flimmer/src/lib/universes.ts

import "server-only";
import { prisma } from "./db";
import { SPECIALS_SEASON } from "./catalog";
import type { OrderKind, SharePermission, TitleType } from "@/generated/prisma/client";

/**
 * Universen: eigene Sammlungen aus Filmen **und** Serien.
 *
 * Zwei Dinge unterscheiden ein Universum von einer Liste:
 *
 *  1. Es hat **mehrere Reihenfolgen**. Die Erscheinungsreihenfolge wird aus den
 *     Daten berechnet und nie gespeichert — sie stimmt damit immer. Alles
 *     andere (Story-Chronologie, Einsteiger-Route) ist frei sortierbar.
 *  2. Der **Fortschritt** ist der des jeweiligen Betrachters. Ein geteiltes
 *     Universum zeigt jeder Person ihren eigenen Stand.
 */

export class UniverseError extends Error {}

// ---------------------------------------------------------------------------
// Zugriff
// ---------------------------------------------------------------------------

export type UniverseAccess = { canRead: boolean; canWrite: boolean; isOwner: boolean };

export async function getAccess(userId: string, universeId: string): Promise<UniverseAccess> {
  const universe = await prisma.universe.findFirst({
    where: { id: universeId, deletedAt: null },
    select: {
      ownerId: true,
      members: { where: { userId }, select: { permission: true } },
    },
  });

  if (!universe) return { canRead: false, canWrite: false, isOwner: false };

  const isOwner = universe.ownerId === userId;
  const membership = universe.members[0];

  return {
    isOwner,
    canRead: isOwner || Boolean(membership),
    canWrite: isOwner || membership?.permission === "WRITE",
  };
}

async function requireWrite(userId: string, universeId: string) {
  const access = await getAccess(userId, universeId);
  if (!access.canRead) throw new UniverseError("Dieses Universum gibt es nicht.");
  if (!access.canWrite) throw new UniverseError("Du darfst dieses Universum nur ansehen.");
  return access;
}

// ---------------------------------------------------------------------------
// Anlegen und pflegen
// ---------------------------------------------------------------------------

function slugify(value: string): string {
  return value
    .toLocaleLowerCase("de-DE")
    .replace(/ä/g, "ae")
    .replace(/ö/g, "oe")
    .replace(/ü/g, "ue")
    .replace(/ß/g, "ss")
    .replace(/[^a-z0-9]+/g, "-")
    .replace(/^-+|-+$/g, "")
    .slice(0, 60) || "universum";
}

export async function createUniverse(userId: string, name: string, description?: string) {
  const base = slugify(name);
  let slug = base;

  // Der Slug ist je Besitzer eindeutig — bei Dubletten durchzählen.
  for (let suffix = 2; suffix < 100; suffix += 1) {
    const taken = await prisma.universe.findUnique({
      where: { ownerId_slug: { ownerId: userId, slug } },
      select: { id: true },
    });
    if (!taken) break;
    slug = `${base}-${suffix}`;
  }

  const universe = await prisma.universe.create({
    data: {
      ownerId: userId,
      name: name.trim(),
      slug,
      description: description?.trim() || null,
      orders: {
        create: [
          // Die Erscheinungsreihenfolge braucht keine Einträge — sie wird
          // aus den Erscheinungsdaten berechnet.
          { name: "Erscheinungsreihenfolge", kind: "RELEASE", isDefault: true },
        ],
      },
    },
  });

  return universe;
}

export async function renameUniverse(
  userId: string,
  universeId: string,
  data: { name?: string; description?: string | null },
) {
  await requireWrite(userId, universeId);
  return prisma.universe.update({
    where: { id: universeId },
    data: {
      ...(data.name ? { name: data.name.trim() } : {}),
      ...(data.description !== undefined ? { description: data.description?.trim() || null } : {}),
    },
  });
}

export async function trashUniverse(userId: string, universeId: string) {
  const access = await getAccess(userId, universeId);
  if (!access.isOwner) throw new UniverseError("Nur wer das Universum angelegt hat, darf es löschen.");
  return prisma.universe.update({
    where: { id: universeId },
    data: { deletedAt: new Date() },
  });
}

/** Nimmt einen Titel ins Universum auf und hängt ihn an alle Reihenfolgen an. */
export async function addTitle(userId: string, universeId: string, titleId: string) {
  await requireWrite(userId, universeId);

  const existing = await prisma.universeItem.findUnique({
    where: { universeId_titleId: { universeId, titleId } },
    select: { id: true },
  });
  if (existing) return existing;

  const item = await prisma.universeItem.create({
    data: { universeId, titleId },
    select: { id: true },
  });

  await appendToCustomOrders(universeId, item.id);
  return item;
}

/** Neue Einträge landen ans Ende jeder frei sortierten Reihenfolge. */
async function appendToCustomOrders(universeId: string, itemId: string) {
  const orders = await prisma.universeOrder.findMany({
    where: { universeId, kind: "CUSTOM" },
    select: { id: true },
  });

  for (const order of orders) {
    const last = await prisma.universeOrderItem.findFirst({
      where: { orderId: order.id },
      orderBy: { position: "desc" },
      select: { position: true },
    });
    await prisma.universeOrderItem.create({
      data: { orderId: order.id, itemId, position: (last?.position ?? -1) + 1 },
    });
  }
}

export async function removeTitle(userId: string, universeId: string, itemId: string) {
  await requireWrite(userId, universeId);
  await prisma.universeItem.delete({ where: { id: itemId } });
}

/**
 * Übernimmt alle Filme einer TMDB-Collection, die bereits im Katalog liegen.
 * Der eigentliche Abruf bei TMDB passiert vorher in der Katalogschicht.
 */
export async function addCollection(
  userId: string,
  universeId: string,
  tmdbCollectionId: number,
): Promise<number> {
  await requireWrite(userId, universeId);

  const titles = await prisma.title.findMany({
    where: { tmdbCollectionId },
    orderBy: { releaseDate: "asc" },
    select: { id: true },
  });

  let added = 0;
  for (const title of titles) {
    const existing = await prisma.universeItem.findUnique({
      where: { universeId_titleId: { universeId, titleId: title.id } },
      select: { id: true },
    });
    if (existing) continue;
    const item = await prisma.universeItem.create({
      data: { universeId, titleId: title.id },
      select: { id: true },
    });
    await appendToCustomOrders(universeId, item.id);
    added += 1;
  }

  return added;
}

// ---------------------------------------------------------------------------
// Reihenfolgen
// ---------------------------------------------------------------------------

export async function createOrder(userId: string, universeId: string, name: string) {
  await requireWrite(userId, universeId);

  const order = await prisma.universeOrder.create({
    data: { universeId, name: name.trim(), kind: "CUSTOM" },
    select: { id: true },
  });

  // Startbelegung: Erscheinungsreihenfolge — von dort aus umsortiert es sich
  // leichter als aus einer zufälligen Anordnung.
  const items = await prisma.universeItem.findMany({
    where: { universeId },
    orderBy: [{ title: { releaseDate: "asc" } }, { title: { title: "asc" } }],
    select: { id: true },
  });

  await prisma.universeOrderItem.createMany({
    data: items.map((item, index) => ({ orderId: order.id, itemId: item.id, position: index })),
  });

  return order;
}

export async function renameOrder(userId: string, orderId: string, name: string) {
  const order = await prisma.universeOrder.findUniqueOrThrow({
    where: { id: orderId },
    select: { universeId: true, kind: true },
  });
  await requireWrite(userId, order.universeId);
  if (order.kind === "RELEASE") {
    throw new UniverseError("Die Erscheinungsreihenfolge lässt sich nicht umbenennen.");
  }
  return prisma.universeOrder.update({ where: { id: orderId }, data: { name: name.trim() } });
}

export async function deleteOrder(userId: string, orderId: string) {
  const order = await prisma.universeOrder.findUniqueOrThrow({
    where: { id: orderId },
    select: { universeId: true, kind: true },
  });
  await requireWrite(userId, order.universeId);
  if (order.kind === "RELEASE") {
    throw new UniverseError("Die Erscheinungsreihenfolge gehört fest dazu.");
  }
  await prisma.universeOrder.delete({ where: { id: orderId } });
}

/** Schreibt eine neue Anordnung — die Liste enthält alle Einträge in Wunschfolge. */
export async function setOrderPositions(userId: string, orderId: string, itemIds: string[]) {
  const order = await prisma.universeOrder.findUniqueOrThrow({
    where: { id: orderId },
    select: { universeId: true, kind: true },
  });
  await requireWrite(userId, order.universeId);
  if (order.kind === "RELEASE") {
    throw new UniverseError("Die Erscheinungsreihenfolge ergibt sich aus den Daten.");
  }

  // Erst alle auf negative Positionen schieben: die Eindeutigkeit von
  // (orderId, itemId) bleibt, aber wir vermeiden Kollisionen beim Umnummerieren.
  await prisma.$transaction(
    itemIds.map((itemId, index) =>
      prisma.universeOrderItem.updateMany({
        where: { orderId, itemId },
        data: { position: index },
      }),
    ),
  );
}

// ---------------------------------------------------------------------------
// Teilen
// ---------------------------------------------------------------------------

export async function shareUniverse(
  userId: string,
  universeId: string,
  targetEmail: string,
  permission: SharePermission,
) {
  const access = await getAccess(userId, universeId);
  if (!access.isOwner) throw new UniverseError("Nur wer das Universum angelegt hat, darf es teilen.");

  const target = await prisma.user.findUnique({
    where: { email: targetEmail.trim().toLowerCase() },
    select: { id: true, name: true },
  });
  if (!target) throw new UniverseError("Zu dieser E-Mail-Adresse gibt es auf dieser Instanz kein Konto.");
  if (target.id === userId) throw new UniverseError("Mit dir selbst musst du nicht teilen.");

  await prisma.universeMember.upsert({
    where: { universeId_userId: { universeId, userId: target.id } },
    create: { universeId, userId: target.id, permission },
    update: { permission },
  });

  return target;
}

export async function unshareUniverse(userId: string, universeId: string, memberId: string) {
  const access = await getAccess(userId, universeId);
  if (!access.isOwner) throw new UniverseError("Nur wer das Universum angelegt hat, darf das ändern.");
  await prisma.universeMember.delete({ where: { id: memberId } });
}

// ---------------------------------------------------------------------------
// Lesen und Fortschritt
// ---------------------------------------------------------------------------

export type UniverseEntry = {
  itemId: string;
  titleId: string;
  title: string;
  type: TitleType;
  posterPath: string | null;
  year: number | null;
  note: string | null;
  /** Gesamtlaufzeit des Titels in Minuten. */
  totalMinutes: number;
  /** Noch offene Laufzeit für diesen Betrachter. */
  remainingMinutes: number;
  watchedMinutes: number;
  inLibrary: boolean;
  completed: boolean;
  status: string | null;
  watchedEpisodes: number;
  totalEpisodes: number;
};

export type UniverseView = {
  id: string;
  name: string;
  description: string | null;
  isOwner: boolean;
  canWrite: boolean;
  ownerName: string;
  orders: { id: string; name: string; kind: OrderKind; isDefault: boolean }[];
  activeOrderId: string;
  entries: UniverseEntry[];
  progress: {
    completed: number;
    total: number;
    percent: number;
    watchedMinutes: number;
    remainingMinutes: number;
    totalMinutes: number;
  };
  /** Der erste noch nicht abgeschlossene Eintrag in der gewählten Reihenfolge. */
  nextUp: UniverseEntry | null;
  members: { id: string; name: string; email: string; permission: SharePermission }[];
};

export async function getUniverse(
  userId: string,
  universeId: string,
  orderId?: string,
): Promise<UniverseView | null> {
  const access = await getAccess(userId, universeId);
  if (!access.canRead) return null;

  const universe = await prisma.universe.findUnique({
    where: { id: universeId },
    include: {
      owner: { select: { name: true } },
      orders: { orderBy: [{ kind: "asc" }, { createdAt: "asc" }] },
      members: {
        include: { user: { select: { name: true, email: true } } },
        orderBy: { createdAt: "asc" },
      },
      items: {
        include: {
          title: {
            select: {
              id: true,
              title: true,
              type: true,
              posterPath: true,
              releaseDate: true,
              runtime: true,
              episodeCount: true,
            },
          },
          positions: true,
        },
      },
    },
  });

  if (!universe) return null;

  const activeOrder =
    universe.orders.find((order) => order.id === orderId) ??
    universe.orders.find((order) => order.isDefault) ??
    universe.orders[0];
  if (!activeOrder) return null;

  const titleIds = universe.items.map((item) => item.titleId);

  const [entries, seriesRuntimes, watchedByTitle, watchedEpisodes] = await Promise.all([
    prisma.libraryEntry.findMany({
      where: { userId, titleId: { in: titleIds }, deletedAt: null },
      select: { titleId: true, status: true, currentRun: true },
    }),
    // Gesamtlaufzeit je Serie aus den Episoden (ohne Specials).
    prisma.episode.groupBy({
      by: ["titleId"],
      where: { titleId: { in: titleIds }, seasonNumber: { gt: SPECIALS_SEASON } },
      _sum: { runtime: true },
      _count: { _all: true },
    }),
    prisma.watch.groupBy({
      by: ["titleId"],
      where: { userId, titleId: { in: titleIds } },
      _sum: { minutes: true },
    }),
    // Gesehene reguläre Episoden im jeweils aktuellen Durchlauf.
    prisma.watch.groupBy({
      by: ["titleId", "run"],
      where: {
        userId,
        titleId: { in: titleIds },
        episode: { seasonNumber: { gt: SPECIALS_SEASON } },
      },
      _count: { _all: true },
    }),
  ]);

  const entryByTitle = new Map(entries.map((entry) => [entry.titleId, entry]));
  const runtimeByTitle = new Map(
    seriesRuntimes.map((row) => [row.titleId, { minutes: row._sum.runtime ?? 0, episodes: row._count._all }]),
  );
  const minutesByTitle = new Map(watchedByTitle.map((row) => [row.titleId, row._sum.minutes ?? 0]));

  const seenByTitle = new Map<string, number>();
  for (const row of watchedEpisodes) {
    const entry = entryByTitle.get(row.titleId);
    if (!entry || entry.currentRun !== row.run) continue;
    seenByTitle.set(row.titleId, row._count._all);
  }

  const built: UniverseEntry[] = universe.items.map((item) => {
    const title = item.title;
    const isSeries = title.type === "SERIES";
    const runtimeInfo = runtimeByTitle.get(title.id);

    const totalEpisodes = isSeries ? (runtimeInfo?.episodes ?? title.episodeCount) : 1;
    const totalMinutes = isSeries
      ? (runtimeInfo?.minutes ?? (title.runtime ?? 0) * title.episodeCount)
      : (title.runtime ?? 0);

    const entry = entryByTitle.get(title.id);
    const watchedEpisodeCount = isSeries
      ? Math.min(seenByTitle.get(title.id) ?? 0, totalEpisodes)
      : entry?.status === "COMPLETED"
        ? 1
        : 0;

    const completed =
      entry?.status === "COMPLETED" ||
      (totalEpisodes > 0 && watchedEpisodeCount >= totalEpisodes);

    // Verbleibende Zeit: bei Serien anteilig über die offenen Episoden,
    // bei Filmen alles oder nichts.
    const remainingMinutes = completed
      ? 0
      : isSeries && totalEpisodes > 0
        ? Math.round((totalMinutes * (totalEpisodes - watchedEpisodeCount)) / totalEpisodes)
        : totalMinutes;

    return {
      itemId: item.id,
      titleId: title.id,
      title: title.title,
      type: title.type,
      posterPath: title.posterPath,
      year: title.releaseDate?.getFullYear() ?? null,
      note: item.note,
      totalMinutes,
      remainingMinutes,
      watchedMinutes: minutesByTitle.get(title.id) ?? 0,
      inLibrary: Boolean(entry),
      completed,
      status: entry?.status ?? null,
      watchedEpisodes: watchedEpisodeCount,
      totalEpisodes,
    };
  });

  // Sortieren: Erscheinungsreihenfolge rechnerisch, sonst nach den Positionen.
  const positionByItem = new Map<string, number>();
  for (const item of universe.items) {
    const position = item.positions.find((row) => row.orderId === activeOrder.id);
    if (position) positionByItem.set(item.id, position.position);
  }

  const releaseYear = new Map(
    universe.items.map((item) => [item.id, item.title.releaseDate?.getTime() ?? Number.MAX_SAFE_INTEGER]),
  );

  const sorted = [...built].sort((a, b) => {
    if (activeOrder.kind === "RELEASE") {
      const diff = (releaseYear.get(a.itemId) ?? 0) - (releaseYear.get(b.itemId) ?? 0);
      return diff !== 0 ? diff : a.title.localeCompare(b.title, "de");
    }
    const positionA = positionByItem.get(a.itemId) ?? Number.MAX_SAFE_INTEGER;
    const positionB = positionByItem.get(b.itemId) ?? Number.MAX_SAFE_INTEGER;
    return positionA !== positionB
      ? positionA - positionB
      : a.title.localeCompare(b.title, "de");
  });

  const completed = sorted.filter((entry) => entry.completed).length;
  const watchedMinutes = sorted.reduce((sum, entry) => sum + entry.watchedMinutes, 0);
  const remainingMinutes = sorted.reduce((sum, entry) => sum + entry.remainingMinutes, 0);
  const totalMinutes = sorted.reduce((sum, entry) => sum + entry.totalMinutes, 0);

  return {
    id: universe.id,
    name: universe.name,
    description: universe.description,
    isOwner: access.isOwner,
    canWrite: access.canWrite,
    ownerName: universe.owner.name,
    orders: universe.orders.map((order) => ({
      id: order.id,
      name: order.name,
      kind: order.kind,
      isDefault: order.isDefault,
    })),
    activeOrderId: activeOrder.id,
    entries: sorted,
    progress: {
      completed,
      total: sorted.length,
      percent: sorted.length > 0 ? Math.round((completed / sorted.length) * 100) : 0,
      watchedMinutes,
      remainingMinutes,
      totalMinutes,
    },
    nextUp: sorted.find((entry) => !entry.completed) ?? null,
    members: universe.members.map((member) => ({
      id: member.id,
      name: member.user.name,
      email: member.user.email,
      permission: member.permission,
    })),
  };
}

export type UniverseSummary = {
  id: string;
  name: string;
  description: string | null;
  isOwner: boolean;
  ownerName: string;
  itemCount: number;
  completed: number;
  percent: number;
  posters: string[];
};

/** Eigene und mit einem geteilte Universen. */
export async function listUniverses(userId: string): Promise<UniverseSummary[]> {
  const universes = await prisma.universe.findMany({
    where: {
      deletedAt: null,
      OR: [{ ownerId: userId }, { members: { some: { userId } } }],
    },
    orderBy: { updatedAt: "desc" },
    include: {
      owner: { select: { name: true } },
      items: {
        include: {
          title: { select: { id: true, posterPath: true, releaseDate: true, type: true } },
        },
        orderBy: { title: { releaseDate: "asc" } },
      },
    },
  });

  if (universes.length === 0) return [];

  const allTitleIds = universes.flatMap((universe) => universe.items.map((item) => item.titleId));
  const completedEntries = await prisma.libraryEntry.findMany({
    where: { userId, titleId: { in: allTitleIds }, status: "COMPLETED", deletedAt: null },
    select: { titleId: true },
  });
  const completedTitles = new Set(completedEntries.map((entry) => entry.titleId));

  return universes.map((universe) => {
    const completed = universe.items.filter((item) => completedTitles.has(item.titleId)).length;
    return {
      id: universe.id,
      name: universe.name,
      description: universe.description,
      isOwner: universe.ownerId === userId,
      ownerName: universe.owner.name,
      itemCount: universe.items.length,
      completed,
      percent: universe.items.length > 0 ? Math.round((completed / universe.items.length) * 100) : 0,
      posters: universe.items
        .map((item) => item.title.posterPath)
        .filter((path): path is string => Boolean(path))
        .slice(0, 5),
    };
  });
}

/** TMDB-Collections, die in der Bibliothek des Nutzers vorkommen. */
export async function suggestCollections(userId: string) {
  const rows = await prisma.title.findMany({
    where: {
      tmdbCollectionId: { not: null },
      entries: { some: { userId, deletedAt: null } },
    },
    select: { tmdbCollectionId: true, tmdbCollectionName: true },
    distinct: ["tmdbCollectionId"],
    orderBy: { tmdbCollectionName: "asc" },
  });

  return rows
    .filter((row) => row.tmdbCollectionId && row.tmdbCollectionName)
    .map((row) => ({ id: row.tmdbCollectionId!, name: row.tmdbCollectionName! }));
}