/*
 * 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
 * jQueryVersion: 05.16.2009 r1
 * Copyright (c) 2009 Yair Even-Or
 * vsync.design@gmail.com
 */

jQuery.fn.stickyfloat = function(options, lockBottom) {
	return this.each(function(){
        var jQueryobj 				= jQuery(this);
        var parent = jQueryobj.parent();
        if (!parent.length) {
            return;  // No parent, continue with next element, if any.
        }
        
	    var parentPaddingTop 	= parseInt(parent.css('padding-top'));
	    var startOffset 		= parent.offset().top;
	    var opts 				= jQuery.extend({ startOffset: startOffset, offsetY: parentPaddingTop, duration: 200, lockBottom:true }, options);
	    
	    jQueryobj.css({ position: 'absolute' });
	    
	    if(opts.lockBottom){
		    var bottomPos = parent.height() - jQueryobj.height() + parentPaddingTop; //get the maximum scrollTop value
		    if( bottomPos < 0 )
			    bottomPos = 0;
	    }
	    
	    jQuery(window).scroll(function () { 
		    jQueryobj.stop(); // stop all calculations on scroll event

		    var pastStartOffset			= jQuery(document).scrollTop() > opts.startOffset;	// check if the window was scrolled down more than the start offset declared.
		    var objFartherThanTopPos	= jQueryobj.offset().top > startOffset;	// check if the object is at it's top position (starting point)
		    var objBiggerThanWindow 	= jQueryobj.outerHeight() < jQuery(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 = (jQuery(document).scrollTop() -startOffset + opts.offsetY );
			    if ( newpos > bottomPos )
				    newpos = bottomPos;
			    if ( jQuery(document).scrollTop() < opts.startOffset ) // if window scrolled < starting offset, then reset Obj position (opts.offsetY);
				    newpos = parentPaddingTop;

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