessing() call
		this._setExpando(false);	
	},

	_updateItemClasses: function(item){
		// summary: set appropriate CSS classes for icon and label dom node (used to allow for item updates to change respective CSS)
		var tree = this.tree, model = tree.model;
		if(tree._v10Compat && item === model.root){
			// For back-compat with 1.0, need to use null to specify root item (TODO: remove in 2.0)
			item = null;
		}
		this.iconNode.className = "dijitTreeIcon " + tree.getIconClass(item, this.isExpanded);
		this.labelNode.className = "dijitTreeLabel " + tree.getLabelClass(item, this.isExpanded);
	},

	_updateLayout: function(){
		// summary: set appropriate CSS classes for this.domNode
		var parent = this.getParent();
		if(!parent || parent.rowNode.style.display == "none"){
			/* if we are hiding the root node then make every first level child look like a root node */
			dojo.addClass(this.domNode, "dijitTreeIsRoot");
		}else{
			dojo.toggleClass(this.domNode, "dijitTreeIsLast", !this.getNextSibling());
		}
	},

	_setExpando: function(/*Boolean*/ processing){
		// summary: set the right image for the expando node

		// apply the appropriate class to the expando node
		var styles = ["dijitTreeExpandoLoading", "dijitTreeExpandoOpened",
			"dijitTreeExpandoClosed", "dijitTreeExpandoLeaf"];
		var _a11yStates = ["*","-","+","*"];
		
		var idx = processing ? 0 : (this.isExpandable ?	(this.isExpanded ? 1 : 2) : 3);
		dojo.forEach(styles,
			function(s){
				dojo.removeClass(this.expandoNode, s);
			}, this
		);
		dojo.addClass(this.expandoNode, styles[idx]);

		// provide a non-image based indicator for images-off mode
		this.expandoNodeText.innerHTML = _a11yStates[idx];

	},	

	expand: function(){
		// summary: show my children
		if(this.isExpanded){ return; }
		// cancel in progress collapse operation

		this._wipeOut && this._wipeOut.stop();

		this.isExpanded = true;
		dijit.setWaiState(this.labelNode, "expanded", "true");
		dijit.setWaiRole(this.containerNode, "group");
		this.contentNode.className = "dijitTreeContent dijitTreeContentExpanded";
		this._setExpando();
		this._updateItemClasses(this.item);

		if(!this._wipeIn){
			this._wipeIn = dojo.fx.wipeIn({
				node: this.containerNode, duration: dijit.defaultDuration
			});
		}
		this._wipeIn.play();
	},

	collapse: function(){					
		if(!this.isExpanded){ return; }

		// cancel in progress expand operation
		this._wipeIn && this._wipeIn.stop();

		this.isExpanded = false;
		dijit.setWaiState(this.labelNode, "expanded", "false");
		this.contentNode.className = "dijitTreeContent";
		this._setExpando();
		this._updateItemClasses(this.item);

		if(!this._wipeOut){
			this._wipeOut = dojo.fx.wipeOut({
				node: this.containerNode, duration: dijit.defaultDuration
			});
		}
		this._wipeOut.play();
	},

	setLabelNode: function(label){
		this.labelNode.innerHTML = "";
		this.labelNode.appendChild(dojo.doc.createTextNode(label));
	},

	setChildItems: function(/* Object[] */ items){
		// summary:
		//		Sets the child items of this node, removing/adding nodes
		//		from current children to match specified items[] array.

		var tree = this.tree,
			model = tree.model;

		// Orphan all my existing children.
		// If items contains some of the same items as before then we will reattach them.
		// Don't call this.removeChild() because that will collapse the tree etc.
		this.getChildren().forEach(function(child){
			dijit._Container.prototype.removeChild.call(this, child);
		}, this);

		this.state = "LOADED";

		if(items && items.length > 0){
			this.isExpandable = true;

			// Create _TreeNode widget for each specified tree node, unless one already
			// exists and isn't being used (presumably it's from a DnD move and was recently
			// released
			dojo.forEach(items, function(item){
				var id = model.getIdentity(item),
					existingNode = tree._itemNodeMap[id],
					node = 
						( existingNode && !existingNode.getParent() ) ?
						existingNode :
						this.tree._createTreeNode({
							item: item,
							tree: tree,
							isExpandable: model.mayHaveChildren(item),
							label: tree.getLabel(item)
						});
				this.addChild(node);
				// note: this won't work if there are two nodes for one item (multi-parented items); will be fixed later
				tree._itemNodeMap[id] = node;
				if(this.tree.persist){
					if(tree._openedItemIds[id]){
						tree._expandNode(node);
					}
				}
			}, this);

			// note that updateLayout() needs to be called on each child after
			// _all_ the children exist
			dojo.forEach(this.getChildren(), function(child, idx){
				child._updateLayout();
			});
		}else{
			this.isExpandable=false;
		}

		if(this._setExpando){
			// change expando to/from dot or + icon, as appropriate
			this._setExpando(false);
		}

		// On initial tree show, put focus on either the root node of the tree,
		// or the first child, if the root node is hidden
		if(this == tree.rootNode){
			var fc = this.tree.showRoot ? this : this.getChildren()[0],
				tabnode = fc ? fc.labelNode : this.domNode;
			tabnode.setAttribute("tabIndex", "0");
			tree.lastFocused = fc;
		}
	},

	removeChild: function(/* treeNode */ node){
		this.inherited(arguments);

		var children = this.getChildren();		
		if(children.length == 0){
			this.isExpandable = false;
			this.collapse();
		}

		dojo.forEach(children, function(child){
				child._updateLayout();
		});
	},

	makeExpandable: function(){
		//summary:
		//		if this node wasn't already showing the expando node,
		//		turn it into one and call _setExpando()
		this.isExpandable = true;
		this._setExpando(false);
	},

	_onNodeFocus: function(evt){
		var node = dijit.getEnclosingWidget(evt.target);
		this.tree._onTreeFocus(node);
	},
	
	_onMouseEnter: function(evt){
		dojo.addClass(this.contentNode, "dijitTreeNodeHover");
	},

	_onMouseLeave: function(evt){
		dojo.removeClass(this.contentNode, "dijitTreeNodeHover");
	}
});

dojo.declare(
	"dijit.Tree",
	[dijit._Widget, dijit._Templated],
{
	// summary:
	//	This widget displays hierarchical data from a store.  A query is specified
	//	to get the "top level children" from a data store, and then those items are
	//	queried for their children and so on (but lazily, as the user clicks the expand node).
	//
	//	Thus in the default mode of operation this widget is technically a forest, not a tree,
	//	in that there can be multiple "top level children".  However, if you specify label,
	//	then a special top level node (not corresponding to any item in the datastore) is
	//	created, to father all the top level children.

	// store: String||dojo.data.Store
	//	The store to get data to display in the tree.
	//	May remove for 2.0 in favor of "model".
	store: null,

	// model: dijit.Tree.model
	//	Alternate interface from store to access data (and changes to data) in the tree
	model: null,

	// query: anything
	//	Specifies datastore query to return the root item for the tree.
	//
	//	Deprecated functionality: if the query returns multiple items, the tree is given
	//	a fake root node (not corresponding to any item in the data store), 
	//	whose children are the items that match this query.
	//
	//	The root node is shown or hidden based on whether a label is specified.
	//
	//	Having a query return multiple items is deprecated.
	//	If your store doesn't have a root item, wrap the store with
	//	dijit.tree.ForestStoreModel, and specify model=myModel
	//
	// example:
	//		{type:'continent'}
	query: null,

	// label: String
	//	Deprecated.  Use dijit.tree.ForestStoreModel directly instead.
	//	Used in conjunction with query parameter.
	//	If a query is specified (rather than a root node id), and a label is also specified,
	//	then a fake root node is created and displayed, with this label.
	label: "",

	// showRoot: Boolean
	//	Should the root node be displayed, or hidden?
	showRoot: true,

	// childrenAttr: String[]
	//		one ore more attributes that holds children of a tree node
	childrenAttr: ["children"],

	// openOnClick: Boolean
	//		If true, clicking a folder node's label will open it, rather than calling onClick()
	openOnClick: false,

	templatePath: dojo.moduleUrl("dijit", "_tree/Tree.html"),		

	isExpandable: true,

	isTree: true,

	// persist: Boolean
	//	enables/disables use of cookies for state saving.
	persist: true,
	
	// dndController: String
	//	class name to use as as the dnd controller
	dndController: null,

	//parameters to pull off of the tree and pass on to the dndController as its params
	dndParams: ["onDndDrop","itemCreator","onDndCancel","checkAcceptance", "checkItemAcceptance", "dragThreshold"],

	//declare the above items so they can be pulled from the tree's markup
	onDndDrop:null,
	itemCreator:null,
	onDndCancel:null,
	checkAcceptance:null,	
	checkItemAcceptance:null,
	dragThreshold:0,

	_publish: function(/*String*/ topicName, /*Object*/ message){
		// summary:
		//		Publish a message for this widget/topic
		dojo.publish(this.id, [dojo.mixin({tree: this, event: topicName}, message||{})]);
	},

	postMixInProperties: function(){
		this.tree = this;

		this._itemNodeMap={};

		if(!this.cookieName){
			this.cookieName = this.id + "SaveStateCookie";
		}
	},

	postCreate: function(){
		// load in which nodes should be opened automatically
		if(this.persist){
			var cookie = dojo.cookie(this.cookieName);
			this._openedItemIds = {};
			if(cookie){
				dojo.forEach(cookie.split(','), function(item){
					this._openedItemIds[item] = true;
				}, this);
			}
		}
		
		// Create glue between store and Tree, if not specified directly by user
		if(!this.model){
			this._store2model();
		}

		// monitor changes to items
		this.connect(this.model, "onChange", "_onItemChange");
		this.connect(this.model, "onChildrenChange", "_onItemChildrenChange");
		this.connect(this.model, "onDelete", "_onItemDelete");

		this._load();

		this.inherited(arguments);

		if(this.dndController){
			if(dojo.isString(this.dndController)){
				this.dndController = dojo.getObject(this.dndController);
			}	
			var params={};
			for (var i=0; i<this.dndParams.length;i++){
				if(this[this.dndParams[i]]){
					params[this.dndParams[i]] = this[this.dndParams[i]];
				}
			}
			this.dndController = new this.dndController(this, params);
		}
	},

	_store2model: function(){
		// summary: user specified a store&query rather than model, so create model from store/query
		this._v10Compat = true;
		dojo.deprecated("Tree: from version 2.0, should specify a model object rather than a store/query");

		var modelParams = {
			id: this.id + "_ForestStoreModel",
			store: this.store,
			query: this.query,
			childrenAttrs: this.childrenAttr
		};

		// Only override the model's mayHaveChildren() method if the user has specified an override
		if(this.params.mayHaveChildren){
			modelParams.mayHaveChildren = dojo.hitch(this, "mayHaveChildren");
		}
					
		if(this.params.getItemChildren){
			modelParams.getChildren = dojo.hitch(this, function(item, onComplete, onError){
				this.getItemChildren((this._v10Compat && item === this.model.root) ? null : item, onComplete, onError);
			});
		}
		this.model = new dijit.tree.ForestStoreModel(modelParams);
		
		// For backwards compatibility, the visibility of the root node is controlled by
		// whether or not the user has specified a label
		this.showRoot = Boolean(this.label);
	},

	_load: function(){
		// summary: initial load of the tree
		// load root node (possibly hidden) and it's children
		this.model.getRoot(
			dojo.hitch(this, function(item){
				var rn = this.rootNode = this.tree._createTreeNode({
					item: item,
					tree: this,
					isExpandable: true,
					label: this.label || this.getLabel(item)
				});
				if(!this.showRoot){
					rn.rowNode.style.display="none";
				}
				this.domNode.appendChild(rn.domNode);
				this._itemNodeMap[this.model.getIdentity(item)] = rn;

				rn._updateLayout();		// sets "dijitTreeIsRoot" CSS classname

				// load top level children
				this._expandNode(rn);
			}),
			function(err){
				console.error(this, ": error loading root: ", err);
			}
		);
	},

	////////////// Data store related functions //////////////////////
	// These just get passed to the model; they are here for back-compat

	mayHaveChildren: function(/*dojo.data.Item*/ item){
		// summary:
		//		User overridable function to tell if an item has or may have children.
		//		Controls whether or not +/- expando icon is shown.
		//		(For efficiency reasons we may not want to check if an element actually
		//		has children until user clicks the expando node)
	},

	getItemChildren: function(/*dojo.data.Item*/ parentItem, /*function(items)*/ onComplete){
		// summary:
		// 		User overridable function that return array of child items of given parent item,
		//		or if parentItem==null then return top items in tree
	},

	///////////////////////////////////////////////////////
	// Functions for converting an item to a TreeNode
	getLabel: function(/*dojo.data.Item*/ item){
		// summary: user overridable function to get the label for a tree node (given the item)
		return this.model.getLabel(item);	// String
	},

	getIconClass: function(/*dojo.data.Item*/ item, /*Boolean*/ opened){
		// summary: user overridable function to return CSS class name to display icon
		return (!item || this.model.mayHaveChildren(item)) ? (opened ? "dijitFolderOpened" : "dijitFolderClosed") : "dijitLeaf"
	},

	getLabelClass: function(/*dojo.data.Item*/ item, /*Boolean*/ opened){
		// summary: user overridable function to return CSS class name to display label
	},

	/////////// Keyboard and Mouse handlers ////////////////////

	_onKeyPress: function(/*Event*/ e){
		// summary: translates keypress events into commands for the controller
		if(e.altKey){ return; }
		var dk = dojo.keys;
		var treeNode = dijit.getEnclosingWidget(e.target);
		if(!treeNode){ return; }

		var key = e.charOrCode;
		if(typeof key == "string"){  // handle printables (letter navigation)
			// Check for key navigation.
			if(!e.altKey && !e.ctrlKey && !e.shiftKey && !e.metaKey){
				this._onLetterKeyNav( { node: treeNode, key: key.toLowerCase() } );
				dojo.stopEvent(e);
			}
		}else{  // handle non-printables (arrow keys)
			var map = this._keyHandlerMap;
			if(!map){
				// setup table mapping keys to events
				map = {};
				map[dk.ENTER]="_onEnterKey";
				map[this.isLeftToRight() ? dk.LEFT_ARROW : dk.RIGHT_ARROW]="_onLeftArrow";
				map[this.isLeftToRight() ? dk.RIGHT_ARROW : dk.LEFT_ARROW]="_onRightArrow";
				map[dk.UP_ARROW]="_onUpArrow";
				map[dk.DOWN_ARROW]="_onDownArrow";
				map[dk.HOME]="_onHomeKey";
				map[dk.END]="_onEndKey";
				this._keyHandlerMap = map;
			}
			if(this._keyHandlerMap[key]){
				this[this._keyHandlerMap[key]]( { node: treeNode, item: treeNode.item } );	
				dojo.stopEvent(e);
			}
		}
	},

	_onEnterKey: function(/*Object*/ message){
		this._publish("execute", { item: message.item, node: message.node} );
		this.onClick(message.item, message.node);
	},

	_onDownArrow: function(/*Object*/ message){
		// summary: down arrow pressed; get next visible node, set focus there
		var node = this._getNextNode(message.node);
		if(node && node.isTreeNode){
			this.focusNode(node);
		}	
	},

	_onUpArrow: function(/*Object*/ message){
		// summary: up arrow pressed; move to previous visible node

		var node = message.node;

		// if younger siblings		
		var previousSibling = node.getPreviousSibling();
		if(previousSibling){
			node = previousSibling;
			// if the previous node is expanded, dive in deep
			while(node.isExpandable && node.isExpanded && node.hasChildren()){
				// move to the last child
				var children = node.getChildren();
				node = children[children.length-1];
			}
		}else{
			// if this is the first child, return the parent
			// unless the parent is the root of a tree with a hidden root
			var parent = node.getParent();
			if(!(!this.showRoot && parent === this.rootNode)){
				node = parent;
			}
		}

		if(node && node.isTreeNode){
			this.focusNode(node);
		}
	},

	_onRightArrow: function(/*Object*/ message){
		// summary: right arrow pressed; go to child node
		var node = message.node;

		// if not expanded, expand, else move to 1st child
		if(node.isExpandable && !node.isExpanded){
			this._expandNode(node);
		}else if(node.hasChildren()){
			node = node.getChildren()[0];
			if(node && node.isTreeNode){
				this.focusNode(node);
			}
		}
	},

	_onLeftArrow: function(/*Object*/ message){
		// summary:
		//		Left arrow pressed.
		//		If not collapsed, collapse, else move to parent.

		var node = message.node;

		if(node.isExpandable && node.isExpanded){
			this._collapseNode(node);
		}else{
			var parent = node.getParent();
			if(parent && parent.isTreeNode && !(!this.showRoot && parent === this.rootNode)){
				this.focusNode(parent);
			}
		}
	},

	_onHomeKey: function(){
		// summary: home pressed; get first visible node, set focus there
		var node = this._getRootOrFirstNode();
		if(node){
			this.focusNode(node);
		}
	},

	_onEndKey: function(/*Object*/ message){
		// summary: end pressed; go to last visible node

		var node = this;
		while(node.isExpanded){
			var c = node.getChildren();
			node = c[c.length - 1];
		}

		if(node && node.isTreeNode){
			this.focusNode(node);
		}
	},

	_onLetterKeyNav: function(message){
		// summary: letter key pressed; search for node starting with first char = key
		var node = message.node, startNode = node, 
			key = message.key;
		do{
			node = this._getNextNode(node);
			//check for last node, jump to first node if necessary
			if(!node){
				node = this._getRootOrFirstNode();
			}
		}while(node !== startNode && (node.label.charAt(0).toLowerCase() != key));
		if(node && node.isTreeNode){
			// no need to set focus if back where we started
			if(node !== startNode){
				this.focusNode(node);
			}
		}
	},

	_onClick: function(/*Event*/ e){
		// summary: translates click events into commands for the controller to process
		var domElement = e.target;

		// find node
		var nodeWidget = dijit.getEnclosingWidget(domElement);	
		if(!nodeWidget || !nodeWidget.isTreeNode){
			return;
		}

		if( (this.openOnClick && nodeWidget.isExpandable) ||
			(domElement == nodeWidget.expandoNode || domElement == nodeWidget.expandoNodeText) ){
			// expando node was clicked, or label of a folder node was clicked; open it
			if(nodeWidget.isExpandable){
				this._onExpandoClick({node:nodeWidget});
			}
		}else{
			this._publish("execute", { item: nodeWidget.item, node: nodeWidget} );
			this.onClick(nodeWidget.item, nodeWidget);
			this.focusNode(nodeWidget);
		}
		dojo.stopEvent(e);
	},

	_onExpandoClick: function(/*Object*/ message){
		// summary: user clicked the +/- icon; expand or collapse my children.
		var node = message.node;
		
		// If we are collapsing, we might be hiding the currently focused node.
		// Also, clicking the expando node might have erased focus from the current node.
		// For simplicity's sake just focus on the node with the expando.
		this.focusNode(node);

		if(node.isExpanded){
			this._collapseNode(node);
		}else{
			this._expandNode(node);
		}
	},

	onClick: function(/* dojo.data */ item, /*TreeNode*/ node){
		// summary: user overridable function for executing a tree item
	},
	onOpen: function(/* dojo.data */ item, /*TreeNode*/ node){
		// summary: callback when a node is opened
	},
	onClose: function(/* dojo.data */ item, /*TreeNode*/ node){
		// summary: callback when a node is closed
	},

	_getNextNode: function(node){
		// summary: get next visible node

		if(node.isExpandable && node.isExpanded && node.hasChildren()){
			// if this is an expanded node, get the first child
			return node.getChildren()[0];		// _TreeNode	
		}else{
			// find a parent node with a sibling
			while(node && node.isTreeNode){
				var returnNode = node.getNextSibling();
				if(returnNode){
					return returnNode;		// _TreeNode
				}
				node = node.getParent();
			}
			return null;
		}
	},

	_getRootOrFirstNode: function(){
		// summary: get first visible node
		return this.showRoot ? this.rootNode : this.rootNode.getChildren()[0];
	},

	_collapseNode: function(/*_TreeNode*/ node){
		// summary: called when the user has requested to collapse the node

		if(node.isExpandable){
			if(node.state == "LOADING"){
				// ignore clicks while we are in the process of loading data
				return;
			}

			node.collapse();
			this.onClose(node.item, node);

			if(this.persist && node.item){
				delete this._openedItemIds[this.model.getIdentity(node.item)];
				this._saveState();
			}
		}
	},

	_expandNode: function(/*_TreeNode*/ node){
		// summary: called when the user has requested to expand the node

		if(!node.isExpandable){
			return;
		}

		var model = this.model,
			item = node.item;

		switch(node.state){
			case "LOADING":
				// ignore clicks while we are in the process of loading data
				return;

			case "UNCHECKED":
				// need to load all the children, and then expand
				node.markProcessing();
				var _this = this;
				model.getChildren(item, function(items){
						node.unmarkProcessing();
						node.setChildItems(items);
						_this._expandNode(node);
					},
					function(err){
						console.error(_this, ": error loading root children: ", err);
					});
				break;

			default:
				// data is already loaded; just proceed
				node.expand();
				this.onOpen(node.item, node);

				if(this.persist && item){
					this._openedItemIds[model.getIdentity(item)] = true;
					this._saveState();
				}
		}
	},

	////////////////// Miscellaneous functions ////////////////

	blurNode: function(){
		// summary:
		//	Removes focus from the currently focused node (which must be visible).
		//	Usually not called directly (just call focusNode() on another node instead)
		var node = this.lastFocused;
		if(!node){ return; }
		var labelNode = node.labelNode;
		dojo.removeClass(labelNode, "dijitTreeLabelFocused");
		labelNode.setAttribute("tabIndex", "-1");
		dijit.setWaiState(labelNode, "selected", false);
		this.lastFocused = null;
	},

	focusNode: function(/* _tree.Node */ node){
		// summary:
		//	Focus on the specified node (which must be visible)

		// set focus so that the label will be voiced using screen readers
		node.labelNode.focus();
	},

	_onBlur: function(){
		// summary:
		// 		We've moved away from the whole tree.  The currently "focused" node
		//		(see focusNode above) should remain as the lastFocused node so we can
		//		tab back into the tree.  Just change CSS to get rid of the dotted border
		//		until that time

		this.inherited(arguments);
		if(this.lastFocused){
			var labelNode = this.lastFocused.labelNode;
			dojo.removeClass(labelNode, "dijitTreeLabelFocused");	
		}
	},

	_onTreeFocus: function(/*Widget*/ node){
		// summary:
		//		called from onFocus handler of treeitem labelNode to set styles, wai state and tabindex
		//		for currently focused treeitem.
		
		if (node){
			if(node != this.lastFocused){
				this.blurNode();
			}
			var labelNode = node.labelNode;
			// set tabIndex so that the tab key can find this node
			labelNode.setAttribute("tabIndex", "0");
			dijit.setWaiState(labelNode, "selected", true);
			dojo.addClass(labelNode, "dijitTreeLabelFocused");
			this.lastFocused = node;
		}
	},

	//////////////// Events from the model //////////////////////////
	
	_onItemDelete: function(/*Object*/ item){
		//summary: delete event from the store
		// TODO: currently this isn't called, and technically doesn't need to be,
		// but it would help with garbage collection

		var identity = this.model.getIdentity(item);
		var node = this._itemNodeMap[identity];

		if(node){
			var parent = node.getParent();
			if(parent){
				// if node has not already been orphaned from a _onSetItem(parent, "children", ..) call...
				parent.removeChild(node);
			}
			delete this._itemNodeMap[identity];
			node.destroyRecursive();
		}
	},

	_onItemChange: function(/*Item*/ item){
		//summary: processes notification of a change to an item's scalar values like label
		var model = this.model,
			identity = model.getIdentity(item),
			node = this._itemNodeMap[identity];

		if(node){
			node.setLabelNode(this.getLabel(item));
			node._updateItemClasses(item);
		}
	},

	_onItemChildrenChange: function(/*dojo.data.Item*/ parent, /*dojo.data.Item[]*/ newChildrenList){
		//summary: processes notification of a change to an item's children
		var model = this.model,
			identity = model.getIdentity(parent),
			parentNode = this._itemNodeMap[identity];

		if(parentNode){
			parentNode.setChildItems(newChildrenList);
		}
	},

	_onItemDelete: function(/*Item*/ item){
		//summary: processes notification of a deletion of an item
		var model = this.model,
			identity = model.getIdentity(item),
			node = this._itemNodeMap[identity];

		if(node){
			node.destroyRecursive();
			delete this._itemNodeMap[identity];
		}
	},

	/////////////// Miscellaneous funcs
	
	_saveState: function(){
		//summary: create and save a cookie with the currently expanded nodes identifiers
		if(!this.persist){
			return;
		}
		var ary = [];
		for(var id in this._openedItemIds){
			ary.push(id);
		}
		dojo.cookie(this.cookieName, ary.join(","), {expires:365});
	},

	destroy: function(){
		if(this.rootNode){
			this.rootNode.destroyRecursive();
		}
		if(this.dndController && !dojo.isString(this.dndController)){
			this.dndController.destroy();
		}
		this.rootNode = null;
		this.inherited(arguments);
	},
	
	destroyRecursive: function(){
		// A tree is treated as a leaf, not as a node with children (like a grid),
		// but defining destroyRecursive for back-compat.
		this.destroy();
	},

	_createTreeNode: function(/*Object*/ args){
		// summary:
		//		creates a TreeNode
		// description:
		//		Developers can override this method to define their own TreeNode class;
		//		However it will probably be removed in a future release in favor of a way
		//		of just specifying a widget for the label, rather than one that contains
		//		the children too.
		return new dijit._TreeNode(args);
	}
});


dojo.declare(
	"dijit.tree.TreeStoreModel",
	null,
{
	// summary:
	//		Implements dijit.Tree.model connecting to a store with a single
	//		root item.  Any methods passed into the constructor will override
	//		the ones defined here.

	// store: dojo.data.Store
	//		Underlying store
	store: null,

	// childrenAttrs: String[]
	//		one ore more attributes that holds children of a tree node
	childrenAttrs: ["children"],

	// labelAttr: String
	//		If specified, get label for tree node from this attribute, rather
	//		than by calling store.getLabel()
	labelAttr: "",
 
 	// root: dojo.data.Item
	//		Pointer to the root item (read only, not a parameter)
	root: null,

	// query: anything
	//		Specifies datastore query to return the root item for the tree.
	//		Must only return a single item.   Alternately can just pass in pointer
	//		to root item.
	// example:
	//		{id:'ROOT'}
	query: null,

	constructor: function(/* Object */ args){
		// summary: passed the arguments listed above (store, etc)
		dojo.mixin(this, args);

		this.connects = [];

		var store = this.store;
		if(!store.getFeatures()['dojo.data.api.Identity']){
			throw new Error("dijit.Tree: store must support dojo.data.Identity");			
		}

		// if the store supports Notification, subscribe to the notification events
		if(store.getFeatures()['dojo.data.api.Notification']){
			this.connects = this.connects.concat([
				dojo.connect(store, "onNew", this, "_onNewItem"),
				dojo.connect(store, "onDelete", this, "_onDeleteItem"),
				dojo.connect(store, "onSet", this, "_onSetItem")
			]);
		}
	},

	destroy: function(){
		dojo.forEach(this.connects, dojo.disconnect);
	},

	// =======================================================================
	// Methods for traversing hierarchy

	getRoot: function(onItem, onError){
		// summary:
		//		Calls onItem with the root item for the tree, possibly a fabricated item.
		//		Calls onError on error.
		if(this.root){
			onItem(this.root);
		}else{
			this.store.fetch({
				query: this.query,
				onComplete: dojo.hitch(this, function(items){
					if(items.length != 1){
						throw new Error(this.declaredClass + ": query " + dojo.toJson(this.query) + " returned " + items.length +
						 	" items, but must return exactly one item");
					}
					this.root = items[0];
					onItem(this.root);
				}),
				onError: onError
			});
		}
	},

	mayHaveChildren: function(/*dojo.data.Item*/ item){
		// summary:
		//		Tells if an item has or may have children.  Implementing logic here
		//		avoids showing +/- expando icon for nodes that we know don't have children.
		//		(For efficiency reasons we may not want to check if an element actually
		//		has children until user clicks the expando node)
		return dojo.some(this.childrenAttrs, function(attr){
			return this.store.hasAttribute(item, attr);
		}, this);
	},

	getChildren: function(/*dojo.data.Item*/ parentItem, /*function(items)*/ onComplete, /*function*/ onError){
		// summary:
		// 		Calls onComplete() with array of child items of given parent item, all loaded.

		var store = this.store;

		// get children of specified item
		var childItems = [];
		for (var i=0; i<this.childrenAttrs.length; i++){
			var vals = store.getValues(parentItem, this.childrenAttrs[i]);
			childItems = childItems.concat(vals);
		}

		// count how many items need to be loaded
		var _waitCount = 0;
		dojo.forEach(childItems, function(item){ if(!store.isItemLoaded(item)){ _waitCount++; } });

		if(_waitCount == 0){
			// all items are already loaded.  proceed...
			onComplete(childItems);
		}else{
			// still waiting for some or all of the items to load
			var onItem = function onItem(item){
				if(--_waitCount == 0){
					// all nodes have been loaded, send them to the tree
					onComplete(childItems);
				}
			}
			dojo.forEach(childItems, function(item){
				if(!store.isItemLoaded(item)){
					store.loadItem({
						item: item,
						onItem: onItem,
						onError: onError
					});
				}
			});
		}
	},

	// =======================================================================
	// Inspecting items

	getIdentity: function(/* item */ item){
		return this.store.getIdentity(item);	// Object
	},

	getLabel: function(/*dojo.data.Item*/ item){
		// summary: get the label for an item
		if(this.labelAttr){
			return this.store.getValue(item,this.labelAttr);	// String
		}else{
			return this.store.getLabel(item);	// String
		}
	},

	// =======================================================================
	// Write interface

	newItem: function(/* Object? */ args, /*Item*/ parent){
		// summary:
		//		Creates a new item.   See dojo.data.api.Write for details on args.
		//		Used in drag & drop when item from external source dropped onto tree.
		var pInfo = {parent: parent, attribute: this.childrenAttrs[0]};
		return this.store.newItem(args, pInfo);
	},

	pasteItem: function(/*Item*/ childItem, /*Item*/ oldParentItem, /*Item*/ newParentItem, /*Boolean*/ bCopy){
		// summary:
		//		Move or copy an item from one parent item to another.
		//		Used in drag & drop
		var store = this.store,
			parentAttr = this.childrenAttrs[0];	// name of "children" attr in parent item

		// remove child from source item, and record the attributee that child occurred in	
		if(oldParentItem){
			dojo.forEach(this.childrenAttrs, function(attr){
				if(store.containsValue(oldParentItem, attr, childItem)){
					if(!bCopy){
						var values = dojo.filter(store.getValues(oldParentItem, attr), function(x){
							return x != childItem;
						});
						store.setValues(oldParentItem, attr, values);
					}
					parentAttr = attr;
				}
			});
		}

		// modify target item's children attribute to include this item
		if(newParentItem){
			store.setValues(newParentItem, parentAttr,
				store.getValues(newParentItem, parentAttr).concat(childItem));
		}
	},

	// =======================================================================
	// Callbacks
	
	onChange: function(/*dojo.data.Item*/ item){
		// summary:
		//		Callback whenever an item has changed, so that Tree
		//		can update the label, icon, etc.   Note that changes
		//		to an item's children or parent(s) will trigger an
		//		onChildrenChange() so you can ignore those changes here.
	},

	onChildrenChange: function(/*dojo.data.Item*/ parent, /*dojo.data.Item[]*/ newChildrenList){
		// summary:
		//		Callback to do notifications about new, updated, or deleted items.
	},

	onDelete: function(/*dojo.data.Item*/ parent, /*dojo.data.Item[]*/ newChildrenList){
		// summary:
		//		Callback when an item has been deleted.
		// description:
		//		Note that there will also be an onChildrenChange() callback for the parent
		//		of this item.
	},

	// =======================================================================
	///Events from data store

	_onNewItem: function(/* dojo.data.Item */ item, /* Object */ parentInfo){
		// summary: handler for when new items appear in the store.

		//	In this case there's no correspond onSet() call on the parent of this
		//	item, so need to get the new children list of the parent manually somehow.
		if(!parentInfo){
			return;
		}
		this.getChildren(parentInfo.item, dojo.hitch(this, function(children){
			// NOTE: maybe can be optimized since parentInfo contains the new and old attribute value
			this.onChildrenChange(parentInfo.item, children);
		}));
	},
	
	_onDeleteItem: function(/*Object*/ item){
		// summary: handler for delete notifications from underlying store
		this.onDelete(item);
	},

	_onSetItem: function(/* item */ item, 
					/* attribute-name-string */ attribute, 
					/* object | array */ oldValue,
					/* object | array */ newValue){
		//summary: set data event on an item in the store
	
		if(dojo.indexOf(this.childrenAttrs, attribute) != -1){
			// item's children list changed
			this.getChildren(item, dojo.hitch(this, function(children){
				// NOTE: maybe can be optimized since parentInfo contains the new and old attribute value
				this.onChildrenChange(item, children);
			}));
		}else{
			// item's label/icon/etc. changed.
			this.onChange(item);
		}
	}
});

dojo.declare("dijit.tree.ForestStoreModel", dijit.tree.TreeStoreModel, {
	// summary:
	//		Interface between Tree and a dojo.store that doesn't have a root item, ie,
	//		has multiple "top level" items.
	//
	// description
	//		Use this class to wrap a dojo.store, making all the items matching the specified query
	//		appear as children of a fabricated "root item".  If no query is specified then all the
	//		items returned by fetch() on the underlying store become children of the root item.
	//		It allows dijit.Tree to assume a single root item, even if the store doesn't have one.

	// Parameters to constructor

	// rootId: String
	//	ID of fabricated root item
	rootId: "$root$",

	// rootLabel: String
	//	Label of fabricated root item
	rootLabel: "ROOT",

	// query: String
	//	Specifies the set of children of the root item.
	// example:
	//		{type:'continent'}
	query: null,

	// End of parameters to constructor

	constructor: function(params){
		// Make dummy root item
		this.root = {
			store: this,
			root: true,
			id: params.rootId,
			label: params.rootLabel,
			children: params.rootChildren	// optional param
		};
	},

	// =======================================================================
	// Methods for traversing hierarchy

	mayHaveChildren: function(/*dojo.data.Item*/ item){
		// summary:
		//		Tells if an item has or may have children.  Implementing logic here
		//		avoids showing +/- expando icon for nodes that we know don't have children.
		//		(For efficiency reasons we may not want to check if an element actually
		//		has children until user clicks the expando node)
		return item === this.root || this.inherited(arguments);
	},

	getChildren: function(/*dojo.data.Item*/ parentItem, /*function(items)*/ callback, /*function*/ onError){
		// summary:
		// 		Calls onComplete() with array of child items of given parent item, all loaded.
		if(parentItem === this.root){
			if(this.root.children){
				// already loaded, just return
				callback(this.root.children);
			}else{
				this.store.fetch({
					query: this.query,
					onComplete: dojo.hitch(this, function(items){
						this.root.children = items;
						callback(items);
					}),
					onError: onError
				});
			}
		}else{
			this.inherited(arguments);
		}
	},

	// =======================================================================
	// Inspecting items

	getIdentity: function(/* item */ item){
		return (item === this.root) ? this.root.id : this.inherited(arguments);
	},

	getLabel: function(/* item */ item){
		return	(item === this.root) ? this.root.label : this.inherited(arguments);
	},

	// =======================================================================
	// Write interface

	newItem: function(/* Object? */ args, /*Item*/ parent){
		// summary:
		//		Creates a new item.   See dojo.data.api.Write for details on args.
		//		Used in drag & drop when item from external source dropped onto tree.
		if(parent===this.root){
			this.onNewRootItem(args);
			return this.store.newItem(args);
		}else{
			return this.inherited(arguments);
		}
	},
 
	onNewRootItem: function(args){
		// summary:
		//		User can override this method to modify a new element that's being
		//		added to the root of the tree, for example to add a flag like root=true
	},

	pasteItem: function(/*Item*/ childItem, /*Item*/ oldParentItem, /*Item*/ newParentItem, /*Boolean*/ bCopy){
		// summary:
		//		Move or copy an item from one parent item to another.
		//		Used in drag & drop
		if(oldParentItem === this.root){
			if(!bCopy){
				// It's onLeaveRoot()'s responsibility to modify the item so it no longer matches
				// this.query... thus triggering an onChildrenChange() event to notify the Tree
				// that this element is no longer a child of the root node
				this.onLeaveRoot(childItem);
			}
		}
		dijit.tree.TreeStoreModel.prototype.pasteItem.call(this, childItem,
			oldParentItem === this.root ? null : oldParentItem,
			newParentItem === this.root ? null : newParentItem
		);
		if(newParentItem === this.root){
			// It's onAddToRoot()'s responsibility to modify the item so it matches
			// this.query... thus triggering an onChildrenChange() event to notify the Tree
			// that this element is now a child of the root node
			this.onAddToRoot(childItem);
		}
	},

	// =======================================================================
	// Callbacks
	
	onAddToRoot: function(/* item */ item){
		// summary:
		//		Called when item added to root of tree; user must override
		//		to modify the item so that it matches the query for top level items
		// example
		//	|	store.setValue(item, "root", true);
		console.log(this, ": item ", item, " added to root");
	},

	onLeaveRoot: function(/* item */ item){
		// summary:
		//		Called when item removed from root of tree; user must override
		//		to modify the item so it doesn't match the query for top level items
		// example
		// 	|	store.unsetAttribute(item, "root");
		console.log(this, ": item ", item, " removed from root");
	},
	
	// =======================================================================
	// Events from data store

	_requeryTop: function(){
		// reruns the query for the children of the root node,
		// sending out an onSet notification if those children have changed
		var oldChildren = this.root.children || [];
		this.store.fetch({
			query: this.query,
			onComplete: dojo.hitch(this, function(newChildren){
				this.root.children = newChildren;

				// If the list of children or the order of children has changed...	
				if(oldChildren.length != newChildren.length ||
					dojo.some(oldChildren, function(item, idx){ return newChildren[idx] != item;})){
					this.onChildrenChange(this.root, newChildren);
				}
			})
		});
	},

	_onNewItem: function(/* dojo.data.Item */ item, /* Object */ parentInfo){
		// summary: handler for when new items appear in the store.

		//		In theory, any new item could be a top level item.
		//		Do the safe but inefficient thing by requerying the top
		//		level items.   User can override this function to do something
		//		more efficient.
		this._requeryTop();

		this.inherited(arguments);
	},

	_onDeleteItem: function(/*Object*/ item){
		// summary: handler for delete notifications from underlying store

		// check if this was a child of root, and if so send notification that root's children
		// have changed
		if(dojo.indexOf(this.root.children, item) != -1){
			this._requeryTop();
		}

		this.inherited(arguments);
	}
});