import { OWNER_USER_ID } from 'officerdb';
import {
  getActivePhotosCredentials,
  linkPhotosAccount,
  listPhotosAccountLinks,
  setPhotosAccountKey,
} from '../db/queries';
import { establishKey, provision, type ProvisionOutcome } from './provision';
import { getProvisionableUsers, hasProvisionableUsers } from './user-list';
import { invalidateConfig, normalizeBase, type UpstreamTarget } from './upstream';

// The one place that turns "an admin just connected" into Immich accounts and stored keys.
//
// Sits between `addAccount` and `provision()` so neither has to know about the other: `provision` talks to
// Immich and returns what it did, this writes it down, and the caller only has to say when.
//
// ── Why it never throws ──
//
// A failure here must not fail the connection. Registering the instance is the thing the owner asked for
// and it has already succeeded by the time this runs — losing it because provisioning went wrong would
// leave them with no library AND no accounts, which is strictly worse than the accounts alone.
//
// ── Temporary passwords come back to the caller ──
//
// `handover` is the half that has to reach a person. It is returned, never logged, and never stored: see
// the header of provision.ts for why Immich gets a hand-over password where Jellyfin gets none.

export type Handover = { userId: number; email: string; temporaryPassword: string };

export type ProvisioningReport =
  | { ran: false; reason: string }
  | {
      ran: true;
      linked: number;
      created: number;
      untouched: number;
      failed: { email: string; error: string }[];
      log: string[];
      /** One entry per person who now has a key. Carries a live credential — do not log it. */
      handover: Handover[];
      /**
       * Linked, but deliberately left without a key: an account that pre-dated Officer, found by a run
       * that was not allowed to touch its password. They reach Photos once somebody runs the deliberate
       * provision. Named rather than counted, because the owner has to know WHO to go and do.
       */
      pending: string[];
    };

/**
 * Record one person's pairing and give them a key.
 *
 * Written one at a time rather than in a batch: a key minted upstream whose row fails to write is the bad
 * case, because it leaves an Immich API key nothing in Officer knows about. Recording each as soon as it is
 * known keeps that window as small as it can be.
 */
async function linkAndKey(params: {
  cfg: UpstreamTarget;
  configId: number;
  userId: number;
  immichUserId: string;
  email: string;
  adopted: boolean;
}): Promise<Handover> {
  const { cfg, configId, userId, immichUserId, email, adopted } = params;

  await linkPhotosAccount({ userId, configId, immichUserId, immichEmail: email, adopted });
  const { apiKey, temporaryPassword } = await establishKey(cfg, { immichUserId, email });
  await setPhotosAccountKey({ userId, configId, apiKey });
  // Their cached config says "nothing configured" and would hold that for up to a minute.
  invalidateConfig(userId);

  return { userId, email, temporaryPassword };
}

/**
 * `keyAdopted` decides what happens to an account that existed before Officer did.
 *
 * Keying one means resetting its password, because that is the only way Immich will issue a key. For an
 * account Officer just created that costs nothing — nobody has ever held that password. For an adopted one
 * it takes away a login somebody is using, most likely in Immich's own app, and hands back a replacement
 * that only reaches them if the owner passes it on.
 *
 * So it is TRUE when a person asked for it (the `/provision` route) and FALSE when the trigger was a
 * background event (a new account appearing). An automatic action must not reset a password nobody
 * knew was at stake; the adopted account is linked and named in `pending` instead.
 */
export async function runProvisioning(params: {
  cfg: UpstreamTarget;
  configId: number;
  keyAdopted: boolean;
}): Promise<ProvisioningReport> {
  const { cfg, configId, keyAdopted } = params;

  // Never told, versus told there is nobody. The first means the push has not arrived or this plugin is
  // not entitled to it; the second is a server with only an owner.
  if (!hasProvisionableUsers()) {
    return { ran: false, reason: 'the platform has not sent the account list yet' };
  }

  const users = getProvisionableUsers();
  if (users.length === 0) return { ran: false, reason: 'no accounts to provision — this server has only an owner' };

  try {
    const existing = await listPhotosAccountLinks(configId);
    const outcome: ProvisionOutcome = await provision({
      cfg,
      users,
      existing: existing.map((e) => ({ userId: e.userId, immichUserId: e.immichUserId })),
    });

    const handover: Handover[] = [];
    const pending: string[] = [];
    const failed = [...outcome.failed];

    // Created accounts always get a key: their password was set moments ago by this process and has never
    // been anybody's, so spending it costs nothing.
    for (const entry of outcome.created) {
      try {
        handover.push(await linkAndKey({ cfg, configId, adopted: false, ...entry }));
      } catch (error) {
        failed.push({ email: entry.email, error: error instanceof Error ? error.message : String(error) });
      }
    }

    // Adopted ones are recorded either way — the pairing is a fact and costs nothing to write. Whether they
    // also get a key is the caller's decision, for the reason on `keyAdopted` above.
    for (const entry of outcome.linked) {
      try {
        if (keyAdopted) {
          handover.push(await linkAndKey({ cfg, configId, adopted: true, ...entry }));
        } else {
          await linkPhotosAccount({
            userId: entry.userId,
            configId,
            immichUserId: entry.immichUserId,
            immichEmail: entry.email,
            adopted: true,
          });
          pending.push(entry.email);
        }
      } catch (error) {
        failed.push({ email: entry.email, error: error instanceof Error ? error.message : String(error) });
      }
    }

    for (const line of outcome.log) console.log(`[photos:provision] ${line}`);
    for (const email of pending) {
      console.log(`[photos:provision] ${email} is linked but has no key — it had an Immich account already.`);
      console.log(`[photos:provision]   run POST /_config/${configId}/provision to give them one.`);
    }
    for (const f of failed) console.error(`[photos:provision] ${f.email}: ${f.error}`);

    return {
      ran: true,
      linked: outcome.linked.length,
      created: outcome.created.length,
      untouched: outcome.untouched.length,
      failed,
      log: outcome.log,
      handover,
      pending,
    };
  } catch (error) {
    const reason = error instanceof Error ? error.message : String(error);
    console.error('[photos:provision] failed:', reason);
    return { ran: false, reason };
  }
}

/**
 * Provision because the ACCOUNT LIST changed, rather than because somebody asked.
 *
 * This is what makes an Officer account created next month reach Photos without anyone remembering that a
 * plugin needed telling. `users:list` arrives on every create and delete — and on every sidecar
 * registration, so a restart is also a reconciliation.
 *
 * Three properties it has to have, because nobody is watching it run:
 *
 *   - **Idempotent.** The plan shrinks as links are recorded, so the common case does no upstream writes
 *     at all and the run costs two GETs.
 *   - **Never destructive.** `keyAdopted: false` — see `runProvisioning`. An account that pre-dated
 *     Officer keeps its password; the owner is told it is waiting.
 *   - **Quiet about the outcome, not about the plan.** `runProvisioning` logs its plan either way, so a
 *     restart prints a few lines describing the world as this plugin sees it. Only the "something
 *     changed" summary below is suppressed when nothing did, which is what stops a run that mattered from
 *     reading like the dozen that did not.
 *
 * Never throws. It runs detached from the command handler, and a plugin failing to provision must not take
 * down the socket carrying the message.
 */
export async function provisionForAccountChange(): Promise<void> {
  try {
    // The instance members inherit is the owner's selected one. A member who registered an Immich of their
    // own is not a provisioning target — that is their connection, not a shared library.
    const creds = await getActivePhotosCredentials(OWNER_USER_ID);
    if (!creds) return; // nothing connected yet; connecting is itself a provisioning trigger

    const report = await runProvisioning({
      cfg: { base: normalizeBase(creds.url), key: creds.apiKey },
      configId: creds.id,
      keyAdopted: false,
    });

    if (!report.ran) {
      console.log(`[photos:provision] not run — ${report.reason}`);
      return;
    }
    if (report.created === 0 && report.linked === 0 && report.failed.length === 0) return; // nothing changed

    console.log(
      `[photos:provision] account list changed: ${report.created} created, ${report.linked} linked, ` +
        `${report.pending.length} awaiting a key`,
    );
  } catch (error) {
    console.error('[photos:provision] automatic run failed:', error instanceof Error ? error.message : error);
  }
}

export type BackfillReport = {
  minted: Handover[];
  /** Already had a key. Reported rather than silent, so a re-run visibly does nothing. */
  alreadyKeyed: string[];
  failed: { email: string; error: string }[];
};

/**
 * Give a key to every linked account that has none.
 *
 * The repair path, for rows recorded before the key column existed or whose minting failed. Cheap when
 * there is nothing to do: an account that already has a key costs no upstream call, so this is safe to run
 * on every re-provision.
 *
 * Unlike the Jellyfin equivalent there is no `includeAdopted` switch, and the difference is the
 * must-change-password flag. There, minting for an adopted account destroys the person's own access,
 * because the new password is discarded and Jellyfin cannot demand a change. Here they get the password
 * back and are made to replace it, so an adopted account ends the run with MORE access than it started —
 * their library, through Officer, plus their own app once they sign in. There is nothing to opt into.
 */
export async function backfillAccountKeys(params: {
  cfg: UpstreamTarget;
  configId: number;
}): Promise<BackfillReport> {
  const { cfg, configId } = params;
  const report: BackfillReport = { minted: [], alreadyKeyed: [], failed: [] };

  for (const account of await listPhotosAccountLinks(configId)) {
    if (account.hasKey) {
      report.alreadyKeyed.push(account.immichEmail);
      continue;
    }
    try {
      const { apiKey, temporaryPassword } = await establishKey(cfg, {
        immichUserId: account.immichUserId,
        email: account.immichEmail,
      });
      await setPhotosAccountKey({ userId: account.userId, configId, apiKey });
      invalidateConfig(account.userId);
      report.minted.push({ userId: account.userId, email: account.immichEmail, temporaryPassword });
      console.log(`[photos:provision] minted a key for ${account.immichEmail}`);
    } catch (error) {
      const message = error instanceof Error ? error.message : String(error);
      report.failed.push({ email: account.immichEmail, error: message });
      console.error(`[photos:provision] ${account.immichEmail}: ${message}`);
    }
  }

  return report;
}