/**
 * jquery.scrollto
 * copyright (c) 2008 ariel flesler - aflesler(at)gmail(dot)com | http://flesler.blogspot.com
 * dual licensed under the mit (http://www.opensource.org/licenses/mit-license.php)
 * and gpl (http://www.opensource.org/licenses/gpl-license.php) licenses.
 * date: 2/19/2008
 *
 * @projectdescription easy element scrolling using jquery.
 * tested with jquery 1.2.1. on ff 2.0.0.11, ie 6, opera 9.22 and safari 3 beta. on windows.
 *
 * @author ariel flesler
 * @version 1.3.3
 *
 * @id jquery.scrollto
 * @id jquery.fn.scrollto
 * @param {string, number, domelement, jquery, object} target where to scroll the matched elements.
 *	  the different options for target are:
 *		- a number position (will be applied to all axes).
 *		- a string position ('44', '100px', '+=90', etc ) will be applied to all axes
 *		- a jquery/dom element ( logically, child of the element to scroll )
 *		- a string selector, that will be relative to the element to scroll ( 'li:eq(2)', etc )
 *		- a hash { top:x, left:y }, x and y can be any kind of number/string like above.
 * @param {number} duration the overall length of the animation, this argument can be the settings object instead.
 * @param {object} settings hash of settings, optional.
 *	 @option {string} axis which axis must be scrolled, use 'x', 'y', 'xy' or 'yx'.
 *	 @option {number} duration the overall length of the animation.
 *	 @option {string} easing the easing method for the animation.
 *	 @option {boolean} margin if true, the margin of the target element will be deducted from the final position.
 *	 @option {object, number} offset add/deduct from the end position. one number for both axes or { top:x, left:y }.
 *	 @option {object, number} over add/deduct the height/width multiplied by 'over', can be { top:x, left:y } when using both axes.
 *	 @option {boolean} queue if true, and both axis are given, the 2nd axis will only be animated after the first one ends.
 *	 @option {function} onafter function to be called after the scrolling ends. 
 *	 @option {function} onafterfirst if queuing is activated, this function will be called after the first scrolling ends.
 * @return {jquery} returns the same jquery object, for chaining.
 *
 * @example $('div').scrollto( 340 );
 *
 * @example $('div').scrollto( '+=340px', { axis:'y' } );
 *
 * @example $('div').scrollto( 'p.paragraph:eq(2)', 500, { easing:'swing', queue:true, axis:'xy' } );
 *
 * @example var second_child = document.getelementbyid('container').firstchild.nextsibling;
 *			$('#container').scrollto( second_child, { duration:500, axis:'x', onafter:function(){
 *				alert('scrolled!!');																   
 *			}});
 *
 * @example $('div').scrollto( { top: 300, left:'+=200' }, { offset:-20 } );
 *
 * notes:
 *  - jquery.scrollto will make the whole window scroll, it accepts the same arguments as jquery.fn.scrollto.
 *	- if you are interested in animated anchor navigation, check http://jquery.com/plugins/project/localscroll.
 *	- the options margin, offset and over are ignored, if the target is not a jquery object or a dom element.
 *	- the option 'queue' won't be taken into account, if only 1 axis is given.
 */
;(function( $ ){

	var $scrollto = $.scrollto = function( target, duration, settings ){
		$scrollto.window().scrollto( target, duration, settings );
	};

	$scrollto.defaults = {
		axis:'y',
		duration:1
	};

	//returns the element that needs to be animated to scroll the window
	$scrollto.window = function(){
		return $( $.browser.safari ? 'body' : 'html' );
	};

	$.fn.scrollto = function( target, duration, settings ){
		if( typeof duration == 'object' ){
			settings = duration;
			duration = 0;
		}
		settings = $.extend( {}, $scrollto.defaults, settings );
		duration = duration || settings.speed || settings.duration;//speed is still recognized for backwards compatibility
		settings.queue = settings.queue && settings.axis.length > 1;//make sure the settings are given right
		if( settings.queue )
			duration /= 2;//let's keep the overall speed, the same.
		settings.offset = both( settings.offset );
		settings.over = both( settings.over );

		return this.each(function(){
			var elem = this, $elem = $(elem),
				t = target, toff, attr = {},
				win = $elem.is('html,body');
			switch( typeof t ){
				case 'number'://will pass the regex
				case 'string':
					if( /^([+-]=)?\d+(px)?$/.test(t) ){
						t = both( t );
						break;//we are done
					}
					t = $(t,this);// relative selector, no break!
				case 'object':
					if( t.is || t.style )//dom/jquery
						toff = (t = $(t)).offset();//get the real position of the target 
			}
			$.each( settings.axis.split(''), function( i, axis ){
				var pos	= axis == 'x' ? 'left' : 'top',
					pos = pos.tolowercase(),
					key = 'scroll' + pos,
					act = elem[key],
					dim = axis == 'x' ? 'width' : 'height',
					dim = dim.tolowercase();

				if( toff ){//jquery/dom
					attr[key] = toff[pos] + ( win ? 0 : act - $elem.offset()[pos] );

					if( settings.margin ){//if it's a dom element, reduce the margin
						attr[key] -= parseint(t.css('margin'+pos)) || 0;
						attr[key] -= parseint(t.css('border'+pos+'width')) || 0;
					}
					
					attr[key] += settings.offset[pos] || 0;//add/deduct the offset
					
					if( settings.over[pos] )//scroll to a fraction of its width/height
						attr[key] += t[dim]() * settings.over[pos];
				}else
					attr[key] = t[pos];//remove the unnecesary 'px'

				if( /^\d+$/.test(attr[key]) )//number or 'number'
					attr[key] = attr[key] <= 0 ? 0 : math.min( attr[key], max(dim) );//check the limits

				if( !i && settings.queue ){//queueing each axis is required					
					if( act != attr[key] )//don't waste time animating, if there's no need.
						animate( settings.onafterfirst );//intermediate animation
					delete attr[key];//don't animate this axis again in the next iteration.
				}
			});			
			animate( settings.onafter );			

			function animate( callback ){
				$elem.animate( attr, duration, settings.easing, callback && function(){
					callback.call(this, target);
				});
			};
			function max( dim ){
				var el = win ? $.browser.opera ? document.body : document.documentelement : elem;
				return el['scroll'+dim] - el['client'+dim];
			};
		});
	};

	function both( val ){
		return typeof val == 'object' ? val : { top:val, left:val };
	};

})( jquery );