import 'package:flutter/material.dart';
import 'package:hooks_riverpod/hooks_riverpod.dart';
import 'package:immich_mobile/modules/album/services/album.service.dart';
import 'package:immich_mobile/shared/models/exif_info.dart';
import 'package:immich_mobile/shared/models/store.dart';
import 'package:immich_mobile/shared/models/user.dart';
import 'package:immich_mobile/shared/providers/db.provider.dart';
import 'package:immich_mobile/shared/services/asset.service.dart';
import 'package:immich_mobile/modules/home/ui/asset_grid/asset_grid_data_structure.dart';
import 'package:immich_mobile/modules/settings/providers/app_settings.provider.dart';
import 'package:immich_mobile/modules/settings/services/app_settings.service.dart';
import 'package:immich_mobile/shared/models/asset.dart';
import 'package:collection/collection.dart';
import 'package:immich_mobile/shared/services/sync.service.dart';
import 'package:immich_mobile/utils/async_mutex.dart';
import 'package:immich_mobile/utils/db.dart';
import 'package:intl/intl.dart';
import 'package:isar/isar.dart';
import 'package:logging/logging.dart';
import 'package:openapi/api.dart';
import 'package:photo_manager/photo_manager.dart';

/// State does not contain archived assets.
/// Use database provider if you want to access the isArchived assets
class AssetsState {
  final List<Asset> allAssets;
  final RenderList? renderList;

  AssetsState(this.allAssets, {this.renderList});

  Future<AssetsState> withRenderDataStructure(
    AssetGridLayoutParameters layout,
  ) async {
    return AssetsState(
      allAssets,
      renderList: await RenderList.fromAssets(
        allAssets,
        layout,
      ),
    );
  }

  AssetsState withAdditionalAssets(List<Asset> toAdd) {
    return AssetsState([...allAssets, ...toAdd]);
  }

  static AssetsState fromAssetList(List<Asset> assets) {
    return AssetsState(assets);
  }

  static AssetsState empty() {
    return AssetsState([]);
  }
}

class AssetNotifier extends StateNotifier<AssetsState> {
  final AssetService _assetService;
  final AppSettingsService _settingsService;
  final AlbumService _albumService;
  final SyncService _syncService;
  final Isar _db;
  final log = Logger('AssetNotifier');
  bool _getAllAssetInProgress = false;
  bool _deleteInProgress = false;
  final AsyncMutex _stateUpdateLock = AsyncMutex();

  AssetNotifier(
    this._assetService,
    this._settingsService,
    this._albumService,
    this._syncService,
    this._db,
  ) : super(AssetsState.fromAssetList([]));

  Future<void> _updateAssetsState(List<Asset> newAssetList) async {
    final layout = AssetGridLayoutParameters(
      _settingsService.getSetting(AppSettingsEnum.tilesPerRow),
      _settingsService.getSetting(AppSettingsEnum.dynamicLayout),
      GroupAssetsBy
          .values[_settingsService.getSetting(AppSettingsEnum.groupAssetsBy)],
    );

    state = await AssetsState.fromAssetList(newAssetList)
        .withRenderDataStructure(layout);
  }

  // Just a little helper to trigger a rebuild of the state object
  Future<void> rebuildAssetGridDataStructure() async {
    await _updateAssetsState(state.allAssets);
  }

  Future<void> getAllAsset({bool clear = false}) async {
    if (_getAllAssetInProgress || _deleteInProgress) {
      // guard against multiple calls to this method while it's still working
      return;
    }
    final stopwatch = Stopwatch()..start();
    try {
      _getAllAssetInProgress = true;
      final User me = Store.get(StoreKey.currentUser);
      if (clear) {
        await clearAssetsAndAlbums(_db);
        log.info("Manual refresh requested, cleared assets and albums from db");
      } else if (_stateUpdateLock.enqueued <= 1) {
        final int cachedCount =
            await _db.assets.filter().ownerIdEqualTo(me.isarId).count();
        if (cachedCount > 0 && cachedCount != state.allAssets.length) {
          await _stateUpdateLock.run(
            () async => _updateAssetsState(await _getUserAssets(me.isarId)),
          );
          log.info(
            "Reading assets ${state.allAssets.length} from DB: ${stopwatch.elapsedMilliseconds}ms",
          );
          stopwatch.reset();
        }
      }
      final bool newRemote = await _assetService.refreshRemoteAssets();
      final bool newLocal = await _albumService.refreshDeviceAlbums();
      debugPrint("newRemote: $newRemote, newLocal: $newLocal");
      log.info("Load assets: ${stopwatch.elapsedMilliseconds}ms");
      stopwatch.reset();
      if (!newRemote &&
          !newLocal &&
          state.allAssets.length ==
              await _db.assets.filter().ownerIdEqualTo(me.isarId).count()) {
        log.info("state is already up-to-date");
        return;
      }
      stopwatch.reset();
      if (_stateUpdateLock.enqueued <= 1) {
        _stateUpdateLock.run(() async {
          final assets = await _getUserAssets(me.isarId);
          if (!const ListEquality().equals(assets, state.allAssets)) {
            log.info("setting new asset state");
            await _updateAssetsState(assets);
          }
        });
      }
    } finally {
      _getAllAssetInProgress = false;
    }
  }

  Future<List<Asset>> _getUserAssets(int userId) => _db.assets
      .filter()
      .ownerIdEqualTo(userId)
      .isArchivedEqualTo(false)
      .sortByFileCreatedAtDesc()
      .findAll();

  Future<void> clearAllAsset() {
    state = AssetsState.empty();
    return clearAssetsAndAlbums(_db);
  }

  Future<void> onNewAssetUploaded(Asset newAsset) async {
    final bool ok = await _syncService.syncNewAssetToDb(newAsset);
    if (ok && _stateUpdateLock.enqueued <= 1) {
      // run this sequentially if there is at most 1 other task waiting
      await _stateUpdateLock.run(() async {
        final userId = Store.get(StoreKey.currentUser).isarId;
        final assets = await _getUserAssets(userId);
        await _updateAssetsState(assets);
      });
    }
  }

  Future<void> deleteAssets(Set<Asset> deleteAssets) async {
    _deleteInProgress = true;
    try {
      _updateAssetsState(
        state.allAssets.whereNot(deleteAssets.contains).toList(),
      );
      final localDeleted = await _deleteLocalAssets(deleteAssets);
      final remoteDeleted = await _deleteRemoteAssets(deleteAssets);
      if (localDeleted.isNotEmpty || remoteDeleted.isNotEmpty) {
        final dbIds = deleteAssets.map((e) => e.id).toList();
        await _db.writeTxn(() async {
          await _db.exifInfos.deleteAll(dbIds);
          await _db.assets.deleteAll(dbIds);
        });
      }
    } finally {
      _deleteInProgress = false;
    }
  }

  Future<List<String>> _deleteLocalAssets(Set<Asset> assetsToDelete) async {
    final int deviceId = Store.get(StoreKey.deviceIdHash);
    final List<String> local = [];
    // Delete asset from device
    for (final Asset asset in assetsToDelete) {
      if (asset.isLocal) {
        local.add(asset.localId);
      } else if (asset.deviceId == deviceId) {
        // Delete asset on device if it is still present
        var localAsset = await AssetEntity.fromId(asset.localId);
        if (localAsset != null) {
          local.add(localAsset.id);
        }
      }
    }
    if (local.isNotEmpty) {
      try {
        await PhotoManager.editor.deleteWithIds(local);
      } catch (e, stack) {
        log.severe("Failed to delete asset from device", e, stack);
      }
    }
    return [];
  }

  Future<Iterable<String>> _deleteRemoteAssets(
    Set<Asset> assetsToDelete,
  ) async {
    final Iterable<Asset> remote = assetsToDelete.where((e) => e.isRemote);
    final List<DeleteAssetResponseDto> deleteAssetResult =
        await _assetService.deleteAssets(remote) ?? [];
    return deleteAssetResult
        .where((a) => a.status == DeleteAssetStatus.SUCCESS)
        .map((a) => a.id);
  }

  Future<bool> toggleFavorite(Asset asset, bool status) async {
    final newAsset = await _assetService.changeFavoriteStatus(asset, status);

    if (newAsset == null) {
      log.severe("Change favorite status failed for asset ${asset.id}");
      return asset.isFavorite;
    }

    final index = state.allAssets.indexWhere((a) => asset.id == a.id);
    if (index != -1) {
      state.allAssets[index] = newAsset;
      _updateAssetsState(state.allAssets);
    }

    return newAsset.isFavorite;
  }

  Future<void> toggleArchive(Iterable<Asset> assets, bool status) async {
    final newAssets = await Future.wait(
      assets.map((a) => _assetService.changeArchiveStatus(a, status)),
    );
    int i = 0;
    bool unArchived = false;
    for (Asset oldAsset in assets) {
      final newAsset = newAssets[i++];
      if (newAsset == null) {
        log.severe("Change archive status failed for asset ${oldAsset.id}");
        continue;
      }
      final index = state.allAssets.indexWhere((a) => oldAsset.id == a.id);
      if (newAsset.isArchived) {
        // remove from state
        if (index != -1) {
          state.allAssets.removeAt(index);
        }
      } else {
        // add to state is difficult because the list is sorted
        unArchived = true;
      }
    }
    if (unArchived) {
      final User me = Store.get(StoreKey.currentUser);
      await _stateUpdateLock.run(
        () async => _updateAssetsState(await _getUserAssets(me.isarId)),
      );
    } else {
      _updateAssetsState(state.allAssets);
    }
  }
}

final assetProvider = StateNotifierProvider<AssetNotifier, AssetsState>((ref) {
  return AssetNotifier(
    ref.watch(assetServiceProvider),
    ref.watch(appSettingsServiceProvider),
    ref.watch(albumServiceProvider),
    ref.watch(syncServiceProvider),
    ref.watch(dbProvider),
  );
});

final assetGroupByMonthYearProvider = StateProvider((ref) {
  // TODO: remove `where` once temporary workaround is no longer needed (to only
  // allow remote assets to be added to album). Keep `toList()` as to NOT sort
  // the original list/state
  final assets =
      ref.watch(assetProvider).allAssets.where((e) => e.isRemote).toList();

  assets.sortByCompare<DateTime>(
    (e) => e.fileCreatedAt,
    (a, b) => b.compareTo(a),
  );

  return assets.groupListsBy(
    (element) => DateFormat('MMMM, y').format(element.fileCreatedAt.toLocal()),
  );
});