Redesign invoice PDFs, add correction-invoice downloads, return reasons, and per-product tax/bundle support

Invoice + Stornorechnung/Gutschrift PDFs get a modern header-band layout,
a "bereits beglichen" badge for immediately-paid orders, labelled bank
details, and a per-tax-rate summary breakdown. Correction invoices can
now be re-downloaded from the account (regenerated deterministically,
not stored as files, same approach as the original invoice). Return
requests capture a reason. Products can define bundles (bundleItems) and
a per-product VAT rate override, both snapshotted onto order items.

app/api/account/orders/[orderNumber]/correction-invoice/route.ts

@@ -0,0 +1,60 @@
+import { NextResponse } from "next/server";
+import { getSessionCustomer, getCustomerOrderDetail } from "../../../../../lib/customerAuth";
+import { generateCorrectionInvoicePdf, getSellerForInvoice } from "../../../../../lib/invoiceData";
+
+// On-demand download for "Stornorechnung/Gutschrift herunterladen" on
+// /konto/bestellungen/[orderNumber]. The real document was generated once
+// by Payload's Orders.ts afterChange hook and emailed at the moment of the
+// status change — this regenerates the identical PDF from the order's own
+// stored correctionInvoiceNumber/correctionInvoiceIssuedAt (immutable once
+// set) rather than storing the file anywhere, same approach as the
+// original invoice's own download route.
+export async function GET(request: Request, { params }: { params: Promise<{ orderNumber: string }> }) {
+  const session = await getSessionCustomer();
+  if (!session) return NextResponse.json({ ok: false, reason: "Bitte zuerst einloggen." }, { status: 401 });
+
+  const { orderNumber } = await params;
+  const order = await getCustomerOrderDetail(session.token, session.customer.id, decodeURIComponent(orderNumber));
+  if (!order) return NextResponse.json({ ok: false, reason: "Bestellung nicht gefunden." }, { status: 404 });
+  if (!order.correctionInvoiceNumber || !order.correctionInvoiceIssuedAt || !order.invoiceNumber || !order.invoiceIssuedAt) {
+    return NextResponse.json({ ok: false, reason: "Für diese Bestellung liegt keine Korrekturrechnung vor." }, { status: 404 });
+  }
+  const kind = order.status === "returned" ? "gutschrift" : "storno";
+
+  const seller = await getSellerForInvoice();
+  const pdf = await generateCorrectionInvoicePdf(
+    kind,
+    {
+      orderNumber: order.orderNumber,
+      invoiceNumber: order.invoiceNumber,
+      invoiceIssuedAt: order.invoiceIssuedAt,
+      correctionInvoiceNumber: order.correctionInvoiceNumber,
+      correctionInvoiceIssuedAt: order.correctionInvoiceIssuedAt,
+      customerFirstName: order.customerFirstName,
+      customerLastName: order.customerLastName,
+      deliveryMethod: order.deliveryMethod,
+      street: order.street,
+      packstationNumber: order.packstationNumber,
+      postNumber: order.postNumber,
+      zip: order.zip,
+      city: order.city,
+      country: order.country,
+      items: order.items,
+      subtotal: order.subtotal,
+      shippingCost: order.shippingCost,
+      discountAmount: order.discountAmount,
+      total: order.total,
+    },
+    seller,
+  );
+  if (!pdf) return NextResponse.json({ ok: false, reason: "Korrekturrechnung konnte nicht erzeugt werden." }, { status: 500 });
+
+  const filename = kind === "storno" ? `Stornorechnung-${order.correctionInvoiceNumber}.pdf` : `Gutschrift-${order.correctionInvoiceNumber}.pdf`;
+  return new NextResponse(new Uint8Array(pdf), {
+    status: 200,
+    headers: {
+      "Content-Type": "application/pdf",
+      "Content-Disposition": `attachment; filename="${filename}"`,
+    },
+  });
+}

app/api/account/orders/[orderNumber]/invoice/route.ts

@@ -1,6 +1,6 @@
 import { NextResponse } from "next/server";
 import { getSessionCustomer, getCustomerOrderDetail } from "../../../../../lib/customerAuth";
-import { generateInvoicePdf } from "../../../../../lib/invoiceData";
+import { generateInvoicePdf, getSellerForInvoice } from "../../../../../lib/invoiceData";
 
 // On-demand download for "Rechnung herunterladen" on
 // /konto/bestellungen/[orderNumber] — reuses the exact same render call as
@@ -18,26 +18,31 @@ export async function GET(request: Request, { params }: { params: Promise<{ orde
     return NextResponse.json({ ok: false, reason: "Für diese Bestellung liegt noch keine Rechnung vor." }, { status: 404 });
   }
 
-  const pdf = await generateInvoicePdf({
-    orderNumber: order.orderNumber,
-    invoiceNumber: order.invoiceNumber,
-    invoiceIssuedAt: order.invoiceIssuedAt,
-    customerFirstName: order.customerFirstName,
-    customerLastName: order.customerLastName,
-    deliveryMethod: order.deliveryMethod,
-    street: order.street,
-    packstationNumber: order.packstationNumber,
-    postNumber: order.postNumber,
-    zip: order.zip,
-    city: order.city,
-    country: order.country,
-    items: order.items,
-    subtotal: order.subtotal,
-    shippingCost: order.shippingCost,
-    discountAmount: order.discountAmount,
-    discountCode: order.discountCode,
-    total: order.total,
-  });
+  const seller = await getSellerForInvoice();
+  const pdf = await generateInvoicePdf(
+    {
+      orderNumber: order.orderNumber,
+      invoiceNumber: order.invoiceNumber,
+      invoiceIssuedAt: order.invoiceIssuedAt,
+      customerFirstName: order.customerFirstName,
+      customerLastName: order.customerLastName,
+      deliveryMethod: order.deliveryMethod,
+      street: order.street,
+      packstationNumber: order.packstationNumber,
+      postNumber: order.postNumber,
+      zip: order.zip,
+      city: order.city,
+      country: order.country,
+      paymentMethodTitle: order.paymentMethodTitle,
+      items: order.items,
+      subtotal: order.subtotal,
+      shippingCost: order.shippingCost,
+      discountAmount: order.discountAmount,
+      discountCode: order.discountCode,
+      total: order.total,
+    },
+    seller,
+  );
   if (!pdf) return NextResponse.json({ ok: false, reason: "Rechnung konnte nicht erzeugt werden." }, { status: 500 });
 
   return new NextResponse(new Uint8Array(pdf), {

app/api/account/orders/[orderNumber]/route.ts

@@ -21,6 +21,10 @@ export async function PATCH(request: Request, { params }: { params: Promise<{ or
   if (action !== "cancel" && action !== "request-return") {
     return NextResponse.json({ ok: false, reason: "Ungültige Aktion." }, { status: 400 });
   }
+  const returnReason = typeof body?.returnReason === "string" ? body.returnReason.trim() : "";
+  if (action === "request-return" && !returnReason) {
+    return NextResponse.json({ ok: false, reason: "Bitte kurz angeben, warum du zurücksenden möchtest." }, { status: 400 });
+  }
 
   const order = await getCustomerOrderDetail(session.token, session.customer.id, decodeURIComponent(orderNumber));
   if (!order) return NextResponse.json({ ok: false, reason: "Bestellung nicht gefunden." }, { status: 404 });
@@ -28,6 +32,6 @@ export async function PATCH(request: Request, { params }: { params: Promise<{ or
     return NextResponse.json({ ok: false, reason: "Diese Aktion ist für diese Bestellung gerade nicht möglich." }, { status: 400 });
   }
 
-  const result = await requestOrderStatusChange(session.token, order.id, action);
+  const result = await requestOrderStatusChange(session.token, order.id, action, returnReason || undefined);
   return NextResponse.json(result, { status: result.ok ? 200 : 400 });
 }

app/api/checkout/route.ts

@@ -1,13 +1,28 @@
 import { NextResponse } from "next/server";
 import type { CartItem } from "../../lib/cart";
-import { getShippingMethods, getPaymentMethods } from "../../lib/payload";
+import { getShippingMethods, getPaymentMethods, getInvoiceSettings } from "../../lib/payload";
 import { validateDiscountCode, redeemDiscountCode } from "../../lib/discountServer";
 import { createOrder } from "../../lib/orderServer";
 import { getSessionCustomer, registerCustomer, setSessionCookie, type CustomerSummary } from "../../lib/customerAuth";
-import { fetchProductsBySlug } from "../../lib/productsServer";
+import { fetchProductsBySlug, type RawProduct } from "../../lib/productsServer";
 import { sendCriticalAlert } from "../../lib/alertAdmin";
 import { sendOrderConfirmationEmail } from "../../lib/orderEmail";
 
+// A bundle's `bundleItems` is only ever resolved once, right here, into a
+// plain readable string — the order line stores this snapshot
+// (`items[].bundleContents`), not a structured sub-list, so a later change
+// to the bundle's own composition can never rewrite what a past order
+// actually contained. `product.bundleItems[].product` is a relationship
+// resolved by fetchProductsBySlug's depth:2 fetch — {id, name} objects
+// when populated, a bare id if depth somehow didn't reach it (skipped).
+function describeBundleContents(product: RawProduct): string | null {
+  if (!product.bundleItems || product.bundleItems.length === 0) return null;
+  return product.bundleItems
+    .map((line) => (typeof line.product === "object" ? `${line.quantity}× ${line.product.name}` : null))
+    .filter((s): s is string => Boolean(s))
+    .join(", ");
+}
+
 type CheckoutBody = {
   cart: CartItem[];
   shippingMethodId: number;
@@ -87,13 +102,30 @@ export async function POST(request: Request) {
   }
 
   // Re-price everything server-side — never trust client-submitted prices.
-  const productsBySlug = await fetchProductsBySlug();
-  const items: { productId: number; productName: string; quantity: number; unitPrice: number; imageUrl: string | null }[] = [];
+  const [productsBySlug, invoiceSettings] = await Promise.all([fetchProductsBySlug(), getInvoiceSettings()]);
+  const defaultTaxRate = invoiceSettings?.taxRatePercent ?? 19;
+  const items: {
+    productId: number;
+    productName: string;
+    quantity: number;
+    unitPrice: number;
+    imageUrl: string | null;
+    taxRatePercent: number;
+    bundleContents: string | null;
+  }[] = [];
   for (const line of body.cart) {
     const product = productsBySlug.get(line.id);
     if (!product) return NextResponse.json({ ok: false, reason: "Ein Artikel im Warenkorb ist nicht mehr verfügbar." }, { status: 400 });
     const imageUrl = typeof product.image === "object" && product.image ? product.image.url : null;
-    items.push({ productId: product.id, productName: product.name, quantity: line.qty, unitPrice: product.price, imageUrl });
+    items.push({
+      productId: product.id,
+      productName: product.name,
+      quantity: line.qty,
+      unitPrice: product.price,
+      imageUrl,
+      taxRatePercent: product.taxRatePercent ?? defaultTaxRate,
+      bundleContents: describeBundleContents(product),
+    });
   }
   const subtotal = items.reduce((sum, i) => sum + i.quantity * i.unitPrice, 0);
 
@@ -176,7 +208,15 @@ export async function POST(request: Request) {
       zip: body.zip,
       city: body.city,
       country: body.country,
-      items: items.map((i) => ({ productName: i.productName, quantity: i.quantity, unitPrice: i.unitPrice, imageUrl: i.imageUrl })),
+      paymentMethodTitle: paymentMethod.title,
+      items: items.map((i) => ({
+        productName: i.productName,
+        quantity: i.quantity,
+        unitPrice: i.unitPrice,
+        imageUrl: i.imageUrl,
+        taxRatePercent: i.taxRatePercent,
+        bundleContents: i.bundleContents,
+      })),
       subtotal,
       shippingCost,
       discountAmount,