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

    /**

     * Extends the dd-ddm-base Class to add support for the viewport shim to allow a draggable

     * anode to drag to be dragged over an iframe or any other node that traps mousemove events.

     * It is also required to have Drop Targets enabled, as the viewport shim will contain the shims for the Drop Targets.

     * @module dd

     * @submodule dd-ddm

     * @for DDM

     * @namespace DD

     */

    Y.mix(Y.DD.DDM, {

        /**

        * The shim placed over the screen to track the mousemove event.

        * @private

        * @property _pg

        * @type {Node}

        */

        _pg: null,

        /**

        * Set this to true to set the shims opacity to .5 for debugging it, default: false.

        * @private

        * @property _debugShim

        * @type {Boolean}

        */

        _debugShim: false,

        _activateTargets: function() { },

        _deactivateTargets: function() {},

        _startDrag: function() {

            if (this.activeDrag && this.activeDrag.get('useShim')) {

                this._shimming = true;

                this._pg_activate();

                this._activateTargets();

            }

        },

        _endDrag: function() {

            this._pg_deactivate();

            this._deactivateTargets();

        },

        /**

        * Deactivates the shim

        * @private

        * @method _pg_deactivate

        */

        _pg_deactivate: function() {

            this._pg.setStyle('display', 'none');

        },

        /**

        * Activates the shim

        * @private

        * @method _pg_activate

        */

        _pg_activate: function() {

            if (!this._pg) {

                this._createPG();

            }

            var ah = this.activeDrag.get('activeHandle'), cur = 'auto';

            if (ah) {

                cur = ah.getStyle('cursor');

            }

            if (cur === 'auto') {

                cur = this.get('dragCursor');

            }

            this._pg_size();

            this._pg.setStyles({

                top: 0,

                left: 0,

                display: 'block',

                opacity: ((this._debugShim) ? '.5' : '0'),

                cursor: cur

            });

        },

        /**

        * Sizes the shim on: activatation, window:scroll, window:resize

        * @private

        * @method _pg_size

        */

        _pg_size: function() {

            if (this.activeDrag) {

                var b = Y.one('body'),

                h = b.get('docHeight'),

                w = b.get('docWidth');

                this._pg.setStyles({

                    height: h + 'px',

                    width: w + 'px'

                });

            }

        },

        /**

        * Creates the shim and adds it's listeners to it.

        * @private

        * @method _createPG

        */

        _createPG: function() {

            var pg = Y.Node.create('<div></div>'),

            bd = Y.one('body'), win;

            pg.setStyles({

                top: '0',

                left: '0',

                position: 'absolute',

                zIndex: '9999',

                overflow: 'hidden',

                backgroundColor: 'red',

                display: 'none',

                height: '5px',

                width: '5px'

            });

            pg.set('id', Y.stamp(pg));

            pg.addClass(Y.DD.DDM.CSS_PREFIX + '-shim');

            bd.prepend(pg);

            this._pg = pg;

            this._pg.on('mousemove', Y.throttle(Y.bind(this._move, this), this.get('throttleTime')));

            this._pg.on('mouseup', Y.bind(this._end, this));

            win = Y.one('win');

            Y.on('window:resize', Y.bind(this._pg_size, this));

            win.on('scroll', Y.bind(this._pg_size, this));

        }

    }, true);

}, '@VERSION@', {"requires": ["dd-ddm-base", "event-resize"]});