Integra InvoCash con Magento

<!-- app/code/Vendor/InvoCash/etc/events.xml -->
<config>
  <event name="sales_order_invoice_pay">
    <observer
      name="invocash_crear_factura"
      instance="Vendor\InvoCash\Observer\CrearFactura"
    />
  </event>
</config>

namespace Vendor\InvoCash\Observer;

use Magento\Framework\Event\ObserverInterface;

class CrearFactura implements ObserverInterface
{
    public function execute(\Magento\Framework\Event\Observer $observer): void
    {
        $invoice = $observer->getEvent()->getInvoice();
        $order   = $invoice->getOrder();
        $lines   = [];

        foreach ($invoice->getAllItems() as $item) {
            if (!$item->getQty()) continue;
            $taxBase   = (float) $item->getRowTotalInclTax() - (float) $item->getTaxAmount();
            $taxAmount = (float) $item->getTaxAmount();
            $taxPctge  = $taxBase > 0 ? round($taxAmount / $taxBase * 100) : 21;

            $lines[] = [
                'description'             => $item->getName(),
                'quantity'                => (int) $item->getQty(),
                'unit_price'              => $taxBase / $item->getQty(),
                'tax_base'                => $taxBase,
                'tax_pctge'               => $taxPctge,
                'tax_amount'              => $taxAmount,
                'tax_withholding_pctge'   => 0,
                'tax_withholding_amount'  => 0,
                'tax_type'                => 'IVA',
                'clave_regimen'           => '01',
                'qualification_operation' => 'S1',
                'exempt_operation'        => null,
                'total'                   => $taxBase,
            ];
        }

        $ch = curl_init('https://{su-tenant}.invo.cash/api/invoices');
        curl_setopt_array($ch, [
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_POST           => true,
            CURLOPT_HTTPHEADER     => [
                'Content-Type: application/json',
                'X-API-Key: {tu_api_key}',
            ],
            CURLOPT_POSTFIELDS => json_encode([
                'verifactu_issuer_territory' => 'MAINLAND',
                'simplified'                 => false,
                'lines'                      => $lines,
                'total'                      => (float) $invoice->getGrandTotal(),
            ]),
        ]);
        curl_exec($ch);
        curl_close($ch);
    }
}