public function show($payload = null)
{
    global $db;

    $id = $payload['id'];

    require_once DOL_DOCUMENT_ROOT . '/compta/facture/class/facture.class.php';

    $invoice = new \Facture($db);
    $res = $invoice->fetch($id);

    if ($res <= 0) {
        return ['Invoice not found', 404];
    }

    // Charger les données additionnelles
    $invoice->fetch_optionals();  // Extrafields
    $invoice->fetch_lines();      // Lignes

    // Mapper
    $mapper = new dmInvoice();
    $data = $mapper->exportMappedData($invoice);

    return [$data, 200];
}