Build a guestbook

<?php
$pdo = new PDO('sqlite:' . __DIR__ . '/guestbook.db', null, null, [
    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
]);
$pdo->exec('CREATE TABLE IF NOT EXISTS messages (
    id INTEGER PRIMARY KEY, name TEXT NOT NULL, body TEXT NOT NULL, created_at TEXT NOT NULL
)');

$error = null;
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $name = trim($_POST['name'] ?? '');
    $body = trim($_POST['body'] ?? '');
    if ($name === '' || $body === '') {
        $error = 'Name and message are required.';
    } else {
        $stmt = $pdo->prepare('INSERT INTO messages (name, body, created_at) VALUES (?, ?, ?)');
        $stmt->execute([$name, $body, date('c')]);
    }
}

$page = max(1, (int) ($_GET['page'] ?? 1));
$offset = ($page - 1) * 5;
$stmt = $pdo->prepare('SELECT * FROM messages ORDER BY id DESC LIMIT 5 OFFSET ?');
$stmt->bindValue(1, $offset, PDO::PARAM_INT);
$stmt->execute();
$messages = $stmt->fetchAll();
?>
<?php foreach ($messages as $message): ?>
  <article>
    <h2><?= htmlspecialchars($message['name']) ?></h2>
    <p><?= nl2br(htmlspecialchars($message['body'])) ?></p>
  </article>
<?php endforeach; ?>