// Must stay first: see setup.ts.
import { TEST_DIR } from "./setup.ts";

import { stub } from "@std/testing/mock";
import { app } from "../main.ts";
import { db } from "../db/connection.ts";
import {
  createJWT,
  createMediaToken,
  generateInstanceKey,
  importInstanceKey,
  signInstanceToken,
} from "../lib/jwt.ts";
import { hashPassword } from "../lib/password.ts";
import { uniqueSlug } from "../lib/slugify.ts";
import { slugify } from "../../shared/slug.ts";
import { dumpPath, playlistPath } from "../../shared/paths.ts";
import { canonicalizeUrl } from "../lib/canonical-url.ts";
import { clearRichContentCache } from "../services/rich-content-service.ts";
import { clearImageCache } from "../remote/image-proxy.ts";
import { clearInstanceCaches } from "../remote/gerbeur-instance.ts";
import { FEDERATION } from "../config.ts";
import {
  type OutgoingEmail,
  setEmailTransport,
} from "../services/email-service.ts";
import type { APIError, APIResponse } from "../../shared/api.ts";
import type { Role } from "../../shared/user.ts";

export { app, db, TEST_DIR };

// ── Database ─────────────────────────────────────────────────────────────────

const TABLES = [
  "user_identities",
  "federation_peers",
  "federation_logins",
  "oauth_codes",
  "federation_grants",
  "federation_outbox",
  "dump_backlinks",
  "dump_categories",
  "playlist_dumps",
  "comment_likes",
  "comments",
  "votes",
  "follows",
  "notifications",
  "password_reset_tokens",
  "invites",
  "attachments",
  "chat_messages",
  "user_settings",
  "digest_schedule",
  "dump_slug_aliases",
  "playlist_slug_aliases",
  "user_aliases",
  "categories",
  "playlists",
  "dumps",
  "users",
];

/** Empties every table, the default admin included. */
export function resetDb(): void {
  db.exec("PRAGMA foreign_keys = OFF;");
  for (const table of TABLES) db.exec(`DELETE FROM ${table};`);
  db.exec("PRAGMA foreign_keys = ON;");
}

/**
 * Wraps a test body so it starts from an empty database. Usernames and emails
 * still have to be unique across the whole run where the rate limiter keys on
 * them (login, password reset), since its buckets live for the process.
 */
export function test(
  name: string,
  fn: (t: Deno.TestContext) => void | Promise<void>,
  options: Omit<Deno.TestDefinition, "name" | "fn"> = {},
): void {
  Deno.test({
    name,
    ...options,
    async fn(t) {
      resetDb();
      await fn(t);
    },
  });
}

// ── Users ────────────────────────────────────────────────────────────────────

export const PASSWORD = "correct-horse";
// scrypt is deliberately slow; hash the shared password once.
let passwordHash: Promise<string> | undefined;

let seq = 0;
/** A name no other test in this process has used. */
export function uniqueName(prefix = "user"): string {
  return `${prefix}_${++seq}_${crypto.randomUUID().slice(0, 6)}`;
}

export interface TestUser {
  id: string;
  username: string;
  email: string;
  role: Role;
  token: string;
  mediaToken: string;
  /** Authorization header for this user. */
  auth: { Authorization: string };
}

export async function createUser(
  opts: {
    username?: string;
    role?: Role;
    email?: string;
    invitedBy?: string;
    createdAt?: string;
  } = {},
): Promise<TestUser> {
  const id = crypto.randomUUID();
  const username = opts.username ?? uniqueName();
  const email = opts.email ?? `${username}@example.test`;
  const role = opts.role ?? "user";
  passwordHash ??= hashPassword(PASSWORD);
  db.prepare(
    `INSERT INTO users (id, username, password_hash, role, created_at, email, invited_by)
     VALUES (?, ?, ?, ?, ?, ?, ?);`,
  ).run(
    id,
    username,
    await passwordHash,
    role,
    opts.createdAt ?? new Date().toISOString(),
    email,
    opts.invitedBy ?? null,
  );
  const token = await createJWT({ userId: id, username, role });
  return {
    id,
    username,
    email,
    role,
    token,
    mediaToken: await createMediaToken(id),
    auth: { Authorization: `Bearer ${token}` },
  };
}

// ── Content ──────────────────────────────────────────────────────────────────

export interface InsertDumpOptions {
  userId: string;
  title?: string;
  kind?: "url" | "file";
  url?: string;
  comment?: string;
  isPrivate?: boolean;
  createdAt?: string;
  fileName?: string;
  fileMime?: string;
  /** Bytes written to the uploads directory for a file dump. */
  fileData?: Uint8Array;
  richContent?: Record<string, unknown>;
}

/** Returns the name of user `userId`, for the page paths of their things. */
function usernameOf(userId: string): string {
  return (db.prepare(`SELECT username FROM users WHERE id = ?;`).get(
    userId,
  ) as { username: string }).username;
}

/**
 * Inserts a dump row directly, skipping the metadata fetch the create route
 * does, with a slug made from its title as the service would. Returns its id,
 * slug and page path.
 */
export function insertDump(
  opts: InsertDumpOptions,
): { id: string; slug: string; path: string } {
  const id = crypto.randomUUID();
  const title = opts.title ?? "A dump";
  const slug = uniqueSlug(db, "dump", opts.userId, slugify(title));
  const kind = opts.kind ?? (opts.fileName ? "file" : "url");
  const url = kind === "url" ? (opts.url ?? `https://example.com/${id}`) : null;
  const data = opts.fileData ?? new TextEncoder().encode("hello");
  db.prepare(
    `INSERT INTO dumps (id, kind, title, slug, comment, user_id, created_at, url, url_canonical,
       rich_content, file_name, file_mime, file_size, is_private)
     VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?);`,
  ).run(
    id,
    kind,
    title,
    slug,
    opts.comment ?? null,
    opts.userId,
    opts.createdAt ?? new Date().toISOString(),
    url,
    url ? canonicalizeUrl(url) : null,
    opts.richContent ? JSON.stringify(opts.richContent) : null,
    kind === "file" ? (opts.fileName ?? "file.txt") : null,
    kind === "file" ? (opts.fileMime ?? "text/plain") : null,
    kind === "file" ? data.byteLength : null,
    opts.isPrivate ? 1 : 0,
  );
  if (kind === "file") {
    Deno.mkdirSync(`${TEST_DIR}/uploads/dumps`, { recursive: true });
    Deno.writeFileSync(`${TEST_DIR}/uploads/dumps/${id}`, data);
  }
  return {
    id,
    slug,
    path: dumpPath({ ownerUsername: usernameOf(opts.userId), slug }),
  };
}

/** Inserts a playlist row as {@link insertDump} does a dump. */
export function insertPlaylist(
  opts: { userId: string; title?: string; isPublic?: boolean },
): { id: string; slug: string; path: string } {
  const id = crypto.randomUUID();
  const title = opts.title ?? "A playlist";
  const slug = uniqueSlug(db, "playlist", opts.userId, slugify(title));
  db.prepare(
    `INSERT INTO playlists (id, user_id, title, slug, is_public, created_at)
     VALUES (?, ?, ?, ?, ?, ?);`,
  ).run(
    id,
    opts.userId,
    title,
    slug,
    opts.isPublic === false ? 0 : 1,
    new Date().toISOString(),
  );
  return {
    id,
    slug,
    path: playlistPath({ ownerUsername: usernameOf(opts.userId), slug }),
  };
}

export function insertComment(
  opts: {
    dumpId: string;
    userId: string;
    body?: string;
    parentId?: string;
    createdAt?: string;
  },
): string {
  const id = crypto.randomUUID();
  db.prepare(
    `INSERT INTO comments (id, dump_id, user_id, parent_id, body, created_at)
     VALUES (?, ?, ?, ?, ?, ?);`,
  ).run(
    id,
    opts.dumpId,
    opts.userId,
    opts.parentId ?? null,
    opts.body ?? "A comment",
    opts.createdAt ?? new Date().toISOString(),
  );
  return id;
}

export function insertCategory(
  opts: { slug: string; name?: string; position?: number },
): string {
  const id = crypto.randomUUID();
  db.prepare(
    `INSERT INTO categories (id, slug, name, position, created_at) VALUES (?, ?, ?, ?, ?);`,
  ).run(
    id,
    opts.slug,
    opts.name ?? opts.slug,
    opts.position ?? 0,
    new Date().toISOString(),
  );
  return id;
}

export function count(sql: string, ...params: (string | number)[]): number {
  return (db.prepare(sql).get(...params) as { n: number }).n;
}

// ── HTTP ─────────────────────────────────────────────────────────────────────

export const BASE_URL = "http://gerbeur.test";

export interface ApiResponse<T = unknown> {
  status: number;
  headers: Headers;
  /** The parsed body when it's JSON, null otherwise. */
  body: APIResponse<T> | null;
  bytes: Uint8Array;
  /** The body's `data`; throws if the request didn't succeed. */
  readonly data: T;
  /** The body's `error`; throws if the request didn't fail. */
  readonly error: APIError;
}

type RequestOptions = {
  auth?: { Authorization: string };
  json?: unknown;
  form?: FormData;
  headers?: Record<string, string>;
};

/**
 * Sends a request through the full middleware stack in-process — no socket.
 * `json` sends a JSON body, `form` a multipart one. `T` is what the endpoint
 * answers with in `data`.
 */
export async function request<T = unknown>(
  method: string,
  path: string,
  opts: RequestOptions = {},
): Promise<ApiResponse<T>> {
  const headers = new Headers({ ...opts.auth, ...opts.headers });
  let body: BodyInit | undefined;
  if (opts.json !== undefined) {
    headers.set("Content-Type", "application/json");
    body = JSON.stringify(opts.json);
  } else if (opts.form) {
    body = opts.form;
  }
  const res = await app.handle(
    new Request(`${BASE_URL}${path}`, { method, headers, body }),
  );
  if (!res) throw new Error(`No response for ${method} ${path}`);
  const bytes = new Uint8Array(await res.arrayBuffer());
  const text = new TextDecoder().decode(bytes);
  let parsed: APIResponse<T> | null = null;
  if ((res.headers.get("content-type") ?? "").includes("json") && text) {
    parsed = JSON.parse(text);
  }
  const what = `${method} ${path} (${res.status})`;
  return {
    status: res.status,
    headers: res.headers,
    body: parsed,
    bytes,
    get data() {
      if (!parsed?.success) {
        throw new Error(`${what} failed: ${parsed?.error.message ?? text}`);
      }
      return parsed.data;
    },
    get error() {
      if (parsed?.success !== false) {
        throw new Error(`${what} didn't fail`);
      }
      return parsed.error;
    },
  };
}

export const get = <T = unknown>(path: string, opts?: RequestOptions) =>
  request<T>("GET", path, opts);
export const post = <T = unknown>(path: string, opts?: RequestOptions) =>
  request<T>("POST", path, opts);
export const put = <T = unknown>(path: string, opts?: RequestOptions) =>
  request<T>("PUT", path, opts);
export const patch = <T = unknown>(path: string, opts?: RequestOptions) =>
  request<T>("PATCH", path, opts);
export const del = <T = unknown>(path: string, opts?: RequestOptions) =>
  request<T>("DELETE", path, opts);

// ── Files ────────────────────────────────────────────────────────────────────

/** Smallest valid PNG: a 1×1 transparent pixel. */
export const PNG: Uint8Array<ArrayBuffer> = Uint8Array.from(
  atob(
    "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNkYPhfDwAChwGA60e6kgAAAABJRU5ErkJggg==",
  ),
  (c) => c.charCodeAt(0),
);

export function formWithFile(
  bytes: Uint8Array<ArrayBuffer>,
  name = "file.png",
  type = "image/png",
  fields: Record<string, string> = {},
): FormData {
  const form = new FormData();
  form.set("file", new File([bytes], name, { type }));
  for (const [key, value] of Object.entries(fields)) form.set(key, value);
  return form;
}

// ── Network ──────────────────────────────────────────────────────────────────

/**
 * Replaces outbound fetches and DNS for the life of the returned handle
 * (`using net = stubNetwork(...)`). Every hostname resolves to a public
 * address unless `dns` says otherwise; `handler` answers every fetch.
 */
export function stubNetwork(
  handler: (url: URL, init?: RequestInit) => Response | Promise<Response>,
  dns: Record<string, string[]> = {},
): { calls: URL[] } & Disposable {
  const calls: URL[] = [];
  // A new network: metadata cached from the last one no longer describes it.
  clearRichContentCache();
  clearImageCache();
  clearInstanceCaches();
  const fetchStub = stub(
    globalThis,
    "fetch",
    (input: string | URL | Request, init?: RequestInit) => {
      const url = new URL(input instanceof Request ? input.url : input);
      calls.push(url);
      return Promise.resolve(handler(url, init));
    },
  );
  const dnsStub = stub(
    Deno,
    "resolveDns",
    ((host: string, type: string) =>
      Promise.resolve(
        dns[host] ?? (type === "A" ? ["93.184.216.34"] : []),
      )) as typeof Deno.resolveDns,
  );
  return {
    calls,
    [Symbol.dispose]() {
      fetchStub.restore();
      dnsStub.restore();
    },
  };
}

// ── Federation ───────────────────────────────────────────────────────────────

/** A user of a {@link FakeInstance}, as its identity tokens describe them. */
export interface FakeIdentity {
  sub: string;
  preferred_username: string;
  email: string;
  picture?: string;
}

/**
 * Another gerbeur instance at `origin`, answering through {@link stubNetwork}
 * (`stubNetwork((url, init) => fake.handle(url, init) ?? ...)`): its metadata,
 * its keys, a token endpoint that trades the codes the test `issue`s, an
 * events endpoint recording what it receives, and avatars.
 */
export interface FakeInstance {
  origin: string;
  /**
   * Makes a code for `identity`, answering the authorize URL `authorizeUrl`
   * (this instance's request) as the home would after consent.
   */
  issue(authorizeUrl: string, identity: FakeIdentity): string;
  /** Signs an event about `sub` for this instance, as its outbox would. */
  event(sub: string, payload: Record<string, unknown>): Promise<string>;
  /** The events posted to it, as their JWTs. */
  received: string[];
  /** Answers a request to it, or null when `url` isn't on it. */
  handle(url: URL, init?: RequestInit): Promise<Response> | null;
}

/**
 * Makes a {@link FakeInstance} at `origin` with a fresh key, its metadata
 * with `metadata` over the defaults.
 */
export async function fakeInstance(
  origin: string,
  metadata: Record<string, unknown> = {},
): Promise<FakeInstance> {
  const { kid, privateJwk, publicJwk } = await generateInstanceKey();
  const key = await importInstanceKey(kid, privateJwk);
  const codes = new Map<
    string,
    { identity: FakeIdentity; nonce: string; challenge: string; client: string }
  >();
  const received: string[] = [];
  const json = (body: unknown, status = 200) =>
    new Response(JSON.stringify(body), {
      status,
      headers: { "content-type": "application/json" },
    });
  const handle = async (url: URL, init?: RequestInit): Promise<Response> => {
    switch (url.pathname) {
      case "/.well-known/openid-configuration":
        return json({
          issuer: origin,
          authorization_endpoint: `${origin}/authorize`,
          token_endpoint: `${origin}/api/oauth/tokens`,
          jwks_uri: `${origin}/.well-known/jwks.json`,
          response_types_supported: ["code"],
          grant_types_supported: ["authorization_code"],
          subject_types_supported: ["public"],
          id_token_signing_alg_values_supported: ["EdDSA"],
          code_challenge_methods_supported: ["S256"],
          scopes_supported: ["openid", "profile", "email"],
          gerbeur_federation: 1,
          gerbeur_site_name: `Fake ${new URL(origin).host}`,
          gerbeur_redirect_uri: `${origin}/federation/callback`,
          gerbeur_events_endpoint: `${origin}/api/federation/events`,
          ...metadata,
        });
      case "/.well-known/jwks.json":
        return json({ keys: [publicJwk] });
      case "/api/oauth/tokens": {
        const form = new URLSearchParams(String(init?.body));
        const entry = codes.get(form.get("code") ?? "");
        codes.delete(form.get("code") ?? "");
        const verifier = form.get("code_verifier") ?? "";
        const hash = new Uint8Array(
          await crypto.subtle.digest(
            "SHA-256",
            new TextEncoder().encode(verifier),
          ),
        );
        const challenge = btoa(String.fromCharCode(...hash))
          .replace(/\+/g, "-").replace(/\//g, "_").replace(/=+$/, "");
        if (
          !entry || entry.challenge !== challenge ||
          entry.client !== form.get("client_id")
        ) {
          return json({ error: "invalid_grant" }, 400);
        }
        const { sub, ...claims } = entry.identity;
        return json({
          id_token: await signInstanceToken(
            { ...claims, nonce: entry.nonce },
            key,
            { issuer: origin, audience: entry.client, subject: sub },
            "5m",
          ),
        });
      }
      case "/api/federation/events":
        received.push(JSON.parse(String(init?.body)).event);
        return new Response(null, { status: 204 });
      default:
        if (url.pathname.endsWith("/avatar")) {
          return new Response(PNG, {
            headers: { "content-type": "image/png" },
          });
        }
        return json({ error: "not found" }, 404);
    }
  };
  return {
    origin,
    received,
    issue(authorizeUrl, identity) {
      const q = new URL(authorizeUrl).searchParams;
      const code = crypto.randomUUID();
      codes.set(code, {
        identity,
        nonce: q.get("nonce") ?? "",
        challenge: q.get("code_challenge") ?? "",
        client: q.get("client_id") ?? "",
      });
      return code;
    },
    event: (sub, payload) =>
      signInstanceToken(payload, key, {
        issuer: origin,
        audience: BASE_URL,
        subject: sub,
      }, "1h"),
    handle: (url, init) => url.origin === origin ? handle(url, init) : null,
  };
}

/**
 * Turns one way of federated sign-in off for the life of the returned handle
 * (`using _off = federationOff("incoming")`), as `GERBEUR_FEDERATION_*=0`
 * would for the server's life.
 */
export function federationOff(way: keyof typeof FEDERATION): Disposable {
  FEDERATION[way] = false;
  return {
    [Symbol.dispose]() {
      FEDERATION[way] = true;
    },
  };
}

// ── Email ────────────────────────────────────────────────────────────────────

/**
 * Turns email on for the life of the returned handle
 * (`using mail = captureEmails()`), recording each message instead of sending
 * it. Sends that aren't awaited by their route land on the next tick.
 */
export function captureEmails(): { sent: OutgoingEmail[] } & Disposable {
  const sent: OutgoingEmail[] = [];
  setEmailTransport({
    sendMail(message) {
      sent.push(message);
      return Promise.resolve();
    },
  });
  return {
    sent,
    [Symbol.dispose]() {
      setEmailTransport(null);
    },
  };
}

export function html(body: string, status = 200): Response {
  return new Response(body, {
    status,
    headers: { "content-type": "text/html; charset=utf-8" },
  });
}