import 'dart:async';
import 'dart:developer';
import 'dart:typed_data';

import 'package:archive/archive_io.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/widgets.dart';
import 'package:mnemo_cards/features/packs/loading_packs_holder.dart';
import 'package:mnemo_cards/features/packs/preview_packs_poller.dart';
import 'package:mnemo_cards_common/mnemo_cards_common.dart';
import 'package:package_info_plus/package_info_plus.dart';
import 'package:rxdart/rxdart.dart';
import '../analytics/analytics.dart';
import 'pack_cache_manager.dart';
import 'pack_holder.dart';
import 'packs_api.dart';
import 'preview_pack_holder.dart';

/// Updates cache and state holders for available packs
/// Does polling
class PackUpdater {
  final PacksApi _packsApi;
  final PackCacheManager _cacheManager;
  final PackHolder _packHolder;
  final PreviewPackHolder _previewPackHolder;
  final LoadingPacksHolder _loadingPacksHolder;
  final PreviewPacksPoller _previewPacksPoller;

  Completer? _updateCompleter;

  PackUpdater(
    this._packsApi,
    this._cacheManager,
    this._packHolder,
    this._previewPackHolder,
    this._loadingPacksHolder,
    this._previewPacksPoller,
  );

  Future<void> init() async {
    final pollStream = Stream.periodic(const Duration(seconds: 600));
    pollStream.startWith(0).listen((event) async {
      await updateAvailablePacks();
      await _previewPacksPoller.poll();
    });
  }

  Future<void> updateAvailablePacks() async {
    if (_updateCompleter?.isCompleted ?? true) {
      _updateCompleter = Completer();
    }
    try {
      print('Updating packs started');
      await _updateAvailablePacks();
    } catch (e, s) {
      log('Error when updating packs', error: e, stackTrace: s);
      print('Error when updating pack: ${e}');
      // Future.delayed(Duration(seconds: 5), () => updateAvailablePacks());
    } finally {
      print('Updating packs complete');
      if (_updateCompleter?.isCompleted == false) {
        _updateCompleter?.complete();
      }
    }
    return _updateCompleter!.future;
  }

  Future<void> _updateAvailablePacks() async {
    final savedList = await _cacheManager.loadAllPacks();
    final packData = Map.fromEntries(
      savedList.map(
        (e) => MapEntry(
          e.id.toString(),
          e.version,
        ),
      ),
    );
    final actions = await _packsApi.getPacksActions(packData);
    Map<String, CardPackDto> updatedPacks = {};
    bool shouldUpdateHolder = false;

    for (final action in actions) {
      switch (action.action) {
        case PackAction.delete:
          log('DELETE ${action.id}');
          shouldUpdateHolder = true;
          await _cacheManager.deletePack(action.id);
          savedList.removeWhere((p) => p.id == action.id);
          break;
        case PackAction.update:
          log('UPDATE ${action.id}');
          shouldUpdateHolder = true;
          try {
            final updatedPack = await _updatePackAndSaveImages(action.id);
            updatedPacks[action.id] = updatedPack;
          } catch (e) {
            log('Error while download cards for ${action.id} $e');
          }
          break;
        case PackAction.unknown:
          log('Unknown action on update ${action.id}');
          break;
      }
    }
    if (shouldUpdateHolder) {
      List<CardPackDto> packs = [];
      for (final saved in savedList) {
        if (updatedPacks[saved.id] != null) {
          packs.add(updatedPacks[saved.id]!);
          updatedPacks.remove(saved.id);
        } else {
          packs.add(saved);
        }
      }
      packs.addAll(updatedPacks.values);
      _packHolder.setPacksWithCards(packs.map((p) => p.id).toList());
    }
  }

  Future<CardPackDto> updatePackAndSaveImages(
    String packId, {
    bool shouldUpdateHolder = false,
  }) {
    _previewPacksPoller.poll();
    return _updatePackAndSaveImages(
      packId,
      shouldUpdateHolder: shouldUpdateHolder,
    );
  }

  Future<CardPackDto> _updatePackAndSaveImages(
    String packId, {
    bool shouldUpdateHolder = false,
  }) async {
    final loadingDto = _previewPackHolder.state?.previewPacks
            .firstWhereOrNull((p) => p.id == packId)
            ?.let(CardPackLoadingDto.fromPreviewDto) ??
        CardPackLoadingDto.fromId(packId, message: 'Загружаем карточки...');
    try {
      _loadingPacksHolder.addLoadingPack(loadingDto);
      log('Updating with cards ${packId}', name: 'updatePackWithCards');
      final s = Stopwatch()..start();
      final packDto = await _packsApi.getPackDto(packId);
      print('get from api ${s.elapsedMilliseconds} mills');
      if (packDto == null) {
        throw Exception('Cant update pack $packId');
      }
      final imagesData = await _packsApi.packImagesArchive(packId);
      print('get cards from api ${s.elapsedMilliseconds} mills');
      _loadingPacksHolder.addLoadingPack(
        loadingDto.copyWith(message: 'Распаковываем карточки...'),
      );
      final appVersion = (await PackageInfo.fromPlatform()).version;
      final images = await compute(
        _decodeArchive,
        _Envelope(
          data: imagesData,
          packId: packId,
          appVersion: appVersion,
        ),
      );
      _loadingPacksHolder.addLoadingPack(
        loadingDto.copyWith(message: 'Почти всё'),
      );
      await _cacheManager.savePack(packDto, images: images);
      print('saved pack ${s.elapsedMilliseconds} mills');
      log('Pack ${packId} updated with cards');
      if (shouldUpdateHolder) {
        _packHolder.setPacksWithCards(
          [
            ..._packHolder.state.packsWithCards,
            packDto.id,
          ],
        );
      }
      return packDto;
    } catch (e, s) {
      log('Cant update pack', error: e, stackTrace: s);
      Analytics.crashlyticsError(
        message: 'Cant update pack',
        e: e,
        s: s,
      );
      rethrow;
    } finally {
      _loadingPacksHolder.removeLoadingPack(packId);
    }
  }
}

Map<String, List<int>> _decodeArchive(_Envelope envelope) {
  final s = Stopwatch()..start();
  final password = TokenGenerator.generateArchivePassword(
    appVersion: envelope.appVersion,
    packId: envelope.packId,
  );
  print('generate token ${s.elapsedMilliseconds} mills');
  final imagesArchive = ZipDecoder().decodeBytes(
    envelope.data,
    password: password,
  );
  print('deflate archive ${s.elapsedMilliseconds} mills');
  final images = Map<String, List<int>>();
  for (final file in imagesArchive) {
    images[file.name] = file.content as List<int>;
  }
  print('loaded images ${s.elapsedMilliseconds} mills');
  return images;
}

class _Envelope {
  final List<int> data;
  final String packId;
  final String appVersion;

  _Envelope({
    required this.data,
    required this.packId,
    required this.appVersion,
  });
}