import { describe, test, expect, beforeEach, afterEach, vi } from "vitest";
import { render, screen, waitFor } from "@testing-library/react";
import userEvent from "@testing-library/user-event";
import { CheckoutForm } from "./checkout-form";
import { useCartStore, type CartItem } from "@/store/cart-store";
import { I18nProvider } from "@/i18n/i18n-provider";
import type { ShippingTierLike } from "@/lib/shipping-calc";
import type { BulkDiscountTierLike } from "@/lib/bulk-discount-calc";

// Geteilte Instanz statt eines frischen vi.fn() je Aufruf: nur so laesst sich
// pruefen, dass NICHT navigiert wurde.
const routerPush = vi.fn();
vi.mock("next/navigation", () => ({
  useRouter: () => ({ push: routerPush }),
}));

// Stripe.js laesst sich in jsdom nicht laden — der Zahlungsschritt wird
// durch einen Platzhalter ersetzt, der zeigt, was er bekommen hat, und den
// Abbruch-Rueckruf ausloesen kann.
vi.mock("./embedded-payment", () => ({
  EmbeddedPayment: (props: {
    clientSecret: string;
    cancelToken: string;
    cancelLabel: string;
    onCancelled: () => void;
  }) => (
    <div data-testid="embedded-payment" data-client-secret={props.clientSecret}>
      <button type="button" onClick={props.onCancelled}>
        {props.cancelLabel}
      </button>
    </div>
  ),
}));

const fetchMock = vi.fn();
const PUBLISHABLE_KEY = "pk_test_abc123";

const tiers: ShippingTierLike[] = [{ minQuantity: 0, maxQuantity: null, priceCents: 700 }];
const bulkDiscountTiers: BulkDiscountTierLike[] = [];

const item = (overrides: Partial<CartItem> = {}): CartItem => ({
  key: "p1",
  productId: "p1",
  slug: "fruehtracht-2026",
  name: "Frühtracht 2026",
  weightGrams: 500,
  priceCents: 990,
  image: null,
  quantity: 1,
  ...overrides,
});

function renderCheckout(items: CartItem[], stripePublishableKey: string | undefined = PUBLISHABLE_KEY) {
  useCartStore.setState({ items, isOpen: false });
  return render(
    <I18nProvider locale="de">
      <CheckoutForm
        tiers={tiers}
        bulkDiscountTiers={bulkDiscountTiers}
        stripePublishableKey={stripePublishableKey}
      />
    </I18nProvider>
  );
}

const sponsorshipItem = (key: string, beeName: string, honeyJars = 0): CartItem => ({
  key,
  productId: "pkg-bienenfreund",
  slug: "bienenfreund",
  name: "Bienenfreund",
  weightGrams: 0,
  priceCents: 1900,
  image: null,
  quantity: 1,
  sponsorship: {
    offerSlug: "bienenfreund",
    offerName: "Bienenfreund",
    isPhysical: honeyJars > 0,
    honeyJars,
    personalization: { beeName, recipientName: "Erika Muster", occasion: "GEBURTSTAG", startDate: "2026-11-01" },
  },
});

async function fillAndSubmit(userEventInstance: ReturnType<typeof userEvent.setup>) {
  await userEventInstance.type(screen.getByLabelText(/vorname/i), "Erika");
  await userEventInstance.type(screen.getByLabelText(/nachname/i), "Mustermann");
  await userEventInstance.type(screen.getByLabelText(/e-mail/i), "erika@example.org");
  await userEventInstance.type(screen.getByLabelText(/straße|strasse/i), "Wiesenweg 1");
  await userEventInstance.type(screen.getByLabelText(/plz|postleitzahl/i), "86450");
  await userEventInstance.type(screen.getByLabelText(/ort|stadt/i), "Altenmünster");
  await userEventInstance.click(screen.getByRole("button", { name: /kostenpflichtig bestellen/i }));
}

beforeEach(() => {
  useCartStore.setState({ items: [], isOpen: false });
  routerPush.mockClear();
  fetchMock.mockReset();
  vi.stubGlobal("fetch", fetchMock);
});

afterEach(() => {
  vi.unstubAllGlobals();
});

describe("CheckoutForm", () => {
  test("shows the empty-cart message instead of the form when the cart is empty", () => {
    renderCheckout([]);
    expect(screen.queryByRole("button", { name: /kostenpflichtig bestellen/i })).not.toBeInTheDocument();
  });

  test("charges shipping by default and drops it when switching to pickup", async () => {
    const userEventInstance = userEvent.setup();
    renderCheckout([item()]);

    expect(screen.getByText("7,00 €")).toBeInTheDocument();

    await userEventInstance.click(screen.getByRole("button", { name: /abholung/i }));

    expect(screen.queryByText("7,00 €")).not.toBeInTheDocument();
    expect(screen.getByText("kostenlos")).toBeInTheDocument();
  });

  /**
   * Regression: Antwortet /api/checkout mit 502 (Stripe nicht erreichbar),
   * schickte das Formular frueher auf die Erfolgsseite mit dem Hinweis "wir
   * melden uns". Es gab zu dieser Bestellung aber gar keine Zahlungssitzung —
   * sie war auf keinem Weg bezahlbar, und die Seite versprach etwas, das
   * niemand einloesen konnte.
   */
  test("shows the server error instead of the success page when the payment session cannot be created", async () => {
    const userEventInstance = userEvent.setup();
    const serverError =
      "Die Zahlung konnte nicht gestartet werden — es wurde nichts abgebucht. Bitte versuche es in ein paar Minuten erneut oder melde dich bei uns.";
    fetchMock.mockResolvedValue({
      ok: false,
      status: 502,
      json: async () => ({ error: serverError }),
    } as Response);

    renderCheckout([item()]);

    await userEventInstance.type(screen.getByLabelText(/vorname/i), "Erika");
    await userEventInstance.type(screen.getByLabelText(/nachname/i), "Mustermann");
    await userEventInstance.type(screen.getByLabelText(/e-mail/i), "erika@example.org");
    await userEventInstance.type(screen.getByLabelText(/straße|strasse/i), "Wiesenweg 1");
    await userEventInstance.type(screen.getByLabelText(/plz|postleitzahl/i), "86450");
    await userEventInstance.type(screen.getByLabelText(/ort|stadt/i), "Altenmünster");

    await userEventInstance.click(screen.getByRole("button", { name: /kostenpflichtig bestellen/i }));

    await waitFor(() => expect(screen.getByText(serverError)).toBeInTheDocument());
    // Das Formular navigiert inzwischen gar nicht mehr — diese Zusicherung
    // faellt erst dann wieder auf, wenn jemand die Weiterleitung auf die
    // Erfolgsseite erneut einbaut. Genau dafuer steht sie hier.
    expect(routerPush).not.toHaveBeenCalled();
  });

  test("shows the embedded payment step on this page instead of redirecting to Stripe", async () => {
    const userEventInstance = userEvent.setup();
    fetchMock.mockResolvedValue({
      ok: true,
      status: 200,
      json: async () => ({ clientSecret: "cs_test_1_secret_abc", cancelToken: "d".repeat(64) }),
    } as Response);

    renderCheckout([item()]);
    await fillAndSubmit(userEventInstance);

    const payment = await screen.findByTestId("embedded-payment");
    expect(payment).toHaveAttribute("data-client-secret", "cs_test_1_secret_abc");
    // Das Formular tritt zurueck, bleibt aber erhalten.
    expect(screen.getByLabelText(/vorname/i)).not.toBeVisible();
  });

  test("brings back the filled-in form after leaving the payment step", async () => {
    const userEventInstance = userEvent.setup();
    fetchMock.mockResolvedValue({
      ok: true,
      status: 200,
      json: async () => ({ clientSecret: "cs_test_1_secret_abc", cancelToken: "d".repeat(64) }),
    } as Response);

    renderCheckout([item()]);
    await fillAndSubmit(userEventInstance);
    await userEventInstance.click(await screen.findByRole("button", { name: /zurück zu deinen angaben/i }));

    expect(screen.queryByTestId("embedded-payment")).not.toBeInTheDocument();
    expect(screen.getByLabelText(/vorname/i)).toBeVisible();
    expect(screen.getByLabelText(/vorname/i)).toHaveValue("Erika");
  });

  test("creates no order when no publishable key is configured", async () => {
    const userEventInstance = userEvent.setup();
    renderCheckout([item()], "");

    await fillAndSubmit(userEventInstance);

    expect(await screen.findByText(/zahlung ist gerade nicht verfügbar/i)).toBeInTheDocument();
    expect(fetchMock).not.toHaveBeenCalled();
  });

  test("a cart with only digital sponsorships needs no delivery and is sent as DIGITAL with personalization", async () => {
    const userEventInstance = userEvent.setup();
    fetchMock.mockResolvedValue({
      ok: true,
      status: 200,
      json: async () => ({ clientSecret: "cs_test_1_secret_abc", cancelToken: "d".repeat(64) }),
    } as Response);

    renderCheckout([sponsorshipItem("sp_1", "Frieda"), sponsorshipItem("sp_2", "Frieda")]);

    expect(screen.queryByRole("button", { name: /abholung/i })).not.toBeInTheDocument();
    expect(screen.queryByLabelText(/straße|strasse/i)).not.toBeInTheDocument();
    expect(screen.getAllByText("Biene „Frieda“")).toHaveLength(2);

    await userEventInstance.type(screen.getByLabelText(/vorname/i), "Erika");
    await userEventInstance.type(screen.getByLabelText(/nachname/i), "Mustermann");
    await userEventInstance.type(screen.getByLabelText(/e-mail/i), "erika@example.org");
    await userEventInstance.click(screen.getByRole("button", { name: /kostenpflichtig bestellen/i }));

    await screen.findByTestId("embedded-payment");
    const body = JSON.parse(String(fetchMock.mock.calls[0][1].body)) as {
      fulfillmentMethod: string;
      street?: string;
      items: { productId: string; quantity: number; personalization?: { beeName: string } }[];
    };
    expect(body.fulfillmentMethod).toBe("DIGITAL");
    expect(body.street).toBeUndefined();
    // Zwei gleiche Pakete bleiben zwei Positionen, jede mit eigener Personalisierung.
    expect(body.items).toHaveLength(2);
    expect(body.items.every((line) => line.quantity === 1 && line.personalization?.beeName === "Frieda")).toBe(true);
  });

  test("a package with honey keeps the delivery choice and counts its jars for shipping", () => {
    renderCheckout([sponsorshipItem("sp_1", "Lotte", 1)]);

    expect(screen.getByRole("button", { name: /abholung/i })).toBeInTheDocument();
    expect(screen.getByText("7,00 €")).toBeInTheDocument();
  });

  test("shows the account message with a login link when the server answers 401", async () => {
    const userEventInstance = userEvent.setup();
    const message = "Für eine Bienenpatenschaft brauchst du ein Kundenkonto. Bitte melde dich an.";
    fetchMock.mockResolvedValue({ ok: false, status: 401, json: async () => ({ error: message }) } as Response);

    renderCheckout([sponsorshipItem("sp_1", "Frieda")]);
    await userEventInstance.type(screen.getByLabelText(/vorname/i), "Erika");
    await userEventInstance.type(screen.getByLabelText(/nachname/i), "Mustermann");
    await userEventInstance.type(screen.getByLabelText(/e-mail/i), "erika@example.org");
    await userEventInstance.click(screen.getByRole("button", { name: /kostenpflichtig bestellen/i }));

    expect(await screen.findByText(message, { exact: false })).toBeInTheDocument();
    expect(screen.getByRole("link", { name: "Zur Anmeldung" })).toHaveAttribute("href", "/konto?next=%2Fcheckout");
  });
});