USER::login PHP Method

    function login($email, $password)
    {
        global $db;
        // Prepare e-mail address
        $email = $db->escape_string($email);
        $email = strtolower($email);
        $password = $db->escape_string($password);
        $email_part = explode("@", $email);
        $username = $email_part[0];
        $domain = $email_part[1];
        // Check e-mail address
        $sql = "SELECT `" . DBC_USERS_ID . "`, `" . DBC_USERS_PASSWORD . "` FROM `" . DBT_USERS . "` WHERE `" . DBC_USERS_USERNAME . "` = '{$username}' AND `" . DBC_USERS_DOMAIN . "` = '{$domain}' LIMIT 1;";
        if (!($result = $db->query($sql))) {
            dbError($db->error);
        }
        if ($result->num_rows === 1) {
            $userdata = $result->fetch_array(MYSQLI_ASSOC);
            $uid = $userdata[DBC_USERS_ID];
            $password_hash = $userdata[DBC_USERS_PASSWORD];
            // Check password
            if (crypt($password, $password_hash) === $password_hash) {
                // Password is valid, start a logged-in user session
                $this->loggedin = true;
                $_SESSION['uid'] = $uid;
                $_SESSION['email'] = $email;
                return true;
            } else {
                // Password is invalid
                return false;
            }
        } else {
            // User could not be found
            return false;
        }
    }

if (empty($type) || !isset($type)) {
    echo 'Request type is not set';
} else {
    if ($type == 'signup') {
        $data = USER::addNewUser($_REQUEST);
        $_SESSION = $data;
        if ($data['status'] == 'error') {
            header("location:register.php");
        } else {
            header("location:index.php");
        }
    } else {
        if ($type == 'login') {
            $username = addslashes($_REQUEST['username']);
            $password = addslashes($_REQUEST['password']);
            $_SESSION = USER::login($username, $password);
            if ($_SESSION['status'] == 'error') {
                header("location:index.php");
            } else {
                header("location:profile.php");
            }
        } else {
            if ($type == 'logout') {
                unset($_SESSION);
                session_destroy();
                header("location:index.php");
            }
        }
    }
}
?>