public function getUserByEmailAndPassword($email, $password) {

        $stmt = $this->conn->prepare("SELECT * FROM UZYTKOWNICY WHERE EMAIL = ?");

        $stmt->bind_param("s", $email);

        if ($stmt->execute()) {
            $user = $stmt->get_result()->fetch_assoc();
            $stmt->close();

            $salt = $user['SALT'];
            $encrypted_password = $user['ENCRYPTED_PASSWORD'];
            $hash = $this->checkhashSSHA($salt, $password);
            if ($encrypted_password == $hash) {
                return $user;
            }
        } else {
            return NULL;
        }
    }