hey guys , im writing a class and im wondering how i can write a condition statement in this way :

$this->referer= (!empty($_SERVER['HTTP_REFERER'])) ? htmlspecialchars((string) $_SERVER['HTTP_REFERER']) : '';

i need to find my user_id and this is the usual condtion :

    if(is_user($user)){ 
        $cookie=cookiedecode($user);
        $user_id=intval($cookie[0]);
    }

and i think it should be something like this :

    $this->user_id = (is_user($user)) ? (cookiedecode($user)) : $cookie[0];

but it didnt work