Phase8: Auto bill credit card

src/app/api/stripe/webhook/route.ts

@@ -1,12 +1,18 @@
 import { NextResponse } from "next/server";
 import type Stripe from "stripe";
-import { getStripeClient, getWebhookSecret } from "@/lib/stripe";
+import {
+  getPaymentMethodDisplay,
+  getStripeClient,
+  getWebhookSecret,
+} from "@/lib/stripe";
 import {
   getInvoiceByStripePaymentIntent,
+  getOrgIdByStripeCustomerId,
   isStripeRefundRecorded,
   markInvoicePaid,
   markStripeEventProcessed,
   setInvoiceStripePaymentIntent,
+  setSavedPaymentMethod,
   tryRecordStripeEvent,
 } from "@/lib/db";
 import { refundInvoice, RefundNotAllowedError } from "@/lib/billing";
@@ -161,6 +167,14 @@ export async function POST(request: Request) {
 async function handleCheckoutCompleted(
   session: Stripe.Checkout.Session
 ): Promise<void> {
+  // Phase 9: setup-mode sessions don't pay anything — they
+  // authorize a card for off-session future charges. The
+  // PaymentMethod is attached to the customer and the session's
+  // setup_intent.payment_method holds the id we save.
+  if (session.mode === "setup") {
+    await handleSetupCompleted(session);
+    return;
+  }
   // Defensive: paid sessions are what we want; sessions can also
   // complete in "unpaid" state (rare for mode=payment, more common
   // for async/delayed methods like SEPA). Only flip the invoice
@@ -211,6 +225,97 @@ async function handleCheckoutCompleted(
   );
 }
 
+/**
+ * Phase 9: handle setup-mode Checkout completion. The customer
+ * authorized a card for future off-session charges; persist the
+ * display fields against their org so the portal can show the
+ * saved card and use it for auto-charge.
+ *
+ * The session carries:
+ *   - mode: 'setup'
+ *   - customer: 'cus_xxx' (the Stripe customer id we created)
+ *   - setup_intent: 'seti_xxx' (the SetupIntent — has payment_method)
+ *
+ * We look up which org owns the customer (via
+ * org_billing_config.stripe_customer_id), fetch the SetupIntent
+ * to find the resulting PaymentMethod id, then fetch the PM for
+ * its display fields. Three Stripe round-trips total — acceptable
+ * for a one-off setup event.
+ */
+async function handleSetupCompleted(
+  session: Stripe.Checkout.Session
+): Promise<void> {
+  const customerId =
+    typeof session.customer === "string"
+      ? session.customer
+      : session.customer?.id;
+  if (!customerId) {
+    console.error(
+      `Setup session ${session.id} completed without a customer; cannot link to org.`
+    );
+    return;
+  }
+  const orgId = await getOrgIdByStripeCustomerId(customerId);
+  if (!orgId) {
+    console.error(
+      `Setup session ${session.id} for customer ${customerId} has no matching org.`
+    );
+    return;
+  }
+  const setupIntentId =
+    typeof session.setup_intent === "string"
+      ? session.setup_intent
+      : session.setup_intent?.id;
+  if (!setupIntentId) {
+    console.error(
+      `Setup session ${session.id} completed without a setup_intent id.`
+    );
+    return;
+  }
+  // Read the SetupIntent for the resulting PaymentMethod id.
+  const stripe = getStripeClient();
+  const setupIntent = await stripe.setupIntents.retrieve(setupIntentId);
+  const paymentMethodId =
+    typeof setupIntent.payment_method === "string"
+      ? setupIntent.payment_method
+      : setupIntent.payment_method?.id;
+  if (!paymentMethodId) {
+    console.error(
+      `Setup session ${session.id}: setup_intent ${setupIntentId} has no payment_method.`
+    );
+    return;
+  }
+  // Fetch the PM details for display columns.
+  const display = await getPaymentMethodDisplay(paymentMethodId);
+  await setSavedPaymentMethod({
+    zitadelOrgId: orgId,
+    stripeCustomerId: customerId,
+    paymentMethodId,
+    brand: display.brand,
+    last4: display.last4,
+    expMonth: display.expMonth,
+    expYear: display.expYear,
+  });
+  // Also tell Stripe this PM is the customer's default for invoice
+  // payments — so a future stripe.paymentIntents.create against
+  // this customer without an explicit payment_method picks it up.
+  // Best-effort: a failure here doesn't undo the save (we have the
+  // pm id, we can pass it explicitly when charging in Phase 9b).
+  try {
+    await stripe.customers.update(customerId, {
+      invoice_settings: { default_payment_method: paymentMethodId },
+    });
+  } catch (e) {
+    console.warn(
+      `Setup session ${session.id}: failed to set default_payment_method on customer ${customerId}; will pass pm id explicitly on charges.`,
+      e
+    );
+  }
+  console.log(
+    `Saved PaymentMethod ${paymentMethodId} (${display.brand} ${display.last4}) for org ${orgId}.`
+  );
+}
+
 async function handleChargeRefunded(charge: Stripe.Charge): Promise<void> {
   // Phase 7: mirror Stripe refunds into the portal so credit notes
   // are issued for refunds initiated in the Stripe Dashboard. For