/**
 * @class Ext.dd.DragZone
 * @extends Ext.dd.DragSource
 * 
This class provides a container DD instance that allows dragging of multiple child source nodes.
 * 
This class does not move the drag target nodes, but a proxy element which may contain
 * any DOM structure you wish. The DOM element to show in the proxy is provided by either a
 * provided implementation of {@link #getDragData}, or by registered draggables registered with {@link Ext.dd.Registry}
 * 
If you wish to provide draggability for an arbitrary number of DOM nodes, each of which represent some
 * application object (For example nodes in a {@link Ext.DataView DataView}) then use of this class
 * is the most efficient way to "activate" those nodes.
 * 
By default, this class requires that draggable child nodes are registered with {@link Ext.dd.Registry}.
 * However a simpler way to allow a DragZone to manage any number of draggable elements is to configure
 * the DragZone with  an implementation of the {@link #getDragData} method which interrogates the passed
 * mouse event to see if it has taken place within an element, or class of elements. This is easily done
 * by using the event's {@link Ext.EventObject#getTarget getTarget} method to identify a node based on a
 * {@link Ext.DomQuery} selector. For example, to make the nodes of a DataView draggable, use the following
 * technique. Knowledge of the use of the DataView is required:

myDataView.on('render', function(v) {
    myDataView.dragZone = new Ext.dd.DragZone(v.getEl(), {

//      On receipt of a mousedown event, see if it is within a DataView node.
//      Return a drag data object if so.
        getDragData: function(e) {

//          Use the DataView's own itemSelector (a mandatory property) to
//          test if the mousedown is within one of the DataView's nodes.
            var sourceEl = e.getTarget(v.itemSelector, 10);

//          If the mousedown is within a DataView node, clone the node to produce
//          a ddel element for use by the drag proxy. Also add application data
//          to the returned data object.
            if (sourceEl) {
                d = sourceEl.cloneNode(true);
                d.id = Ext.id();
                return {
                    ddel: d,
                    sourceEl: sourceEl,
                    repairXY: Ext.fly(sourceEl).getXY(),
                    sourceStore: v.store,
                    draggedRecord: v.{@link Ext.DataView#getRecord getRecord}(sourceEl)
                }
            }
        },

//      Provide coordinates for the proxy to slide back to on failed drag.
//      This is the original XY coordinates of the draggable element captured
//      in the getDragData method.
        getRepairXY: function() {
            return this.dragData.repairXY;
        }
    });
});
 * See the {@link Ext.dd.DropZone DropZone} documentation for details about building a DropZone which
 * cooperates with this DragZone.
 * @constructor
 * @param {Mixed} el The container element
 * @param {Object} config
 */
Ext.dd.DragZone = function(el, config){
    Ext.dd.DragZone.superclass.constructor.call(this, el, config);
    if(this.containerScroll){
        Ext.dd.ScrollManager.register(this.el);
    }
};

Ext.extend(Ext.dd.DragZone, Ext.dd.DragSource, {
    
/**
     * This property contains the data representing the dragged object. This data is set up by the implementation
     * of the {@link #getDragData} method. It must contain a ddel property, but can contain
     * any other data according to the application's needs.
     * @type Object
     * @property dragData
     */
    
/**
     * @cfg {Boolean} containerScroll True to register this container with the Scrollmanager
     * for auto scrolling during drag operations.
     */
    
/**
     * @cfg {String} hlColor The color to use when visually highlighting the drag source in the afterRepair
     * method after a failed drop (defaults to "c3daf9" - light blue)
     */

    
/**
     * Called when a mousedown occurs in this container. Looks in {@link Ext.dd.Registry}
     * for a valid target to drag based on the mouse down. Override this method
     * to provide your own lookup logic (e.g. finding a child by class name). Make sure your returned
     * object has a "ddel" attribute (with an HTML Element) for other functions to work.
     * @param {EventObject} e The mouse down event
     * @return {Object} The dragData
     */
    getDragData : function(e){
        return Ext.dd.Registry.getHandleFromEvent(e);
    },
    
    
/**
     * Called once drag threshold has been reached to initialize the proxy element. By default, it clones the
     * this.dragData.ddel
     * @param {Number} x The x position of the click on the dragged object
     * @param {Number} y The y position of the click on the dragged object
     * @return {Boolean} true to continue the drag, false to cancel
     */
    onInitDrag : function(x, y){
        this.proxy.update(this.dragData.ddel.cloneNode(true));
        this.onStartDrag(x, y);
        return true;
    },
    
    
/**
     * Called after a repair of an invalid drop. By default, highlights this.dragData.ddel 
     */
    afterRepair : function(){
        if(Ext.enableFx){
            Ext.Element.fly(this.dragData.ddel).highlight(this.hlColor || "c3daf9");
        }
        this.dragging = false;
    },

    
/**
     * Called before a repair of an invalid drop to get the XY to animate to. By default returns
     * the XY of this.dragData.ddel
     * @param {EventObject} e The mouse up event
     * @return {Array} The xy location (e.g. [100, 200])
     */
    getRepairXY : function(e){
        return Ext.Element.fly(this.dragData.ddel).getXY();  
    }
});