define([
	"dojo/_base/kernel",
	"dojo/_base/lang",
	"./sync",
	"./_atBindingExtension"
], function(kernel, lang, sync){

	kernel.experimental("dojox.mvc");

	var at = function(/*dojo/Stateful|String*/ target, /*String*/ targetProp){
		// summary:
		//		Returns a pointer to data binding target (a dojo/Stateful property), called at handle, which is used for start synchronization with data binding source (another dojo/Stateful property).
		// description:
		//		Typically used in data-dojo-props so that a widget can synchronize its attribute with another dojo/Stateful, like shown in the example.
		// target: dojo/Stateful|String
		//		dojo/Stateful to be synchronized.
		// targetProp: String
		//		The property name in target to be synchronized.
		// returns:
		//		A pointer to data binding target (a dojo/Stateful property), called at handle, which is used for start synchronization with data binding source (another dojo/Stateful property).
		// example:
		//		Two seconds later, the text box changes from "Foo" to "Bar" as the "value" property in model changes.
		// |		<html>
		// |			<head>
		// |				<script src="/path/to/dojo-toolkit/dojo/dojo.js" type="text/javascript" data-dojo-config="parseOnLoad: 0"></script>
		// |				<script type="text/javascript">
		// |					require([
		// |						"dojo/parser", "dojo/Stateful", "dijit/form/TextBox", "dojo/domReady!"
		// |					], function(parser, Stateful){
		// |						model = new Stateful({value: "Foo"});
		// |						setTimeout(function(){ model.set("value", "Bar"); }, 2000);
		// |						parser.parse();
		// |					});
		// |				</script>
		// |			</head>
		// |			<body>
		// |				<script type="dojo/require">at: "dojox/mvc/at"</script>
		// |				<input type="text" data-dojo-type="dijit/form/TextBox" data-dojo-props="value: at(model, 'value')">
		// |			</body>
		// |		</html>
		// example:
		//		Edit in text box is reflected to the text next to it.
		// |		<html>
		// |			<head>
		// |				<script src="/path/to/dojo-toolkit/dojo/dojo.js" type="text/javascript" data-dojo-config="parseOnLoad: 0"></script>
		// |				<script type="text/javascript">
		// |					require([
		// |						"dojo/parser", "dojo/Stateful", "dojo/domReady!"
		// |					], function(parser, Stateful){
		// |						model = new Stateful({value: "Foo"});
		// |						parser.parse();
		// |					});
		// |				</script>
		// |			</head>
		// |			<body>
		// |				<script type="dojo/require">at: "dojox/mvc/at"</script>
		// |				<input type="text" data-dojo-type="dijit/form/TextBox" data-dojo-props="value: at(model, 'value')">
		// |				<span data-dojo-type="dijit/_WidgetBase" data-dojo-props="_setValueAttr: {node: 'domNode', type: 'innerText'}, value: at(model, 'value')"></span>
		// |			</body>
		// |		</html>

		return { // dojox/mvc/at.handle
			atsignature: "dojox.mvc.at",
			target: target,
			targetProp: targetProp,
			bindDirection: sync.both,
			direction: function(/*Number*/ bindDirection){
				this.bindDirection = bindDirection;
				return this;
			},
			transform: function(/*dojox/mvc/sync.converter*/ converter){
				this.converter = converter;
				return this;
			},
			equals: function(/*Function*/ equals){
				this.equalsCallback = equals;
				return this;
			}
		};
	};

	/*=====
	at.handle = {
		// summary:
		//		A handle of data binding target (a dojo/Stateful property), which is used for start synchronization with data binding source (another dojo/Stateful property).

		// target: dojo/Stateful|String
		//		The data binding literal or dojo/Stateful to be synchronized.
		target: new dojo/Stateful(),

		// targetProp: String
		//		The property name in target to be synchronized.
		targetProp: "",

		// bindDirection: Number
		//		The data binding bindDirection, choose from: dojox/mvc/sync.from, dojox/mvc/sync.to or dojox/mvc/sync.both.
		bindDirection: dojox/mvc/sync.both,

		// converter: dojox/mvc/sync.converter
		//		Class/object containing the converter functions used when the data goes between data binding target (e.g. data model or controller) to data binding origin (e.g. widget).
		converter: null,

		direction: function(bindDirection){
			// summary:
			//		Sets data binding bindDirection.
			// bindDirection: Number
			//		The data binding bindDirection, choose from: dojox/mvc/sync.from, dojox/mvc/sync.to or dojox/mvc/sync.both.
		},

		transform: function(converter){
			// summary:
			//		Attach a data converter.
			// converter: dojox/mvc/sync.converter
			//		Class/object containing the converter functions used when the data goes between data binding target (e.g. data model or controller) to data binding origin (e.g. widget).
		},

		equals: function(equals){
			// summary:
			//		Sets a function to check if a value has really been changed when source/target dojo/Stateful changes.
			// equals: Function
			//		The function to check for the change.
			//		Should take two arguments, and should return true when those two are considered equal.
		}
	};
	=====*/

	// Data binding bindDirections
	at.from = sync.from;
	at.to = sync.to;
	at.both = sync.both;

	// lang.setObject() thing is for back-compat, remove it in 2.0
	return lang.setObject("dojox.mvc.at", at);
});
