import { prisma } from "@/lib/prisma";
import type { SponsorshipCycle, SubscriptionStatus, DeliveryStatus } from "@/generated/prisma/client";
import { deliveryProgress } from "@/lib/sponsorship-subscription/entitlement";
import { contractReference } from "@/lib/sponsorship-subscription/cancellation";

/**
 * Abo eines Kontos fuer die Kontoseite und den Kuendigungsknopf. Gefiltert
 * nach customerId: ein fremdes Abo ist hier schlicht nicht vorhanden (404).
 */

export interface OwnedSubscriptionView {
  id: string;
  status: SubscriptionStatus;
  offerName: string;
  cycle: SponsorshipCycle | null;
  /** Zuletzt eingezogener Monatsbetrag, sonst der Preis des Angebots. */
  monthlyCents: number;
  contractReference: string;
  beeName: string | null;
  sponsorshipId: string | null;
  currentPeriodEnd: Date | null;
  cancelAt: Date | null;
  endedAt: Date | null;
  paidMonths: number;
  progress: { paid: number; required: number } | null;
  /** Bezahlte Monate, die wegen der SEPA-Neukunden-Frist noch nicht zaehlen. */
  heldPayments: number;
  deliveries: { id: string; dueAt: Date; jars: number; status: DeliveryStatus }[];
  stripeCustomerId: string | null;
  customerEmail: string;
}

function beeNameOf(personalization: unknown): string | null {
  const inner = (personalization as { personalization?: { beeName?: unknown } } | null)?.personalization;
  return typeof inner?.beeName === "string" ? inner.beeName : null;
}

export async function getOwnedSubscription(customerId: string, id: string, now: Date = new Date()): Promise<OwnedSubscriptionView | null> {
  const subscription = await prisma.sponsorshipSubscription.findFirst({
    where: { id, customerId },
    include: {
      offer: { select: { name: true, cycle: true, priceCents: true, honeyJars: true } },
      sponsorship: { select: { id: true, number: true } },
      customer: { select: { email: true, stripeCustomerId: true } },
      payments: {
        orderBy: { paidAt: "asc" },
        select: { id: true, paidAt: true, countsFrom: true, reversedAt: true, deliveryId: true, amountCents: true },
      },
      deliveries: { orderBy: { dueAt: "desc" }, select: { id: true, dueAt: true, jars: true, status: true } },
    },
  });
  if (!subscription) return null;

  const valid = subscription.payments.filter((p) => p.reversedAt === null);
  const last = valid[valid.length - 1];
  const hasHoney = subscription.offer.honeyJars > 0 && subscription.offer.cycle !== null;
  return {
    id: subscription.id,
    status: subscription.status,
    offerName: subscription.offer.name,
    cycle: subscription.offer.cycle,
    monthlyCents: last?.amountCents ?? subscription.offer.priceCents,
    contractReference: contractReference(subscription),
    beeName: beeNameOf(subscription.personalization),
    sponsorshipId: subscription.sponsorship?.id ?? null,
    currentPeriodEnd: subscription.currentPeriodEnd,
    cancelAt: subscription.cancelAt,
    endedAt: subscription.endedAt,
    paidMonths: valid.length,
    progress: hasHoney && subscription.offer.cycle ? deliveryProgress(subscription.offer.cycle, subscription.payments) : null,
    heldPayments: valid.filter((p) => p.deliveryId === null && p.countsFrom > now).length,
    deliveries: subscription.deliveries,
    stripeCustomerId: subscription.customer.stripeCustomerId,
    customerEmail: subscription.customer.email,
  };
}

/** Kuendigung moeglich? Nur laufende Vertraege; ein gekuendigtes Abo zeigt stattdessen sein Ende. */
export function canCancel(view: Pick<OwnedSubscriptionView, "status" | "cancelAt">): boolean {
  return (view.status === "AKTIV" || view.status === "IM_VERZUG") && view.cancelAt === null;
}