/*
* 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
* $Version: 05.16.2009 r1
* Copyright (c) 2009 Yair Even-Or
* vsync.design@gmail.com
*/
jQuery(document).ready(function($){
    $.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:false }, options);

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

        if(opts.lockBottom){
            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 );
            }
        });
    };
});