dojo.provide("lib.CheckBoxTree");
dojo.provide("lib.CheckBoxStoreModel");

// THIS WIDGET IS BASED ON DOJO/DIJIT 1.4.0 AND WILL NOT WORK WITH PREVIOUS VERSIONS
//
//	Release date: 02/05/2010
//

dojo.require("dijit.Tree");
dojo.require("dijit.form.CheckBox");

dojo.declare( "lib.CheckBoxStoreModel", dijit.tree.TreeStoreModel, 
{
	// checkboxAll: Boolean
	//		If true, every node in the tree will receive a checkbox regardless if the 'checkbox' attribute 
	//		is specified in the dojo.data.
	checkboxAll: true,

	// checkboxState: Boolean
	// 		The default state applied to every checkbox unless otherwise specified in the dojo.data.
	//		(see also: checkboxIdent)
	checkboxState: false,

	// checkboxRoot: Boolean
	//		If true, the root node will receive a checkbox eventhough it's not a true entry in the store.
	//		This attribute is independent of the showRoot attribute of the tree itself. If the tree
	//		attribute 'showRoot' is set to false to checkbox for the root will not show either.  
	checkboxRoot: false,

	// checkboxStrict: Boolean
	//		If true, a strict parent-child checkbox relation is maintained. For example, if all children 
	//		are checked the parent will automatically be checked or if any of the children are unchecked
	//		the parent will be unchecked. 
	checkboxStrict: true,

	// checkboxIdent: String
	//		The attribute name (attribute of the dojo.data.item) that specifies that items checkbox initial
	//		state. Example:	{ name:'Egypt', type:'country', checkbox: true }
	//		If a dojo.data.item has no 'checkbox' attribute specified it will depend on the attribute
	//		'checkboxAll' if one will be created automatically and if so what the initial state will be as
	//		specified by 'checkboxState'. 
	checkboxIdent: "checkbox",

	updateCheckbox: function(/*dojo.data.Item*/ storeItem, /*Boolean*/ newState ) {
		// summary:
		//		Update the checkbox state (true/false) for the item and the associated parent and 
		//		child checkboxes if any. 
		// description:
		//		Update a single checkbox state (true/false) for the item and the associated parent 
		//		and child checkboxes if any. This function is called from the tree if a user checked
		//		or unchecked a checkbox on the tree. The parent and child tree nodes are updated to 
		//		maintain consistency if 'checkboxStrict' is set to true.
		//	storeItem:
		//		The item in the dojo.data.store whos checkbox state needs updating.
		//	newState:
		//		The new state of the checkbox: true or false
		//	example:
		//	| model.updateCheckboxState(item, true);
		//
		this._setCheckboxState( storeItem, newState );
		if( this.checkboxStrict ) {
			this._updateChildCheckbox( storeItem, newState );
			this._updateParentCheckbox( storeItem, newState );
		}
	},
	setAllChecked: function(checked) {
		var items = this.store._arrayOfAllItems;
		this.setCheckboxState(items, checked);
	},
	setCheckboxState: function(items, checked) {
		for (var i = 0; i < items.length; i++) {
			this._setCheckboxState(items[i], checked);
		}
	},
	getCheckedItems: function() {
		var items = this.store._arrayOfAllItems;
		var result = [];

		for (var i = 0; i < items.length; i++) {
			if (this.store.getValue(items[i], 'checkbox')) 
				result.push(items[i]);
		}

		return result;
   },

	getCheckboxState: function(/*dojo.data.Item*/ storeItem) {
		// summary:
		//		Get the current checkbox state from the dojo.data.store.
		// description:
		//		Get the current checkbox state from the dojo.data store. A checkbox can have three
		//		different states: true, false or undefined. Undefined in this context means no
		//		checkbox identifier (checkboxIdent) was found in the dojo.data store. Depending on
		//		the checkbox attributes as specified above the following will take place:
		//		a) 	If the current checkbox state is undefined and the checkbox attribute 'checkboxAll' or
		//			'checkboxRoot' is true one will be created and the default state 'checkboxState' will
		//			be applied.
		//		b)	If the current state is undefined and 'checkboxAll' is false the state undefined remains
		//			unchanged and is returned. This will prevent any tree node from creating a checkbox.
		//
		//	storeItem:
		//		The item in the dojo.data.store whos checkbox state is returned.
		//	example:
		//	| var currState = model.getCheckboxState(item);
		//		
		var currState = undefined;
		
		// Special handling required for the 'fake' root entry (the root is NOT a dojo.data.item).
		if ( storeItem == this.root ) {
			if( typeof(storeItem.checkbox) == "undefined" ) {
				this.root.checkbox = undefined;		// create a new checbox reference as undefined.
				if( this.checkboxRoot ) {
					currState = this.root.checkbox = this.checkboxState;
				}
			} else {
				currState = this.root.checkbox;
			}
		} else {	// a valid dojo.store.item
			currState = this.store.getValue(storeItem, this.checkboxIdent);
			if( currState == undefined && this.checkboxAll) {
				this._setCheckboxState( storeItem, this.checkboxState );
				currState = this.checkboxState;
			}
		}
		return currState  // the current state of the checkbox (true/false or undefined)
	},

	_setCheckboxState: function(/*dojo.data.Item*/ storeItem, /*Boolean*/ newState ) {
		// summary:
		//		Set/update the checkbox state on the dojo.data store.
		// description:
		//		Set/update the checkbox state on the dojo.data.store. Retreive the current
		//		state of the checkbox and validate if an update is required, this will keep 
		//		update events to a minimum. On completion a 'onCheckboxChange' event is
		//		triggered. 
		//		If the current state is undefined (ie: no checkbox attribute specified for 
		//		this dojo.data.item) the 'checkboxAll' attribute is checked	to see if one 
		//		needs to be created. In case of the root the 'checkboxRoot' attribute is checked.
		//		NOTE: the store.setValue function will create the 'checkbox' attribute for the 
		//		item if none exists.   
		//	storeItem:
		//		The item in the dojo.data.store whos checkbox state is updated.
		//	newState:
		//		The new state of the checkbox: true or false
		//	example:
		//	| model.setCheckboxState(item, true);
		//
		var stateChanged = true;
		
		if( storeItem != this.root ) {
			var currState = this.store.getValue(storeItem, this.checkboxIdent);
			if( currState != newState && ( currState !== undefined || this.checkboxAll ) ) {
				this.store.setValue(storeItem, this.checkboxIdent, newState);
			} else {
				stateChanged = false;	// No changes to the checkbox
			}
		} else {  // Tree root instance
			if( this.root.checkbox != newState && ( this.root.checkbox !== undefined || this.checkboxRoot ) ) {
				this.root.checkbox = newState;
			} else {
				stateChanged = false;
			}
		}
		if( stateChanged ) {	// In case of any changes trigger the update event.
			this.onCheckboxChange(storeItem);
		}
		return stateChanged;
	},
	
	_updateChildCheckbox: function(/*dojo.data.Item*/ parentItem, /*Boolean*/ newState ) {
		//	summary:
		//		Set all child checkboxes to true/false depending on the parent checkbox state.
		//	description:
		//		If a parent checkbox changes state, all child and grandchild checkboxes will be 
		//		updated to reflect the change. For example, if the parent state is set to true, 
		//		all child and grandchild checkboxes will receive that same 'true' state.
		//		If a child checkbox changes state and has multiple parent, all of its parents
		//		need to be re-evaluated.
		//	parentItem:
		//		The parent dojo.data.item whos child/grandchild checkboxes require updating.
		//	newState:
		//		The new state of the checkbox: true or false
		//
		if( this.mayHaveChildren( parentItem )) {
			this.getChildren( parentItem, dojo.hitch( this,
				function( children ) {
					dojo.forEach( children, function(child) {
						if( this._setCheckboxState(child, newState) ) {					
							var parents = this._getParentsItem(child);
							if( parents.length > 1 ) {
								this._updateParentCheckbox( child, newState );
							}
						}
						if( this.mayHaveChildren( child )) {
							this._updateChildCheckbox( child, newState );
						}
					}, this );
				}),
				function(err) {
					console.error(this, ": updating child checkboxes: ", err);
				} 
			);
		}
	},

	_updateParentCheckbox: function(/*dojo.data.Item*/ storeItem, /*Boolean*/ newState ) {
		//	summary:
		//		Update the parent checkbox state depending on the state of all child checkboxes.
		//	description:
		//		Update the parent checkbox state depending on the state of all child checkboxes.
		//		The parent checkbox automatically changes state if ALL child checkboxes are true
		//		or false. If, as a result, the parent checkbox changes state, we will check if 
		//		its parent needs to be updated as well all the way upto the root.
		//	storeItem:
		//		The dojo.data.item whos parent checkboxes require updating.
		//	newState:
		//		The new state of the checkbox: true or false
		//
		var parents = this._getParentsItem(storeItem);
		dojo.forEach( parents, function( parentItem ) {
			if( newState ) { // new state = true (checked)
				this.getChildren( parentItem, dojo.hitch( this,
					function(siblings) {
						var allChecked  = true;			
						dojo.some( siblings, function(sibling) {
							siblState = this.getCheckboxState(sibling);
							if( siblState !== undefined && allChecked )
								allChecked = siblState; 
							return !(allChecked);
						}, this );
						if( allChecked ) {
							this._setCheckboxState( parentItem, true );
							this._updateParentCheckbox( parentItem, true );
						}
					}),
					function(err) {
						console.error(this, ": updating parent checkboxes: ", err);
					}
				);
			} else { 	// new state = false (unchecked)
				if( this._setCheckboxState( parentItem, false ) ) {
					this._updateParentCheckbox( parentItem, false );
				}
			}
		}, this );
	},
	
	_getParentsItem: function(/*dojo.data.Item*/ storeItem ) {
		// summary:
		//		Get the parent(s) of a dojo.data item.  
		// description:
		//		Get the parent(s) of a dojo.data item. The '_reverseRefMap' entry of the item is
		//		used to identify the parent(s). A child will have a parent reference if the parent 
		//		specified the '_reference' attribute. 
		//		For example: children:[{_reference:'Mexico'}, {_reference:'Canada'}, ...
		//	storeItem:
		//		The dojo.data.item whos parent(s) will be returned.
		//
		var parents = [];

		if( storeItem != this.root ) {
			var references = storeItem[this.store._reverseRefMap];
			for(itemId in references ) {
				parents.push(this.store._itemsByIdentity[itemId]);
			}
			if (!parents.length) {
				parents.push(this.root);
			}
		}
		return parents // parent(s) of a dojo.data.item (Array of dojo.data.items)
	},

	validateData: function(/*dojo.data.Item*/ storeItem, /*thisObject*/ scope ) {
		// summary:
		//		Validate/normalize the parent(s) checkbox data in the dojo.data store.
		// description:
		//		Validate/normalize the parent-child checkbox relationship if the attribute
		//		'checkboxStrict' is set to true. This function is called as part of the post 
		//		creation of the Tree instance. All parent checkboxes are set to the appropriate
		//		state according to the actual state(s) of their children. 
		//		This will potentionally overwrite whatever was specified for the parent in the
		//		dojo.data store. This will garantee the tree is in a consistent state after startup.
		//	storeItem:
		//		The element to start traversing the dojo.data.store, typically model.root
		//	scope:
		//		The scope to use when this method executes.
		//	example:
		//	| this.model.validateData(this.model.root, this.model);
		//
		if( !scope.checkboxStrict ) {
			return;
		}
		scope.getChildren( storeItem, dojo.hitch( scope,
			function(children) {
				var allChecked  = true;
				var childState;
				dojo.forEach( children, function( child ) {
					if( this.mayHaveChildren( child )) {
						this.validateData( child, this );
					}
					childState = this.getCheckboxState( child );
					if( childState !== undefined && allChecked )
						allChecked = childState; 
				}, this);

				if ( this._setCheckboxState( storeItem, allChecked) ) {
					this._updateParentCheckbox( storeItem, allChecked);
				}
			}),
			function(err) {
				console.error(this, ": validating checkbox data: ", err);
			} 
		);
	},

	onCheckboxChange: function(/*dojo.data.Item*/ storeItem ) {
		// summary:
		//		Callback whenever a checkbox state has changed state, so that 
		//		the Tree can update the checkbox.  This callback is generally
		//		triggered by the '_setCheckboxState' function. 
		// tags:
		//		callback
	}
		
});

dojo.declare( "lib._CheckBoxTreeNode", dijit._TreeNode,
{
	// _checkbox: [protected] dojo.doc.element
	//		Local reference to the dojo.doc.element of type 'checkbox'
	_checkbox: null,

	_createCheckbox: function() {
		// summary:
		//		Create a checkbox on the CheckBoxTreeNode
		// description:
		//		Create a checkbox on the CheckBoxTreeNode. The checkbox is ONLY created if a
		//		valid reference was found in the dojo.data store or the attribute 'checkboxAll'
		//		is set to true. If the current state is 'undefined' no reference was found and 
		//		'checkboxAll' is set to false.
		//		Note: the attribute 'checkboxAll' is validated by the getCheckboxState function
		//		therefore no need to do that here. (see getCheckboxState for details).
		//		
		var	currState = this.tree.model.getCheckboxState( this.item );
		if( currState !== undefined ) {
			this._checkbox = new dijit.form.CheckBox();
			//this._checkbox = dojo.doc.createElement('input');
			this._checkbox.type    = 'checkbox';
			this._checkbox.attr('checked', currState);
			dojo.place(this._checkbox.domNode, this.expandoNode, 'after');
		}
	},
	
	postCreate: function() {
		// summary:
		//		Handle the creation of the checkbox after the CheckBoxTreeNode has been instanciated.
		// description:
		//		Handle the creation of the checkbox after the CheckBoxTreeNode has been instanciated.
		this._createCheckbox();
		this.inherited( arguments );
	}

});

dojo.declare( "lib.CheckBoxTree", dijit.Tree,
{
	
	onNodeChecked: function(/*dojo.data.Item*/ storeItem, /*treeNode*/ treeNode) {
		// summary:
		//		Callback when a checkbox tree node is checked
		// tags:
		//		callback
	},
	
	onNodeUnchecked: function(/*dojo.data.Item*/ storeItem, /* treeNode */ treeNode) {
		// summary:
		//		Callback when a checkbox tree node is unchecked
		// tags:
		//		callback
	},
	
	_onClick: function(/*TreeNode*/ nodeWidget, /*Event*/ e) {
		// summary:
		//		Translates click events into commands for the controller to process
		// description:
		//		the _onClick function is called whenever a 'click' is detected. This
		//		instance of _onClick only handles the click events associated with
		//		the checkbox whos DOM name is INPUT.
		// 
		var domElement = e.target;

		// Only handle checkbox clicks here
		if(domElement.type != 'checkbox') {
			return this.inherited( arguments );
		}

		this._publish("execute", { item: nodeWidget.item, node: nodeWidget} );
		// Go tell the model to update the checkbox state
		
		this.model.updateCheckbox( nodeWidget.item, nodeWidget._checkbox.checked ); 
		// Generate some additional events
		//this.onClick( nodeWidget.item, nodeWidget, e );
		if(nodeWidget._checkbox.checked) {
			this.onNodeChecked( nodeWidget.item, nodeWidget);
		} else {
			this.onNodeUnchecked( nodeWidget.item, nodeWidget);
		}
		this.focusNode(nodeWidget);
	},
	
	_onCheckboxChange: function(/*dojo.data.Item*/ storeItem ) {
		// summary:
		//		Processes notification of a change to a checkbox state (triggered by the model).
		// description:
		//		Whenever the model changes the state of a checkbox in the dojo.data.store it will 
		//		trigger the 'onCheckboxChange' event allowing the Tree to make the same changes 
		//		on the tree Node. There are several conditions why a tree node or checkbox does not
		//		exists:
		//		a) 	The node has not been created yet (the user has not expanded the tree node yet).
		//		b) 	The checkbox may be null if condition (a) exists or no 'checkbox' attribute was
		//			specified for the associated dojo.data.item and the attribute 'checkboxAll' is 
		//			set to false. 
		// tags:
		//		callback
		var model 	 = this.model,
			identity = model.getIdentity(storeItem),
			nodes 	 = this._itemNodesMap[identity];

		// As of dijit.Tree 1.4 multiple references (parents) are supported, therefore we may have
		// to update multiple nodes which are all associated with the same dojo.data.item.
		if( nodes ) {
			dojo.forEach( nodes, function(node) {
				if( node._checkbox != null ) {
					node._checkbox.attr('checked', this.model.getCheckboxState( storeItem ));
				}
			}, this );
		}
	}, 

	postCreate: function() {
		// summary:
		//		Handle any specifics related to the tree and model after the instanciation of the Tree. 
		// description:
		//		Validate if we have a 'write' store first. Subscribe to the 'onCheckboxChange' event 
		//		(triggered by the model) and kickoff the initial checkbox data validation.
		//
		var store = this.model.store;
		if(!store.getFeatures()['dojo.data.api.Write']){
			throw new Error("lib.CheckboxTree: store must support dojo.data.Write");
		}
		this.connect(this.model, "onCheckboxChange", "_onCheckboxChange");
		this.model.validateData( this.model.root, this.model );
		this.inherited(arguments);
	},

	_createTreeNode: function( args ) {
		// summary:
		//		Create a new CheckboxTreeNode instance.
		// description:
		//		Create a new CheckboxTreeNode instance.
		return new lib._CheckBoxTreeNode(args);
	}

});