(function ($) {
    "use strict";
    $(document).ready(function () {
        var $back_to_top = $("#back-to-top");

        if( $back_to_top.length) {

            var $min         = 200;
            var $inDelay     = 600;
            var $outDelay    = 400;
            var $scrollSpeed = 300;
            var $easingType  = 'linear';            

            $( $back_to_top ).hide().on("click",function(e){
                $('html, body').animate({scrollTop:0}, $scrollSpeed, $easingType);
                $('#back-to-top-hover').stop().animate({'opacity': 0 }, $inDelay, $easingType);
                return false;
            }).hover(function(){
                $('#back-to-top-hover').stop().animate({
                    'opacity': 1
                }, 600, 'linear');
            },function(){
                $('#back-to-top-hover').stop().animate({
                    'opacity': 0
                }, 700, 'linear');
            });

            $(window).scroll(function(){
                var $sd = $(window).scrollTop();
                if(typeof document.body.style.maxHeight === "undefined") {
                    $($back_to_top).css({
                        'position': 'absolute',
                        'top': sd + $(window).height() - 50
                    });
                }

                if ( $sd > $min ){
                    $($back_to_top).fadeIn($inDelay);
                } else {
                    $($back_to_top).fadeOut($outDelay);
                }
            });
        }
    });
})(jQuery);