/*
* stickyfloat - jQuery plugin for verticaly floating anything in a constrained area
* 
* Example: jQuery('#menu').stickyfloat({duration: 400});
* parameters:
* 		duration 	- the duration of the animation
*		startOffset - the amount of scroll offset after it the animations kicks in
*		offsetY		- the offset from the top when the object is animated
*		lockBottom	- 'true' by default, set to false if you don't want your floating box to stop at parent's bottom
* $Version: 05.16.2009 r1
* Copyright (c) 2009 Yair Even-Or
* vsync.design@gmail.com
*/
$.fn.stickyfloat = function(options, lockBottom) {
    var $obj = this;
    var parentPaddingTop = parseInt($obj.parent().css('padding-top'));
    var startOffset = $obj.parent().offset().top;
    var opts = $.extend({ startOffset: startOffset, offsetY: parentPaddingTop, duration: 200, lockBottom: true, documentHeight: -1 }, options);

    $obj.css({ position: 'absolute' });

    if (opts.lockBottom) {
		if (opts.documentHeight > 0)
		{
			var bottomPos = opts.documentHeight - $obj.height() + parentPaddingTop; //get the maximum scrollTop value
		}
		else
		{
			var bottomPos = $obj.parent().height() - $obj.height() + parentPaddingTop; //get the maximum scrollTop value
		}
		if (bottomPos < 0)
            bottomPos = 0;
    }

    $(window).scroll(function() {
        $obj.stop(); // stop all calculations on scroll event

        var pastStartOffset = $(document).scrollTop() > opts.startOffset; // check if the window was scrolled down more than the start offset declared.
        var objFartherThanTopPos = $obj.offset().top > startOffset; // check if the object is at it's top position (starting point)
        var objBiggerThanWindow = $obj.outerHeight() < $(window).height(); // if the window size is smaller than the Obj size, then do not animate.

        // if window scrolled down more than startOffset OR obj position is greater than
        // the top position possible (+ offsetY) AND window size must be bigger than Obj size
        if ((pastStartOffset || objFartherThanTopPos) && objBiggerThanWindow) {
            var newpos = ($(document).scrollTop() - startOffset + opts.offsetY);
			if (newpos > bottomPos)
                newpos = bottomPos;
            if ($(document).scrollTop() < opts.startOffset) // if window scrolled < starting offset, then reset Obj position (opts.offsetY);
                newpos = parentPaddingTop;

            $obj.animate({ top: newpos }, opts.duration);
        }
    });
};