import 'dart:async';
import 'dart:io';

import 'package:halkyon_base_server/base.dart';
import 'package:halkyon_learn_server/src/auth/learn_base.dart';
import 'package:halkyon_learn_server/src/dictionary/device_dictionaries.dart';
import 'package:halkyon_learn_server/src/dictionary/dictionary_loader.dart';
import 'package:halkyon_learn_server/src/generated/serverpod.dart';
import 'package:halkyon_learn_server/src/grammar/grammar_checking.dart';
import 'package:halkyon_learn_server/src/instance/jellyfin_suggestion.dart';
import 'package:serverpod_auth_idp_server/core.dart';

/// The starting point of the Serverpod server.
Future<void> run(List<String> args) async {
  // Initialize Serverpod. The generated Serverpod class is already connected
  // with your project's generated code.
  final pod = Serverpod(args);
  // What every Halkyon server has (ADR 0014): sign-in, the account and its
  // deletion, the pruning, the instance's basics, set up for Learn.
  // Learn holds the instance's register of accounts (ADR 0016), telling the
  // instance's other services when one goes.
  HalkyonBase.configure(pod, learnBase(accounts: learnAccounts()));
  pod
    // Token managers validate and issue authentication keys; identity
    // providers are the ways people can sign in (halkyon_base's
    // auth_config.dart).
    ..initializeAuthServices(
      tokenManagerBuilders: tokenManagerBuilders,
      identityProviderBuilders: identityProviderBuilders(pod),
    )
    // Files live in Postgres until the self-hosted S3-compatible storage arrives later.
    ..addCloudStorage(DatabaseCloudStorage('private'))
    ..addCloudStorage(DatabaseCloudStorage('public'));

  // The calls of the instance's other services, on the web server
  // (ADR 0016); Caddy never forwards them.
  addInstanceRoutes(pod);
  // Where SimpleLogin sends a sign-in back, which forwards it to the app
  // (ADR 0020): the register's page, as its SimpleLogin app is.
  addSimpleLoginCallbackRoute(pod);
  // The instance's privacy page, `/privacy`, made from its settings (ADR
  // 0021, D39), before the profile pages' route, whose one segment would
  // take it.
  addPrivacyPageRoute(pod);
  // Profile pages, `/@handle`, which profile links link back to (ADR 0011),
  // halkyon_base's since profiles are the instance's register's (ADR 0016).
  addProfilePageRoute(pod);
  // What devices download to look Japanese up by themselves (ADR 0012).
  addDeviceDictionaryRoute(pod);

  // Start the server.
  await pod.start();

  // Whether a Jellyfin server answers where the instance would suggest one
  // (decided 2026-10-13), so instance.info() can name it from the first ask.
  unawaited(JellyfinSuggestion.of(pod).look());
  // Which languages the instance's LanguageTool checks (ADR 0024), likewise.
  unawaited(GrammarChecking.of(pod).look());

  // The accounts nobody signs into any more, daily (decided 2026-09-30;
  // every anonymous account left since ADR 0020, D25). Scheduling always
  // adds an entry, so the previous one goes first, and the one scheduled
  // under the earlier name, which would call nothing.
  await pod.futureCalls.cancel(_anonymousPruning);
  await pod.futureCalls.cancel(_pruning);
  await pod.futureCalls
      .callRecurring(identifier: _pruning)
      .cron('17 3 * * *')
      .pruning
      .pruneAccounts();

  // The IP addresses of sign-up attempts, hourly, once the rate limit is
  // done with them (decided 2026-10-10).
  await pod.futureCalls.cancel(_attemptPruning);
  await pod.futureCalls
      .callRecurring(identifier: _attemptPruning)
      .cron('27 * * * *')
      .pruning
      .forgetSignUpAttempts();

  // The deletions the instance's members haven't confirmed yet, hourly
  // (ADR 0016).
  await pod.futureCalls.cancel(_deletionNotices);
  await pod.futureCalls
      .callRecurring(identifier: _deletionNotices)
      .cron('52 * * * *')
      .pruning
      .tellMembersOfDeletions();

  // The assistant connector went with its codes and tokens (ADR 0022): what
  // an earlier server scheduled to forget them would call nothing.
  await pod.futureCalls.cancel(_connectorPruning);

  // The files nobody can reach any more, daily (ADR 0004, rule 5).
  await pod.futureCalls.cancel(_filePruning);
  await pod.futureCalls
      .callRecurring(identifier: _filePruning)
      .cron('47 3 * * *')
      .filePruning
      .pruneFiles();

  // How many people learn each published studyset here (ADR 0005, rule 4).
  await pod.futureCalls.cancel(_learnerCount);
  await pod.futureCalls
      .callRecurring(identifier: _learnerCount)
      .cron('37 4 * * *')
      .learnerCount
      .countLearners();

  // The dictionaries in the server's folder, those that changed since; in
  // the background, as loading takes a minute or two. Then again hourly, as
  // the dictionaries service replaces them weekly (and fills its volume
  // first after an instance's first start).
  unawaited(_loadDictionaries(pod));
  await pod.futureCalls.cancel(_dictionaryReload);
  await pod.futureCalls
      .callRecurring(identifier: _dictionaryReload)
      .cron('7 * * * *')
      .dictionaryReload
      .reloadDictionaries();
}

/// Loads the dictionaries in the server's folder ([dictionaryFolder]).
/// [loadDictionaries] throws nothing; a session that can't be had is
/// reported here, as an error in the background would end the server.
Future<void> _loadDictionaries(Serverpod pod) async {
  try {
    await pod.withSession((session) async {
      await loadDictionaries(session, dictionaryFolder());
      // What devices download, ready before the first asks (ADR 0012).
      await DeviceDictionaries.of(pod).prepare(session);
    });
  } on Object catch (error) {
    stderr.writeln('Loading the dictionaries failed: $error');
  }
}

/// The identifier of the daily pruning.
const _pruning = 'prune-accounts';

/// The identifier the daily pruning had until ADR 0020, D25.
const _anonymousPruning = 'prune-abandoned-anonymous-people';

/// The identifier of the hourly forgetting of sign-up attempts.
const _attemptPruning = 'forget-sign-up-attempts';

/// The identifier of the hourly telling of the members of deleted accounts.
const _deletionNotices = 'tell-members-of-deletions';

/// The identifier of the daily forgetting of the connector's expired secrets,
/// scheduled until ADR 0022.
const _connectorPruning = 'forget-connector-secrets';

/// The identifier of the daily pruning of files.
const _filePruning = 'prune-unreferenced-files';

/// The identifier of the hourly rereading of the dictionaries.
const _dictionaryReload = 'reload-dictionaries';

/// The identifier of the daily count of each published studyset's learners.
const _learnerCount = 'count-learners';