import Stripe from "stripe";
import { beforeEach, describe, expect, test } from "vitest";
import { startCheckout, startInstallmentCheckout } from "@/lib/checkout";
import { applyRefundState, MAX_OFF_SESSION_ATTEMPTS } from "@/lib/payment-events";
import { verifyStripeWebhook } from "@/lib/payment-gateway";
import { handleStripeEvent, settleCheckoutSession } from "@/lib/webhook";
import { chargeDueInstallments, detachFinishedPaymentMethods, releaseExpiredReservations } from "@/lib/worker-jobs";
import { STRIPE_ACTOR } from "@/lib/audit";
import type { PlanType } from "@/lib/payment-plan";
import { bookingRequest, db, EARLY_BIRD_NOW, resetDb, SECRET, setupCamp } from "./support/db";
import { FakeGateway } from "./support/fake-gateway";

const ctx = { now: EARLY_BIRD_NOW, secret: SECRET, adminEmail: "admin@example.org" };
let gateway: FakeGateway;

beforeEach(async () => {
  await resetDb();
  await setupCamp();
  gateway = new FakeGateway("test");
});

async function checkout(planType: PlanType = "FULL", voucherCode?: string) {
  const request = bookingRequest({ planType, voucherCode });
  const result = await startCheckout(db, gateway, request, ctx);
  if (!result.ok) throw new Error(`Checkout fehlgeschlagen: ${result.error.code}`);
  const booking = await db.booking.findUniqueOrThrow({ where: { reference: result.reference } });
  return { request, result, booking };
}

function sessionEvent(type: string, session: ReturnType<FakeGateway["completeSession"]>, id = `evt_${crypto.randomUUID()}`) {
  return {
    id,
    type,
    livemode: false,
    data: {
      object: {
        id: session.id,
        object: "checkout.session",
        status: session.status,
        payment_status: session.paymentStatus,
        payment_intent: session.paymentIntentId,
        customer: session.customerId,
        url: null,
        metadata: session.metadata,
      },
    },
  } as unknown as Stripe.Event;
}

async function paidBooking(planType: PlanType = "FULL") {
  const { booking } = await checkout(planType);
  const session = gateway.completeSession(booking.stripeCheckoutSessionId!);
  await handleStripeEvent(db, gateway, sessionEvent("checkout.session.completed", session), ctx);
  return db.booking.findUniqueOrThrow({ where: { id: booking.id }, include: { installments: { orderBy: { seq: "asc" } } } });
}

describe("Checkout-Erstellung", () => {
  test("idempotent: derselbe Buchungsversuch liefert dieselbe Stripe-Session", async () => {
    const { request, result } = await checkout();
    const again = await startCheckout(db, gateway, request, ctx);
    expect(again.ok && again.url).toBe(result.url);
    expect(gateway.sessions.size).toBe(1);
  });

  test("Session laeuft mit der Preisbindung ab; Ratenplan speichert die Zahlungsmethode", async () => {
    const { booking } = await checkout("THREE_INSTALLMENTS");
    const session = gateway.sessions.get(booking.stripeCheckoutSessionId!)!;
    expect(session.params.amountCents).toBe(80_000);
    expect(session.params.saveForFutureUsage).toBe(true);
    expect(session.params.expiresAt.getTime()).toBe(booking.priceLockedUntil.getTime());
    expect(session.params.submitMessage).toContain("Heute fällig: 800,00 €");
  });

  test("Stripe-Ausfall gibt Platz und Gutschein sofort wieder frei", async () => {
    await db.voucher.create({ data: { code: "CODE-X" } });
    gateway.failNextCheckout = true;
    const result = await startCheckout(db, gateway, bookingRequest({ voucherCode: "CODE-X" }), ctx);
    expect(result.ok ? "ok" : result.error.code).toBe("PAYMENT_PROVIDER");
    expect(await db.seatReservation.count({ where: { status: "RELEASED" } })).toBe(1);
    expect(await db.voucherRedemption.count({ where: { status: "RELEASED" } })).toBe(1);
  });
});

describe("Webhook", () => {
  test("Signatur wird gegen den unveraenderten Body geprueft", () => {
    const secret = "whsec_test_secret";
    const payload = JSON.stringify({ id: "evt_1", object: "event", type: "checkout.session.completed", data: { object: {} } });
    const header = Stripe.webhooks.generateTestHeaderString({ payload, secret });
    expect(verifyStripeWebhook(payload, header, secret).id).toBe("evt_1");
    expect(() => verifyStripeWebhook(payload.replace("evt_1", "evt_2"), header, secret)).toThrow();
    expect(() => verifyStripeWebhook(payload, header, "whsec_falsch")).toThrow();
  });

  test("Einmalzahlung: bestaetigt und vollstaendig bezahlt, Mail im Postausgang", async () => {
    const booking = await paidBooking("FULL");
    expect(booking.status).toBe("CONFIRMED");
    expect(booking.paymentStatus).toBe("PAID");
    expect(booking.paidCents).toBe(220_000);
    expect(await db.seatReservation.count({ where: { status: "CONVERTED" } })).toBe(1);
    expect(await db.emailMessage.count({ where: { dedupeKey: `booking-confirmed:${booking.id}` } })).toBe(1);
  });

  test("Ratenzahlung: erste Rate bezahlt heisst Teilzahlung, nicht vollstaendig bezahlt", async () => {
    const booking = await paidBooking("TWO_INSTALLMENTS");
    expect(booking.status).toBe("CONFIRMED");
    expect(booking.paymentStatus).toBe("PARTIALLY_PAID");
    expect(booking.paidCents).toBe(110_000);
    expect(booking.stripePaymentMethodId).toMatch(/^pm_/);
    expect(booking.installments.map((i) => i.status)).toEqual(["PAID", "PENDING"]);
  });

  test("doppelt zugestelltes Event wird nur einmal verbucht", async () => {
    const { booking } = await checkout();
    const session = gateway.completeSession(booking.stripeCheckoutSessionId!);
    const event = sessionEvent("checkout.session.completed", session, "evt_dup");
    expect((await handleStripeEvent(db, gateway, event, ctx)).outcome).toBe("processed");
    expect((await handleStripeEvent(db, gateway, event, ctx)).outcome).toBe("duplicate");
    // Anderes Event, gleicher Inhalt (z. B. async_payment_succeeded): idempotent.
    await handleStripeEvent(db, gateway, sessionEvent("checkout.session.async_payment_succeeded", session), ctx);
    const after = await db.booking.findUniqueOrThrow({ where: { id: booking.id } });
    expect(after.paidCents).toBe(220_000);
  });

  test("ungeordnet: 'expired' nach 'completed' hebt die Buchung nicht auf", async () => {
    const { booking } = await checkout();
    const session = gateway.completeSession(booking.stripeCheckoutSessionId!);
    await handleStripeEvent(db, gateway, sessionEvent("checkout.session.completed", session), ctx);
    await handleStripeEvent(db, gateway, sessionEvent("checkout.session.expired", { ...session, status: "expired" }), ctx);
    const after = await db.booking.findUniqueOrThrow({ where: { id: booking.id } });
    expect(after.status).toBe("CONFIRMED");
  });

  test("Abbruch/Ablauf: unbezahlte Buchung verfaellt, Platz wird frei", async () => {
    const { booking } = await checkout();
    const session = await gateway.retrieveCheckoutSession(booking.stripeCheckoutSessionId!);
    await handleStripeEvent(
      db,
      gateway,
      sessionEvent("checkout.session.expired", { ...session, status: "expired" } as ReturnType<FakeGateway["completeSession"]>),
      ctx,
    );
    const after = await db.booking.findUniqueOrThrow({ where: { id: booking.id }, include: { reservation: true } });
    expect(after.status).toBe("EXPIRED");
    expect(after.reservation!.status).toBe("RELEASED");
  });

  test("Livemodus-Event im Testbetrieb wird ignoriert", async () => {
    const { booking } = await checkout();
    const session = gateway.completeSession(booking.stripeCheckoutSessionId!);
    const event = { ...sessionEvent("checkout.session.completed", session), livemode: true } as Stripe.Event;
    expect((await handleStripeEvent(db, gateway, event, ctx)).outcome).toBe("ignored");
    expect((await db.booking.findUniqueOrThrow({ where: { id: booking.id } })).status).toBe("PENDING");
  });
});

describe("Verzoegerte und verspaetete Zahlung", () => {
  test("verzoegerte Zahlung haelt den Platz, Fehlschlag gibt ihn frei", async () => {
    const { booking } = await checkout();
    const session = gateway.completeSession(booking.stripeCheckoutSessionId!, { paid: false });
    await handleStripeEvent(db, gateway, sessionEvent("checkout.session.completed", session), ctx);
    let after = await db.booking.findUniqueOrThrow({ where: { id: booking.id }, include: { reservation: true } });
    expect(after.paymentStatus).toBe("PROCESSING");
    expect(after.reservation!.status).toBe("HELD");

    // Reservierungsfrist laeuft ab, der Platz bleibt trotzdem gehalten.
    const later = { ...ctx, now: new Date(EARLY_BIRD_NOW.getTime() + 3 * 86_400_000) };
    await releaseExpiredReservations(db, gateway, later);
    after = await db.booking.findUniqueOrThrow({ where: { id: booking.id }, include: { reservation: true } });
    expect(after.reservation!.status).toBe("HELD");

    await handleStripeEvent(db, gateway, sessionEvent("checkout.session.async_payment_failed", session), later);
    after = await db.booking.findUniqueOrThrow({ where: { id: booking.id }, include: { reservation: true } });
    expect(after.status).toBe("EXPIRED");
    expect(after.paymentStatus).toBe("FAILED");
    expect(after.reservation!.status).toBe("RELEASED");
  });

  test("verlorener Webhook: Worker fragt Stripe und verbucht die Zahlung statt freizugeben", async () => {
    const { booking } = await checkout();
    gateway.completeSession(booking.stripeCheckoutSessionId!);
    const later = { ...ctx, now: new Date(EARLY_BIRD_NOW.getTime() + 60 * 60_000) };
    const result = await releaseExpiredReservations(db, gateway, later);
    expect(result.settled).toBe(1);
    expect((await db.booking.findUniqueOrThrow({ where: { id: booking.id } })).status).toBe("CONFIRMED");
  });

  test("verspaetete Zahlung nach Freigabe: Platz noch frei -> bestaetigt", async () => {
    const { booking } = await checkout();
    const session = gateway.completeSession(booking.stripeCheckoutSessionId!);
    // Platz wurde (z. B. durch einen Fehler) bereits freigegeben.
    await db.seatReservation.update({ where: { bookingId: booking.id }, data: { status: "RELEASED" } });
    await db.booking.update({ where: { id: booking.id }, data: { status: "EXPIRED" } });
    await settleCheckoutSession(db, gateway, session, ctx, STRIPE_ACTOR);
    const after = await db.booking.findUniqueOrThrow({ where: { id: booking.id }, include: { reservation: true } });
    expect(after.status).toBe("CONFIRMED");
    expect(after.reservation!.status).toBe("CONVERTED");
  });

  test("verspaetete Zahlung nach Freigabe ohne freien Platz -> Pruefung statt Ueberbuchung", async () => {
    await setupCamp({ capacity: 1 });
    const { booking } = await checkout();
    const session = gateway.completeSession(booking.stripeCheckoutSessionId!);
    await db.seatReservation.update({ where: { bookingId: booking.id }, data: { status: "RELEASED" } });
    await db.booking.update({ where: { id: booking.id }, data: { status: "EXPIRED" } });
    await paidBooking("FULL"); // jemand anderes bekommt den letzten Platz
    await settleCheckoutSession(db, gateway, session, ctx, STRIPE_ACTOR);
    const after = await db.booking.findUniqueOrThrow({ where: { id: booking.id } });
    expect(after.status).toBe("NEEDS_REVIEW");
    expect(after.paidCents).toBe(220_000);
    expect(await db.seatReservation.count({ where: { status: "CONVERTED" } })).toBe(1);
    expect(await db.emailMessage.count({ where: { toAddress: "admin@example.org" } })).toBe(1);
  });
});

describe("Folgeraten", () => {
  const afterLastDue = (booking: { installments: { dueAt: Date | null }[] }) => ({
    ...ctx,
    now: new Date(Math.max(...booking.installments.map((i) => i.dueAt?.getTime() ?? 0)) + 60_000),
  });

  test("Einzug aller Raten, danach keine weitere Abbuchung und Zahlungsmethode getrennt", async () => {
    const booking = await paidBooking("THREE_INSTALLMENTS");
    const runCtx = afterLastDue(booking);
    const summary = await chargeDueInstallments(db, gateway, runCtx);
    expect(summary.charged).toBe(2);
    let after = await db.booking.findUniqueOrThrow({ where: { id: booking.id } });
    expect(after.paymentStatus).toBe("PAID");
    expect(after.paidCents).toBe(220_000);

    await detachFinishedPaymentMethods(db, gateway);
    after = await db.booking.findUniqueOrThrow({ where: { id: booking.id } });
    expect(after.paymentMethodDetachedAt).not.toBeNull();
    expect(gateway.detached).toEqual([booking.stripePaymentMethodId]);

    // Weitere Laeufe buchen nichts mehr ab.
    await chargeDueInstallments(db, gateway, runCtx);
    await chargeDueInstallments(db, gateway, { ...runCtx, now: new Date(runCtx.now.getTime() + 30 * 86_400_000) });
    expect(gateway.offSessionCharges).toHaveLength(2);
    expect(gateway.offSessionCharges.reduce((s, c) => s + c.amountCents, 0)).toBe(140_000);
  });

  test("nur faellige Raten werden eingezogen", async () => {
    const booking = await paidBooking("THREE_INSTALLMENTS");
    const between = { ...ctx, now: new Date(booking.installments[1]!.dueAt!.getTime() + 60_000) };
    expect((await chargeDueInstallments(db, gateway, between)).charged).toBe(1);
    const after = await db.booking.findUniqueOrThrow({ where: { id: booking.id } });
    expect(after.paymentStatus).toBe("PARTIALLY_PAID");
    expect(after.paidCents).toBe(150_000);
  });

  test("Fehlschlag: Wiederholung nach Wartezeit, nach dem letzten Versuch manuelle Pruefung", async () => {
    const booking = await paidBooking("TWO_INSTALLMENTS");
    gateway.offSessionOutcomes = ["failed", "failed", "failed"];
    let runCtx = afterLastDue(booking);
    for (let attempt = 1; attempt <= MAX_OFF_SESSION_ATTEMPTS; attempt++) {
      await chargeDueInstallments(db, gateway, runCtx);
      const inst = await db.installment.findFirstOrThrow({ where: { bookingId: booking.id, seq: 2 } });
      expect(inst.status).toBe("FAILED");
      expect(inst.attemptCount).toBe(attempt);
      // Vor Ablauf der Wartezeit kein erneuter Versuch.
      await chargeDueInstallments(db, gateway, runCtx);
      expect((await db.installment.findFirstOrThrow({ where: { id: inst.id } })).attemptCount).toBe(attempt);
      runCtx = { ...runCtx, now: new Date(runCtx.now.getTime() + 4 * 86_400_000) };
    }
    const after = await db.booking.findUniqueOrThrow({ where: { id: booking.id } });
    expect(after.status).toBe("NEEDS_REVIEW");
    expect(after.paymentStatus).toBe("PARTIALLY_PAID");
    expect(gateway.offSessionCharges).toHaveLength(0);
  });

  test("Bank verlangt Authentifizierung: Kundin bekommt Link und zahlt selbst", async () => {
    const booking = await paidBooking("TWO_INSTALLMENTS");
    gateway.offSessionOutcomes = ["requires_action"];
    const runCtx = afterLastDue(booking);
    await chargeDueInstallments(db, gateway, runCtx);
    const inst = await db.installment.findFirstOrThrow({ where: { bookingId: booking.id, seq: 2 } });
    expect(inst.status).toBe("REQUIRES_ACTION");
    expect(await db.emailMessage.count({ where: { dedupeKey: { startsWith: `installment-action:${inst.id}` } } })).toBe(1);

    const pay = await startInstallmentCheckout(db, gateway, { bookingId: booking.id, installmentId: inst.id }, runCtx);
    expect(pay.ok).toBe(true);
    // Waehrend die Session offen ist, zieht der Worker nicht parallel ein.
    await chargeDueInstallments(db, gateway, { ...runCtx, now: new Date(runCtx.now.getTime() + 60_000) });
    expect(gateway.offSessionCharges).toHaveLength(0);

    const sessionId = (await db.installment.findUniqueOrThrow({ where: { id: inst.id } })).checkoutSessionId!;
    const session = gateway.completeSession(sessionId);
    await handleStripeEvent(db, gateway, sessionEvent("checkout.session.completed", session), runCtx);
    const after = await db.booking.findUniqueOrThrow({ where: { id: booking.id } });
    expect(after.paymentStatus).toBe("PAID");
    expect(after.paidCents).toBe(220_000);
  });

  test("Webhook und Worker melden denselben Erfolg: nur einmal verbucht", async () => {
    const booking = await paidBooking("TWO_INSTALLMENTS");
    const runCtx = afterLastDue(booking);
    await chargeDueInstallments(db, gateway, runCtx);
    const inst = await db.installment.findFirstOrThrow({ where: { bookingId: booking.id, seq: 2 } });
    const pi = await gateway.retrievePaymentIntent(inst.stripePaymentIntentId!);
    const event = {
      id: "evt_pi_ok",
      type: "payment_intent.succeeded",
      livemode: false,
      data: {
        object: {
          id: pi.id,
          object: "payment_intent",
          amount_received: pi.amountReceived,
          latest_charge: pi.chargeId,
          payment_method: pi.paymentMethodId,
          customer: null,
          metadata: pi.metadata,
        },
      },
    } as unknown as Stripe.Event;
    await handleStripeEvent(db, gateway, event, runCtx);
    const after = await db.booking.findUniqueOrThrow({ where: { id: booking.id } });
    expect(after.paidCents).toBe(220_000);
    expect(after.status).toBe("CONFIRMED");
  });

  test("Erstattung aktualisiert Zahlungsstatus absolut (ungeordnete Events harmlos)", async () => {
    const booking = await paidBooking("FULL");
    const pi = booking.installments[0]!.stripePaymentIntentId!;
    const ectx = { ...ctx, actor: STRIPE_ACTOR };
    await db.$transaction((tx) => applyRefundState(tx, { paymentIntentId: pi, amountRefundedCents: 220_000 }, ectx));
    await db.$transaction((tx) => applyRefundState(tx, { paymentIntentId: pi, amountRefundedCents: 50_000 }, ectx));
    await db.$transaction((tx) => applyRefundState(tx, { paymentIntentId: pi, amountRefundedCents: 220_000 }, ectx));
    const after = await db.booking.findUniqueOrThrow({ where: { id: booking.id } });
    expect(after.refundedCents).toBe(220_000);
    expect(after.paymentStatus).toBe("REFUNDED");
  });
});