/source/chrome/javascript/common/jquery/tablednd.js

/**
 * TableDnD plug-in for JQuery, allows you to drag and drop table rows
 * You can set up various options to control how the system will work
 * Copyright © Denis Howlett <denish@isocra.com>
 * Licensed like jQuery, see http://docs.jquery.com/License.
 *
 * Configuration options:
 *
 * onDragStyle
 *		 This is the style that is assigned to the row during drag. There are limitations to the styles that can be
 *		 associated with a row (such as you can't assign a border—well you can, but it won't be
 *		 displayed). (So instead consider using onDragClass.) The CSS style to apply is specified as
 *		 a map (as used in the jQuery css(...) function).
 * onDropStyle
 *		 This is the style that is assigned to the row when it is dropped. As for onDragStyle, there are limitations
 *		 to what you can do. Also this replaces the original style, so again consider using onDragClass which
 *		 is simply added and then removed on drop.
 * onDragClass
 *		 This class is added for the duration of the drag and then removed when the row is dropped. It is more
 *		 flexible than using onDragStyle since it can be inherited by the row cells and other content. The default
 *		 is class is tDnD_whileDrag. So to use the default, simply customise this CSS class in your
 *		 stylesheet.
 * onDrop
 *		 Pass a function that will be called when the row is dropped. The function takes 2 parameters: the table
 *		 and the row that was dropped. You can work out the new order of the rows by using
 *		 table.rows.
 * onDragStart
 *		 Pass a function that will be called when the user starts dragging. The function takes 2 parameters: the
 *		 table and the row which the user has started to drag.
 * onAllowDrop
 *		 Pass a function that will be called as a row is over another row. If the function returns true, allow
 *		 dropping on that row, otherwise not. The function takes 2 parameters: the dragged row and the row under
 *		 the cursor. It returns a boolean: true allows the drop, false doesn't allow it.
 * scrollAmount
 *		 This is the number of pixels to scroll if the user moves the mouse cursor to the top or bottom of the
 *		 window. The page should automatically scroll up or down as appropriate (tested in IE6, IE7, Safari, FF2,
 *		 FF3 beta)
 *
 * Other ways to control behaviour:
 *
 * Add class="nodrop" to any rows for which you don't want to allow dropping, and class="nodrag" to any rows
 * that you don't want to be draggable.
 *
 * Inside the onDrop method you can also call $.tableDnD.serialize() this returns a string of the form
 * <tableID>[]=<rowID1>&<tableID>[]=<rowID2> so that you can send this back to the server. The table must have
 * an ID as must all the rows.
 *
 * Known problems:
 * - Auto-scoll has some problems with IE7	(it scrolls even when it shouldn't), work-around: set scrollAmount to 0
 *
 * Version 0.2: 2008-02-20 First public version
 * Version 0.3: 2008-02-07 Added onDragStart option
 *												 Made the scroll amount configurable (default is 5 as before)
 * Version 0.4: 2008-03-15 Changed the noDrag/noDrop attributes to nodrag/nodrop classes
 *												 Added onAllowDrop to control dropping
 *												 Fixed a bug which meant that you couldn't set the scroll amount in both directions
 *												 Added serialise method
 */
jQuery.tableDnD = {
		/** Keep hold of the current table being dragged */
		currentTable : null,
		/** Keep hold of the current drag object if any */
		dragObject: null,
		/** The current mouse offset */
		mouseOffset: null,
		/** Remember the old value of Y so that we don't do too much processing */
		oldY: 0,

		/** Actually build the structure */
		build: function(options) {
				// Make sure options exists
				options = options || {};
				// Set up the defaults if any

				this.each(function() {
						// Remember the options
						this.tableDnDConfig = {
								onDragStyle: options.onDragStyle,
								onDropStyle: options.onDropStyle,
				// Add in the default class for whileDragging
				onDragClass: options.onDragClass ? options.onDragClass : "tDnD_whileDrag",
								onDrop: options.onDrop,
								onDragStart: options.onDragStart,
								scrollAmount: options.scrollAmount ? options.scrollAmount : 5
						};
						// Now make the rows draggable
						jQuery.tableDnD.makeDraggable(this);
				});

				// Now we need to capture the mouse up and mouse move event
				// We can use bind so that we don't interfere with other event handlers
				jQuery(document)
						.bind('mousemove', jQuery.tableDnD.mousemove)
						.bind('mouseup', jQuery.tableDnD.mouseup);

				// Don't break the chain
				return this;
		},

		/** This function makes all the rows on the table draggable apart from those marked as "NoDrag" */
		makeDraggable: function(table) {
				// Now initialise the rows
				var rows = table.rows; //getElementsByTagName("tr")
				var config = table.tableDnDConfig;
				for (var i=0; i<rows.length; i++) {
						// To make non-draggable rows, add the nodrag class (eg for Category and Header rows)
			// inspired by John Tarr and Famic
						var nodrag = $(rows[i]).hasClass("nodrag");
						if (! nodrag) { //There is no NoDnD attribute on rows I want to drag
								jQuery(rows[i]).mousedown(function(ev) {
										if (ev.target.tagName == "TD") {
												jQuery.tableDnD.dragObject = this;
												jQuery.tableDnD.currentTable = table;
												jQuery.tableDnD.mouseOffset = jQuery.tableDnD.getMouseOffset(this, ev);
												if (config.onDragStart) {
														// Call the onDrop method if there is one
														config.onDragStart(table, this);
												}
												return false;
										}
								}).css("cursor", "move"); // Store the tableDnD object
						}
				}
		},

		/** Get the mouse coordinates from the event (allowing for browser differences) */
		mouseCoords: function(ev){
				if(ev.pageX || ev.pageY){
						return {x:ev.pageX, y:ev.pageY};
				}
				return {
						x:ev.clientX + document.body.scrollLeft - document.body.clientLeft,
						y:ev.clientY + document.body.scrollTop	- document.body.clientTop
				};
		},

		/** Given a target element and a mouse event, get the mouse offset from that element.
				To do this we need the element's position and the mouse position */
		getMouseOffset: function(target, ev) {
				ev = ev || window.event;

				var docPos		= this.getPosition(target);
				var mousePos	= this.mouseCoords(ev);
				return {x:mousePos.x - docPos.x, y:mousePos.y - docPos.y};
		},

		/** Get the position of an element by going up the DOM tree and adding up all the offsets */
		getPosition: function(e){
				var left = 0;
				var top  = 0;
				/** Safari fix -- thanks to Luis Chato for this! */
				if (e.offsetHeight == 0) {
						/** Safari 2 doesn't correctly grab the offsetTop of a table row
						this is detailed here:
						http://jacob.peargrove.com/blog/2006/technical/table-row-offsettop-bug-in-safari/
						the solution is likewise noted there, grab the offset of a table cell in the row - the firstChild.
						note that firefox will return a text node as a first child, so designing a more thorough
						solution may need to take that into account, for now this seems to work in firefox, safari, ie */
						e = e.firstChild; // a table cell
				}

				while (e.offsetParent){
						left += e.offsetLeft;
						top  += e.offsetTop;
						e		= e.offsetParent;
				}

				left += e.offsetLeft;
				top  += e.offsetTop;

				return {x:left, y:top};
		},

		mousemove: function(ev) {
				if (jQuery.tableDnD.dragObject == null) {
						return;
				}

				var dragObj = jQuery(jQuery.tableDnD.dragObject);
				var config = jQuery.tableDnD.currentTable.tableDnDConfig;
				var mousePos = jQuery.tableDnD.mouseCoords(ev);
				var y = mousePos.y - jQuery.tableDnD.mouseOffset.y;
				//auto scroll the window
			var yOffset = window.pageYOffset;
		if (document.all) {
					// Windows version
					//yOffset=document.body.scrollTop;
					if (typeof document.compatMode != 'undefined' &&
							 document.compatMode != 'BackCompat') {
						 yOffset = document.documentElement.scrollTop;
					}
					else if (typeof document.body != 'undefined') {
						 yOffset=document.body.scrollTop;
					}

			}

		if (mousePos.y-yOffset < config.scrollAmount) {
				window.scrollBy(0, -config.scrollAmount);
			} else {
						var windowHeight = window.innerHeight ? window.innerHeight
										: document.documentElement.clientHeight ? document.documentElement.clientHeight : document.body.clientHeight;
						if (windowHeight-(mousePos.y-yOffset) < config.scrollAmount) {
								window.scrollBy(0, config.scrollAmount);
						}
				}


				if (y != jQuery.tableDnD.oldY) {
						// work out if we're going up or down...
						var movingDown = y > jQuery.tableDnD.oldY;
						// update the old value
						jQuery.tableDnD.oldY = y;
						// update the style to show we're dragging
			if (config.onDragClass) {
				dragObj.addClass(config.onDragClass);
			} else {
							dragObj.css(config.onDragStyle);
			}
						// If we're over a row then move the dragged row to there so that the user sees the
						// effect dynamically
						var currentRow = jQuery.tableDnD.findDropTargetRow(dragObj, y);
						if (currentRow) {
								// TODO worry about what happens when there are multiple TBODIES
								if (movingDown && jQuery.tableDnD.dragObject != currentRow) {
										jQuery.tableDnD.dragObject.parentNode.insertBefore(jQuery.tableDnD.dragObject, currentRow.nextSibling);
								} else if (! movingDown && jQuery.tableDnD.dragObject != currentRow) {
										jQuery.tableDnD.dragObject.parentNode.insertBefore(jQuery.tableDnD.dragObject, currentRow);
								}
						}
				}

				return false;
		},

		/** We're only worried about the y position really, because we can only move rows up and down */
		findDropTargetRow: function(draggedRow, y) {
				var rows = jQuery.tableDnD.currentTable.rows;
				for (var i=0; i<rows.length; i++) {
						var row = rows[i];
						var rowY		= this.getPosition(row).y;
						var rowHeight = parseInt(row.offsetHeight)/2;
						if (row.offsetHeight == 0) {
								rowY = this.getPosition(row.firstChild).y;
								rowHeight = parseInt(row.firstChild.offsetHeight)/2;
						}
						// Because we always have to insert before, we need to offset the height a bit
						if ((y > rowY - rowHeight) && (y < (rowY + rowHeight))) {
								// that's the row we're over
				// If it's the same as the current row, ignore it
				if (row == draggedRow) {return null;}
								var config = jQuery.tableDnD.currentTable.tableDnDConfig;
								if (config.onAllowDrop) {
										if (config.onAllowDrop(draggedRow, row)) {
												return row;
										} else {
												return null;
										}
								} else {
					// If a row has nodrop class, then don't allow dropping (inspired by John Tarr and Famic)
										var nodrop = $(row).hasClass("nodrop");
										if (! nodrop) {
												return row;
										} else {
												return null;
										}
								}
								return row;
						}
				}
				return null;
		},

		mouseup: function(e) {
				if (jQuery.tableDnD.currentTable && jQuery.tableDnD.dragObject) {
						var droppedRow = jQuery.tableDnD.dragObject;
						var config = jQuery.tableDnD.currentTable.tableDnDConfig;
						// If we have a dragObject, then we need to release it,
						// The row will already have been moved to the right place so we just reset stuff
			if (config.onDragClass) {
							jQuery(droppedRow).removeClass(config.onDragClass);
			} else {
							jQuery(droppedRow).css(config.onDropStyle);
			}
						jQuery.tableDnD.dragObject	 = null;
						if (config.onDrop) {
								// Call the onDrop method if there is one
								config.onDrop(jQuery.tableDnD.currentTable, droppedRow);
						}
						jQuery.tableDnD.currentTable = null; // let go of the table too
				}
		},

		serialize: function() {
				if (jQuery.tableDnD.currentTable) {
						var result = "";
						var tableId = jQuery.tableDnD.currentTable.id;
						var rows = jQuery.tableDnD.currentTable.rows;
						for (var i=0; i<rows.length; i++) {
								if (result.length > 0) result += "&";
								result += tableId + '[]=' + rows[i].id;
						}
						return result;
				} else {
						return "Error: No Table id set, you need to set an id on your table and every row";
				}
		}
}

jQuery.fn.extend(
	{
		tableDnD : jQuery.tableDnD.build
	}
);