// Managing catalogs (docs/products.md, docs/console.md): settings, keys, teams, members, invites, what they host,
// suspension, and the changes feed catalogs poll. Permission checks are the routes'; this is what they do.
import { createHash } from "node:crypto";
import { and, asc, count, desc, eq, gt, inArray, isNull, or, sql, schema, type Database } from "@t5de/db";
import { ProductError } from "./products";

const { catalog, catalogChange, catalogInvite, catalogMember, hosting, product, productRevision, roleAssignment, user } =
  schema;

export type Catalog = typeof catalog.$inferSelect;
export type MemberStatus = "requested" | "member" | "banned";

const sha256 = (s: string) => createHash("sha256").update(s).digest("hex");
const randomKey = () => Buffer.from(crypto.getRandomValues(new Uint8Array(24))).toString("base64url");
// Invite codes: 10 letters and digits without look-alikes.
const inviteCode = () => {
  const alphabet = "abcdefghjkmnpqrstuvwxyz23456789";
  return [...crypto.getRandomValues(new Uint8Array(10))].map((b) => alphabet[b % alphabet.length]).join("");
};

const plain = (s: unknown, max: number) => {
  const v = typeof s === "string" ? s.trim() : "";
  // eslint-disable-next-line no-control-regex
  if (!v || v.length > max || /[\u0000-\u001f\u007f]/.test(v)) return undefined;
  return v;
};

/** A catalog's address, checked and without a trailing slash (https, or localhost for development). */
export function catalogURL(input: string): string {
  let url: URL;
  try {
    url = new URL(input);
  } catch {
    throw new ProductError(400, "invalid", "That address isn't a URL.");
  }
  if (url.protocol !== "https:" && url.hostname !== "localhost" && url.hostname !== "127.0.0.1")
    throw new ProductError(400, "invalid", "Catalogs need an https address.");
  return url.origin + url.pathname.replace(/\/+$/, "");
}

export type CatalogSettings = {
  name?: string;
  url?: string;
  contact?: string;
  visibility?: "public" | "private";
  membership?: "open" | "approval" | "invite";
  maxRating?: "general" | "adult";
  uploads?: "anyone" | "members" | "team";
  mirrors?: "auto" | "approve" | "off";
};

export class Catalogs {
  constructor(
    private readonly db: Database,
    /** Whether a catalog answers at an address (its /health); checked when its address changes. */
    private readonly healthy: (url: string) => Promise<boolean> = defaultHealthy,
  ) {}

  async get(id: string): Promise<Catalog> {
    const [c] = await this.db.select().from(catalog).where(eq(catalog.id, id));
    if (!c) throw new ProductError(404, "not_found", "No such catalog.");
    return c;
  }

  /** Changes a catalog's settings; returns the catalog and the fields that changed (old and new values). */
  async update(id: string, input: CatalogSettings) {
    const c = await this.get(id);
    const set: Partial<Catalog> = {};
    if (input.name !== undefined) {
      const name = plain(input.name, 64);
      if (!name) throw new ProductError(400, "invalid", "Names are 1-64 characters.");
      set.name = name;
    }
    if (input.contact !== undefined) {
      const contact = plain(input.contact, 200);
      if (!contact) throw new ProductError(400, "invalid", "A takedown contact is needed.");
      set.contact = contact;
    }
    if (input.url !== undefined) {
      const url = catalogURL(input.url);
      if (url !== c.url) {
        const [taken] = await this.db.select({ id: catalog.id }).from(catalog).where(eq(catalog.url, url));
        if (taken) throw new ProductError(409, "taken", "A catalog at that address is already registered.");
        if (!(await this.healthy(url)))
          throw new ProductError(400, "unreachable", "Nothing answered at that address's /health. Is the catalog running there?");
        set.url = url;
      }
    }
    for (const k of ["visibility", "membership", "maxRating", "uploads", "mirrors"] as const)
      if (input[k] !== undefined) (set as Record<string, unknown>)[k] = input[k];
    const changed: Record<string, { from: unknown; to: unknown }> = {};
    for (const [k, v] of Object.entries(set)) {
      const before = (c as Record<string, unknown>)[k];
      if (before !== v) changed[k] = { from: before, to: v };
    }
    if (Object.keys(changed).length === 0) return { catalog: c, changed };
    const [updated] = await this.db.update(catalog).set(set).where(eq(catalog.id, id)).returning();
    return { catalog: updated!, changed };
  }

  /** A new key for the catalog; the old one stops working at once. */
  async rotateKey(id: string): Promise<string> {
    await this.get(id);
    const key = randomKey();
    await this.db.update(catalog).set({ keyHash: sha256(key) }).where(eq(catalog.id, id));
    return key;
  }

  /** Suspends or reinstates an approved catalog; tells it through its changes feed. */
  async setSuspended(id: string, suspended: boolean, reason: string) {
    const c = await this.get(id);
    if (suspended && c.status !== "approved")
      throw new ProductError(409, "not_approved", "Only an approved catalog can be suspended.");
    if (!suspended && c.status !== "suspended") throw new ProductError(409, "not_suspended", "That catalog isn't suspended.");
    const status = suspended ? "suspended" : "approved";
    const [updated] = await this.db
      .update(catalog)
      .set({ status, statusReason: suspended ? reason : "" })
      .where(eq(catalog.id, id))
      .returning();
    await this.change(id, { type: "status", status });
    return updated!;
  }

  // ---- teams ----

  async addRole(catalogId: string, personId: string, role: string, by: string) {
    const c = await this.get(catalogId);
    if (c.ownerId === personId) throw new ProductError(409, "owner", "That's the catalog's owner.");
    await this.db
      .insert(roleAssignment)
      .values({ userId: personId, role, scopeType: "catalog", scopeId: catalogId, grantedBy: by })
      .onConflictDoNothing();
  }

  async removeRole(catalogId: string, personId: string, role: string) {
    const gone = await this.db
      .delete(roleAssignment)
      .where(
        and(
          eq(roleAssignment.userId, personId),
          eq(roleAssignment.role, role),
          eq(roleAssignment.scopeType, "catalog"),
          eq(roleAssignment.scopeId, catalogId),
        ),
      )
      .returning();
    if (gone.length === 0) throw new ProductError(404, "not_found", "They don't have that role here.");
  }

  // ---- members ----

  async membership(catalogId: string, personId: string): Promise<MemberStatus | undefined> {
    const [m] = await this.db
      .select({ status: catalogMember.status })
      .from(catalogMember)
      .where(and(eq(catalogMember.catalogId, catalogId), eq(catalogMember.userId, personId)));
    return m?.status as MemberStatus | undefined;
  }

  /**
   * A person joins: an open catalog at once, an approval one as a request, an invite one only with an invite (which
   * also lets them into approval catalogs at once). Returns their status.
   */
  async join(catalogId: string, personId: string, invite?: string): Promise<MemberStatus> {
    const c = await this.get(catalogId);
    if (c.status !== "approved") throw new ProductError(404, "not_found", "No such catalog.");
    const now = await this.membership(catalogId, personId);
    if (now === "banned") throw new ProductError(403, "banned", "This catalog's team banned you from it.");
    if (now === "member") return "member";
    let status: MemberStatus;
    let usedInvite: string | null = null;
    if (invite) {
      const updated = await this.db
        .update(catalogInvite)
        .set({ uses: sql`${catalogInvite.uses} + 1` })
        .where(
          and(
            eq(catalogInvite.code, invite),
            eq(catalogInvite.catalogId, catalogId),
            isNull(catalogInvite.revokedAt),
            or(isNull(catalogInvite.expiresAt), gt(catalogInvite.expiresAt, new Date())),
            or(isNull(catalogInvite.maxUses), sql`${catalogInvite.uses} < ${catalogInvite.maxUses}`),
          ),
        )
        .returning();
      if (updated.length === 0) throw new ProductError(410, "invite_invalid", "That invitation is used up, expired or revoked.");
      status = "member";
      usedInvite = invite;
    } else if (c.membership === "open") status = "member";
    else if (c.membership === "approval") status = "requested";
    else throw new ProductError(403, "invite_only", "This catalog takes members by invitation only.");
    await this.db
      .insert(catalogMember)
      .values({ catalogId, userId: personId, status, invite: usedInvite })
      .onConflictDoUpdate({ target: [catalogMember.catalogId, catalogMember.userId], set: { status, invite: usedInvite } });
    return status;
  }

  /** A person leaves (or withdraws their request). A ban stays. */
  async leave(catalogId: string, personId: string) {
    await this.db
      .delete(catalogMember)
      .where(
        and(eq(catalogMember.catalogId, catalogId), eq(catalogMember.userId, personId), sql`${catalogMember.status} <> 'banned'`),
      );
  }

  async members(catalogId: string, status?: MemberStatus) {
    const conds = [eq(catalogMember.catalogId, catalogId)];
    if (status) conds.push(eq(catalogMember.status, status));
    const rows = await this.db
      .select({
        personId: catalogMember.userId,
        username: user.username,
        name: user.displayUsername,
        status: catalogMember.status,
        invite: catalogMember.invite,
        since: catalogMember.updatedAt,
      })
      .from(catalogMember)
      .innerJoin(user, eq(user.id, catalogMember.userId))
      .where(and(...conds))
      .orderBy(desc(catalogMember.updatedAt))
      .limit(500);
    return rows.map((r) => ({
      personId: r.personId,
      username: r.name ?? r.username ?? "",
      status: r.status as MemberStatus,
      invited: r.invite !== null,
      since: r.since.toISOString(),
    }));
  }

  async memberCounts(catalogId: string) {
    const rows = await this.db
      .select({ status: catalogMember.status, n: count() })
      .from(catalogMember)
      .where(eq(catalogMember.catalogId, catalogId))
      .groupBy(catalogMember.status);
    const get = (s: string) => rows.find((r) => r.status === s)?.n ?? 0;
    return { members: get("member"), requests: get("requested"), banned: get("banned") };
  }

  /** The team sets a person's membership: let them in, or ban them. */
  async setMember(catalogId: string, personId: string, status: "member" | "banned", by: string) {
    await this.get(catalogId);
    await this.db
      .insert(catalogMember)
      .values({ catalogId, userId: personId, status, decidedBy: by })
      .onConflictDoUpdate({ target: [catalogMember.catalogId, catalogMember.userId], set: { status, decidedBy: by } });
  }

  async removeMember(catalogId: string, personId: string) {
    const gone = await this.db
      .delete(catalogMember)
      .where(and(eq(catalogMember.catalogId, catalogId), eq(catalogMember.userId, personId)))
      .returning();
    if (gone.length === 0) throw new ProductError(404, "not_found", "They aren't a member, and haven't asked to be.");
  }

  // ---- invites ----

  async createInvite(catalogId: string, by: string, opts: { maxUses?: number; expiresInDays?: number }) {
    await this.get(catalogId);
    const [inv] = await this.db
      .insert(catalogInvite)
      .values({
        code: inviteCode(),
        catalogId,
        createdBy: by,
        maxUses: opts.maxUses ?? null,
        expiresAt: opts.expiresInDays ? new Date(Date.now() + opts.expiresInDays * 86_400_000) : null,
      })
      .returning();
    return inv!;
  }

  async invites(catalogId: string) {
    return this.db
      .select()
      .from(catalogInvite)
      .where(and(eq(catalogInvite.catalogId, catalogId), isNull(catalogInvite.revokedAt)))
      .orderBy(desc(catalogInvite.createdAt));
  }

  async revokeInvite(catalogId: string, code: string) {
    const r = await this.db
      .update(catalogInvite)
      .set({ revokedAt: new Date() })
      .where(and(eq(catalogInvite.catalogId, catalogId), eq(catalogInvite.code, code), isNull(catalogInvite.revokedAt)))
      .returning();
    if (r.length === 0) throw new ProductError(404, "not_found", "No such invitation.");
  }

  // ---- what it hosts ----

  /** The products a catalog hosts, newest first, with the revisions it hosts of each. */
  async hosted(catalogId: string) {
    const rows = await this.db
      .select({
        id: product.id,
        name: product.name,
        rating: product.rating,
        creator: user.displayUsername,
        creatorUsername: user.username,
        removed: product.removedAt,
        deleted: product.deletedAt,
        revisions: sql<number[]>`array_agg(${hosting.number} order by ${hosting.number})`,
        since: sql<string>`min(${hosting.createdAt})`,
      })
      .from(hosting)
      .innerJoin(product, eq(product.id, hosting.productId))
      .innerJoin(user, eq(user.id, product.creatorId))
      .where(eq(hosting.catalogId, catalogId))
      .groupBy(product.id, user.id)
      .orderBy(desc(sql`min(${hosting.createdAt})`))
      .limit(500);
    return rows.map((r) => ({
      id: r.id,
      name: r.name,
      rating: r.rating,
      creator: r.creator ?? r.creatorUsername ?? "",
      removed: r.removed !== null,
      deleted: r.deleted !== null,
      revisions: r.revisions,
      since: new Date(r.since).toISOString(),
    }));
  }

  async hostedCounts(catalogId: string) {
    const [r] = await this.db
      .select({
        products: sql<number>`count(distinct ${hosting.productId})::int`,
        revisions: sql<number>`count(*)::int`,
        bytes: sql<number>`coalesce(sum((select sum((f->>'size')::bigint) from jsonb_array_elements(${productRevision.files}) f)), 0)::bigint`,
      })
      .from(hosting)
      .innerJoin(
        productRevision,
        and(eq(productRevision.productId, hosting.productId), eq(productRevision.number, hosting.number)),
      )
      .where(eq(hosting.catalogId, catalogId));
    return { products: r?.products ?? 0, revisions: r?.revisions ?? 0, bytes: Number(r?.bytes ?? 0) };
  }

  /** The catalog stops hosting every revision of a product; its files go in the changes feed for deletion. */
  async delist(catalogId: string, productId: string) {
    const gone = await this.db
      .delete(hosting)
      .where(and(eq(hosting.catalogId, catalogId), eq(hosting.productId, productId)))
      .returning();
    if (gone.length === 0) throw new ProductError(404, "not_found", "This catalog doesn't host that product.");
    const revs = await this.db
      .select({ number: productRevision.number, files: productRevision.files })
      .from(productRevision)
      .where(and(eq(productRevision.productId, productId), inArray(productRevision.number, gone.map((g) => g.number))));
    for (const r of revs) await this.change(catalogId, { type: "delete", product: productId, revision: r.number, files: r.files });
    return gone.map((g) => g.number);
  }

  // ---- the changes feed ----

  async change(catalogId: string, data: Record<string, unknown>) {
    await this.db.insert(catalogChange).values({ catalogId, data });
  }

  /** Changes after a cursor, oldest first (at most 500 at a time). */
  async changes(catalogId: string, after: number) {
    const rows = await this.db
      .select()
      .from(catalogChange)
      .where(and(eq(catalogChange.catalogId, catalogId), gt(catalogChange.id, after)))
      .orderBy(asc(catalogChange.id))
      .limit(500);
    return { changes: rows.map((r) => r.data), cursor: rows.length ? rows[rows.length - 1]!.id : after };
  }
}

async function defaultHealthy(url: string): Promise<boolean> {
  try {
    const res = await fetch(`${url}/health`, { signal: AbortSignal.timeout(5000) });
    return res.ok;
  } catch {
    return false;
  }
}