Guest room Wi-Fi

guest-room-wifi.php

<?php

$name = $_POST["name"] ?? "";

$is_allowed = false;

if ($name == "Thomas") {
    $is_allowed = true;
}

?>

<?php if ( !$is_allowed ): ?>

<?php 
if ($name !== "") {
    echo "<p>Incorrect guest name.</p>";
} 
?>

<form action="" method="POST">
  <p>Please input your name.</p>
  Name: <input type="text" name="name">
  <input type="submit">
</form>

<?php elseif ($is_allowed) : ?>

<h1>Welcome <?= $name ?></h1>
<p>The Wi-Fi passcode is <strong>13579</strong></p>

<?php endif; ?>