define("dijit/layout/_ContentPaneResizeMixin", [
	"dojo/_base/array", // array.filter array.forEach
	"dojo/_base/declare", // declare
	"dojo/dom-class",	// domClass.contains domClass.toggle
	"dojo/dom-geometry",// domGeometry.contentBox domGeometry.marginBox
	"dojo/dom-style",
	"dojo/_base/lang", // lang.mixin
	"dojo/query", // query
	"dojo/sniff", // has("ie")
	"../registry",	// registry.byId
	"../Viewport",
	"./utils"	// marginBox2contextBox
], function(array, declare, domClass, domGeometry, domStyle, lang, query, has,
			registry, Viewport, layoutUtils){

// module:
//		dijit/layout/_ContentPaneResizeMixin


return declare("dijit.layout._ContentPaneResizeMixin", null, {
	// summary:
	//		Resize() functionality of ContentPane.   If there's a single layout widget
	//		child then it will call resize() with the same dimensions as the ContentPane.
	//		Otherwise just calls resize on each child.
	//
	//		Also implements basic startup() functionality, where starting the parent
	//		will start the children

	// doLayout: Boolean
	//		- false - don't adjust size of children
	//		- true - if there is a single visible child widget, set it's size to however big the ContentPane is
	doLayout: true,

	// isLayoutContainer: [protected] Boolean
	//		Indicates that this widget will call resize() on it's child widgets
	//		when they become visible.
	isLayoutContainer: true,

	startup: function(){
		// summary:
		//		See `dijit/layout/_LayoutWidget.startup()` for description.
		//		Although ContentPane doesn't extend _LayoutWidget, it does implement
		//		the same API.

		if(this._started){ return; }

		var parent = this.getParent();
		this._childOfLayoutWidget = parent && parent.isLayoutContainer;

		// I need to call resize() on my child/children (when I become visible), unless
		// I'm the child of a layout widget in which case my parent will call resize() on me and I'll do it then.
		this._needLayout = !this._childOfLayoutWidget;

		this.inherited(arguments);

		if(this._isShown()){
			this._onShow();
		}

		if(!this._childOfLayoutWidget){
			// Since my parent isn't a layout container, and my style *may be* width=height=100%
			// or something similar (either set directly or via a CSS class),
			// monitor when viewport size changes so that I can re-layout.
			// This is more for subclasses of ContentPane than ContentPane itself, although it
			// could be useful for a ContentPane if it has a single child widget inheriting ContentPane's size.
			this.own(Viewport.on("resize", lang.hitch(this, "resize")));
		}
	},

	_checkIfSingleChild: function(){
		// summary:
		//		Test if we have exactly one visible widget as a child,
		//		and if so assume that we are a container for that widget,
		//		and should propagate startup() and resize() calls to it.
		//		Skips over things like data stores since they aren't visible.

		var candidateWidgets = [],
			otherVisibleNodes = false;

		query("> *", this.containerNode).some(function(node){
			var widget = registry.byNode(node);
			if(widget && widget.resize){
				candidateWidgets.push(widget);
			}else if(node.offsetHeight){
				otherVisibleNodes = true;
			}
		});

		this._singleChild = candidateWidgets.length == 1 && !otherVisibleNodes ?
			candidateWidgets[0] : null;

		// So we can set overflow: hidden to avoid a safari bug w/scrollbars showing up (#9449)
		domClass.toggle(this.containerNode, this.baseClass + "SingleChild", !!this._singleChild);
	},

	resize: function(changeSize, resultSize){
		// summary:
		//		See `dijit/layout/_LayoutWidget.resize()` for description.
		//		Although ContentPane doesn't extend _LayoutWidget, it does implement
		//		the same API.

		this._resizeCalled = true;

		this._scheduleLayout(changeSize, resultSize);
	},

	_scheduleLayout: function(changeSize, resultSize){
		// summary:
		//		Resize myself, and call resize() on each of my child layout widgets, either now
		//		(if I'm currently visible) or when I become visible
		if(this._isShown()){
			this._layout(changeSize, resultSize);
		}else{
			this._needLayout = true;
			this._changeSize = changeSize;
			this._resultSize = resultSize;
		}
	},

	_layout: function(changeSize, resultSize){
		// summary:
		//		Resize myself according to optional changeSize/resultSize parameters, like a layout widget.
		//		Also, since I am an isLayoutContainer widget, each of my children expects me to
		//		call resize() or layout() on it.
		//
		//		Should be called on initialization and also whenever we get new content
		//		(from an href, or from set('content', ...))... but deferred until
		//		the ContentPane is visible

		delete this._needLayout;

		// For the TabContainer --> BorderContainer --> ContentPane case, _onShow() is
		// never called directly, so resize() is our trigger to do the initial href download (see [20099]).
		// However, don't load href for closed TitlePanes.
		if(!this._wasShown && this.open !== false){
			this._onShow();
		}

		// Set margin box size, unless it wasn't specified, in which case use current size.
		if(changeSize){
			domGeometry.setMarginBox(this.domNode, changeSize);
		}

		// Compute content box size of containerNode in case we [later] need to size our single child.
		var cn = this.containerNode;
		if(cn === this.domNode){
			// If changeSize or resultSize was passed to this method and this.containerNode ==
			// this.domNode then we can compute the content-box size without querying the node,
			// which is more reliable (similar to LayoutWidget.resize) (see for example #9449).
			var mb = resultSize || {};
			lang.mixin(mb, changeSize || {}); // changeSize overrides resultSize
			if(!("h" in mb) || !("w" in mb)){
				mb = lang.mixin(domGeometry.getMarginBox(cn), mb); // just use domGeometry.setMarginBox() to fill in missing values
			}
			this._contentBox = layoutUtils.marginBox2contentBox(cn, mb);
		}else{
			this._contentBox = domGeometry.getContentBox(cn);
		}

		this._layoutChildren();
	},

	_layoutChildren: function(){
		// Call _checkIfSingleChild() again in case app has manually mucked w/the content
		// of the ContentPane (rather than changing it through the set("content", ...) API.
		if(this.doLayout){
			this._checkIfSingleChild();
		}

		if(this._singleChild && this._singleChild.resize){
			var cb = this._contentBox || domGeometry.getContentBox(this.containerNode);

			// note: if widget has padding this._contentBox will have l and t set,
			// but don't pass them to resize() or it will doubly-offset the child
			this._singleChild.resize({w: cb.w, h: cb.h});
		}else{
			// All my child widgets are independently sized (rather than matching my size),
			// but I still need to call resize() on each child to make it layout.
			array.forEach(this.getChildren(), function(widget){
				if(widget.resize){
					widget.resize();
				}
			});
		}
	},

	_isShown: function(){
		// summary:
		//		Returns true if the content is currently shown.
		// description:
		//		If I am a child of a layout widget then it actually returns true if I've ever been visible,
		//		not whether I'm currently visible, since that's much faster than tracing up the DOM/widget
		//		tree every call, and at least solves the performance problem on page load by deferring loading
		//		hidden ContentPanes until they are first shown

		if(this._childOfLayoutWidget){
			// If we are TitlePane, etc - we return that only *IF* we've been resized
			if(this._resizeCalled && "open" in this){
				return this.open;
			}
			return this._resizeCalled;
		}else if("open" in this){
			return this.open;		// for TitlePane, etc.
		}else{
			var node = this.domNode, parent = this.domNode.parentNode;
			return (node.style.display != 'none') && (node.style.visibility != 'hidden') && !domClass.contains(node, "dijitHidden") &&
					parent && parent.style && (parent.style.display != 'none');
		}
	},

	_onShow: function(){
		// summary:
		//		Called when the ContentPane is made visible
		// description:
		//		For a plain ContentPane, this is called on initialization, from startup().
		//		If the ContentPane is a hidden pane of a TabContainer etc., then it's
		//		called whenever the pane is made visible.
		//
		//		Does layout/resize of child widget(s)

		// Need to keep track of whether ContentPane has been shown (which is different than
		// whether or not it's currently visible).
		this._wasShown = true;

		if(this._needLayout){
			// If a layout has been scheduled for when we become visible, do it now
			this._layout(this._changeSize, this._resultSize);
		}

		this.inherited(arguments);
	}
});

});