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

/**

Provides extended/advanced XY positioning support for Widgets, through an

extension.

It builds on top of the `widget-position` module, to provide alignment and

centering support. Future releases aim to add constrained and fixed positioning

support.

@module widget-position-align

**/

var Lang = Y.Lang,

    ALIGN        = 'align',

    ALIGN_ON     = 'alignOn',

    VISIBLE      = 'visible',

    BOUNDING_BOX = 'boundingBox',

    OFFSET_WIDTH    = 'offsetWidth',

    OFFSET_HEIGHT   = 'offsetHeight',

    REGION          = 'region',

    VIEWPORT_REGION = 'viewportRegion';

/**

Widget extension, which can be used to add extended XY positioning support to

the base Widget class, through the `Base.create` method.

**Note:** This extension requires that the `WidgetPosition` extension be added

to the Widget (before `WidgetPositionAlign`, if part of the same extension list

passed to `Base.build`).

@class WidgetPositionAlign

@param {Object} config User configuration object.

@constructor

**/

function PositionAlign (config) {}

PositionAlign.ATTRS = {

    /**

    The alignment configuration for this widget.

    The `align` attribute is used to align a reference point on the widget, with

    the reference point on another `Node`, or the viewport. The object which

    `align` expects has the following properties:

      * __`node`__: The `Node` to which the widget is to be aligned. If set to

        `null`, or not provided, the widget is aligned to the viewport.

      * __`points`__: A two element Array, defining the two points on the widget

        and `Node`/viewport which are to be aligned. The first element is the

        point on the widget, and the second element is the point on the

        `Node`/viewport. Supported alignment points are defined as static

        properties on `WidgetPositionAlign`.

    @example Aligns the top-right corner of the widget with the top-left corner

    of the viewport:

        myWidget.set('align', {

            points: [Y.WidgetPositionAlign.TR, Y.WidgetPositionAlign.TL]

        });

    @attribute align

    @type Object

    @default null

    **/

    align: {

        value: null

    },

    /**

    A convenience Attribute, which can be used as a shortcut for the `align`

    Attribute.

    If set to `true`, the widget is centered in the viewport. If set to a `Node`

    reference or valid selector String, the widget will be centered within the

    `Node`. If set to `false`, no center positioning is applied.

    @attribute centered

    @type Boolean|Node

    @default false

    **/

    centered: {

        setter : '_setAlignCenter',

        lazyAdd:false,

        value  :false

    },

    /**

    An Array of Objects corresponding to the `Node`s and events that will cause

    the alignment of this widget to be synced to the DOM.

    The `alignOn` Attribute is expected to be an Array of Objects with the

    following properties:

      * __`eventName`__: The String event name to listen for.

      * __`node`__: The optional `Node` that will fire the event, it can be a

        `Node` reference or a selector String. This will default to the widget's

        `boundingBox`.

    @example Sync this widget's alignment on window resize:

        myWidget.set('alignOn', [

            {

                node     : Y.one('win'),

                eventName: 'resize'

            }

        ]);

    @attribute alignOn

    @type Array

    @default []

    **/

    alignOn: {

        value    : [],

        validator: Y.Lang.isArray

    }

};

/**

Constant used to specify the top-left corner for alignment

@property TL

@type String

@value 'tl'

@static

**/

PositionAlign.TL = 'tl';

/**

Constant used to specify the top-right corner for alignment

@property TR

@type String

@value 'tr'

@static

**/

PositionAlign.TR = 'tr';

/**

Constant used to specify the bottom-left corner for alignment

@property BL

@type String

@value 'bl'

@static

**/

PositionAlign.BL = 'bl';

/**

Constant used to specify the bottom-right corner for alignment

@property BR

@type String

@value 'br'

@static

**/

PositionAlign.BR = 'br';

/**

Constant used to specify the top edge-center point for alignment

@property TC

@type String

@value 'tc'

@static

**/

PositionAlign.TC = 'tc';

/**

Constant used to specify the right edge, center point for alignment

@property RC

@type String

@value 'rc'

@static

**/

PositionAlign.RC = 'rc';

/**

Constant used to specify the bottom edge, center point for alignment

@property BC

@type String

@value 'bc'

@static

**/

PositionAlign.BC = 'bc';

/**

Constant used to specify the left edge, center point for alignment

@property LC

@type String

@value 'lc'

@static

**/

PositionAlign.LC = 'lc';

/**

Constant used to specify the center of widget/node/viewport for alignment

@property CC

@type String

@value 'cc'

@static

*/

PositionAlign.CC = 'cc';

PositionAlign.prototype = {

    // -- Protected Properties -------------------------------------------------

    initializer : function() {

        if (!this._posNode) {

            Y.error('WidgetPosition needs to be added to the Widget, ' +

                'before WidgetPositionAlign is added');

        }

        Y.after(this._bindUIPosAlign, this, 'bindUI');

        Y.after(this._syncUIPosAlign, this, 'syncUI');

    },

    /**

    Holds the alignment-syncing event handles.

    @property _posAlignUIHandles

    @type Array

    @default null

    @protected

    **/

    _posAlignUIHandles: null,

    // -- Lifecycle Methods ----------------------------------------------------

    destructor: function () {

        this._detachPosAlignUIHandles();

    },

    /**

    Bind event listeners responsible for updating the UI state in response to

    the widget's position-align related state changes.

    This method is invoked after `bindUI` has been invoked for the `Widget`

    class using the AOP infrastructure.

    @method _bindUIPosAlign

    @protected

    **/

    _bindUIPosAlign: function () {

        this.after('alignChange', this._afterAlignChange);

        this.after('alignOnChange', this._afterAlignOnChange);

        this.after('visibleChange', this._syncUIPosAlign);

    },

    /**

    Synchronizes the current `align` Attribute value to the DOM.

    This method is invoked after `syncUI` has been invoked for the `Widget`

    class using the AOP infrastructure.

    @method _syncUIPosAlign

    @protected

    **/

    _syncUIPosAlign: function () {

        var align = this.get(ALIGN);

        this._uiSetVisiblePosAlign(this.get(VISIBLE));

        if (align) {

            this._uiSetAlign(align.node, align.points);

        }

    },

    // -- Public Methods -------------------------------------------------------

    /**

    Aligns this widget to the provided `Node` (or viewport) using the provided

    points. This method can be invoked with no arguments which will cause the

    widget's current `align` Attribute value to be synced to the DOM.

    @example Aligning to the top-left corner of the `<body>`:

        myWidget.align('body',

            [Y.WidgetPositionAlign.TL, Y.WidgetPositionAlign.TR]);

    @method align

    @param {Node|String|null} [node] A reference (or selector String) for the

      `Node` which with the widget is to be aligned. If null is passed in, the

      widget will be aligned with the viewport.

    @param {Array[2]} [points] A two item array specifying the points on the

      widget and `Node`/viewport which will to be aligned. The first entry is

      the point on the widget, and the second entry is the point on the

      `Node`/viewport. Valid point references are defined as static constants on

      the `WidgetPositionAlign` extension.

    @chainable

    **/

    align: function (node, points) {

        if (arguments.length) {

            // Set the `align` Attribute.

            this.set(ALIGN, {

                node  : node,

                points: points

            });

        } else {

            // Sync the current `align` Attribute value to the DOM.

            this._syncUIPosAlign();

        }

        return this;

    },

    /**

    Centers the widget in the viewport, or if a `Node` is passed in, it will

    be centered to that `Node`.

    @method centered

    @param {Node|String} [node] A `Node` reference or selector String defining

      the `Node` which the widget should be centered. If a `Node` is not  passed

      in, then the widget will be centered to the viewport.

    @chainable

    **/

    centered: function (node) {

        return this.align(node, [PositionAlign.CC, PositionAlign.CC]);

    },

    // -- Protected Methods ----------------------------------------------------

    /**

    Default setter for `center` Attribute changes. Sets up the appropriate

    value, and passes it through the to the align attribute.

    @method _setAlignCenter

    @param {Boolean|Node} val The Attribute value being set.

    @return {Boolean|Node} the value passed in.

    @protected

    **/

    _setAlignCenter: function (val) {

        if (val) {

            this.set(ALIGN, {

                node  : val === true ? null : val,

                points: [PositionAlign.CC, PositionAlign.CC]

            });

        }

        return val;

    },

    /**

    Updates the UI to reflect the `align` value passed in.

    **Note:** See the `align` Attribute documentation, for the Object structure

    expected.

    @method _uiSetAlign

    @param {Node|String|null} [node] The node to align to, or null to indicate

      the viewport.

    @param {Array} points The alignment points.

    @protected

    **/

    _uiSetAlign: function (node, points) {

        if ( ! Lang.isArray(points) || points.length !== 2) {

            Y.error('align: Invalid Points Arguments');

            return;

        }

        var nodeRegion = this._getRegion(node),

            widgetPoint, nodePoint, xy;

        if ( ! nodeRegion) {

            // No-op, nothing to align to.

            return;

        }

        widgetPoint = points[0];

        nodePoint   = points[1];

        // TODO: Optimize KWeight - Would lookup table help?

        switch (nodePoint) {

        case PositionAlign.TL:

            xy = [nodeRegion.left, nodeRegion.top];

            break;

        case PositionAlign.TR:

            xy = [nodeRegion.right, nodeRegion.top];

            break;

        case PositionAlign.BL:

            xy = [nodeRegion.left, nodeRegion.bottom];

            break;

        case PositionAlign.BR:

            xy = [nodeRegion.right, nodeRegion.bottom];

            break;

        case PositionAlign.TC:

            xy = [

                nodeRegion.left + Math.floor(nodeRegion.width / 2),

                nodeRegion.top

            ];

            break;

        case PositionAlign.BC:

            xy = [

                nodeRegion.left + Math.floor(nodeRegion.width / 2),

                nodeRegion.bottom

            ];

            break;

        case PositionAlign.LC:

            xy = [

                nodeRegion.left,

                nodeRegion.top + Math.floor(nodeRegion.height / 2)

            ];

            break;

        case PositionAlign.RC:

            xy = [

                nodeRegion.right,

                nodeRegion.top + Math.floor(nodeRegion.height / 2)

            ];

            break;

        case PositionAlign.CC:

            xy = [

                nodeRegion.left + Math.floor(nodeRegion.width / 2),

                nodeRegion.top + Math.floor(nodeRegion.height / 2)

            ];

            break;

        default:

            Y.log('align: Invalid Points Arguments', 'info',

                'widget-position-align');

            break;

        }

        if (xy) {

            this._doAlign(widgetPoint, xy[0], xy[1]);