API Integration

app.post('/your-backend/charge', async (req, res) => {
  const { paymentMethodId, amount, stripeCustomerId } = req.body;

  let declineCode;

  // 1. Try charging through YOUR primary gateway using YOUR token
  //    (Your normal checkout — Revtain not involved yet)
  try {
    const charge = await stripe.paymentIntents.create({
      amount,
      currency: 'usd',
      customer: stripeCustomerId,
      payment_method: 'pm_xxx',
      confirm: true
    });

    // Log the organic success so Revtain can calculate Lift
    await fetch(`${REVTAIN_BASE_URL}/api/recovery/pulse`, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'X-API-KEY': process.env.REVTAIN_API_KEY
      },
      body: JSON.stringify({ amount, currency: 'USD', transactionId: charge.id })
    });

    return res.json({ success: true, chargeId: charge.id });
  } catch (stripeError) {
    declineCode = stripeError.decline_code;
  }

  // 2. Primary failed — hand off to Revtain
  const recovery = await fetch(`${REVTAIN_BASE_URL}/api/recovery/execute`, {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'X-API-KEY': process.env.REVTAIN_API_KEY
    },
    body: JSON.stringify({
      paymentMethodToken: paymentMethodId,
      amount,
      currency: 'USD',
      originalDeclineCode: declineCode,
      cardOrigin: 'US',
      idempotencyKey: `order_${orderId}_recovery`,
      // Set when the failed charge came from Apple Pay / Google Pay / PayPal.
      // Defaults to 'card' if omitted. Wallet payments get a higher predicted
      // recovery score, so passing this correctly meaningfully lifts results.
      paymentMethodType: payment.paymentMethodType || 'card',
      // Optional: pass any alternative payment tokens you hold for this
      // customer (e.g. a backup card-on-file when the primary is a wallet).
      // Revtain tries each in order if the primary's cascade exhausts on a
      // recoverable decline. Up to 5 supported. No orchestration code needed.
      fallbackPaymentMethodTokens: payment.fallbackTokens || []
    })
  });

  const result = await recovery.json();

  if (recovery.status === 200 && result.success) {
    return res.json({ success: true, recovered: true, transactionId: result.transactionId });
  } else if (recovery.status === 202) {
    return res.json({ success: false, queued: true, message: result.message });
  } else if (recovery.status === 403) {
    return res.status(403).json({ success: false, blocked: true, error: result.error });
  } else if (recovery.status === 409) {
    return res.json({ success: false, duplicate: true, existing: result.existingTransactionId });
  }

  return res.json({ success: false, error: result.error || result.message });
});