مدیریت پرداخت‌های ناموفق و لغوشده

type PaymentState = 'pending' | 'paid' | 'declined' | 'expired';

app.get('/api/payment/callback', async (req, res) => {
  const payment = await findPaymentByAuthority(req.query.Authority);
  if (!payment) return res.status(404).send('unknown authority');

  // A repeated callback is normal: ZarinPal answers 101 the second time.
  // Make the state transition itself idempotent, not just the gateway call.
  if (payment.state === 'paid') {
    return res.send('already confirmed');
  }

  let result;
  try {
    result = await unopay.verifyCallback('zarinpal', {
      method: req.method,
      query: req.query as Record<string, string>,
      body: {},
    });
  } catch (err) {
    // Faulted: stay pending. The payer may still complete the payment.
    console.error('verification faulted', err);
    return res.status(502).send('try again');
  }

  if (result.isSuccessful) {
    await markPaid(payment.id, {
      refId: result.transactionId,      // the bank's reference
      amount: result.settledAmount,      // echoed from the callback
    });
    return res.send('paid');
  }

  await markDeclined(payment.id, result.errorReason ?? 'unknown');
  return res.status(400).send('declined');
});

// Run on a schedule. Nothing in the SDK does this for you.
const STALE_AFTER_MS = 30 * 60 * 1000;

export async function expireStalePayments() {
  const stale = await db.payments.findMany({
    where: { state: 'pending', createdAt: { lt: new Date(Date.now() - STALE_AFTER_MS) } },
  });

  for (const p of stale) {
    // Guard on state: a callback that lands mid-loop flips this to 'paid'
    // and the update below will simply match nothing.
    await db.payments.updateMany({
      where: { id: p.id, state: 'pending' },
      data: { state: 'expired' },
    });
    await releaseOrderHold(p.orderId);
  }
}