Phase4: Stripe

src/app/api/billing/invoices/[invoiceNumber]/pay/route.ts

@@ -0,0 +1,105 @@
+import { NextResponse } from "next/server";
+import { getSessionUser } from "@/lib/session";
+import {
+  getInvoiceByNumberForOrg,
+  getOrgBilling,
+} from "@/lib/db";
+import {
+  createCheckoutSessionForInvoice,
+  ensureStripeCustomerForOrg,
+} from "@/lib/stripe";
+import { safeError } from "@/lib/errors";
+
+/**
+ * POST /api/billing/invoices/[invoiceNumber]/pay
+ *
+ * Initiates a Stripe Checkout Session for an open invoice. Returns
+ * `{ url }` — the browser is expected to navigate to that URL,
+ * where Stripe hosts the payment UI.
+ *
+ * Authorization: caller must belong to the invoice's org (the DB
+ * query enforces this — wrong-org returns 404, indistinguishable
+ * from a non-existent invoice).
+ *
+ * Preconditions enforced server-side:
+ *   - Invoice exists for caller's org
+ *   - Invoice status is 'open' or 'overdue' (paid/void/draft/uncollectible
+ *     all reject — already-paid invoices in particular must not
+ *     create a second Checkout Session, even though Stripe would
+ *     deduplicate the actual charge)
+ *
+ * The Stripe Customer for the org is lazily ensured here — first
+ * card click on an org creates the customer; subsequent clicks
+ * reuse the persisted stripe_customer_id.
+ */
+export async function POST(
+  _request: Request,
+  { params }: { params: Promise<{ invoiceNumber: string }> }
+) {
+  const user = await getSessionUser();
+  if (!user) {
+    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+  }
+  const { invoiceNumber } = await params;
+
+  const detail = await getInvoiceByNumberForOrg(invoiceNumber, user.orgId);
+  if (!detail) {
+    return NextResponse.json({ error: "Not found" }, { status: 404 });
+  }
+  const inv = detail.invoice;
+  if (inv.status !== "open" && inv.status !== "overdue") {
+    return NextResponse.json(
+      {
+        error:
+          inv.status === "paid"
+            ? "This invoice has already been paid."
+            : `This invoice cannot be paid online (status: ${inv.status}).`,
+      },
+      { status: 409 }
+    );
+  }
+
+  // We need org_billing for the customer creation address. The
+  // invoice has a SNAPSHOT but that's frozen at issue time; for
+  // creating/updating the Stripe customer we want the current
+  // address (which may have been corrected since the invoice).
+  // Snapshot is still authoritative on the invoice PDF and total.
+  const orgBilling = await getOrgBilling(user.orgId);
+  if (!orgBilling) {
+    return NextResponse.json(
+      { error: "Billing details are not configured for your organization." },
+      { status: 400 }
+    );
+  }
+
+  try {
+    const customerId = await ensureStripeCustomerForOrg({
+      zitadelOrgId: user.orgId,
+      companyName: orgBilling.companyName,
+      billingEmail: orgBilling.billingEmail,
+      address: {
+        line1: orgBilling.streetAddress,
+        postalCode: orgBilling.postalCode,
+        city: orgBilling.city,
+        country: orgBilling.country,
+      },
+    });
+    const baseUrl =
+      process.env.APP_BASE_URL ?? "https://app.pieced.ch";
+    const { url } = await createCheckoutSessionForInvoice({
+      invoice: inv,
+      customerId,
+      baseUrl,
+    });
+    return NextResponse.json({ url });
+  } catch (e) {
+    console.error(
+      `Failed to create Checkout Session for invoice ${invoiceNumber}:`,
+      e
+    );
+    return NextResponse.json(
+      { error: safeError(e, "Failed to start card payment.") },
+      { status: 500 }
+    );
+  }
+}