/**
 * EGroupware clientside API 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 (as AT stylite.de)
 * @author Ralf Becker <RalfBecker@outdoor-training.de>
 * @version $Id$
 */

"use strict";

/*egw:uses
	jquery.jquery;
	egw_core;
*/

egw.extend('tooltip', egw.MODULE_WND_LOCAL, function(_app, _wnd) {

	var tooltip_div = null;
	var current_elem = null;

	var time_delta = 100;
	var show_delta = 0;
	var show_delay = 200;

	var x = 0;
	var y = 0;

	/**
	 * Removes the tooltip_div from the DOM if it does exist.
	 */
	function hide()
	{
		if (tooltip_div != null)
		{
			tooltip_div.remove();
			tooltip_div = null;
		}
	}

	/**
	 * Shows the tooltip at the current cursor position.
	 */
	function show()
	{
		if (tooltip_div)
		{
			//Calculate the cursor_rectangle - this is a space the tooltip might
			//not overlap with
			var cursor_rect = {
				left: (x - 8),
				top: (y - 8),
				right: (x + 8),
				bottom: (y + 8)
			};

			//Calculate how much space is left on each side of the rectangle
			var window_width = $j(_wnd.document).width();
			var window_height = $j(_wnd.document).height();
			var space_left = {
				left: (cursor_rect.left),
				top: (cursor_rect.top),
				right: (window_width - cursor_rect.right),
				bottom: (window_height - cursor_rect.bottom)
			};

			//Get the width and the height of the tooltip
			var tooltip_width = tooltip_div.width();
			if (tooltip_width > 300) tooltip_width = 300;
			var tooltip_height = tooltip_div.height();

			if (space_left.right < tooltip_width) {
				tooltip_div.css('left', Math.max(0,cursor_rect.left - tooltip_width));
			} else if (space_left.left >= tooltip_width) {
				tooltip_div.css('left', cursor_rect.right);
			} else	{
				tooltip_div.css('left', cursor_rect.right);
				tooltip_div.css('max-width', space_left.right);
			}

			if (space_left.bottom < tooltip_height) {
				tooltip_div.css('top', cursor_rect.top - tooltip_height);
			} else if (space_left.top >= tooltip_height) {
				tooltip_div.css('top', cursor_rect.bottom);
			} else	{
				tooltip_div.css('top', cursor_rect.bottom);
				tooltip_div.css('max-height', space_left.bottom);
			}

			tooltip_div.fadeIn(100);
		}
	}

	/**
	 * Creates the tooltip_div with the given text.
	 */
	function prepare(_html)
	{
		// Free and null the old tooltip_div
		hide();

		//Generate the tooltip div, set it's text and append it to the body tag
		tooltip_div = $j(_wnd.document.createElement('div'));
		tooltip_div.hide();
		tooltip_div.append(_html);
		tooltip_div.addClass("egw_tooltip");
		$j(_wnd.document.body).append(tooltip_div);

		//The tooltip should automatically hide when the mouse comes over it
		tooltip_div.mouseenter(function() {
				hide();
		});
	}

	/**
	 * showTooltipTimeout is used to prepare showing the tooltip.
	 */
	function showTooltipTimeout()
	{
		if (current_elem != null)
		{
			show_delta += time_delta;
			if (show_delta < show_delay)
			{
				//Repeat the call of timeout
				_wnd.setTimeout(showTooltipTimeout, time_delta);
			}
			else
			{
				show_delta = 0;
				show();
			}
		}
	}

	return {
		/**
		 * Binds a tooltip to the given DOM-Node with the given html.
		 * It is important to remove all tooltips from all elements which are
		 * no longer needed, in order to prevent memory leaks.
		 * 
		 * @param _elem is the element to which the tooltip should get bound. It
		 * 	has to be a jQuery node.
		 * @param _html is the html code which should be shown as tooltip.
		 */
		tooltipBind: function(_elem, _html) {
			if (_html != '')
			{
				_elem.bind('mouseenter.tooltip', function(e) {
					if (_elem != current_elem)
					{
						//Prepare the tooltip
						prepare(_html);

						// Set the current element the mouse is over and
						// initialize the position variables
						current_elem = _elem;
						show_delta = 0;
						x = e.clientX;
						y = e.clientY;

						// Create the timeout for showing the timeout
						_wnd.setTimeout(showTooltipTimeout, time_delta);
					}

					return false;
				});

				_elem.bind('mouseleave.tooltip', function() {
					current_elem = null;
					show_delta = 0;
					if (tooltip_div)
					{
						tooltip_div.fadeOut(100);
					}
				});

				_elem.bind('mousemove.tooltip', function(e) {
					//Calculate the distance the mouse took since the last call of mousemove
					var dx = x - e.clientX;
					var dy = y - e.clientY;
					var movedist = Math.sqrt(dx * dx + dy * dy);

					//Block appereance of the tooltip on fast movements (with small movedistances)
					if (movedist > 2)
					{
						show_delta = 0;
					}

					x = e.clientX;
					y = e.clientY;
				});
			}
		},

		/**
		 * Unbinds the tooltip from the given DOM-Node.
		 * 
		 * @param _elem is the element from which the tooltip should get
		 * removed. _elem has to be a jQuery node.
		 */
		tooltipUnbind: function(_elem) {
			if (current_elem == _elem)
			{
				hide();
				current_elem = null;
			}

			// Unbind all "tooltip" events from the given element
			_elem.unbind('.tooltip');
		}
	}

});