YUI.add('dd-constrain', function (Y, NAME) {

    /**

     * The Drag & Drop Utility allows you to create a draggable interface efficiently,

     * buffering you from browser-level abnormalities and enabling you to focus on the interesting

     * logic surrounding your particular implementation. This component enables you to create a

     * variety of standard draggable objects with just a few lines of code and then,

     * using its extensive API, add your own specific implementation logic.

     * @module dd

     * @main dd

     * @submodule dd-constrain

     */

    /**

     * Plugin for the dd-drag module to add the constraining methods to it.

     * It supports constraining to a node or viewport. It supports tick based moves and XY axis constraints.

     * @class DDConstrained

     * @extends Base

     * @constructor

     * @namespace Plugin

     */

    var DRAG_NODE = 'dragNode',

        OFFSET_HEIGHT = 'offsetHeight',

        OFFSET_WIDTH = 'offsetWidth',

        HOST = 'host',

        TICK_X_ARRAY = 'tickXArray',

        TICK_Y_ARRAY = 'tickYArray',

        DDM = Y.DD.DDM,

        TOP = 'top',

        RIGHT = 'right',

        BOTTOM = 'bottom',

        LEFT = 'left',

        VIEW = 'view',

        proto = null,

        /**

        * Fires when this node is aligned with the tickX value.

        * @event drag:tickAlignX

        * @param {EventFacade} event An Event Facade object

        * @type {CustomEvent}

        */

        EV_TICK_ALIGN_X = 'drag:tickAlignX',

        /**

        * Fires when this node is aligned with the tickY value.

        * @event drag:tickAlignY

        * @param {EventFacade} event An Event Facade object

        * @type {CustomEvent}

        */

        EV_TICK_ALIGN_Y = 'drag:tickAlignY',

        C = function() {

            this._lazyAddAttrs = false;

            C.superclass.constructor.apply(this, arguments);

        };

    C.NAME = 'ddConstrained';

    /**

    * The Constrained instance will be placed on the Drag instance under the con namespace.

    * @property NS

    * @default con

    * @readonly

    * @protected

    * @static

    * @type {String}

    */

    C.NS = 'con';

    C.ATTRS = {

        host: {

        },

        /**

        * Stick the drag movement to the X-Axis. Default: false

        * @attribute stickX

        * @type Boolean

        */

        stickX: {

            value: false

        },

        /**

        * Stick the drag movement to the Y-Axis

        * @type Boolean

        * @attribute stickY

        */

        stickY: {

            value: false

        },

        /**

        * The X tick offset the drag node should snap to on each drag move. False for no ticks. Default: false

        * @type Number/false

        * @attribute tickX

        */

        tickX: {

            value: false

        },

        /**

        * The Y tick offset the drag node should snap to on each drag move. False for no ticks. Default: false

        * @type Number/false

        * @attribute tickY

        */

        tickY: {

            value: false

        },

        /**

        * An array of page coordinates to use as X ticks for drag movement.

        * @type Array

        * @attribute tickXArray

        */

        tickXArray: {

            value: false

        },

        /**

        * An array of page coordinates to use as Y ticks for drag movement.

        * @type Array

        * @attribute tickYArray

        */

        tickYArray: {

            value: false

        },

        /**

        * CSS style string for the gutter of a region (supports negative values): '5 0'

        * (sets top and bottom to 5px, left and right to 0px), '1 2 3 4' (top 1px, right 2px, bottom 3px, left 4px)

        * @attribute gutter

        * @type String

        */

        gutter: {

            value: '0',

            setter: function(gutter) {

                return Y.DD.DDM.cssSizestoObject(gutter);

            }

        },

        /**

        * Will attempt to constrain the drag node to the boundaries. Arguments:<br>

        * 'view': Contrain to Viewport<br>

        * '#selector_string': Constrain to this node<br>

        * '{Region Object}': An Object Literal containing a valid region (top, right, bottom, left) of page positions

        * @attribute constrain

        * @type {String/Object/Node}

        */

        constrain: {

            value: VIEW,

            setter: function(con) {

                var node = Y.one(con);

                if (node) {

                    con = node;

                }

                return con;

            }

        },

        /**

        * An Object Literal containing a valid region (top, right, bottom, left) of page positions to constrain the drag node to.

        * @deprecated

        * @attribute constrain2region

        * @type Object

        */

        constrain2region: {

            setter: function(r) {

                return this.set('constrain', r);

            }

        },

        /**

        * Will attempt to constrain the drag node to the boundaries of this node.

        * @deprecated

        * @attribute constrain2node

        * @type Object

        */

        constrain2node: {

            setter: function(n) {

                return this.set('constrain', Y.one(n));

            }

        },

        /**

        * Will attempt to constrain the drag node to the boundaries of the viewport region.

        * @deprecated

        * @attribute constrain2view

        * @type Object

        */

        constrain2view: {

            setter: function() {

                return this.set('constrain', VIEW);

            }

        },

        /**

        * Should the region be cached for performace. Default: true

        * @attribute cacheRegion

        * @type Boolean

        */

        cacheRegion: {

            value: true

        }

    };

    proto = {

        _lastTickXFired: null,

        _lastTickYFired: null,

        initializer: function() {

            this._createEvents();

            this._eventHandles = [

                this.get(HOST).on('drag:end', Y.bind(this._handleEnd, this)),

                this.get(HOST).on('drag:start', Y.bind(this._handleStart, this)),

                this.get(HOST).after('drag:align', Y.bind(this.align, this)),

                this.get(HOST).after('drag:drag', Y.bind(this.drag, this))

            ];

        },

        destructor: function() {

            Y.Array.each(

                this._eventHandles,

                function(handle) {

                    handle.detach();

                }

            );

            this._eventHandles.length = 0;

        },

        /**

        * This method creates all the events for this Event Target and publishes them so we get Event Bubbling.

        * @private

        * @method _createEvents

        */

        _createEvents: function() {

            var ev = [

                EV_TICK_ALIGN_X,

                EV_TICK_ALIGN_Y

            ];

            Y.Array.each(ev, function(v) {

                this.publish(v, {

                    type: v,

                    emitFacade: true,

                    bubbles: true,

                    queuable: false,

                    prefix: 'drag'

                });

            }, this);

        },

        /**

        * Fires on drag:end

        * @private

        * @method _handleEnd

        */

        _handleEnd: function() {

            this._lastTickYFired = null;

            this._lastTickXFired = null;

        },

        /**

        * Fires on drag:start and clears the _regionCache

        * @private

        * @method _handleStart

        */

        _handleStart: function() {

            this.resetCache();

        },

        /**

        * Store a cache of the region that we are constraining to

        * @private

        * @property _regionCache

        * @type Object

        */

        _regionCache: null,

        /**

        * Get's the region and caches it, called from window.resize and when the cache is null

        * @private

        * @method _cacheRegion

        */

        _cacheRegion: function() {

            this._regionCache = this.get('constrain').get('region');

        },

        /**

        * Reset the internal region cache.

        * @method resetCache

        */

        resetCache: function() {

            this._regionCache = null;

        },

        /**

        * Standardizes the 'constraint' attribute

        * @private

        * @method _getConstraint

        */

        _getConstraint: function() {

            var con = this.get('constrain'),

                g = this.get('gutter'),

                region;

            if (con) {

                if (con instanceof Y.Node) {

                    if (!this._regionCache) {

                        this._eventHandles.push(Y.on('resize', Y.bind(this._cacheRegion, this), Y.config.win));

                        this._cacheRegion();

                    }

                    region = Y.clone(this._regionCache);

                    if (!this.get('cacheRegion')) {

                        this.resetCache();

                    }

                } else if (Y.Lang.isObject(con)) {

                    region = Y.clone(con);

                }

            }

            if (!con || !region) {

                con = VIEW;

            }

            if (con === VIEW) {

                region = this.get(HOST).get(DRAG_NODE).get('viewportRegion');

            }

            Y.Object.each(g, function(i, n) {

                if ((n === RIGHT) || (n === BOTTOM)) {

                    region[n] -= i;

                } else {

                    region[n] += i;

                }

            });

            return region;

        },

        /**

        * Get the active region: viewport, node, custom region

        * @method getRegion

        * @param {Boolean} inc Include the node's height and width

        * @return {Object} The active region.

        */

        getRegion: function(inc) {

            var r = {}, oh = null, ow = null,

                host = this.get(HOST);

            r = this._getConstraint();

            if (inc) {

                oh = host.get(DRAG_NODE).get(OFFSET_HEIGHT);

                ow = host.get(DRAG_NODE).get(OFFSET_WIDTH);

                r[RIGHT] = r[RIGHT] - ow;

                r[BOTTOM] = r[BOTTOM] - oh;

            }

            return r;

        },

        /**

        * Check if xy is inside a given region, if not change to it be inside.

        * @private

        * @method _checkRegion

        * @param {Array} _xy The XY to check if it's in the current region, if it isn't

        * inside the region, it will reset the xy array to be inside the region.

        * @return {Array} The new XY that is inside the region

        */

        _checkRegion: function(_xy) {

            var oxy = _xy,

                r = this.getRegion(),

                host = this.get(HOST),

                oh = host.get(DRAG_NODE).get(OFFSET_HEIGHT),

                ow = host.get(DRAG_NODE).get(OFFSET_WIDTH);

                if (oxy[1] > (r[BOTTOM] - oh)) {

                    _xy[1] = (r[BOTTOM] - oh);

                }

                if (r[TOP] > oxy[1]) {

                    _xy[1] = r[TOP];

                }

                if (oxy[0] > (r[RIGHT] - ow)) {

                    _xy[0] = (r[RIGHT] - ow);

                }

                if (r[LEFT] > oxy[0]) {

                    _xy[0] = r[LEFT];

                }

            return _xy;

        },

        /**

        * Checks if the XY passed or the dragNode is inside the active region.

        * @method inRegion

        * @param {Array} xy Optional XY to check, if not supplied this.get('dragNode').getXY() is used.

        * @return {Boolean} True if the XY is inside the region, false otherwise.

        */

        inRegion: function(xy) {

            xy = xy || this.get(HOST).get(DRAG_NODE).getXY();

            var _xy = this._checkRegion([xy[0], xy[1]]),

                inside = false;

                if ((xy[0] === _xy[0]) && (xy[1] === _xy[1])) {

                    inside = true;

                }

            return inside;

        },

        /**

        * Modifies the Drag.actXY method from the after drag:align event. This is where the constraining happens.

        * @method align

        */

        align: function() {

            var host = this.get(HOST),

                _xy = [host.actXY[0], host.actXY[1]],

                r = this.getRegion(true);

            if (this.get('stickX')) {

                _xy[1] = (host.startXY[1] - host.deltaXY[1]);

            }

            if (this.get('stickY')) {

                _xy[0] = (host.startXY[0] - host.deltaXY[0]);

            }