dojo.provide("dijit.layout._LayoutWidget");

dojo.require("dijit._Widget");
dojo.require("dijit._Container");
dojo.require("dijit._Contained");

dojo.declare("dijit.layout._LayoutWidget",
	[dijit._Widget, dijit._Container, dijit._Contained],
	{
		// summary:
		//		Base class for a _Container widget which is responsible for laying out its children.
		//		Widgets which mixin this code must define layout() to lay out the children.

		// baseClass: [protected extension] String
		//		This class name is applied to the widget's domNode
		//		and also may be used to generate names for sub nodes,
		//		like for example dijitTabContainer-content.
		baseClass: "dijitLayoutContainer",

		// isLayoutContainer: [private deprecated] Boolean
		//		TODO: this is unused, but maybe it *should* be used for a child to
		//		detect whether the parent is going to call resize() on it or not
		//		(see calls to getParent() and resize() in this file)
		isLayoutContainer: true,

		postCreate: function(){
			dojo.addClass(this.domNode, "dijitContainer");
			dojo.addClass(this.domNode, this.baseClass);
			
			// TODO: this.inherited()
		},

		startup: function(){
			// summary:
			//		Called after all the widgets have been instantiated and their
			//		dom nodes have been inserted somewhere under dojo.doc.body.
			//
			//		Widgets should override this method to do any initialization
			//		dependent on other widgets existing, and then call
			//		this superclass method to finish things off.
			//
			//		startup() in subclasses shouldn't do anything
			//		size related because the size of the widget hasn't been set yet.

			if(this._started){ return; }

			// TODO: seems like this code should be in _Container.startup().
			// Then things that don't extend LayoutContainer (like GridContainer)
			// would get the behavior for free.
			dojo.forEach(this.getChildren(), function(child){ child.startup(); });

			// If I am a top level widget
			if(!this.getParent || !this.getParent()){
				// Do recursive sizing and layout of all my descendants
				// (passing in no argument to resize means that it has to glean the size itself)
				this.resize();

				// Since my parent isn't a layout container, and my style is width=height=100% (or something similar),
				// then I need to watch when the window resizes, and size myself accordingly.
				// (Passing in no arguments to resize means that it has to glean the size itself.)
				// TODO: make one global listener to avoid getViewport() per widget.
				this._viewport = dijit.getViewport();
				this.connect(dojo.global, 'onresize', function(){
					var newViewport = dijit.getViewport();
					if(newViewport.w != this._viewport.w ||  newViewport.h != this._viewport.h){
						this._viewport = newViewport;
						this.resize();
					}
				});
			}
			
			this.inherited(arguments);
		},

		resize: function(changeSize, resultSize){
			// summary:
			//		Call this to resize a widget, or after its size has changed.
			// description:
			//		Change size mode:
			//			When changeSize is specified, changes the marginBox of this widget
			//			 and forces it to relayout its contents accordingly.
			//			changeSize may specify height, width, or both.
			//
			//			If resultSize is specified it indicates the size the widget will
			//			become after changeSize has been applied.
			//
			//		Notification mode:
			//			When changeSize is null, indicates that the caller has already changed
			//			the size of the widget, or perhaps it changed because the browser
			//			window was resized.  Tells widget to relayout it's contents accordingly.
			//
			//			If resultSize is also specified it indicates the size the widget has
			//			become.
			//
			//		In either mode, this method also:
			//			1. Sets this._borderBox and this._contentBox to the new size of
			//				the widget.  Queries the current domNode size if necessary.
			//			2. Calls layout() to resize contents (and maybe adjust child widgets).	
			//
			// changeSize: Object?
			//		Sets the widget to this margin-box size and position.
			//		May include any/all of the following properties:
			//	|	{w: int, h: int, l: int, t: int}
			//
			// resultSize: Object?
			//		The margin-box size of this widget after applying changeSize (if 
			//		changeSize is specified).  If caller knows this size and
			//		passes it in, we don't need to query the browser to get the size.
			//	|	{w: int, h: int}

			var node = this.domNode;

			// set margin box size, unless it wasn't specified, in which case use current size
			if(changeSize){
				dojo.marginBox(node, changeSize);

				// set offset of the node
				if(changeSize.t){ node.style.top = changeSize.t + "px"; }
				if(changeSize.l){ node.style.left = changeSize.l + "px"; }
			}

			// If either height or width wasn't specified by the user, then query node for it.
			// But note that setting the margin box and then immediately querying dimensions may return
			// inaccurate results, so try not to depend on it.
			var mb = resultSize || {};
			dojo.mixin(mb, changeSize || {});	// changeSize overrides resultSize
			if ( !("h" in mb) || !("w" in mb) ){
				mb = dojo.mixin(dojo.marginBox(node), mb);	// just use dojo.marginBox() to fill in missing values
			}

			// Compute and save the size of my border box and content box
			// (w/out calling dojo.contentBox() since that may fail if size was recently set)
			var cs = dojo.getComputedStyle(node);
			var me = dojo._getMarginExtents(node, cs);
			var be = dojo._getBorderExtents(node, cs);
			var bb = (this._borderBox = {
				w: mb.w - (me.w + be.w),
				h: mb.h - (me.h + be.h)
			});
			var pe = dojo._getPadExtents(node, cs);
			this._contentBox = {
				l: dojo._toPixelValue(node, cs.paddingLeft),
				t: dojo._toPixelValue(node, cs.paddingTop),
				w: bb.w - pe.w,
				h: bb.h - pe.h
			};

			// Callback for widget to adjust size of it's children
			this.layout();
		},

		layout: function(){
			// summary:
			//		Widgets override this method to size and position their contents/children.
			//		When this is called this._contentBox is guaranteed to be set (see resize()).
			//
			//		This is called after startup(), and also when the widget's size has been
			//		changed.
			// tags:
			//		protected extension
		},

		_setupChild: function(/*Widget*/child){
			// summary:
			//		Common setup for initial children and children which are added after startup
			// tags:
			//		protected extension

			dojo.addClass(child.domNode, this.baseClass+"-child");
			if(child.baseClass){
				dojo.addClass(child.domNode, this.baseClass+"-"+child.baseClass);
			}
		},

		addChild: function(/*Widget*/ child, /*Integer?*/ insertIndex){
			// Overrides _Container.addChild() to call _setupChild()
			this.inherited(arguments);
			if(this._started){
				this._setupChild(child);
			}
		},

		removeChild: function(/*Widget*/ child){
			// Overrides _Container.removeChild() to remove class added by _setupChild()
			dojo.removeClass(child.domNode, this.baseClass+"-child");
			if(child.baseClass){
				dojo.removeClass(child.domNode, this.baseClass+"-"+child.baseClass);
			}
			this.inherited(arguments);
		}
	}
);

dijit.layout.marginBox2contentBox = function(/*DomNode*/ node, /*Object*/ mb){
	// summary:
	//		Given the margin-box size of a node, return its content box size.
	//		Functions like dojo.contentBox() but is more reliable since it doesn't have
	//		to wait for the browser to compute sizes.
	var cs = dojo.getComputedStyle(node);
	var me = dojo._getMarginExtents(node, cs);
	var pb = dojo._getPadBorderExtents(node, cs);
	return {
		l: dojo._toPixelValue(node, cs.paddingLeft),
		t: dojo._toPixelValue(node, cs.paddingTop),
		w: mb.w - (me.w + pb.w),
		h: mb.h - (me.h + pb.h)
	};
};

(function(){
	var capitalize = function(word){
		return word.substring(0,1).toUpperCase() + word.substring(1);
	};

	var size = function(widget, dim){
		// size the child
		widget.resize ? widget.resize(dim) : dojo.marginBox(widget.domNode, dim);

		// record child's size, but favor our own numbers when we have them.
		// the browser lies sometimes
		dojo.mixin(widget, dojo.marginBox(widget.domNode));
		dojo.mixin(widget, dim);
	};

	dijit.layout.layoutChildren = function(/*DomNode*/ container, /*Object*/ dim, /*Object[]*/ children){
		// summary
		//		Layout a bunch of child dom nodes within a parent dom node
		// container:
		//		parent node
		// dim:
		//		{l, t, w, h} object specifying dimensions of container into which to place children
		// children:
		//		an array like [ {domNode: foo, layoutAlign: "bottom" }, {domNode: bar, layoutAlign: "client"} ]

		// copy dim because we are going to modify it
		dim = dojo.mixin({}, dim);

		dojo.addClass(container, "dijitLayoutContainer");

		// Move "client" elements to the end of the array for layout.  a11y dictates that the author
		// needs to be able to put them in the document in tab-order, but this algorithm requires that
		// client be last.
		children = dojo.filter(children, function(item){ return item.layoutAlign != "client"; })
			.concat(dojo.filter(children, function(item){ return item.layoutAlign == "client"; }));

		// set positions/sizes
		dojo.forEach(children, function(child){
			var elm = child.domNode,
				pos = child.layoutAlign;

			// set elem to upper left corner of unused space; may move it later
			var elmStyle = elm.style;
			elmStyle.left = dim.l+"px";
			elmStyle.top = dim.t+"px";
			elmStyle.bottom = elmStyle.right = "auto";

			dojo.addClass(elm, "dijitAlign" + capitalize(pos));

			// set size && adjust record of remaining space.
			// note that setting the width of a <div> may affect it's height.
			if(pos == "top" || pos == "bottom"){
				size(child, { w: dim.w });
				dim.h -= child.h;
				if(pos=="top"){
					dim.t += child.h;
				}else{
					elmStyle.top = dim.t + dim.h + "px";
				}
			}else if(pos == "left" || pos == "right"){
				size(child, { h: dim.h });
				dim.w -= child.w;
				if(pos == "left"){
					dim.l += child.w;
				}else{
					elmStyle.left = dim.l + dim.w + "px";
				}
			}else if(pos == "client"){
				size(child, dim);
			}
		});
	};

})();