<?php

function userNameValidator($name)
{
    $name = trim($name);
    $namePattern = '/^[a-zA-ZäöüÄÖÜß\s-]{2,50}$/u';

    return preg_match($namePattern, $name) === 1;
}

function userEmailValidator($email)
{
    $email = trim($email);

    return filter_var($email, FILTER_VALIDATE_EMAIL) !== false
        && mb_strlen($email) <= 100;
}

function userPasswordValidator($password)
{
    $zeichenAnzahl = mb_strlen($password);

    return $zeichenAnzahl >= 8 && $zeichenAnzahl <= 72;
}

function userOptionalPasswordValidator($password)
{
    if (!isset($password) || $password === '') {
        return true;
    }

    return userPasswordValidator($password);
}