/*

YUI 3.10.3 (build 2fb5187)

Copyright 2013 Yahoo! Inc. All rights reserved.

Licensed under the BSD License.

http://yuilibrary.com/license/

*/

YUI.add('widget-parent', function (Y, NAME) {

/**

 * Extension enabling a Widget to be a parent of another Widget.

 *

 * @module widget-parent

 */

var Lang = Y.Lang,

    RENDERED = "rendered",

    BOUNDING_BOX = "boundingBox";

/**

 * Widget extension providing functionality enabling a Widget to be a 

 * parent of another Widget.

 *

 * <p>In addition to the set of attributes supported by WidgetParent, the constructor

 * configuration object can also contain a <code>children</code> which can be used

 * to add child widgets to the parent during construction. The <code>children</code>

 * property is an array of either child widget instances or child widget configuration 

 * objects, and is sugar for the <a href="#method_add">add</a> method. See the 

 * <a href="#method_add">add</a> for details on the structure of the child widget 

 * configuration object.

 * @class WidgetParent

 * @constructor

 * @uses ArrayList

 * @param {Object} config User configuration object.

 */

function Parent(config) {

    /**

    * Fires when a Widget is add as a child.  The event object will have a 

    * 'child' property that returns a reference to the child Widget, as well 

    * as an 'index' property that returns a reference to the index specified 

    * when the add() method was called.

    * <p>

    * Subscribers to the "on" moment of this event, will be notified 

    * before a child is added.

    * </p>

    * <p>

    * Subscribers to the "after" moment of this event, will be notified

    * after a child is added.

    * </p>

    *

    * @event addChild

    * @preventable _defAddChildFn

    * @param {EventFacade} e The Event Facade

    */

    this.publish("addChild", { 

        defaultTargetOnly: true,

        defaultFn: this._defAddChildFn 

    });

    /**

    * Fires when a child Widget is removed.  The event object will have a 

    * 'child' property that returns a reference to the child Widget, as well 

    * as an 'index' property that returns a reference child's ordinal position.

    * <p>

    * Subscribers to the "on" moment of this event, will be notified 

    * before a child is removed.

    * </p>

    * <p>

    * Subscribers to the "after" moment of this event, will be notified

    * after a child is removed.

    * </p>

    *

    * @event removeChild

    * @preventable _defRemoveChildFn

    * @param {EventFacade} e The Event Facade

    */

    this.publish("removeChild", { 

        defaultTargetOnly: true,

        defaultFn: this._defRemoveChildFn 

    });

    this._items = [];

    var children,

        handle;

    if (config && config.children) {

        children = config.children;

        handle = this.after("initializedChange", function (e) {

            this._add(children);

            handle.detach();

        });

    }

    //  Widget method overlap

    Y.after(this._renderChildren, this, "renderUI");

    Y.after(this._bindUIParent, this, "bindUI");

    this.after("selectionChange", this._afterSelectionChange);

    this.after("selectedChange", this._afterParentSelectedChange);

    this.after("activeDescendantChange", this._afterActiveDescendantChange);

    this._hDestroyChild = this.after("*:destroy", this._afterDestroyChild);

    this.after("*:focusedChange", this._updateActiveDescendant);

}

Parent.ATTRS = {

    /**

     * @attribute defaultChildType

     * @type {String|Object}

     *

     * @description String representing the default type of the children 

     * managed by this Widget.  Can also supply default type as a constructor

     * reference.

     */

    defaultChildType: {

        setter: function (val) {

            var returnVal = Y.Attribute.INVALID_VALUE,

                FnConstructor = Lang.isString(val) ? Y[val] : val;

            if (Lang.isFunction(FnConstructor)) {

                returnVal = FnConstructor;

            }

            return returnVal;

        }

    },

    /**

     * @attribute activeDescendant

     * @type Widget

     * @readOnly

     *

     * @description Returns the Widget's currently focused descendant Widget.

     */

    activeDescendant: {    

        readOnly: true

    },

    /**

     * @attribute multiple

     * @type Boolean

     * @default false

     * @writeOnce 

     *

     * @description Boolean indicating if multiple children can be selected at 

     * once.  Whether or not multiple selection is enabled is always delegated

     * to the value of the <code>multiple</code> attribute of the root widget

     * in the object hierarchy.

     */

    multiple: {

        value: false,

        validator: Lang.isBoolean,

        writeOnce: true,

        getter: function (value) {

            var root = this.get("root");

            return (root && root != this) ? root.get("multiple") : value;

        }

    },

    /**

     * @attribute selection

     * @type {ArrayList|Widget}

     * @readOnly  

     *

     * @description Returns the currently selected child Widget.  If the 

     * <code>mulitple</code> attribte is set to <code>true</code> will 

     * return an Y.ArrayList instance containing the currently selected 

     * children.  If no children are selected, will return null.

     */

    selection: {

        readOnly: true,

        setter: "_setSelection",

        getter: function (value) {

            var selection = Lang.isArray(value) ? 

                    (new Y.ArrayList(value)) : value;

            return selection;

        }

    },

    selected: {

        setter: function (value) {

            //  Enforces selection behavior on for parent Widgets.  Parent's 

            //  selected attribute can be set to the following:

            //  0 - Not selected

            //  1 - Fully selected (all children are selected).  In order for 

            //  all children to be selected, multiple selection must be 

            //  enabled.  Therefore, you cannot set the "selected" attribute 

            //  on a parent Widget to 1 unless multiple selection is enabled.

            //  2 - Partially selected, meaning one ore more (but not all) 

            //  children are selected.

            var returnVal = value;

            if (value === 1 && !this.get("multiple")) {

                returnVal = Y.Attribute.INVALID_VALUE;

            }

            return returnVal;

        }

    }

};

Parent.prototype = {

    /**

     * The destructor implementation for Parent widgets. Destroys all children.

     * @method destructor

     */

    destructor: function() {

        this._destroyChildren();

    },

    /**

     * Destroy event listener for each child Widget, responsible for removing 

     * the destroyed child Widget from the parent's internal array of children

     * (_items property).

     *

     * @method _afterDestroyChild

     * @protected

     * @param {EventFacade} event The event facade for the attribute change.

     */

    _afterDestroyChild: function (event) {

        var child = event.target;

        if (child.get("parent") == this) {

            child.remove();

        }        

    },

    /**

     * Attribute change listener for the <code>selection</code> 

     * attribute, responsible for setting the value of the 

     * parent's <code>selected</code> attribute.

     *

     * @method _afterSelectionChange

     * @protected

     * @param {EventFacade} event The event facade for the attribute change.

     */

    _afterSelectionChange: function (event) {

        if (event.target == this && event.src != this) {

            var selection = event.newVal,

                selectedVal = 0;    //  Not selected

            if (selection) {

                selectedVal = 2;    //  Assume partially selected, confirm otherwise

                if (Y.instanceOf(selection, Y.ArrayList) && 

                    (selection.size() === this.size())) {

                    selectedVal = 1;    //  Fully selected

                }

            }

            this.set("selected", selectedVal, { src: this });

        }

    },

    /**

     * Attribute change listener for the <code>activeDescendant</code> 

     * attribute, responsible for setting the value of the 

     * parent's <code>activeDescendant</code> attribute.

     *

     * @method _afterActiveDescendantChange

     * @protected

     * @param {EventFacade} event The event facade for the attribute change.

     */

    _afterActiveDescendantChange: function (event) {

        var parent = this.get("parent");

        if (parent) {

            parent._set("activeDescendant", event.newVal);

        }

    },

    /**

     * Attribute change listener for the <code>selected</code> 

     * attribute, responsible for syncing the selected state of all children to 

     * match that of their parent Widget.

     * 

     *

     * @method _afterParentSelectedChange

     * @protected

     * @param {EventFacade} event The event facade for the attribute change.

     */

    _afterParentSelectedChange: function (event) {

        var value = event.newVal;

        if (this == event.target && event.src != this && 

            (value === 0 || value === 1)) {

            this.each(function (child) {

                //  Specify the source of this change as the parent so that 

                //  value of the parent's "selection" attribute isn't 

                //  recalculated

                child.set("selected", value, { src: this });

            }, this);

        }

    },

    /**

     * Default setter for <code>selection</code> attribute changes.

     *

     * @method _setSelection

     * @protected

     * @param child {Widget|Array} Widget or Array of Widget instances.     

     * @return {Widget|Array} Widget or Array of Widget instances.

     */

    _setSelection: function (child) {

        var selection = null,

            selected;

        if (this.get("multiple") && !this.isEmpty()) {

            selected = [];

            this.each(function (v) {

               if (v.get("selected") > 0) {

                   selected.push(v);

               }

            });

            if (selected.length > 0) {

                selection = selected;

            }

        }

        else {

            if (child.get("selected") > 0) {

                selection = child;

            }

        }

        return selection;

    },

    /**

     * Attribute change listener for the <code>selected</code> 

     * attribute of child Widgets, responsible for setting the value of the 

     * parent's <code>selection</code> attribute.

     *

     * @method _updateSelection

     * @protected

     * @param {EventFacade} event The event facade for the attribute change.

     */

    _updateSelection: function (event) {

        var child = event.target,

            selection;

        if (child.get("parent") == this) {

            if (event.src != "_updateSelection") {

                selection = this.get("selection");

                if (!this.get("multiple") && selection && event.newVal > 0) {

                    //  Deselect the previously selected child.

                    //  Set src equal to the current context to prevent

                    //  unnecessary re-calculation of the selection.

                    selection.set("selected", 0, { src: "_updateSelection" });

                }

                this._set("selection", child);

            }

            if (event.src == this) {

                this._set("selection", child, { src: this });

            }

        }

    },

    /**

     * Attribute change listener for the <code>focused</code> 

     * attribute of child Widgets, responsible for setting the value of the 

     * parent's <code>activeDescendant</code> attribute.

     *

     * @method _updateActiveDescendant

     * @protected

     * @param {EventFacade} event The event facade for the attribute change.

     */

    _updateActiveDescendant: function (event) {

        var activeDescendant = (event.newVal === true) ? event.target : null;

        this._set("activeDescendant", activeDescendant);

    },