import type { UpstreamTarget } from './upstream';
import {
  createPhotosAccount,
  deletePhotosAccount,
  getPhotosCredentials,
  listPhotosAccounts,
  recordPhotosProbe,
  setActivePhotosAccount,
  updatePhotosAccount,
} from 'officerdb';
import { UpstreamError, callUpstream, invalidateConfig, mintApiKey, normalizeBase } from './upstream';

// `/_config` — the Immich account registry, driven from the app rather than from a shell on the server.
//
// The API key is WRITE-ONLY across this boundary. The list reports each account's label, URL and whether it
// is selected; it has no field that could carry a key, masked or otherwise. The only way to change one is to
// send a new one, which is the same shape headscale's server registry uses.
//
// "A new one" has two forms: a key the owner pasted from Immich's own settings screen, or an email and
// password the sidecar trades for one (see mintApiKey). The password is used for that exchange and never
// stored — only the key it yields is.
//
// A save is validated before it is stored: an Immich key that is missing, wrong or under-scoped is a 400
// with the reason, not a saved row that makes every later screen fail mysteriously. That matters more here
// than usual — Immich keys are SCOPED, and a key created without the right permissions returns 403 on
// individual routes while looking perfectly valid on the ones it does cover.
//
// Adding, editing, switching and removing all invalidate the upstream cache. Forgetting one would leave the
// sidecar serving the previous account's photos for up to a minute, which reads as a caching bug in the grid
// rather than as what it is.

export type ProbeResult =
  | { ok: true; version: string | null; user: string | null }
  | { ok: false; version: string | null; error: string };

/**
 * Ask an instance whether it is really there and whether the key works.
 *
 * Two calls, because they answer different questions: `/server/version` is unauthenticated, so a failure
 * there means the URL is wrong or Immich is down, while `/users/me` failing after it succeeded means the
 * key is the problem. Collapsing them would report "instance unreachable" for a mistyped key.
 */
export async function probe(cfg: UpstreamTarget): Promise<ProbeResult> {
  let version: string | null = null;

  try {
    const versionRes = await callUpstream(cfg, { path: '/api/server/version', withKey: false });
    if (!versionRes.ok) return { ok: false, version: null, error: `instance returned ${versionRes.status}` };

    const v = (await versionRes.json()) as { major?: number; minor?: number; patch?: number };
    if ([v.major, v.minor, v.patch].every((n) => typeof n === 'number')) {
      version = `${v.major}.${v.minor}.${v.patch}`;
    }
  } catch (err) {
    return { ok: false, version: null, error: `could not reach the instance (${String(err)})` };
  }

  try {
    const meRes = await callUpstream(cfg, { path: '/api/users/me' });
    if (!meRes.ok) {
      const reason = meRes.status === 403 ? 'API key is under-scoped for this instance' : 'API key was rejected';
      return { ok: false, version, error: `${reason} (${meRes.status})` };
    }
    const me = (await meRes.json()) as { email?: string; name?: string };
    return { ok: true, version, user: me.email ?? me.name ?? null };
  } catch (err) {
    return { ok: false, version, error: String(err) };
  }
}

/** What the browser is allowed to know about the registry. Never includes a key. */
async function accountList(userId: number): Promise<Response> {
  const accounts = await listPhotosAccounts(userId);
  const active = accounts.find((account) => account.isActive) ?? null;
  return Response.json({ configured: !!active, activeId: active?.id ?? null, accounts });
}

/** Record that the instance answered, so the UI can tell "never connected" from "was working, now isn't". */
export async function noteProbe(userId: number, id: number, version: string | null): Promise<void> {
  await recordPhotosProbe(userId, id, version).catch(() => {
    /* a stale lastSeenAt is not worth failing a request over */
  });
}

const bad = (error: string, status = 400) => Response.json({ error }, { status });

type AccountBody = { label?: unknown; url?: unknown; apiKey?: unknown; email?: unknown; password?: unknown };

const readBody = async (req: Request): Promise<AccountBody> =>
  ((await req.json().catch(() => null)) as AccountBody | null) ?? {};

const readLabel = (body: AccountBody): string => (typeof body.label === 'string' ? body.label.trim() : '');
const readUrl = (body: AccountBody): string => (typeof body.url === 'string' ? normalizeBase(body.url) : '');
const readKey = (body: AccountBody): string => (typeof body.apiKey === 'string' ? body.apiKey.trim() : '');
const readEmail = (body: AccountBody): string => (typeof body.email === 'string' ? body.email.trim() : '');
const readPassword = (body: AccountBody): string => (typeof body.password === 'string' ? body.password : '');

const isHttpUrl = (url: string): boolean => /^https?:\/\//i.test(url);

/**
 * The key to store, however the owner chose to supply it.
 *
 * A pasted key wins; otherwise an email and password are traded for a fresh one and the password is discarded
 * with this function's stack frame. Returns '' when neither was given, which for an edit means "keep what is
 * stored" and for an add is an error.
 */
async function resolveKey(body: AccountBody, base: string): Promise<string> {
  const apiKey = readKey(body);
  if (apiKey) return apiKey;

  const email = readEmail(body);
  const password = readPassword(body);
  if (!email || !password) return '';

  return mintApiKey(base, email, password);
}

/** A refused sign-in already carries Immich's own words; anything else never reached Immich at all. */
const signInError = (err: unknown): string =>
  err instanceof UpstreamError ? err.message : `could not reach the instance (${String(err)})`;

const duplicateLabel = (err: unknown): boolean => String(err).includes('uq_photos_config_user_label');

/** Add an account: validated against the live instance, then stored encrypted. */
async function addAccount(req: Request, userId: number): Promise<Response> {
  const body = await readBody(req);
  const url = readUrl(body);
  let label = readLabel(body);

  if (!url) return bad('url is required');
  if (!isHttpUrl(url)) return bad('url must start with http:// or https://');

  let apiKey: string;
  try {
    apiKey = await resolveKey(body, url);
  } catch (err) {
    return bad(signInError(err));
  }
  if (!apiKey) return bad('an API key, or an email and password to mint one, is required');

  const result = await probe({ base: url, key: apiKey });
  if (!result.ok) return Response.json({ error: result.error, version: result.version }, { status: 400 });

  // An unlabelled account takes the name Immich itself knows it by, which is nearly always what the owner
  // would have typed. Falling back to the host keeps the switcher readable even for an anonymous key.
  if (!label) label = result.user ?? new URL(url).host;

  // The first account wins the selection: a registry with rows but nothing selected reads as "not connected".
  const existing = await listPhotosAccounts(userId);
  const activate = existing.length === 0;

  try {
    const account = await createPhotosAccount({ userId, label, url, apiKey, version: result.version, activate });
    invalidateConfig(userId);
    return Response.json({ account, user: result.user });
  } catch (err) {
    if (duplicateLabel(err)) return bad(`you already have an account called "${label}"`);
    throw err;
  }
}

/** Edit one account. A blank key means "keep the stored one", so a rename does not need the key re-typed. */
async function editAccount(req: Request, userId: number, id: number): Promise<Response> {
  const body = await readBody(req);
  const label = readLabel(body);
  const url = readUrl(body);

  const current = await getPhotosCredentials(userId, id);
  if (!current) return bad('no such account', 404);
  if (url && !isHttpUrl(url)) return bad('url must start with http:// or https://');

  let apiKey: string;
  try {
    apiKey = await resolveKey(body, url || current.url);
  } catch (err) {
    return bad(signInError(err));
  }

  // Re-validate whenever what we would talk to changes. A rename on its own never touches the instance.
  let version: string | null | undefined;
  if ((url && url !== current.url) || apiKey) {
    const result = await probe({ base: url || current.url, key: apiKey || current.apiKey });
    if (!result.ok) return Response.json({ error: result.error, version: result.version }, { status: 400 });
    version = result.version;
  }

  try {
    const account = await updatePhotosAccount(userId, id, {
      label: label || undefined,
      url: url || undefined,
      apiKey: apiKey || undefined,
      version,
    });
    if (!account) return bad('no such account', 404);
    invalidateConfig(userId);
    return Response.json({ account });
  } catch (err) {
    if (duplicateLabel(err)) return bad(`you already have an account called "${label}"`);
    throw err;
  }
}

/** `subpath` is '' for /_config, or '/<id>' / '/<id>/activate'. */
export async function handleConfigRoute(req: Request, userId: number, subpath: string): Promise<Response> {
  const [, rawId, action] = subpath.split('/');

  if (!rawId) {
    if (req.method === 'GET') return accountList(userId);
    if (req.method === 'POST' || req.method === 'PUT') return addAccount(req, userId);
    return bad('method not allowed', 405);
  }

  const id = Number(rawId);
  if (!Number.isInteger(id) || id <= 0) return bad('invalid account id', 404);

  if (action === 'activate') {
    if (req.method !== 'POST') return bad('method not allowed', 405);
    const account = await setActivePhotosAccount(userId, id);
    if (!account) return bad('no such account', 404);
    invalidateConfig(userId);
    return accountList(userId);
  }

  if (action) return bad('not found', 404);

  if (req.method === 'PATCH' || req.method === 'PUT') return editAccount(req, userId, id);

  if (req.method === 'DELETE') {
    const removed = await deletePhotosAccount(userId, id);
    if (!removed) return bad('no such account', 404);
    invalidateConfig(userId);
    return accountList(userId);
  }

  return bad('method not allowed', 405);
}