/*
This file is part of Ext JS 4.2

Copyright (c) 2011-2013 Sencha Inc

Contact:  http://www.sencha.com/contact

GNU General Public License Usage
This file may be used under the terms of the GNU General Public License version 3.0 as
published by the Free Software Foundation and appearing in the file LICENSE included in the
packaging of this file.

Please review the following information to ensure the GNU General Public License version 3.0
requirements will be met: http://www.gnu.org/copyleft/gpl.html.

If you are unsure which license is appropriate for your use, please contact the sales department
at http://www.sencha.com/contact.

Build date: 2013-05-16 14:36:50 (f9be68accb407158ba2b1be2c226a6ce1f649314)
*/
/**
 * 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.view.View 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.view.View#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.
 */
Ext.define('Ext.dd.DragZone', {
    extend: 'Ext.dd.DragSource',

    /**
     * Creates new DragZone.
     * @param {String/HTMLElement/Ext.Element} el The container element or ID of it.
     * @param {Object} config
     */
    constructor : function(el, config){
        var me = this,
            scroll = me.containerScroll;
        
        me.callParent([el, config]);
        if (scroll) {
            el = me.scrollEl || el;
            el = Ext.get(el);
            if (Ext.isObject(scroll)) {
                el.ddScrollConfig = scroll;
            }
            Ext.dd.ScrollManager.register(el);
        }
    },

    /**
     * @cfg {Object/Boolean} containerScroll
     * True to register this container with the Scrollmanager for auto scrolling during drag operations.
     * A {@link Ext.dd.ScrollManager} configuration may also be passed.
     */
    
    /**
     * @cfg {String/HTMLElement/Ext.dom.Element} scrollEl
     * An element to register with the ScrollManager if {@link #containerScroll}
     * is set. Defaults to the drag element.
     */

    /**
     * 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 {Event} 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
     * @template
     */
    onInitDrag : function(x, y){
        this.proxy.update(this.dragData.ddel.cloneNode(true));
        this.onStartDrag(x, y);
        return true;
    },

    /**
     * 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 {Event} e The mouse up event
     * @return {Number[]} The xy location (e.g. `[100, 200]`)
     * @template
     */
    getRepairXY : function(e){
        return Ext.fly(this.dragData.ddel).getXY();
    },

    destroy : function(){
        this.callParent();
        if (this.containerScroll) {
            Ext.dd.ScrollManager.unregister(this.scrollEl || this.el);
        }
    }
});
