function _validUser($userName, $userPassword) {
    $file = file('users.txt');
    foreach ($file as $value) {
        $line = explode("@", $value);
        if ($line[1] == trim($userName) && trim($line[2]) == trim($userPassword)) {
            $_SESSION['_logged'] = true;
            $_SESSION['_userID'] = (int) $line[0];
            $_SESSION['_userName'] = $line[1];
            $_SESSION['_success'] .= 'Успешен вход !';
            break;
        }
    }
    if (!$_SESSION['_logged'] == true) {
        $_SESSION['_error'] = 'Грешна парола или потребител !';
        return (bool) 0;
    } else {
        return (bool) 1;
    }
}