/*

Copyright (c) 2009, Yahoo! Inc. All rights reserved.

Code licensed under the BSD License:

http://developer.yahoo.net/yui/license.txt

version: 3.0.0b1

build: 1163

*/

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

    /**

     * 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

     * @submodule dd-drop

     */     

    /**

     * This class provides the ability to create a Drop Target.

     * @class Drop

     * @extends Base

     * @constructor

     * @namespace DD

     */

    var NODE = 'node',

        DDM = Y.DD.DDM,

        OFFSET_HEIGHT = 'offsetHeight',

        OFFSET_WIDTH = 'offsetWidth',

        /**

        * @event drop:over

        * @description Fires when a drag element is over this target.

        * @bubbles DDM

        * @type {Event.Custom}

        */

        EV_DROP_OVER = 'drop:over',

        /**

        * @event drop:enter

        * @description Fires when a drag element enters this target.

        * @bubbles DDM

        * @type {Event.Custom}

        */

        EV_DROP_ENTER = 'drop:enter',

        /**

        * @event drop:exit

        * @description Fires when a drag element exits this target.

        * @bubbles DDM

        * @type {Event.Custom}

        */

        EV_DROP_EXIT = 'drop:exit',

        /**

        * @event drop:hit

        * @description Fires when a draggable node is dropped on this Drop Target. (Fired from dd-ddm-drop)

        * @bubbles DDM

        * @type {Event.Custom}

        */

    Drop = function() {

        this._lazyAddAttrs = false;

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

        //DD init speed up.

        Y.on('domready', Y.bind(function() {

            Y.later(100, this, this._createShim);

        }, this));

        DDM._regTarget(this);

        /* TODO

        if (Dom.getStyle(this.el, 'position') == 'fixed') {

            Event.on(window, 'scroll', function() {

                this.activateShim();

            }, this, true);

        }

        */

    };

    Drop.NAME = 'drop';

    Drop.ATTRS = {

        /**

        * @attribute node

        * @description Y.Node instanace to use as the element to make a Drop Target

        * @type Node

        */        

        node: {

            setter: function(node) {

                var n = Y.Node.get(node);

                if (!n) {

                    Y.error('DD.Drop: Invalid Node Given: ' + node);

                }

                return n;               

            }

        },

        /**

        * @attribute groups

        * @description Array of groups to add this drop into.

        * @type Array

        */        

        groups: {

            value: ['default'],

            setter: function(g) {

                this._groups = {};

                Y.each(g, function(v, k) {

                    this._groups[v] = true;

                }, this);

                return g;

            }

        },   

        /**

        * @attribute padding

        * @description CSS style padding to make the Drop Target bigger than the node.

        * @type String

        */

        padding: {

            value: '0',

            setter: function(p) {

                return DDM.cssSizestoObject(p);

            }

        },

        /**

        * @attribute lock

        * @description Set to lock this drop element.

        * @type Boolean

        */        

        lock: {

            value: false,

            setter: function(lock) {

                if (lock) {

                    this.get(NODE).addClass(DDM.CSS_PREFIX + '-drop-locked');

                } else {

                    this.get(NODE).removeClass(DDM.CSS_PREFIX + '-drop-locked');

                }

                return lock;

            }

        },

        /**

        * @attribute bubbles

        * @description Controls the default bubble parent for this Drop instance. Default: Y.DD.DDM. Set to false to disable bubbling.

        * @type Object

        */

        bubbles: {

            writeOnce: true,

            value: Y.DD.DDM

        }

    };

    Y.extend(Drop, Y.Base, {

        /**

        * @private

        * @method _createEvents

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

        */

        _createEvents: function() {

            var ev = [

                EV_DROP_OVER,

                EV_DROP_ENTER,

                EV_DROP_EXIT,

                'drop:hit'

            ];

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

                this.publish(v, {

                    type: v,

                    emitFacade: true,

                    preventable: false,

                    bubbles: true,

                    queuable: false,

                    prefix: 'drop'

                });

            }, this);

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

                this.addTarget(this.get('bubbles'));

            }

        },

        /**

        * @private

        * @property _valid

        * @description Flag for determining if the target is valid in this operation.

        * @type Boolean

        */

        _valid: null,

        /**

        * @private

        * @property _groups

        * @description The groups this target belongs to.

        * @type Array

        */

        _groups: null,

        /**

        * @property shim

        * @description Node reference to the targets shim

        * @type {Object}

        */

        shim: null,

        /**

        * @property region

        * @description A region object associated with this target, used for checking regions while dragging.

        * @type Object

        */

        region: null,

        /**

        * @property overTarget

        * @description This flag is tripped when a drag element is over this target.

        * @type Boolean

        */

        overTarget: null,

        /**

        * @method inGroup

        * @description Check if this target is in one of the supplied groups.

        * @param {Array} groups The groups to check against

        * @return Boolean

        */

        inGroup: function(groups) {

            this._valid = false;

            var ret = false;

            Y.each(groups, function(v, k) {

                if (this._groups[v]) {

                    ret = true;

                    this._valid = true;

                }

            }, this);

            return ret;

        },

        /**

        * @private

        * @method initializer

        * @description Private lifecycle method

        */

        initializer: function() {

            //this._createEvents();

            Y.later(100, this, this._createEvents);

            var node = this.get(NODE), id;

            if (!node.get('id')) {

                id = Y.stamp(node);

                node.set('id', id);

            }

            node.addClass(DDM.CSS_PREFIX + '-drop');

            //Shouldn't have to do this..

            this.set('groups', this.get('groups'));           

        },

        /**

        * @private

        * @method destructor

        * @description Lifecycle destructor, unreg the drag from the DDM and remove listeners

        */

        destructor: function() {

            DDM._unregTarget(this);

            if (this.shim) {

                this.shim.detachAll();

                this.shim.get('parentNode').removeChild(this.shim);

                this.shim = null;

            }

            this.get(NODE).removeClass(DDM.CSS_PREFIX + '-drop');

            this.detachAll();

        },

        /**

        * @private

        * @method _deactivateShim

        * @description Removes classes from the target, resets some flags and sets the shims deactive position [-999, -999]

        */

        _deactivateShim: function() {

            if (!this.shim) {

                return false;

            }

            this.get(NODE).removeClass(DDM.CSS_PREFIX + '-drop-active-valid');

            this.get(NODE).removeClass(DDM.CSS_PREFIX + '-drop-active-invalid');

            this.get(NODE).removeClass(DDM.CSS_PREFIX + '-drop-over');

            this.shim.setStyles({

                top: '-999px',

                left: '-999px',

                zIndex: '2'

            });

            this.overTarget = false;

        },

        /**

        * @private

        * @method _activateShim

        * @description Activates the shim and adds some interaction CSS classes

        */

        _activateShim: function() {

            if (!DDM.activeDrag) {

                return false; //Nothing is dragging, no reason to activate.

            }

            if (this.get(NODE) === DDM.activeDrag.get(NODE)) {

                return false;

            }

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

                return false;

            }

            var node = this.get(NODE);

            //TODO Visibility Check..

            //if (this.inGroup(DDM.activeDrag.get('groups')) && this.get(NODE).isVisible()) {

            if (this.inGroup(DDM.activeDrag.get('groups'))) {

                node.removeClass(DDM.CSS_PREFIX + '-drop-active-invalid');

                node.addClass(DDM.CSS_PREFIX + '-drop-active-valid');

                DDM._addValid(this);

                this.overTarget = false;

                this.sizeShim();

            } else {

                DDM._removeValid(this);

                node.removeClass(DDM.CSS_PREFIX + '-drop-active-valid');

                node.addClass(DDM.CSS_PREFIX + '-drop-active-invalid');

            }

        },

        /**

        * @method sizeShim

        * @description Positions and sizes the shim with the raw data from the node, this can be used to programatically adjust the Targets shim for Animation..

        */

        sizeShim: function() {

            if (!DDM.activeDrag) {

                return false; //Nothing is dragging, no reason to activate.

            }

            if (this.get(NODE) === DDM.activeDrag.get(NODE)) {

                return false;

            }

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

                return false;

            }

            if (!this.shim) {

                Y.later(100, this, this.sizeShim);

                return false;

            }

            var node = this.get(NODE),

                nh = node.get(OFFSET_HEIGHT),

                nw = node.get(OFFSET_WIDTH),

                xy = node.getXY(),

                p = this.get('padding'),

                dd, dH, dW;

            //Apply padding

            nw = nw + p.left + p.right;

            nh = nh + p.top + p.bottom;

            xy[0] = xy[0] - p.left;

            xy[1] = xy[1] - p.top;

            if (DDM.activeDrag.get('dragMode') === DDM.INTERSECT) {

                //Intersect Mode, make the shim bigger

                dd = DDM.activeDrag;

                dH = dd.get(NODE).get(OFFSET_HEIGHT);

                dW = dd.get(NODE).get(OFFSET_WIDTH);

                nh = (nh + dH);

                nw = (nw + dW);

                xy[0] = xy[0] - (dW - dd.deltaXY[0]);

                xy[1] = xy[1] - (dH - dd.deltaXY[1]);

            }

            //Set the style on the shim

            this.shim.setStyles({

                height: nh + 'px',

                width: nw + 'px',

                top: xy[1] + 'px',

                left: xy[0] + 'px'

            });

            //Create the region to be used by intersect when a drag node is over us.

            this.region = {

                '0': xy[0], 

                '1': xy[1],

                area: 0,

                top: xy[1],

                right: xy[0] + nw,

                bottom: xy[1] + nh,

                left: xy[0]

            };

        },

        /**

        * @private

        * @method _createShim

        * @description Creates the Target shim and adds it to the DDM's playground..

        */

        _createShim: function() {

            //No playground, defer

            if (!DDM._pg) {

                Y.later(10, this, this._createShim);

                return;

            }

            //Shim already here, cancel

            if (this.shim) {

                return;

            }

            var s = Y.Node.create('<div id="' + this.get(NODE).get('id') + '_shim"></div>');

            s.setStyles({

                height: this.get(NODE).get(OFFSET_HEIGHT) + 'px',

                width: this.get(NODE).get(OFFSET_WIDTH) + 'px',