dojo.provide("dijit._base.focus");

dojo.require("dojo.window");
dojo.require("dijit._base.manager");	// for dijit.isTabNavigable()

// summary:
//		These functions are used to query or set the focus and selection.
//
//		Also, they trace when widgets become activated/deactivated,
//		so that the widget can fire _onFocus/_onBlur events.
//		"Active" here means something similar to "focused", but
//		"focus" isn't quite the right word because we keep track of
//		a whole stack of "active" widgets.  Example: ComboButton --> Menu -->
//		MenuItem.  The onBlur event for ComboButton doesn't fire due to focusing
//		on the Menu or a MenuItem, since they are considered part of the
//		ComboButton widget.  It only happens when focus is shifted
//		somewhere completely different.

dojo.mixin(dijit, {
	// _curFocus: DomNode
	//		Currently focused item on screen
	_curFocus: null,

	// _prevFocus: DomNode
	//		Previously focused item on screen
	_prevFocus: null,

	isCollapsed: function(){
		// summary:
		//		Returns true if there is no text selected
		return dijit.getBookmark().isCollapsed;
	},

	getBookmark: function(){
		// summary:
		//		Retrieves a bookmark that can be used with moveToBookmark to return to the same range
		var bm, rg, tg, sel = dojo.doc.selection, cf = dijit._curFocus;

		if(dojo.global.getSelection){
			//W3C Range API for selections.
			sel = dojo.global.getSelection();
			if(sel){
				if(sel.isCollapsed){
					tg = cf? cf.tagName : "";
					if(tg){
						//Create a fake rangelike item to restore selections.
						tg = tg.toLowerCase();
						if(tg == "textarea" ||
								(tg == "input" && (!cf.type || cf.type.toLowerCase() == "text"))){
							sel = {
								start: cf.selectionStart,
								end: cf.selectionEnd,
								node: cf,
								pRange: true
							};
							return {isCollapsed: (sel.end <= sel.start), mark: sel}; //Object.
						}
					}
					bm = {isCollapsed:true};
					if(sel.rangeCount){
						bm.mark = sel.getRangeAt(0).cloneRange();
					}
				}else{
					rg = sel.getRangeAt(0);
					bm = {isCollapsed: false, mark: rg.cloneRange()};
				}
			}
		}else if(sel){
			// If the current focus was a input of some sort and no selection, don't bother saving
			// a native bookmark.  This is because it causes issues with dialog/page selection restore.
			// So, we need to create psuedo bookmarks to work with.
			tg = cf ? cf.tagName : "";
			tg = tg.toLowerCase();
			if(cf && tg && (tg == "button" || tg == "textarea" || tg == "input")){
				if(sel.type && sel.type.toLowerCase() == "none"){
					return {
						isCollapsed: true,
						mark: null
					}
				}else{
					rg = sel.createRange();
					return {
						isCollapsed: rg.text && rg.text.length?false:true,
						mark: {
							range: rg,
							pRange: true
						}
					};
				}
			}
			bm = {};

			//'IE' way for selections.
			try{
				// createRange() throws exception when dojo in iframe
				//and nothing selected, see #9632
				rg = sel.createRange();
				bm.isCollapsed = !(sel.type == 'Text' ? rg.htmlText.length : rg.length);
			}catch(e){
				bm.isCollapsed = true;
				return bm;
			}
			if(sel.type.toUpperCase() == 'CONTROL'){
				if(rg.length){
					bm.mark=[];
					var i=0,len=rg.length;
					while(i<len){
						bm.mark.push(rg.item(i++));
					}
				}else{
					bm.isCollapsed = true;
					bm.mark = null;
				}
			}else{
				bm.mark = rg.getBookmark();
			}
		}else{
			console.warn("No idea how to store the current selection for this browser!");
		}
		return bm; // Object
	},

	moveToBookmark: function(/*Object*/bookmark){
		// summary:
		//		Moves current selection to a bookmark
		// bookmark:
		//		This should be a returned object from dijit.getBookmark()

		var _doc = dojo.doc,
			mark = bookmark.mark;
		if(mark){
			if(dojo.global.getSelection){
				//W3C Rangi API (FF, WebKit, Opera, etc)
				var sel = dojo.global.getSelection();
				if(sel && sel.removeAllRanges){
					if(mark.pRange){
						var r = mark;
						var n = r.node;
						n.selectionStart = r.start;
						n.selectionEnd = r.end;
					}else{
						sel.removeAllRanges();
						sel.addRange(mark);
					}
				}else{
					console.warn("No idea how to restore selection for this browser!");
				}
			}else if(_doc.selection && mark){
				//'IE' way.
				var rg;
				if(mark.pRange){
					rg = mark.range;
				}else if(dojo.isArray(mark)){
					rg = _doc.body.createControlRange();
					//rg.addElement does not have call/apply method, so can not call it directly
					//rg is not available in "range.addElement(item)", so can't use that either
					dojo.forEach(mark, function(n){
						rg.addElement(n);
					});
				}else{
					rg = _doc.body.createTextRange();
					rg.moveToBookmark(mark);
				}
				rg.select();
			}
		}
	},

	getFocus: function(/*Widget?*/ menu, /*Window?*/ openedForWindow){
		// summary:
		//		Called as getFocus(), this returns an Object showing the current focus
		//		and selected text.
		//
		//		Called as getFocus(widget), where widget is a (widget representing) a button
		//		that was just pressed, it returns where focus was before that button
		//		was pressed.   (Pressing the button may have either shifted focus to the button,
		//		or removed focus altogether.)   In this case the selected text is not returned,
		//		since it can't be accurately determined.
		//
		// menu: dijit._Widget or {domNode: DomNode} structure
		//		The button that was just pressed.  If focus has disappeared or moved
		//		to this button, returns the previous focus.  In this case the bookmark
		//		information is already lost, and null is returned.
		//
		// openedForWindow:
		//		iframe in which menu was opened
		//
		// returns:
		//		A handle to restore focus/selection, to be passed to `dijit.focus`
		var node = !dijit._curFocus || (menu && dojo.isDescendant(dijit._curFocus, menu.domNode)) ? dijit._prevFocus : dijit._curFocus;
		return {
			node: node,
			bookmark: (node == dijit._curFocus) && dojo.withGlobal(openedForWindow || dojo.global, dijit.getBookmark),
			openedForWindow: openedForWindow
		}; // Object
	},

	focus: function(/*Object || DomNode */ handle){
		// summary:
		//		Sets the focused node and the selection according to argument.
		//		To set focus to an iframe's content, pass in the iframe itself.
		// handle:
		//		object returned by get(), or a DomNode

		if(!handle){ return; }

		var node = "node" in handle ? handle.node : handle,		// because handle is either DomNode or a composite object
			bookmark = handle.bookmark,
			openedForWindow = handle.openedForWindow,
			collapsed = bookmark ? bookmark.isCollapsed : false;

		// Set the focus
		// Note that for iframe's we need to use the <iframe> to follow the parentNode chain,
		// but we need to set focus to iframe.contentWindow
		if(node){
			var focusNode = (node.tagName.toLowerCase() == "iframe") ? node.contentWindow : node;
			if(focusNode && focusNode.focus){
				try{
					// Gecko throws sometimes if setting focus is impossible,
					// node not displayed or something like that
					focusNode.focus();
				}catch(e){/*quiet*/}
			}
			dijit._onFocusNode(node);
		}

		// set the selection
		// do not need to restore if current selection is not empty
		// (use keyboard to select a menu item) or if previous selection was collapsed
		// as it may cause focus shift (Esp in IE).
		if(bookmark && dojo.withGlobal(openedForWindow || dojo.global, dijit.isCollapsed) && !collapsed){
			if(openedForWindow){
				openedForWindow.focus();
			}
			try{
				dojo.withGlobal(openedForWindow || dojo.global, dijit.moveToBookmark, null, [bookmark]);
			}catch(e2){
				/*squelch IE internal error, see http://trac.dojotoolkit.org/ticket/1984 */
			}
		}
	},

	// _activeStack: dijit._Widget[]
	//		List of currently active widgets (focused widget and it's ancestors)
	_activeStack: [],

	registerIframe: function(/*DomNode*/ iframe){
		// summary:
		//		Registers listeners on the specified iframe so that any click
		//		or focus event on that iframe (or anything in it) is reported
		//		as a focus/click event on the <iframe> itself.
		// description:
		//		Currently only used by editor.
		// returns:
		//		Handle to pass to unregisterIframe()
		return dijit.registerWin(iframe.contentWindow, iframe);
	},

	unregisterIframe: function(/*Object*/ handle){
		// summary:
		//		Unregisters listeners on the specified iframe created by registerIframe.
		//		After calling be sure to delete or null out the handle itself.
		// handle:
		//		Handle returned by registerIframe()

		dijit.unregisterWin(handle);
	},

	registerWin: function(/*Window?*/targetWindow, /*DomNode?*/ effectiveNode){
		// summary:
		//		Registers listeners on the specified window (either the main
		//		window or an iframe's window) to detect when the user has clicked somewhere
		//		or focused somewhere.
		// description:
		//		Users should call registerIframe() instead of this method.
		// targetWindow:
		//		If specified this is the window associated with the iframe,
		//		i.e. iframe.contentWindow.
		// effectiveNode:
		//		If specified, report any focus events inside targetWindow as
		//		an event on effectiveNode, rather than on evt.target.
		// returns:
		//		Handle to pass to unregisterWin()

		// TODO: make this function private in 2.0; Editor/users should call registerIframe(),

		var mousedownListener = function(evt){
			dijit._justMouseDowned = true;
			setTimeout(function(){ dijit._justMouseDowned = false; }, 0);
			
			// workaround weird IE bug where the click is on an orphaned node
			// (first time clicking a Select/DropDownButton inside a TooltipDialog)
			if(dojo.isIE && evt && evt.srcElement && evt.srcElement.parentNode == null){
				return;
			}

			dijit._onTouchNode(effectiveNode || evt.target || evt.srcElement, "mouse");
		};
		//dojo.connect(targetWindow, "onscroll", ???);

		// Listen for blur and focus events on targetWindow's document.
		// IIRC, I'm using attachEvent() rather than dojo.connect() because focus/blur events don't bubble
		// through dojo.connect(), and also maybe to catch the focus events early, before onfocus handlers
		// fire.
		// Connect to <html> (rather than document) on IE to avoid memory leaks, but document on other browsers because
		// (at least for FF) the focus event doesn't fire on <html> or <body>.
		var doc = dojo.isIE ? targetWindow.document.documentElement : targetWindow.document;
		if(doc){
			if(dojo.isIE){
				doc.attachEvent('onmousedown', mousedownListener);
				var activateListener = function(evt){
					// IE reports that nodes like <body> have gotten focus, even though they have tabIndex=-1,
					// Should consider those more like a mouse-click than a focus....
					if(evt.srcElement.tagName.toLowerCase() != "#document" &&
						dijit.isTabNavigable(evt.srcElement)){
						dijit._onFocusNode(effectiveNode || evt.srcElement);
					}else{
						dijit._onTouchNode(effectiveNode || evt.srcElement);
					}
				};
				doc.attachEvent('onactivate', activateListener);
				var deactivateListener =  function(evt){
					dijit._onBlurNode(effectiveNode || evt.srcElement);
				};
				doc.attachEvent('ondeactivate', deactivateListener);

				return function(){
					doc.detachEvent('onmousedown', mousedownListener);
					doc.detachEvent('onactivate', activateListener);
					doc.detachEvent('ondeactivate', deactivateListener);
					doc = null;	// prevent memory leak (apparent circular reference via closure)
				};
			}else{
				doc.addEventListener('mousedown', mousedownListener, true);
				var focusListener = function(evt){
					dijit._onFocusNode(effectiveNode || evt.target);
				};
				doc.addEventListener('focus', focusListener, true);
				var blurListener = function(evt){
					dijit._onBlurNode(effectiveNode || evt.target);
				};
				doc.addEventListener('blur', blurListener, true);

				return function(){
					doc.removeEventListener('mousedown', mousedownListener, true);
					doc.removeEventListener('focus', focusListener, true);
					doc.removeEventListener('blur', blurListener, true);
					doc = null;	// prevent memory leak (apparent circular reference via closure)
				};
			}
		}
	},

	unregisterWin: function(/*Handle*/ handle){
		// summary:
		//		Unregisters listeners on the specified window (either the main
		//		window or an iframe's window) according to handle returned from registerWin().
		//		After calling be sure to delete or null out the handle itself.

		// Currently our handle is actually a function
		handle && handle();
	},

	_onBlurNode: function(/*DomNode*/ node){
		// summary:
		// 		Called when focus leaves a node.
		//		Usually ignored, _unless_ it *isn't* follwed by touching another node,
		//		which indicates that we tabbed off the last field on the page,
		//		in which case every widget is marked inactive
		dijit._prevFocus = dijit._curFocus;
		dijit._curFocus = null;

		if(dijit._justMouseDowned){
			// the mouse down caused a new widget to be marked as active; this blur event
			// is coming late, so ignore it.
			return;
		}

		// if the blur event isn't followed by a focus event then mark all widgets as inactive.
		if(dijit._clearActiveWidgetsTimer){
			clearTimeout(dijit._clearActiveWidgetsTimer);
		}
		dijit._clearActiveWidgetsTimer = setTimeout(function(){
			delete dijit._clearActiveWidgetsTimer;
			dijit._setStack([]);
			dijit._prevFocus = null;
		}, 100);
	},

	_onTouchNode: function(/*DomNode*/ node, /*String*/ by){
		// summary:
		//		Callback when node is focused or mouse-downed
		// node:
		//		The node that was touched.
		// by:
		//		"mouse" if the focus/touch was caused by a mouse down event

		// ignore the recent blurNode event
		if(dijit._clearActiveWidgetsTimer){
			clearTimeout(dijit._clearActiveWidgetsTimer);
			delete dijit._clearActiveWidgetsTimer;
		}

		// compute stack of active widgets (ex: ComboButton --> Menu --> MenuItem)
		var newStack=[];
		try{
			while(node){
				var popupParent = dojo.attr(node, "dijitPopupParent");
				if(popupParent){
					node=dijit.byId(popupParent).domNode;
				}else if(node.tagName && node.tagName.toLowerCase() == "body"){
					// is this the root of the document or just the root of an iframe?
					if(node === dojo.body()){
						// node is the root of the main document
						break;
					}
					// otherwise, find the iframe this node refers to (can't access it via parentNode,
					// need to do this trick instead). window.frameElement is supported in IE/FF/Webkit
					node=dojo.window.get(node.ownerDocument).frameElement;
				}else{
					// if this node is the root node of a widget, then add widget id to stack,
					// except ignore clicks on disabled widgets (actually focusing a disabled widget still works,
					// to support MenuItem)
					var id = node.getAttribute && node.getAttribute("widgetId"),
						widget = id && dijit.byId(id);
					if(widget && !(by == "mouse" && widget.get("disabled"))){
						newStack.unshift(id);
					}
					node=node.parentNode;
				}
			}
		}catch(e){ /* squelch */ }

		dijit._setStack(newStack, by);
	},

	_onFocusNode: function(/*DomNode*/ node){
		// summary:
		//		Callback when node is focused

		if(!node){
			return;
		}

		if(node.nodeType == 9){
			// Ignore focus events on the document itself.  This is here so that
			// (for example) clicking the up/down arrows of a spinner
			// (which don't get focus) won't cause that widget to blur. (FF issue)
			return;
		}

		dijit._onTouchNode(node);

		if(node == dijit._curFocus){ return; }
		if(dijit._curFocus){
			dijit._prevFocus = dijit._curFocus;
		}
		dijit._curFocus = node;
		dojo.publish("focusNode", [node]);
	},

	_setStack: function(/*String[]*/ newStack, /*String*/ by){
		// summary:
		//		The stack of active widgets has changed.  Send out appropriate events and records new stack.
		// newStack:
		//		array of widget id's, starting from the top (outermost) widget
		// by:
		//		"mouse" if the focus/touch was caused by a mouse down event

		var oldStack = dijit._activeStack;
		dijit._activeStack = newStack;

		// compare old stack to new stack to see how many elements they have in common
		for(var nCommon=0; nCommon<Math.min(oldStack.length, newStack.length); nCommon++){
			if(oldStack[nCommon] != newStack[nCommon]){
				break;
			}
		}

		var widget;
		// for all elements that have gone out of focus, send blur event
		for(var i=oldStack.length-1; i>=nCommon; i--){
			widget = dijit.byId(oldStack[i]);
			if(widget){
				widget._focused = false;
				widget._hasBeenBlurred = true;
				if(widget._onBlur){
					widget._onBlur(by);
				}
				dojo.publish("widgetBlur", [widget, by]);
			}
		}

		// for all element that have come into focus, send focus event
		for(i=nCommon; i<newStack.length; i++){
			widget = dijit.byId(newStack[i]);
			if(widget){
				widget._focused = true;
				if(widget._onFocus){
					widget._onFocus(by);
				}
				dojo.publish("widgetFocus", [widget, by]);
			}
		}
	}
});

// register top window and all the iframes it contains
dojo.addOnLoad(function(){
	var handle = dijit.registerWin(window);
	if(dojo.isIE){
		dojo.addOnWindowUnload(function(){
			dijit.unregisterWin(handle);
			handle = null;
		})
	}
});
