/**
 * EGroupware eTemplate2 - JS Grid object
 *
 * @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
 * @package etemplate
 * @subpackage api
 * @link http://www.egroupware.org
 * @author Andreas Stöckel
 * @copyright Stylite 2011
 * @version $Id$
 */

"use strict";

/*egw:uses
	jquery.jquery;
	et2_core_DOMWidget;
	et2_core_xml;
*/

/**
 * Class which implements the "grid" XET-Tag
 *
 * This also includes repeating the last row in the grid and filling
 * it with content data
 *
 * @augments et2_DOMWidget
 */
var et2_grid = et2_DOMWidget.extend([et2_IDetachedDOM, et2_IAligned, et2_IResizeable],
{
	createNamespace: true,

	attributes: {
		// Better to use CSS, no need to warn about it
		"border": {
			"ignore": true
		},
		"align": {
			"name": "Align",
			"type": "string",
			"default": "left",
			"description": "Position of this element in the parent hbox"
		},
		"spacing": {
			"ignore": true
		},
		"padding": {
			"ignore": true
		},
		"sortable": {
			"name": "Sortable callback",
			"type": "string",
			"default": et2_no_init,
			"description": "PHP function called when user sorts the grid.  Setting this enables sorting the grid rows.  The callback will be passed the ID of the grid and the new order of the rows."
		}
	},

	/**
	 * Constructor
	 *
	 * @memberOf et2_grid
	 */
	init: function() {
		// Create the table body and the table
		this.table = $j(document.createElement("table"))
			.addClass("et2_grid");
		this.thead = $j(document.createElement("thead"))
			.appendTo(this.table);
		this.tfoot = $j(document.createElement("tfoot"))
			.appendTo(this.table);
		this.tbody = $j(document.createElement("tbody"))
			.appendTo(this.table);

		// Call the parent constructor
		this._super.apply(this, arguments);

		// Counters for rows and columns
		this.rowCount = 0;
		this.columnCount = 0;

		// 2D-Array which holds references to the DOM td tags
		this.cells = [];
		this.rowData = [];
		this.colData = [];
		this.managementArray = [];

		// Keep the template node for later regeneration
		this.template_node = null;

		// Wrapper div for height & overflow, if needed
		this.wrapper = null;
	},

	destroy: function() {
		this._super.call(this, arguments);
	},

	_initCells: function(_colData, _rowData) {
		// Copy the width and height
		var w = _colData.length;
		var h = _rowData.length;

		// Create the 2D-Cells array
		var cells = new Array(h);
		for (var y = 0; y < h; y++)
		{
			cells[y] = new Array(w);

			// Initialize the cell description objects
			for (var x = 0; x < w; x++)
			{
				cells[y][x] = {
					"td": null,
					"widget": null,
					"colData": _colData[x],
					"rowData": _rowData[y],
					"disabled": _colData[x].disabled || _rowData[y].disabled,
					"class": _colData[x]["class"],
					"colSpan": 1,
					"autoColSpan": false,
					"rowSpan": 1,
					"autoRowSpan": false,
					"width": _colData[x].width,
					"x": x,
					"y": y
				};
			}
		}

		return cells;
	},

	_getColDataEntry: function() {
		return {
			"width": "auto",
			"class": "",
			"align": "",
			"span": "1",
			"disabled": false
		};
	},

	_getRowDataEntry: function() {
		return {
			"height": "auto",
			"class": "",
			"valign": "top",
			"span": "1",
			"disabled": false
		};
	},

	_getCell: function(_cells, _x, _y) {
		if ((0 <= _y) && (_y < _cells.length))
		{
			var row = _cells[_y];
			if ((0 <= _x) && (_x < row.length))
			{
				return row[_x];
			}
		}

		throw("Error while accessing grid cells, invalid element count or span value!");
	},

	_forceNumber: function(_val) {
		if (isNaN(_val))
		{
			throw(_val + " is not a number!");
		}

		return parseInt(_val);
	},

	_fetchRowColData: function(columns, rows, colData, rowData) {
		// Parse the columns tag
		et2_filteredNodeIterator(columns, function(node, nodeName) {
			var colDataEntry = this._getColDataEntry();
			colDataEntry["disabled"] = this.getArrayMgr("content")
					.parseBoolExpression(et2_readAttrWithDefault(node, "disabled", ""));
			if (nodeName == "column")
			{
				colDataEntry["width"] = et2_readAttrWithDefault(node, "width", "auto");
				colDataEntry["class"] = et2_readAttrWithDefault(node, "class", "");
				colDataEntry["align"] = et2_readAttrWithDefault(node, "align", "");
				colDataEntry["span"] = et2_readAttrWithDefault(node, "span", "1");

				// Keep any others attributes set, there's no 'column' widget
				for(var i in node.attributes)
				{
					var attr = node.attributes[i];
					if(attr.nodeType == 2 && typeof colDataEntry[attr.nodeName] == 'undefined')
					{
						colDataEntry[attr.nodeName] = attr.value;
					}
				}
			}
			else
			{
				colDataEntry["span"] = "all";
			}
			colData.push(colDataEntry);
		}, this);

		// Parse the rows tag
		et2_filteredNodeIterator(rows, function(node, nodeName) {
			var rowDataEntry = this._getRowDataEntry();
			rowDataEntry["disabled"] = this.getArrayMgr("content")
					.parseBoolExpression(et2_readAttrWithDefault(node, "disabled", ""));
			if (nodeName == "row")
			{
				// Remember this row for auto-repeat - it'll eventually be the last one
				this.lastRowNode = node;

				rowDataEntry["height"] = et2_readAttrWithDefault(node, "height", "auto");
				rowDataEntry["class"] = et2_readAttrWithDefault(node, "class", "");
				rowDataEntry["valign"] = et2_readAttrWithDefault(node, "valign", "");
				rowDataEntry["span"] = et2_readAttrWithDefault(node, "span", "1");
				rowDataEntry["part"] = et2_readAttrWithDefault(node, "part", "body");

				var id = et2_readAttrWithDefault(node, "id", "");
				if(id)
				{
					rowDataEntry["id"] = id;
				}
			}
			else
			{
				rowDataEntry["span"] = "all";
			}
			rowData.push(rowDataEntry);
		}, this);

		// Add in repeated rows
		// TODO: It would be nice if we could skip header (thead) & footer (tfoot) or treat them separately
		if(this.getArrayMgr("content"))
		{
			var content = this.getArrayMgr("content");
			var rowDataEntry = rowData[rowData.length-1];
			var rowIndex = rowData.length-1;
			// Find out if we have any content rows, and how many
			var cont = true;
			while(cont)
			{
				if(content.data[rowIndex])
				{
					rowData[rowIndex] = jQuery.extend({}, rowDataEntry);

					rowIndex++;
				}

				else if (this.lastRowNode != null)
				{
					// Have to look through actual widgets to support const[$row]
					// style names - should be avoided so we can remove this extra check
					// Old etemplate checked first two widgets, or first two box children
					// This cannot be done inside a nextmatch - nm will do the expansion later
					var nm = false;
					var widget = this;
					while(!nm && widget != this.getRoot())
					{
						nm = (widget._type == 'nextmatch');
						widget = widget.getParent();
					}
					if(nm)
					{
						// No further checks for repeated rows
						break;
					}

					// Not in a nextmatch, so we can expand with abandon
					var currentPerspective = jQuery.extend({},content.perspectiveData);
					var check = function(node, nodeName)
					{
						if(nodeName == 'box' || nodeName == 'hbox' || nodeName == 'vbox')
						{
							return et2_filteredNodeIterator(node, check, this);
						}
						content.perspectiveData.row = rowIndex;
						for(var attr in node.attributes)
						{
							var value  = et2_readAttrWithDefault(node, node.attributes[attr].name, "");
							// Don't include first char, those should be handled by normal means
							// and it would break nextmatch
							if(value.indexOf('@') > 0 || value.indexOf('$') > 0)
							{
								// Ok, we found something.  How many? Check for values.
								var ident = content.expandName(value);
								// expandName() handles index into content (@), but we have to look up
								// regular values
								if(value.indexOf('@') < 0)
								{
									// Returns null if there isn't an actual value
									ident = content.getEntry(ident,false,true);
								}
								while(ident != null && rowIndex < 1000)
								{
									rowData[rowIndex] = jQuery.extend({}, rowDataEntry);
									content.perspectiveData.row = ++rowIndex;
									ident = content.expandName(value);
									if(value.indexOf('@') < 0)
									{
										// Returns null if there isn't an actual value
										ident = content.getEntry(ident,false,true);
									}
								}
								if(rowIndex >= 1000)
								{
									egw.debug("error", "Problem in autorepeat fallback: too many rows for '%s'.  Use a nextmatch, or start debugging.",value);
								}
								return;
							}
						}
					};
					et2_filteredNodeIterator(this.lastRowNode, check,this);
					cont = false;
					content.perspectiveData = currentPerspective;
				}

				else
				{
					// No more rows, stop
					break;
				}
			}
		}
		if(rowIndex <= rowData.length - 1)
		{
			// No auto-repeat
			this.lastRowNode = null;
		}
	},

	_fillCells: function(cells, columns, rows) {
		var h = cells.length;
		var w = (h > 0) ? cells[0].length : 0;
		var currentPerspective = jQuery.extend({},this.getArrayMgr("content").perspectiveData);

		// Read the elements inside the columns
		var x = 0;

		et2_filteredNodeIterator(columns, function(node, nodeName) {

			function _readColNode(node, nodeName) {
				if (y >= h)
				{
					this.egw().debug("warn", "Skipped grid cell in column, '" +
						nodeName + "'");
					return;
				}

				var cell = this._getCell(cells, x, y);

				// Read the span value of the element
				if (node.attributes.span)
				{
					cell.rowSpan = node.attributes.span;
				}
				else
				{
					cell.rowSpan = cell.colData["span"];
					cell.autoRowSpan = true;
				}

				if (cell.rowSpan == "all")
				{
					cell.rowSpan = cells.length;
				}

				var span = cell.rowSpan = this._forceNumber(cell.rowSpan);

				// Create the widget
				var widget = this.createElementFromNode(node, nodeName);

				// Fill all cells the widget is spanning
				for (var i = 0; i < span && y < cells.length; i++, y++)
				{
					this._getCell(cells, x, y).widget = widget;
				}
			};

			// If the node is a column, create the widgets which belong into
			// the column
			var y = 0;
			if (nodeName == "column")
			{
				et2_filteredNodeIterator(node, _readColNode, this);
			}
			else
			{
				_readColNode.call(this, node, nodeName);
			}

			x++;
		}, this);

		// Read the elements inside the rows
		var y = 0;
		var x = 0;
		var readRowNode;
		var nm = false;
		var widget = this;
		while(!nm && widget != this.getRoot())
		{
			nm = (widget._type == 'nextmatch');
			widget = widget.getParent();
		}
		et2_filteredNodeIterator(rows, function(node, nodeName) {

			readRowNode = function _readRowNode(node, nodeName) {
				if (x >= w)
				{
					if(nodeName != "description")
					{
						// Only notify it skipping other than description,
						// description used to pad
						this.egw().debug("warn", "Skipped grid cell in row, '" +
							nodeName + "'");
					}
					return;
				}

				var cell = this._getCell(cells, x, y);

				// Read the span value of the element
				if (node.attributes && node.attributes.span)
				{
					cell.colSpan = node.attributes.span;
				}
				else
				{
					cell.colSpan = cell.rowData["span"];
					cell.autoColSpan = true;
				}

				if (cell.colSpan == "all")
				{
					cell.colSpan = cells[y].length;
				}

				var span = cell.colSpan = this._forceNumber(cell.colSpan);

				// Read the align value of the element
				if (node.attributes && node.attributes.align)
				{
					cell.align = node.attributes.align;
				}

				// store id of nextmatch-*headers, so it is available for disabled widgets, which get not instanciated
				if (nodeName.substr(0, 10) == 'nextmatch-')
				{
					cell.nm_id = node.attributes.id;
				}
				// Apply widget's class to td, for backward compatability
				if(node.attributes && node.attributes.class)
				{
					cell.class += (cell.class ? " " : "") + node.attributes.class;
				}

				// Create the element
				if(!cell.disabled)
				{
					//Skip if it is a nextmatch while the nextmatch handles row adjustment by itself
					if(!nm)
					{
						// Adjust for the row
						var mgrs = this.getArrayMgrs();
						for(var name in mgrs)
						{
							this.getArrayMgr(name).perspectiveData.row = y;
						}
						if(this._getCell(cells, x, y).rowData.id)
						{
							this._getCell(cells, x, y).rowData.id = this.getArrayMgr("content").expandName(this._getCell(cells, x, y).rowData.id);
						}
						if(this._getCell(cells, x, y).rowData.class)
						{
							this._getCell(cells, x, y).rowData.class = this.getArrayMgr("content").expandName(this._getCell(cells, x, y).rowData.class);
						}

					}

					var widget = this.createElementFromObject(node, nodeName);
				}

				// Fill all cells the widget is spanning
				for (var i = 0; i < span && x < cells[y].length; i++, x++)
				{
					cell = this._getCell(cells, x, y);
					if (cell.widget == null)
					{
						cell.widget = widget;
					}
					else
					{
						throw("Grid cell collision, two elements " +
							"defined for cell (" + x + "," + y + ")!");
					}
				}
			};

			// If the node is a row, create the widgets which belong into
			// the row
			x = 0;
			if(this.lastRowNode && node == this.lastRowNode)
			{
				return;
			}
			if (nodeName == "row")
			{
				// Adjust for the row
				for(var name in this.getArrayMgrs())
				{
					//this.getArrayMgr(name).perspectiveData.row = y;
				}

				if(this._getCell(cells, x,y).rowData.id)
				{
					this.getArrayMgr("content").expandName(this.rowData[y].id);
				}
				// If row disabled, just skip it
				var disabled = false;
				if(et2_readAttrWithDefault(node, "disabled", false) == "1")
				{
					disabled = true;
				}
				if(!disabled)
				{
					et2_filteredNodeIterator(node, readRowNode, this);
				}
			}
			else
			{
				readRowNode.call(this, node, nodeName);
			}

			y++;
		}, this);

		// Extra content rows
		for(y; y < h; y++) {
			var x = 0;

			et2_filteredNodeIterator(this.lastRowNode, readRowNode, this);
		}
		// Reset
		for(var name in this.getArrayMgrs())
		{
			this.getArrayMgr(name).perspectiveData = currentPerspective;
		}
	},

	_expandLastCells: function(_cells) {
		var h = _cells.length;
		var w = (h > 0) ? _cells[0].length : 0;

		// Determine the last cell in each row and expand its span value if
		// the span has not been explicitly set.
		for (var y = 0; y < h; y++)
		{
			for (var x = w - 1; x >= 0; x--)
			{
				var cell = _cells[y][x];

				if (cell.widget != null)
				{
					if (cell.autoColSpan)
					{
						cell.colSpan = w - x;
					}
					break;
				}
			}
		}

		// Determine the last cell in each column and expand its span value if
		// the span has not been explicitly set.
		for (var x = 0; x < w; x++)
		{
			for (var y = h - 1; y >= 0; y--)
			{
				var cell = _cells[y][x];

				if (cell.widget != null)
				{
					if (cell.autoRowSpan)
					{
						cell.rowSpan = h - y;
					}
					break;
				}
			}
		}
	},

	/**
	 * As the does not fit very well into the default widget structure, we're
	 * overwriting the loadFromJSON function and doing a two-pass reading -
	 * in the first step the
	 *
	 * @param {object} _node xml node to process
	 */
	loadFromJSON: function(_node) {
		// Keep the node for later changing / reloading
		this.template_node = _node;

		// Get the columns and rows tag
		var rowsElems = _node.children[1];
		var columnsElems = _node.children[0];

		if (rowsElems && columnsElems)
		{
			var columns = columnsElems;
			var rows = rowsElems;
			var colData = [];
			var rowData = [];

			// Fetch the column and row data
			this._fetchRowColData(columns, rows, colData, rowData);

			// Initialize the cells
			var cells = this._initCells(colData, rowData);

			// Create the widgets inside the cells and read the span values
			this._fillCells(cells, columns, rows);

			// Expand the span values of the last cells
			this._expandLastCells(cells);

			// Create the table rows
			this.createTableFromCells(cells, colData, rowData);
		}
		else
		{
			throw("Error while parsing grid, none or multiple rows or columns tags!");
		}
	},

	createTableFromCells: function(_cells, _colData, _rowData) {
		this.managementArray = [];
		this.cells = _cells;
		this.colData = _colData;
		this.rowData = _rowData;

		// Set the rowCount and columnCount variables
		var h = this.rowCount = _cells.length;
		var w = this.columnCount = (h > 0) ? _cells[0].length : 0;

		// Create the table rows.
		for (var y = 0; y < h; y++)
		{
			var row = _cells[y];
			var parent = this.tbody;
			switch(this.rowData[y]["part"])
			{
				case 'header':
					if (!this.tbody.children().length && !this.tfoot.children().length)
					{
						parent = this.thead;
					}
					break;
				case 'footer':
					if (!this.tbody.children().length)
					{
						parent = this.tfoot;
					}
					break;
			}
			var tr = $j(document.createElement("tr")).appendTo(parent)
				.addClass(this.rowData[y]["class"]);

			if (this.rowData[y].disabled)
			{
				tr.hide();
			}

			if (this.rowData[y].height != "auto")
			{
				tr.height(this.rowData[y].height);
			}

			if (this.rowData[y].valign)
			{
				tr.attr("valign", this.rowData[y].valign);
			}

			if(this.rowData[y].id)
			{
				tr.attr("id", this.rowData[y].id);
			}
			// Create the cells. x is incremented by the colSpan value of the
			// cell.
			for (var x = 0; x < w;)
			{
				// Fetch a cell from the cells
				var cell = this._getCell(_cells, x, y);

				if (cell.td == null && cell.widget != null)
				{
					// Create the cell
					var td = $j(document.createElement("td")).appendTo(tr)
						.addClass(cell["class"]);

					if (cell.disabled)
					{
						td.hide();
						cell.widget.options = cell.disabled;
					}

					if (cell.width != "auto")
					{
						td.width(cell.width);
					}

					if (cell.align)
					{
						td.attr("align",cell.align);
					}

					// Add the entry for the widget to the management array
					this.managementArray.push({
						"cell": td[0],
						"widget": cell.widget,
						"disabled": cell.disabled
					});

					// Set the span values of the cell
					var cs = (x == w - 1) ? w - x : Math.min(w - x, cell.colSpan);
					var rs = (y == h - 1) ? h - y : Math.min(h - y, cell.rowSpan);

					// Set the col and row span values
					if (cs > 1) {
						td.attr("colspan", cs);
					}

					if (rs > 1) {
						td.attr("rowspan", rs);
					}

					// Assign the td to the cell
					for (var sx = x; sx < x + cs; sx++)
					{
						for (var sy = y; sy < y + rs; sy++)
						{
							this._getCell(_cells, sx, sy).td = td;
						}
					}

					x += cell.colSpan;
				}
				else
				{
					x++;
				}
			}
		}
	},

	getDOMNode: function(_sender) {
		// If the parent class functions are asking for the DOM-Node, return the
		// outer table.
		if (_sender == this || typeof _sender == 'undefined')
		{
			return this.wrapper != null ? this.wrapper[0] : this.table[0];
		}

		// Check whether the _sender object exists inside the management array
		for (var i = 0; i < this.managementArray.length; i++)
		{
			if (this.managementArray[i].widget == _sender)
			{
				return this.managementArray[i].cell;
			}
		}

		return null;
	},

	isInTree: function(_sender) {
		var vis = true;

		if (typeof _sender != "undefined" && _sender != this)
		{
			vis = false;

			// Check whether the _sender object exists inside the management array
			for (var i = 0; i < this.managementArray.length; i++)
			{
				if (this.managementArray[i].widget == _sender)
				{
					vis = !(this.managementArray[i].disabled);
					break;
				}
			}
		}

		return this._super(this, vis);
	},

	/**
	 * Set the overflow attribute
	 *
	 * Grid needs special handling because HTML tables don't do overflow.  We
	 * create a wrapper DIV to handle it.
	 * No value or default visible needs no wrapper, as table is always overflow visible.
	 *
	 * @param {string} _value Overflow value, must be a valid CSS overflow value, default 'visible'
	 */
	set_overflow: function(_value) {
		var wrapper = this.wrapper || this.table.parent('[id$="_grid_wrapper"]');

		this.overflow = _value;

		if(wrapper.length == 0 && _value && _value !== 'visible')
		{
			this.wrapper = wrapper = this.table.wrap('<div id="'+this.id+'_grid_wrapper"></div>').parent();
			if(this.height)
			{
				wrapper.css('height', this.height);
			}
		}
		wrapper.css('overflow', _value);

		if(wrapper.length && (!_value || _value == null || _value === 'visible'))
		{
			this.table.unwrap();
		}
	},

	set_align: function(_value) {
		this.align = _value;
	},

	get_align: function(_value) {
		return this.align;
	},

	/**
	 * Change the content for the grid, and re-generate its contents.
	 *
	 * Changing the content does not allow changing the structure of the grid,
	 * as that is loaded from the template file.  The rows and widgets inside
	 * will be re-created (including auto-repeat).
	 *
	 * @param {Object} _value New data for the grid
	 * @param {Object} [_value.content] New content
	 * @param {Object} [_value.sel_options] New select options
	 * @param {Object} [_value.readonlys] New read-only values
	 */
	set_value: function(_value) {

		// Destroy children, empty grid
		for(var i = 0; i < this.managementArray.length; i++)
		{
			var cell = this.managementArray[i];
			if(cell.widget)
			{
				cell.widget.destroy();
			}
		}
		this.managementArray = [];
		this.thead.empty();
		this.tfoot.empty();
		this.tbody.empty();

		// Update array managers
		for(var key in _value)
		{
			this.getArrayMgr(key).data = _value[key];
		}

		// Rebuild grid
		this.loadFromJSON(this.template_node);

		// New widgets need to finish
		this.loadingFinished();
	},

	/**
	 * Sortable allows you to reorder grid rows using the mouse.
	 * The new order is returned as part of the value of the
	 * grid, in 'sort_order'.
	 *
	 * @param {boolean|function} sortable Callback or false to disable
	 */
	set_sortable: function(sortable) {
		if(!sortable)
		{
			this.tbody.sortable("destroy");
			return;
		}

		// Make sure rows have IDs, so sortable has something to return
		$j('tr', this.tbody).each(function(index) {
			var $this = $j(this);

			// Header does not participate in sorting
			if($this.hasClass('th')) return;

			// If row doesn't have an ID, assign the index as ID
			if(!$this.attr("id")) $this.attr("id", index);
		});

		var self = this;

		// Set up sortable
		this.tbody.sortable({
			// Header does not participate in sorting
			items: "tr:not(.th)",
			distance: 15,
			stop: function(event, ui) {
				self.egw(window).json(sortable,[self.tbody.sortable("toArray"), self.id],
					null,
					self,
					true
				).sendRequest();
			}
		});
	},

	/**
	 * Override parent to apply actions on each row
	 *
	 * @param {array} actions [ {ID: attributes..}+] as for set_actions
	 */
	_link_actions: function(actions)
	{
		 // Get the top level element for the tree
		var objectManager = egw_getAppObjectManager(true);
		objectManager = objectManager.getObjectById(this.getInstanceManager().uniqueId,2) || objectManager;
		var widget_object = objectManager.getObjectById(this.id);
		if (widget_object == null) {
			// Add a new container to the object manager which will hold the widget
			// objects
			widget_object = objectManager.insertObject(false, new egwActionObject(
				this.id, objectManager, new et2_action_object_impl(this),
				this._actionManager || objectManager.manager.getActionById(this.id) || objectManager.manager
			));
		}

		// Delete all old objects
		widget_object.clear();

		// Go over the widget & add links - this is where we decide which actions are
		// 'allowed' for this widget at this time
		var action_links = this._get_action_links(actions);

		// Deal with each row
		for(var i = 0; i < this.rowData.length; i++)
		{
			// Add a new action object to the object manager
			var row = $j('tr', this.tbody)[i];
			var aoi = new et2_action_object_impl(this, row);
			var id = "row_"+i;
			var content = this.getArrayMgr('content').getEntry(i);
			if(content && content.id)
			{
				id = content.id;
			}
			var obj = widget_object.addObject(id, aoi);

			// Set the data to the content so it's available for the action
			if(content)
			{
				obj.data = content;
			}

			obj.updateActionLinks(action_links);
		}
	},

	/**
	 * Code for implementing et2_IDetachedDOM
	 * This doesn't need to be implemented.
	 * Individual widgets are detected and handled by the grid, but the interface is needed for this to happen
	 *
	 * @param {array} _attrs array to add further attributes to
	 */
	getDetachedAttributes: function(_attrs) {
	},

	getDetachedNodes: function() {
		return [this.getDOMNode()];
	},

	setDetachedAttributes: function(_nodes, _values) {
	},

	/**
	 * Generates nextmatch column name for headers in a grid
	 *
	 * Implemented here as default implementation in et2_externsion_nextmatch
	 * only considers children, but grid does NOT instanciate disabled rows as children.
	 *
	 * @return {string}
	 */
	_getColumnName: function()
	{
		var ids = [];
		for(var r=0; r < this.cells.length; ++r)
		{
			var cols = this.cells[r];
			for(var c=0; c < cols.length; ++c)
			{
				if (cols[c].nm_id) ids.push(cols[c].nm_id);
			}
		}
		return ids.join('_');
	},

	resize: function (_height)
	{
		if (typeof this.options != 'undefined' && _height
				&& typeof this.options.resize_ratio != 'undefined' && this.options.resize_ratio)
		{
			// apply the ratio
			_height = (this.options.resize_ratio != '')? _height * this.options.resize_ratio: _height;
			if (_height != 0)
			{
				if (this.wrapper)
				{
					this.wrapper.height(this.wrapper.height() + _height);
				}
				else
				{
					this.table.height(this.table.height() + _height );
				}
			}

		}
	},

	/**
	 * Get a dummy row object containing all widget of a row
	 *
	 * This is only a temp. solution until rows are implemented as eT2 containers and
	 * _sender.getParent() will return a real row container.
	 *
	 * @param {et2_widget} _sender
	 * @returns {Array|undefined}
	 */
	getRow: function(_sender)
	{
		if (!_sender || !this.cells) return;

		for(var r=0; r < this.cells.length; ++r)
		{
			var row = this.cells[r];
			for(var c=0; c < row.length; ++c)
			{
				if (!row[c].widget) continue;

				var found = row[c].widget === _sender;
				if (!found) row[c].widget.iterateOver(function(_widget) {if (_widget === _sender) found = true;});
				if (found)
				{
					// return a fake row object allowing to iterate over it's children
					var row_obj = new et2_widget(this, {});
					for(var c=0; c < row.length; ++c)
					{
						if (row[c].widget) row_obj._children.push(row[c].widget);
					}
					row_obj.isInTree = jQuery.proxy(this.isInTree, this);
					// we must not free the children!
					row_obj.destroy = function(){
						delete row_obj._children;
					};
					return row_obj;
				}
			}
		}
	}
});
et2_register_widget(et2_grid, ["grid"]);