/**
 * Verwaltungsaktionen. Jede Aktion prueft ihre Eingaben, laeuft unter
 * Buchungssperre und wird im AuditLog festgehalten.
 *
 * Stornierung und Erstattung sind bewusst getrennt: Die freigegebenen
 * Stornobedingungen bestimmen, welcher Betrag erstattet wird — diese
 * Entscheidung trifft ein Mensch, nicht die Software (docs/BETRIEB.md).
 */
import "./zod-de";
import { z } from "zod";
import { audit, type Actor } from "./audit";
import { countOccupiedSeats, lockBooking, lockCamp } from "./booking-service";
import { CAMP_ID, type Db } from "./db";
import { enqueueEmail } from "./email";
import { bookingConfirmedEmail } from "./email-templates";
import type { PaymentGateway } from "./payment-gateway";
import { getCamp } from "./camp";
import { stopCanceledInstallmentPlans } from "./installment-billing";
import { addDays, berlinStartOfDay, isoToDbDate } from "./time";
import { statusTokenFor } from "./tokens";
import { normalizeEmail, normalizeVoucherCode } from "./vouchers";
import { detachFinishedPaymentMethods } from "./worker-jobs";

export type ActionResult = { ok: true; message: string } | { ok: false; message: string };

export async function cancelBooking(
  db: Db,
  gateway: PaymentGateway,
  params: { bookingId: string; reason: string },
  actor: Actor,
  now = new Date(),
): Promise<ActionResult> {
  const reason = params.reason.trim().slice(0, 500);
  if (!reason) return { ok: false, message: "Bitte einen Grund angeben." };

  const before = await db.$transaction(async (tx) => {
    await lockBooking(tx, params.bookingId);
    const booking = await tx.booking.findUnique({ where: { id: params.bookingId }, include: { installments: true } });
    if (!booking || booking.status === "CANCELED") return null;
    await tx.installment.updateMany({
      where: { bookingId: booking.id, status: { in: ["PENDING", "FAILED", "REQUIRES_ACTION"] } },
      data: { status: "CANCELED", nextAttemptAt: null },
    });
    await tx.seatReservation.updateMany({
      where: { bookingId: booking.id, status: { not: "RELEASED" } },
      data: { status: "RELEASED", releasedAt: now, releaseReason: "canceled_by_admin" },
    });
    await tx.voucherRedemption.updateMany({
      where: { bookingId: booking.id, status: { not: "RELEASED" } },
      data: { status: "RELEASED", releasedAt: now },
    });
    await tx.booking.update({ where: { id: booking.id }, data: { status: "CANCELED", canceledAt: now, cancelReason: reason } });
    await audit(tx, actor, "booking.canceled", "Booking", booking.id, { reason, previousStatus: booking.status, paidCents: booking.paidCents });
    return booking;
  });
  if (!before) return { ok: false, message: "Buchung nicht gefunden oder bereits storniert." };

  // Offene Session schliessen, Stripe-Ratenplan beenden und gespeicherte
  // Zahlungsmethode trennen: nach einer Stornierung darf nichts mehr
  // abgebucht werden.
  if (before.stripeCheckoutSessionId) await gateway.expireCheckoutSession(before.stripeCheckoutSessionId).catch(() => undefined);
  const plan = await stopCanceledInstallmentPlans(db, gateway, [before.id], actor);
  if (plan.failed > 0) {
    return {
      ok: false,
      message: "Buchung storniert, aber der Ratenplan bei Stripe ließ sich noch nicht beenden. Der Hintergrundlauf versucht es alle 10 Minuten erneut.",
    };
  }
  await detachFinishedPaymentMethods(db, gateway, [before.id]);
  return { ok: true, message: "Buchung storniert. Eine Erstattung wird separat ausgelöst." };
}

export async function refundInstallment(
  db: Db,
  gateway: PaymentGateway,
  params: { installmentId: string; amountCents: number; requestKey: string; reason: string },
  actor: Actor,
): Promise<ActionResult> {
  if (!Number.isSafeInteger(params.amountCents) || params.amountCents <= 0) return { ok: false, message: "Ungültiger Betrag." };
  const installment = await db.installment.findUnique({ where: { id: params.installmentId }, include: { refunds: true } });
  if (!installment || installment.status !== "PAID" || !installment.stripePaymentIntentId) {
    return { ok: false, message: "Nur bezahlte Raten können erstattet werden." };
  }
  const alreadyRequested = installment.refunds.filter((r) => r.status !== "failed" && r.status !== "canceled").reduce((s, r) => s + r.amountCents, 0);
  const refundable = installment.amountCents - Math.max(alreadyRequested, installment.refundedCents);
  if (params.amountCents > refundable) return { ok: false, message: `Höchstens ${(refundable / 100).toFixed(2)} € erstattbar.` };

  const refund = await gateway.createRefund(
    { paymentIntentId: installment.stripePaymentIntentId, amountCents: params.amountCents, metadata: { bookingId: installment.bookingId, installmentId: installment.id } },
    `refund:${params.requestKey}`,
  );
  await db.refund.upsert({
    where: { stripeRefundId: refund.id },
    create: {
      bookingId: installment.bookingId,
      installmentId: installment.id,
      stripeRefundId: refund.id,
      amountCents: refund.amount,
      status: refund.status,
      reason: params.reason.slice(0, 500) || null,
      createdBy: actor.id ?? null,
    },
    update: { status: refund.status },
  });
  await audit(db, actor, "payment.refund_requested", "Installment", installment.id, {
    bookingId: installment.bookingId,
    refundId: refund.id,
    amountCents: refund.amount,
  });
  return { ok: true, message: "Erstattung bei Stripe ausgelöst. Der Zahlungsstatus aktualisiert sich, sobald Stripe sie bestätigt." };
}

/** Entscheidung ueber eine Buchung im Status NEEDS_REVIEW. */
export async function confirmReviewedBooking(db: Db, bookingId: string, actor: Actor, now = new Date()): Promise<ActionResult> {
  return db.$transaction(async (tx) => {
    await lockBooking(tx, bookingId);
    const booking = await tx.booking.findUnique({ where: { id: bookingId }, include: { reservation: true } });
    if (!booking || booking.status !== "NEEDS_REVIEW") return { ok: false, message: "Buchung ist nicht in Prüfung." };
    if (booking.paidCents <= 0) return { ok: false, message: "Ohne Zahlungseingang kann nicht bestätigt werden." };
    if (!booking.reservation) return { ok: false, message: "Zu dieser Buchung gibt es keine Platzreservierung." };
    if (booking.reservation.status !== "CONVERTED") {
      await lockCamp(tx);
      const camp = await getCamp(tx);
      const occupied = await countOccupiedSeats(tx, booking.livemode, now);
      if (occupied >= camp.capacity) {
        return { ok: false, message: "Kein Platz frei. Kapazität in den Einstellungen erhöhen oder die Buchung stornieren." };
      }
      await tx.seatReservation.update({ where: { bookingId }, data: { status: "CONVERTED", releasedAt: null, releaseReason: null } });
    }
    await tx.booking.update({ where: { id: bookingId }, data: { status: "CONFIRMED", confirmedAt: now, reviewReason: null } });
    await audit(tx, actor, "booking.review_confirmed", "Booking", bookingId, { previousReason: booking.reviewReason });
    return { ok: true, message: "Buchung bestätigt." };
  });
}

export async function resendConfirmation(db: Db, bookingId: string, secret: string, actor: Actor): Promise<ActionResult> {
  const booking = await db.booking.findUnique({ where: { id: bookingId }, include: { installments: { orderBy: { seq: "asc" } } } });
  if (!booking || booking.status !== "CONFIRMED") return { ok: false, message: "Nur bestätigte Buchungen." };
  const mail = bookingConfirmedEmail(booking, statusTokenFor(booking.id, secret));
  await enqueueEmail(db, { ...mail, dedupeKey: `${mail.dedupeKey}:resend:${Date.now()}` });
  await audit(db, actor, "booking.confirmation_resent", "Booking", bookingId);
  return { ok: true, message: "Bestätigung erneut in den Postausgang gelegt." };
}

// ---------------------------------------------------------------------------
// Gutscheine
// ---------------------------------------------------------------------------

const dateOnly = z
  .string()
  .trim()
  .refine((v) => v === "" || /^\d{4}-\d{2}-\d{2}$/.test(v), "Datum im Format JJJJ-MM-TT");
/** "Gueltig ab" = 00:00 Uhr Berlin des Tages. */
const validFromDate = dateOnly.transform((v) => (v ? berlinStartOfDay(v) : null));
/** "Gueltig bis einschliesslich" = exklusive Grenze 00:00 Uhr Berlin am Folgetag. */
const validUntilDate = dateOnly.transform((v) => (v ? berlinStartOfDay(addDays(v, 1)) : null));

export const voucherInputSchema = z
  .object({
    code: z.string().transform((v, ctx) => {
      const code = normalizeVoucherCode(v);
      if (!code) {
        ctx.addIssue({ code: "custom", message: "Code: 4–40 Zeichen, nur Buchstaben, Ziffern und Bindestrich." });
        return z.NEVER;
      }
      return code;
    }),
    active: z.boolean(),
    validFrom: validFromDate,
    validUntil: validUntilDate,
    maxRedemptions: z.coerce.number().int().min(1).max(100),
    boundEmail: z
      .string()
      .trim()
      .transform((v) => (v ? normalizeEmail(v) : null))
      .refine((v) => v === null || z.email().safeParse(v).success, "Ungültige E-Mail-Adresse"),
    internalNote: z.string().trim().max(500).transform((v) => v || null),
  })
  .refine((v) => !v.validFrom || !v.validUntil || v.validFrom < v.validUntil, { message: "Gültig bis muss nach Gültig ab liegen.", path: ["validUntil"] });

export type VoucherInput = z.infer<typeof voucherInputSchema>;

export async function saveVoucher(db: Db, id: string | null, input: VoucherInput, actor: Actor): Promise<ActionResult & { id?: string }> {
  const clash = await db.voucher.findUnique({ where: { code: input.code } });
  if (clash && clash.id !== id) return { ok: false, message: "Dieser Code existiert bereits." };
  const voucher = id ? await db.voucher.update({ where: { id }, data: input }) : await db.voucher.create({ data: input });
  await audit(db, actor, id ? "voucher.updated" : "voucher.created", "Voucher", voucher.id, {
    active: input.active,
    maxRedemptions: input.maxRedemptions,
    bound: input.boundEmail !== null,
  });
  return { ok: true, message: id ? "Gutschein gespeichert." : "Gutschein angelegt.", id: voucher.id };
}

// ---------------------------------------------------------------------------
// Camp-Konfiguration
// ---------------------------------------------------------------------------

const text = (max: number) => z.string().trim().max(max).transform((v) => v || null);
const isoDate = z
  .string()
  .trim()
  .refine((v) => v === "" || /^\d{4}-\d{2}-\d{2}$/.test(v), "Datum im Format JJJJ-MM-TT")
  .transform((v) => (v ? isoToDbDate(v) : null));

export const campInputSchema = z.object({
  salesEnabled: z.boolean(),
  capacity: z.coerce.number().int().min(0).max(200),
  capacityConfirmed: z.boolean(),
  stammmodelQuota: z.coerce.number().int().min(0).max(200),
  stammmodelQuotaConfirmed: z.boolean(),
  campStartDate: isoDate,
  campEndDate: isoDate,
  dateConfirmed: z.boolean(),
  locationName: text(200),
  locationRegion: text(200),
  locationConfirmed: z.boolean(),
  accommodationText: text(3000),
  accommodationConfirmed: z.boolean(),
  servicesConfirmed: z.boolean(),
  organizerName: text(200),
  organizerAddress: text(500),
  organizerEmail: text(200).refine((v) => v === null || z.email().safeParse(v).success, "Ungültige E-Mail-Adresse"),
  organizerPhone: text(60),
  organizerConfirmed: z.boolean(),
  taxNote: text(500),
  taxConfirmed: z.boolean(),
  termsVersion: text(60),
  termsUrl: text(500).refine((v) => v === null || v.startsWith("/") || v.startsWith("https://"), "Nur https:// oder ein Pfad dieser Seite"),
  termsApproved: z.boolean(),
  withdrawalText: text(10000),
  withdrawalApproved: z.boolean(),
  travelLawChecked: z.boolean(),
  installmentsApproved: z.boolean(),
  installmentRuleApproved: z.boolean(),
  reservationMinutes: z.coerce.number().int().min(30).max(120),
  finalInstallmentLeadDays: z.coerce.number().int().min(0).max(120),
  minInstallmentGapDays: z.coerce.number().int().min(1).max(90),
  testPhaseOverride: z.enum(["", "EARLY_BIRD", "REGULAR"]).transform((v) => (v ? v : null)),
});

export type CampInput = z.infer<typeof campInputSchema>;

export async function updateCamp(db: Db, input: CampInput, actor: Actor): Promise<ActionResult> {
  if (input.campStartDate && input.campEndDate && input.campEndDate < input.campStartDate) {
    return { ok: false, message: "Das Enddatum liegt vor dem Anreisetag." };
  }
  const before = await getCamp(db);
  const changed = (Object.keys(input) as (keyof CampInput)[]).filter((key) => {
    const a = before[key];
    const b = input[key];
    return (a instanceof Date ? a.getTime() : a) !== (b instanceof Date ? b.getTime() : b);
  });
  await db.camp.update({ where: { id: CAMP_ID }, data: { ...input, updatedBy: actor.id ?? null } });
  await audit(db, actor, "camp.updated", "Camp", CAMP_ID, { changed });
  return { ok: true, message: changed.length ? `Gespeichert (${changed.length} Änderungen).` : "Keine Änderungen." };
}