$data = json_decode(file_get_contents("php://input"), true);

$stmt = $conn->prepare("
  INSERT INTO whatsapp_messages 
  (chat_id, number_id, sender, message, from_me, type)
  VALUES (?, ?, ?, ?, ?, ?)
");

$stmt->execute([
  $data['chat_id'],
  $data['number_id'],
  $data['sender'],
  $data['message'],
  $data['from_me'],
  $data['type'] ?? 'text'
]);

echo json_encode([
  'success' => true,
  'message_id' => $conn->lastInsertId()
]);