/**
* 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);