/**
 * Tests fuer die Stornorechnung: hoechstens eine je Rechnung, auch wenn
 * Admin-Stornierung und Stripe-Webhook derselben Erstattung gleichzeitig
 * ankommen, und sie geht an die Kundschaft und als Kopie hinaus.
 */
import { describe, test, expect, vi, beforeEach } from "vitest";

const tx = {
  cancellationCounter: { upsert: vi.fn() },
  cancellationInvoice: { create: vi.fn() },
};
const db = {
  invoice: { findUnique: vi.fn() },
  cancellationInvoice: { findUnique: vi.fn(), update: vi.fn() },
  $transaction: vi.fn(async (run: (client: typeof tx) => Promise<unknown>) => run(tx)),
};
vi.mock("@/lib/prisma", () => ({ prisma: db }));

const generateInvoicePdf = vi.fn(async () => Buffer.from("storno-pdf"));
vi.mock("@/lib/invoice-pdf", () => ({ generateInvoicePdf: (...args: unknown[]) => generateInvoicePdf(...(args as [])) }));
const storeInvoicePdf = vi.fn(async () => undefined);
vi.mock("@/lib/invoice-storage", () => ({
  invoiceRelativePath: vi.fn(() => "2026/musterfrau-erika/ST-2026-0003.pdf"),
  storeInvoicePdf: (...args: unknown[]) => storeInvoicePdf(...(args as [])),
  readStoredInvoicePdf: vi.fn(async () => null),
}));
const sendMail = vi.fn(async () => true);
vi.mock("@/lib/mail", () => ({ sendMail: (...args: unknown[]) => sendMail(...(args as [])) }));
vi.mock("@/lib/email-templates", () => ({
  cancellationInvoiceEmail: vi.fn(async () => ({ subject: "Stornorechnung", html: "<p>x</p>", text: "x" })),
}));
const sendInvoiceCopy = vi.fn(async () => true);
vi.mock("@/lib/invoice-mail", () => ({ sendInvoiceCopy: (...args: unknown[]) => sendInvoiceCopy(...(args as [])) }));

const { issueCancellationInvoice, isCancellationNumber } = await import("./cancellation-invoice");

const order = {
  orderNumber: "WH-2026-0042",
  email: "erika@example.org",
  firstName: "Erika",
  lastName: "Musterfrau",
  locale: "de",
  items: [],
};
const loaded = {
  number: "ST-2026-0003",
  issuedAt: new Date("2026-10-14T09:00:00Z"),
  pdfPath: null,
  invoice: { invoiceNumber: "RE-2026-0042", issuedAt: new Date("2026-10-12T10:00:00Z"), totalCents: 5375, order },
};

beforeEach(() => {
  vi.clearAllMocks();
  db.invoice.findUnique.mockResolvedValue({ id: "inv1", totalCents: 5375, cancellation: null });
  tx.cancellationCounter.upsert.mockResolvedValue({ lastNumber: 3 });
  tx.cancellationInvoice.create.mockImplementation(async ({ data }: { data: { number: string } }) => ({ number: data.number }));
  db.cancellationInvoice.findUnique.mockResolvedValue(loaded);
});

describe("issueCancellationInvoice", () => {
  test("ohne Rechnung gibt es nichts aufzuheben", async () => {
    db.invoice.findUnique.mockResolvedValue(null);

    expect(await issueCancellationInvoice("order1", "STORNIERUNG")).toBeNull();
    expect(db.$transaction).not.toHaveBeenCalled();
  });

  test("legt die Stornorechnung mit eigener Nummer an und verschickt sie mit Kopie", async () => {
    // Act
    const result = await issueCancellationInvoice("order1", "STORNIERUNG");

    // Assert
    const year = new Date().getFullYear();
    expect(result).toEqual({ number: `ST-${year}-0003`, created: true });
    expect(tx.cancellationInvoice.create).toHaveBeenCalledWith(
      expect.objectContaining({ data: { invoiceId: "inv1", number: `ST-${year}-0003`, totalCents: 5375, reason: "STORNIERUNG" } })
    );
    expect(generateInvoicePdf).toHaveBeenCalledWith(
      expect.objectContaining({ invoiceNumber: "RE-2026-0042", cancellation: { number: "ST-2026-0003", issuedAt: loaded.issuedAt } })
    );
    expect(storeInvoicePdf).toHaveBeenCalledOnce();
    expect(sendMail).toHaveBeenCalledWith(
      expect.objectContaining({ to: "erika@example.org", attachments: [expect.objectContaining({ filename: `ST-${year}-0003.pdf` })] })
    );
    expect(sendInvoiceCopy).toHaveBeenCalledWith(expect.objectContaining({ title: "Stornorechnung", orderNumber: "WH-2026-0042" }));
  });

  test("zweiter Ausloeser findet die vorhandene Stornorechnung, ohne erneut zu verschicken", async () => {
    db.invoice.findUnique.mockResolvedValue({ id: "inv1", totalCents: 5375, cancellation: { number: "ST-2026-0001" } });

    expect(await issueCancellationInvoice("order1", "ERSTATTUNG")).toEqual({ number: "ST-2026-0001", created: false });
    expect(db.$transaction).not.toHaveBeenCalled();
    expect(sendMail).not.toHaveBeenCalled();
  });

  test("gleichzeitig angelegt: die zweite Transaktion scheitert eindeutig und liefert die erste", async () => {
    // Arrange: die Datenbank lehnt die zweite Stornorechnung zur selben Rechnung ab.
    tx.cancellationInvoice.create.mockRejectedValue(Object.assign(new Error("Unique constraint failed"), { code: "P2002" }));
    db.cancellationInvoice.findUnique.mockResolvedValue({ number: "ST-2026-0001" });

    // Act
    const result = await issueCancellationInvoice("order1", "ERSTATTUNG");

    // Assert
    expect(result).toEqual({ number: "ST-2026-0001", created: false });
    expect(sendMail).not.toHaveBeenCalled();
  });

  test("ein Fehler beim Verschicken laesst die Stornorechnung bestehen", async () => {
    generateInvoicePdf.mockRejectedValueOnce(new Error("Schrift fehlt"));
    const errors = vi.spyOn(console, "error").mockImplementation(() => undefined);

    const result = await issueCancellationInvoice("order1", "RETOURE");

    expect(result?.created).toBe(true);
    expect(errors).toHaveBeenCalled();
    errors.mockRestore();
  });
});

test("isCancellationNumber erkennt nur ST-Nummern", () => {
  expect(isCancellationNumber("ST-2026-0001")).toBe(true);
  expect(isCancellationNumber("RE-2026-0001")).toBe(false);
  expect(isCancellationNumber("ST-2026-0001/../x")).toBe(false);
});