import 'dart:async';
import 'package:flutter/foundation.dart';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';

import 'package:aves/model/source/collection_source.dart';
import 'package:aves/remote/remote_settings.dart';
import 'package:aves/remote/remote_sync_bus.dart';
import 'package:aves/remote/remote_repository.dart';
import 'package:aves/services/common/services.dart';
import 'package:aves/remote/remote_client.dart';
import 'package:aves/remote/auth_client.dart';
import 'package:aves/remote/collection_source_remote_ext.dart';

import 'remote_origin.dart';

class RemoteController {
  RemoteController._();
  static final RemoteController instance = RemoteController._();

  static const _kBootstrapDone = 'remote_bootstrap_done';

  bool _syncInFlight = false;

  // 🔥 Retry esterno
  Timer? _retryTimer;
  int _retryCount = 0;

  Future<bool> bootstrapDone() async {
    final storage = FlutterSecureStorage();
    return (await storage.read(key: _kBootstrapDone)) == '1';
  }

  Future<void> _setBootstrapDone() async {
    final storage = FlutterSecureStorage();
    await storage.write(key: _kBootstrapDone, value: '1');
  }

  // 🔥 Stato iniziale corretto: arancione lampeggiante
  Future<void> initBusFromSettings() async {
    final s = await RemoteSettings.load();

    if (!s.enabled) {
      RemoteSyncBus.instance.setDisabled();
      return;
    }

    RemoteSyncBus.instance.stateNotifier.value = RemoteSyncState.syncing;
  }

  Future<void> onAppStart({
    required CollectionSource source,
    bool resumeBootstrapIfEnabled = true,
  }) async {
    final s = await RemoteSettings.load();

    if (!s.enabled) {
      RemoteSyncBus.instance.setDisabled();
      final remotesInMemory =
          source.allEntries.where((e) => e.origin == RemoteOrigin.value).toSet();
      if (remotesInMemory.isNotEmpty) {
        source.removeEntriesFromMemory(remotesInMemory);
      }
      return;
    }

    final done = await bootstrapDone();
    if (done) {
      await source.appendRemoteEntriesFromDb();
      unawaited(fullSync(source: source, showOverlay: false));
    } else {
      if (resumeBootstrapIfEnabled) {
        unawaited(fullSync(
          source: source,
          showOverlay: true,
          markBootstrapDoneOnSuccess: true,
        ));
      }
    }
  }

  Future<void> toggleRemote({required CollectionSource source}) async {
    final s = await RemoteSettings.load();

    if (s.enabled) {
      final upd = RemoteSettings(
        enabled: false,
        baseUrl: s.baseUrl,
        indexPath: s.indexPath,
        email: s.email,
        password: s.password,
      );
      await upd.save();

      debugPrint('[remote] toggle -> OFF');

      final remotesInMemory =
          source.allEntries.where((e) => e.origin == RemoteOrigin.value).toSet();
      if (remotesInMemory.isNotEmpty) {
        source.removeEntriesFromMemory(remotesInMemory);
      }

      RemoteSyncBus.instance.setDisabled();

      // 🔥 Stop retry loop
      _retryTimer?.cancel();
      _retryTimer = null;

      return;
    }

    final upd = RemoteSettings(
      enabled: true,
      baseUrl: s.baseUrl,
      indexPath: s.indexPath,
      email: s.email,
      password: s.password,
    );
    await upd.save();

    debugPrint('[remote] toggle -> ON');

    await source.appendRemoteEntriesFromDb();
    unawaited(fullSync(source: source, showOverlay: false));
  }

  // 🔥 Retry esterno
  void _startRetryLoop(CollectionSource source) {
    _retryTimer?.cancel();
    _retryCount = 0;

    _retryTimer = Timer.periodic(const Duration(seconds: 30), (timer) async {
      _retryCount++;

      print('[remote] retry $_retryCount/10');

      final s = await RemoteSettings.load();
      if (!s.enabled) {
        timer.cancel();
        return;
      }

      final auth = (s.email.isNotEmpty && s.password.isNotEmpty)
          ? RemoteAuth(
              baseUrl: s.baseUrl,
              email: s.email,
              password: s.password,
            )
          : null;

      final retryClient = RemoteJsonClient(
        s.baseUrl,
        s.indexPath,
        auth: auth,
      );

      try {
        await retryClient.ping().timeout(const Duration(seconds: 3));

        print('[remote] retry OK → riprendo sync');

        timer.cancel();
        _retryTimer = null;

        unawaited(fullSync(source: source, showOverlay: false));
        return;

      } catch (_) {
        print('[remote] retry fallito');
      }

      if (_retryCount >= 10) {
        print('[remote] server down per troppo tempo → disattivo remote');

        timer.cancel();
        _retryTimer = null;

        final remotesInMemory =
            source.allEntries.where((e) => e.origin == RemoteOrigin.value).toSet();
        if (remotesInMemory.isNotEmpty) {
          source.removeEntriesFromMemory(remotesInMemory);
        }

        final upd = RemoteSettings(
          enabled: false,
          baseUrl: s.baseUrl,
          indexPath: s.indexPath,
          email: s.email,
          password: s.password,
        );
        await upd.save();

        RemoteSyncBus.instance.setDisabled();
      }
    });
  }

  // 🔥 fullSync pulito, senza retry interno
  Future<void> fullSync({
    required CollectionSource source,
    required bool showOverlay,
    bool markBootstrapDoneOnSuccess = false,
  }) async {
    if (_syncInFlight) {
      debugPrint('[remote] sync skipped (already in flight)');
      return;
    }
    _syncInFlight = true;

    final s = await RemoteSettings.load();
    if (!s.enabled) {
      RemoteSyncBus.instance.setDisabled();
      _syncInFlight = false;
      return;
    }

    try {
      if (s.baseUrl.trim().isEmpty) {
        RemoteSyncBus.instance.stateNotifier.value = RemoteSyncState.serverDown;
        _startRetryLoop(source);
        return;
      }

      RemoteAuth? auth;
      if (s.email.isNotEmpty && s.password.isNotEmpty) {
        auth = RemoteAuth(
          baseUrl: s.baseUrl,
          email: s.email,
          password: s.password,
        );
      }

      final client = RemoteJsonClient(s.baseUrl, s.indexPath, auth: auth);

      // 1️⃣ PING
      await client.ping().timeout(const Duration(seconds: 3));

      // 2️⃣ FETCH LISTA
      final items = await client.fetchAll().timeout(const Duration(seconds: 30));
      final total = items.length;

      // 3️⃣ BANNER
      final opId =
          RemoteSyncBus.instance.start(total: total, showOverlay: showOverlay);

      final repo = RemoteRepository(localMediaDb.rawDb);
      await repo.deleteAllRemotes();

      const chunkSize = 200;
      int done = 0;
      final serverIds =
          items.map((e) => e.id).where((v) => v.isNotEmpty).toSet();

      for (var offset = 0; offset < total; offset += chunkSize) {
        final end =
            (offset + chunkSize < total) ? offset + chunkSize : total;
        await repo.upsertAll(items.sublist(offset, end),
            chunkSize: chunkSize);
        done = end;
        RemoteSyncBus.instance.update(
            opId: opId, done: done, total: total);
      }

      await repo.pruneMissingRemotes(serverIds);
      await source.appendRemoteEntriesFromDb();

      if (markBootstrapDoneOnSuccess) {
        await _setBootstrapDone();
      }

      RemoteSyncBus.instance.finishUpToDate(opId: opId);

      // 🔥 Se la sync va bene → stop retry
      _retryTimer?.cancel();
      _retryTimer = null;

    } catch (e) {
      print('[remote] error during sync: $e');

      final remotesInMemory =
          source.allEntries.where((e) => e.origin == RemoteOrigin.value).toSet();
      if (remotesInMemory.isNotEmpty) {
        source.removeEntriesFromMemory(remotesInMemory);
      }

      RemoteSyncBus.instance.stateNotifier.value = RemoteSyncState.serverDown;

      // 🔥 Avvia retry esterno
      _startRetryLoop(source);

    } finally {
      _syncInFlight = false;
    }
  }
}