/*
			 * 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
    }, 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 );
        }
    });
};