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

/**

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

 *

 * @module widget-child

 */

var Lang = Y.Lang;

/**

 * Widget extension providing functionality enabling a Widget to be a

 * child of another Widget.

 *

 * @class WidgetChild

 * @param {Object} config User configuration object.

*/

function Child() {

    //  Widget method overlap

    Y.after(this._syncUIChild, this, "syncUI");

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

}

Child.ATTRS = {

    /**

     * @attribute selected

     * @type Number

     * @default 0

     *

     * @description Number indicating if the Widget is selected.  Possible

     * values are:

     * <dl>

     * <dt>0</dt> <dd>(Default) Not selected</dd>

     * <dt>1</dt> <dd>Fully selected</dd>

     * <dt>2</dt> <dd>Partially selected</dd>

     * </dl>

    */

    selected: {

        value: 0,

        validator: Lang.isNumber

    },

    /**

     * @attribute index

     * @type Number

     * @readOnly

     *

     * @description Number representing the Widget's ordinal position in its

     * parent Widget.

     */

    index: {

        readOnly: true,

        getter: function () {

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

                index = -1;

            if (parent) {

                index = parent.indexOf(this);

            }

            return index;

        }

    },

    /**

     * @attribute parent

     * @type Widget

     * @readOnly

     *

     * @description Retrieves the parent of the Widget in the object hierarchy.

    */

    parent: {

        readOnly: true

    },

    /**

     * @attribute depth

     * @type Number

     * @default -1

     * @readOnly

     *

     * @description Number representing the depth of this Widget relative to

     * the root Widget in the object heirarchy.

     */

    depth: {

        readOnly: true,

        getter: function () {

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

                root = this.get("root"),

                depth = -1;

            while (parent) {

                depth = (depth + 1);

                if (parent == root) {

                    break;

                }

                parent = parent.get("parent");

            }

            return depth;

        }

    },

    /**

     * @attribute root

     * @type Widget

     * @readOnly

     *

     * @description Returns the root Widget in the object hierarchy.  If the

     * ROOT_TYPE property is set, the search for the root Widget will be

     * constrained to parent Widgets of the specified type.

     */

    root: {

        readOnly: true,

        getter: function () {

            var getParent = function (child) {

                var parent = child.get("parent"),

                    FnRootType = child.ROOT_TYPE,

                    criteria = parent;

                if (FnRootType) {

                    criteria = (parent && Y.instanceOf(parent, FnRootType));

                }

                return (criteria ? getParent(parent) : child);

            };

            return getParent(this);

        }

    }

};

Child.prototype = {

    /**

     * Constructor reference used to determine the root of a Widget-based

     * object tree.

     * <p>

     * Currently used to control the behavior of the <code>root</code>

     * attribute so that recursing up the object heirarchy can be constrained

     * to a specific type of Widget.  Widget authors should set this property

     * to the constructor function for a given Widget implementation.

     * </p>

     *

     * @property ROOT_TYPE

     * @type Object

     */

    ROOT_TYPE: null,

    /**

     * Returns the node on which to bind delegate listeners.

     *

     * Override of Widget's implementation of _getUIEventNode() to ensure that

     * all event listeners are bound to the Widget's topmost DOM element.

     * This ensures that the firing of each type of Widget UI event (click,

     * mousedown, etc.) is facilitated by a single, top-level, delegated DOM

     * event listener.

     *

     * @method _getUIEventNode

     * @for Widget

     * @protected

     */

    _getUIEventNode: function () {

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

            returnVal;

        if (root) {

            returnVal = root.get("boundingBox");

        }

        return returnVal;

    },

    /**

    * @method next

    * @description Returns the Widget's next sibling.

    * @param {Boolean} circular Boolean indicating if the parent's first child

    * should be returned if the child has no next sibling.

    * @return {Widget} Widget instance.

    */

    next: function (circular) {

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

            sibling;

        if (parent) {

            sibling = parent.item((this.get("index")+1));

        }

        if (!sibling && circular) {

            sibling = parent.item(0);

        }

        return sibling;

    },

    /**

    * @method previous

    * @description Returns the Widget's previous sibling.

    * @param {Boolean} circular Boolean indicating if the parent's last child

    * should be returned if the child has no previous sibling.

    * @return {Widget} Widget instance.

    */

    previous: function (circular) {

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

            index = this.get("index"),

            sibling;

        if (parent && index > 0) {

            sibling = parent.item([(index-1)]);

        }

        if (!sibling && circular) {

            sibling = parent.item((parent.size() - 1));

        }

        return sibling;

    },

    //  Override of Y.WidgetParent.remove()

    //  Sugar implementation allowing a child to remove itself from its parent.

    remove: function (index) {

        var parent,

            removed;

        if (Lang.isNumber(index)) {

            removed = Y.WidgetParent.prototype.remove.apply(this, arguments);

        }

        else {

            parent = this.get("parent");

            if (parent) {

                removed = parent.remove(this.get("index"));

            }

        }

        return removed;

    },

    /**

    * @method isRoot

    * @description Determines if the Widget is the root Widget in the

    * object hierarchy.

    * @return {Boolean} Boolean indicating if Widget is the root Widget in the

    * object hierarchy.

    */

    isRoot: function () {

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

    },

    /**

    * @method ancestor

    * @description Returns the Widget instance at the specified depth.

    * @param {number} depth Number representing the depth of the ancestor.

    * @return {Widget} Widget instance.

    */

    ancestor: function (depth) {

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

            parent;

        if (this.get("depth") > depth)  {

            parent = this.get("parent");

            while (parent != root && parent.get("depth") > depth) {

                parent = parent.get("parent");

            }

        }

        return parent;

    },

    /**

     * Updates the UI to reflect the <code>selected</code> attribute value.

     *

     * @method _uiSetChildSelected

     * @protected

     * @param {number} selected The selected value to be reflected in the UI.

     */

    _uiSetChildSelected: function (selected) {

        var box = this.get("boundingBox"),

            sClassName = this.getClassName("selected");

        if (selected === 0) {

            box.removeClass(sClassName);

        }

        else {

            box.addClass(sClassName);

        }

    },

    /**

     * Default attribute change listener for the <code>selected</code>

     * attribute, responsible for updating the UI, in response to

     * attribute changes.

     *

     * @method _afterChildSelectedChange

     * @protected

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

     */

    _afterChildSelectedChange: function (event) {

        this._uiSetChildSelected(event.newVal);

    },

    /**

     * Synchronizes the UI to match the WidgetChild state.

     * <p>

     * This method is invoked after bindUI is invoked for the Widget class

     * using YUI's aop infrastructure.

     * </p>

     *

     * @method _syncUIChild

     * @protected

     */

    _syncUIChild: function () {

        this._uiSetChildSelected(this.get("selected"));

    },

    /**

     * Binds event listeners responsible for updating the UI state in response

     * to WidgetChild related state changes.

     * <p>

     * This method is invoked after bindUI is invoked for the Widget class

     * using YUI's aop infrastructure.

     * </p>

     * @method _bindUIChild

     * @protected

     */

    _bindUIChild: function () {

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

    }

};

Y.WidgetChild = Child;

}, '@VERSION@', {"requires": ["base-build", "widget"]});