<?php

class User
{
    private $values = [];

    public function __construct(string ...$keys)
    {
        foreach ($keys as $key) {
            if (isset($_POST[$key])) {
                $values[$key] = $_POST[$key];
            } else {
                $values['errors'] = array(
                    "error_$key" => true
                );
            }
        }
    }

    public function __get($name)
    {
        return $values[$name] ? : null;
    }
}

$user = new User(['email', 'first', 'last', 'uid', 'pwd1', 'pwd2']);

if (!isset($user->pwd1, $user->pwd2) || $user->pwd1 !== $user->pwd2) {
    $user->errors = array(
        "error_pwds" => true
    );
}

if ($user->errors !== []) {
    header('Location: https://drohneglobal.de/login/registrierung.php?' . http_build_query($user->errors));
    exit();
}

try {
    $passwort = password_hash($_POST['pwd1'], PASSWORD_DEFAULT);
    $db = new PDO('mysql:host=.....;dbname=....', '....', '.....');

    $sql = 'INSERT INTO users (user_first, user_last, user_email, user_uid, user_pwd) VALUES (?, ?, ?, ?, ?)';
    $werte = [$user->first, $user->last, $user->email, $user->uid, $passwort];
    $kommando = $db->prepare($sql);
    $kommando->execute($werte);
    header('Location: https://drohneglobal.de/login/registrierung.php');
} catch (PDOException $e) {
    echo 'Fehler: ' . htmlspecialchars($e->getMessage());
}