/*
 * stickyfloat - jQuery plugin for verticaly floating anything in a constrained area
 * 
 * Example: jQuery('#menu').stickyfloat({duration: 400});
 * parameters:
 * 		duration 	(200)	 - the duration of the animation
 *		startOffset (number) - the amount of scroll offset after the animations kicks in
 *		offsetY		(number) - the offset from the top when the object is animated
 *		lockBottom	(true)	 - set to false if you don't want your floating box to stop at parent's bottom
 *		delay		(0)		 - delay in milliseconds  until the animnations starts
	easing		(linear) - easing function (jQuery has by default only 'swing' & 'linear')
 * $Version: 08.10.2011 r2
 * $Version: 05.16.2009 r1
 * Copyright (c) 2009 Yair Even-Or
 * vsync.design@gmail.com
 */
(function($){
    $.fn.stickyfloat = function(options, lockBottom){
	var $obj 				= this,
	    doc					= $(document),
	    opts, bottomPos, pastStartOffset, objFartherThanTopPos, objBiggerThanWindow, newpos, checkTimer, lastDocPos = doc.scrollTop(),
	    parentPaddingTop 	= parseInt($obj.parent().css('padding-top')),
	    startOffset 		= $obj.parent().offset().top;
	
	$.extend( $.fn.stickyfloat.opts, options, { startOffset:startOffset, offsetY:parentPaddingTop} );
	opts = $.fn.stickyfloat.opts;
	$obj.css({ position: 'absolute' });
	
	if(opts.lockBottom){
	    bottomPos = $obj.parent().height() - $obj.outerHeight() + parentPaddingTop; //get the maximum scrollTop value
	    if( bottomPos < 0 )
		bottomPos = 0;
	}
	
	function checkScroll(){
	    if( opts.duration > 40 ){
		clearTimeout(checkTimer);
		checkTimer = setTimeout(function(){
		    if( Math.abs(doc.scrollTop() - lastDocPos) > 0 ){
			lastDocPos = doc.scrollTop();
			initFloat();
		    }
		},40);
	    }
	    else initFloat();
	}
	
	function initFloat(){
	    $obj.stop(); // stop all calculations on scroll event
	    
	    pastStartOffset			= doc.scrollTop() > opts.startOffset;	// check if the window was scrolled down more than the start offset declared.
	    objFartherThanTopPos	= $obj.offset().top > startOffset;	// check if the object is at it's top position (starting point)
	    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 ){ 
		newpos = (doc.scrollTop() -startOffset + opts.offsetY );

		if ( newpos > bottomPos )
		    newpos = bottomPos;
		if ( doc.scrollTop() < opts.startOffset ) // if window scrolled < starting offset, then reset Obj position (opts.offsetY);
		    newpos = parentPaddingTop;
		
		$obj.delay(opts.delay).animate({ top: newpos }, opts.duration , opts.easing );
	    }
	}
	
	$(window).scroll(checkScroll);
    };
    
    $.fn.stickyfloat.opts = { duration:200, lockBottom:true , delay:0, easing:'linear' };
})(jQuery);