/*
* Copyright (C) 2009 Joel Sutherland
* Licenced under the MIT license
* http://www.newmediacampaigns.com/page/autosprites-jquery-menu-plugin
*/

(function($) {
$.fn.autosprites = function(settings) {
settings = $.extend({
offset: '100%',
orientation: 'horizontal',
over: { opacity: 'show' },
overSpeed: 500,
out: { opacity: 'hide' },
outSpeed: 200,
activeState: false,
activeClass: 'active',
activeSprites: false
}, settings);

function rempx(string){ return Number(string.substr(0, string.length - 2));}
function addpx(number){return number + 'px'; }

$(this).each(function(){
var backgroundImage = $(this).css('background-image');

// Solves IE6 stacking context bug
$(this).css('zIndex', 100).find('a').css('zIndex', 99);

var totalPositionOffset = 0;
$(this).children().each(function(){
var positionOffset = '-' + addpx(totalPositionOffset);

// Assign the background image to each menu item and give it the correct background-position
var baseOffset = '0px';
//If this child is active we need to adjust the base offset to the active level
if(settings.activeState && $(this).hasClass(settings.activeClass)){
baseOffset = '-' + addpx(rempx(settings.offset));
if(settings.activeSprites)
baseOffset = '-' + addpx(rempx(settings.offset) * 2);
}
var position = settings.orientation == 'horizontal' ? positionOffset + ' ' + baseOffset : baseOffset + ' ' + positionOffset;
var offsetPosition = settings.orientation == 'horizontal' ? positionOffset + ' -' + settings.offset : '-' + settings.offset + ' ' + positionOffset;
$(this).css({
backgroundImage: backgroundImage,
backgroundPosition: position
});

// Build the Hover Divs so that the background can be animated
var width = $(this).css('width');
var height = $(this).css('height');
var hover = $('<div>&nbsp;</div>').css({
cursor: 'hand',
zIndex: 1,
position: 'absolute',
top: 0,
left: 0,
width: width,
height: height,
backgroundImage: backgroundImage,
backgroundPosition: offsetPosition
}).hide();
$(this).prepend(hover);

$(this).hover(function(){
$(this).find('div').stop(false, true).animate(settings.over, settings.overSpeed);
}, function(){
$(this).find('div').stop(false, true).animate(settings.out, settings.outSpeed);
});

totalPositionOffset += settings.orientation == 'horizontal' ? rempx(width) : rempx(height);
});
});
}
})(jQuery);