Untitled

<?php

require_once 'global.php';
use wcf\data\user\User;
$json = null;
$code = 0;

if (isset($_POST['Username'], $_POST['Password'])) {

    checkPassword($_POST['Username'], $_POST['Password']);

    function checkPassword($username, $password) {
        if (empty($username)) {
            global $code;
            $code = 2;
            return null;
        } elseif (empty($password)) {
            global $code;
            $code = 2;
            return null;
        }
        $user = User::getUserByUsername($username);
        if (!$user->checkPassword($password)) {
            global $code;
            $code = 32;
            return null;
        }
        else {
            global $code;
            global $json;
            $code = 1;
            $json = ["StatusCode" => $code, "UserData" =>  ["userID" => $user->userID, "username" => $user->username, "banned" => (bool)$user->banned, "banReason" => $user->banReason, "activityPoints" => $user->activityPoints, "likesReceived" => $user->likesReceived]];
            return null;
        }

    }
    if($code != 1)
    {
        echo json_encode(["StatusCode" => $code, "UserData" => []]);
    }
    else
    {
        echo json_encode($json);
    }
}

?>
<html>
<form method="post">
      <label for="Username">Benutzer</label>
      <input id="Username" name="Username">

      <label for="Password">Passwort</label>
      <input id="Password" name="Password" type="password">

      <button>anmelden</button>

</form>
</html>