import 'dart:async';

import '../../../shared/utils/app_logger.dart';
import '../../contracts/contracts.dart';
import '../ports/emby_gateway.dart';
import '../ports/server_repository.dart';
import '../ports/session_repository.dart';
import 'usecase_helpers.dart';

const _ucTag = 'UseCase';


Stream<GlobalSearchServerResult> _fanOutPerServer({
  required SessionRepository sessionRepository,
  required ServerRepository serverRepository,
  required Future<List<EmbyRawItem>?> Function(AuthedRequestContext context)
  fetchItems,
  required String logTag,
}) {
  final controller = StreamController<GlobalSearchServerResult>();
  () async {
    try {
      final allSessions = await sessionRepository.listAll();
      final allServers = await serverRepository.list();
      final serverMap = {for (final s in allServers) s.id: s};

      final futures = allSessions.map((session) async {
        final server = serverMap[session.serverId];
        if (server == null) return;
        final context = AuthedRequestContext(
          baseUrl: server.baseUrl,
          token: session.token,
          userId: session.userId,
        );
        try {
          final items = await fetchItems(context);
          if (items == null || items.isEmpty) return;
          controller.add(
            GlobalSearchServerResult(
              serverId: server.id,
              serverName: server.name,
              serverUrl: server.baseUrl,
              token: session.token,
              userId: session.userId,
              items: items,
            ),
          );
        } catch (e) {
          AppLogger.warn(_ucTag, '$logTag on ${server.name} failed', e);
        }
      });

      await Future.wait(futures);
    } catch (e) {
      controller.addError(e);
    } finally {
      controller.close();
    }
  }();
  return controller.stream;
}

class GetLibraryViewsUseCase extends AuthedUseCase {
  GetLibraryViewsUseCase({
    required super.sessionRepository,
    required super.serverRepository,
    required super.embyGateway,
  });

  Future<LibraryViewsRes> execute() async {
    return embyGateway.getUserViews(await ctx());
  }
}

class GetLibraryResumeUseCase extends AuthedUseCase {
  GetLibraryResumeUseCase({
    required super.sessionRepository,
    required super.serverRepository,
    required super.embyGateway,
  });

  Future<LibraryResumeRes> execute() async {
    return embyGateway.getResumeItems(await ctx(), limit: 20);
  }
}

class GetLibraryLatestUseCase extends AuthedUseCase {
  GetLibraryLatestUseCase({
    required super.sessionRepository,
    required super.serverRepository,
    required super.embyGateway,
  });

  Future<LibraryLatestRes> execute(
    LibraryLatestReq input, {
    CancellationToken? cancelToken,
  }) async {
    return embyGateway.getLatestItems(
      await ctx(),
      input.parentId,
      limit: input.limit ?? 16,
      cancelToken: cancelToken,
    );
  }
}

class GetLibraryItemsUseCase extends AuthedUseCase {
  GetLibraryItemsUseCase({
    required super.sessionRepository,
    required super.serverRepository,
    required super.embyGateway,
  });

  Future<LibraryItemsRes> execute(LibraryItemsReq input) async {
    final items = await embyGateway.getLibraryItems(
      ctx: await ctx(),
      parentId: input.parentId,
      includeItemTypes: input.includeItemTypes,
      genreIds: input.genreIds,
      searchTerm: input.searchTerm,
      anyProviderIdEquals: input.anyProviderIdEquals,
      fields: input.fields,
      enableImageTypes: input.enableImageTypes,
      groupProgramsBySeries: input.groupProgramsBySeries,
      imageTypeLimit: input.imageTypeLimit,
      startIndex: input.startIndex,
      limit: input.limit,
      recursive: input.recursive,
      sortBy: input.sortBy,
      sortOrder: input.sortOrder,
    );
    return LibraryItemsRes(
      parentId: input.parentId ?? '__global__',
      items: items,
    );
  }
}


class GetHomeBannerUseCase extends AuthedUseCase {
  GetHomeBannerUseCase({
    required super.sessionRepository,
    required super.serverRepository,
    required super.embyGateway,
  });

  Future<List<EmbyRawItem>> execute({int fetchLimit = 24, int take = 8}) async {
    final items = await embyGateway.getLibraryItems(
      ctx: await ctx(),
      includeItemTypes: 'Movie,Series',
      recursive: true,
      sortBy: 'DateCreated',
      sortOrder: SortOrder.descending,
      fields:
          'BasicSyncInfo,CommunityRating,ProductionYear,Overview,Genres,ProviderIds,UserData',
      enableImageTypes: 'Backdrop,Logo,Primary,Thumb',
      imageTypeLimit: 2,
      limit: fetchLimit,
    );
    return items
        .where((it) => (it.BackdropImageTags ?? const []).isNotEmpty)
        .take(take)
        .toList(growable: false);
  }
}

class GlobalKeywordSearchUseCase extends AuthedUseCase {
  GlobalKeywordSearchUseCase({
    required super.sessionRepository,
    required super.serverRepository,
    required super.embyGateway,
  });

  static const _defaultTypes = 'Movie,Series';

  Stream<GlobalSearchServerResult> executeStream(GlobalSearchReq input) {
    final controller = StreamController<GlobalSearchServerResult>();
    () async {
      final keyword = input.keyword.trim();
      if (keyword.isEmpty) {
        controller.close();
        return;
      }
      try {
        var sessions = await sessionRepository.listAll();
        if (input.serverId != null) {
          sessions = sessions
              .where((s) => s.serverId == input.serverId)
              .toList();
        }
        final allServers = await serverRepository.list();
        final serverMap = {for (final s in allServers) s.id: s};
        final types = input.includeItemTypes ?? _defaultTypes;

        final futures = sessions.map((session) async {
          final result = await _searchOne(
            session: session,
            server: serverMap[session.serverId],
            keyword: keyword,
            types: types,
            limit: input.limitPerServer ?? 30,
          );
          if (result != null) controller.add(result);
        });

        await Future.wait(futures);
      } catch (error, stackTrace) {
        controller.addError(error, stackTrace);
      } finally {
        controller.close();
      }
    }();
    return controller.stream;
  }

  Future<GlobalSearchServerResult?> _searchOne({
    required SessionData session,
    required EmbyServer? server,
    required String keyword,
    required String types,
    required int limit,
  }) async {
    if (server == null) return null;
    final c = AuthedRequestContext(
      baseUrl: server.baseUrl,
      token: session.token,
      userId: session.userId,
    );
    try {
      final items = await embyGateway.getLibraryItems(
        ctx: c,
        searchTerm: keyword,
        recursive: true,
        includeItemTypes: types,
        limit: limit,
        sortBy: 'SortName',
        sortOrder: SortOrder.ascending,
      );
      if (items.isEmpty) return null;
      return GlobalSearchServerResult(
        serverId: server.id,
        serverName: server.name,
        serverUrl: server.baseUrl,
        token: session.token,
        userId: session.userId,
        items: items,
      );
    } catch (e) {
      AppLogger.warn(_ucTag, 'GlobalKeywordSearch on ${server.name} failed', e);
      return null;
    }
  }
}

class GetAggregatedResumeUseCase extends AuthedUseCase {
  GetAggregatedResumeUseCase({
    required super.sessionRepository,
    required super.serverRepository,
    required super.embyGateway,
  });

  Stream<GlobalSearchServerResult> executeStream({int? limitPerServer}) {
    return _fanOutPerServer(
      sessionRepository: sessionRepository,
      serverRepository: serverRepository,
      logTag: 'AggregatedResume',
      fetchItems: (context) async {
        final res = await embyGateway.getResumeItems(
          context,
          limit: limitPerServer ?? 20,
        );
        return res.Items;
      },
    );
  }
}

class GetAggregatedFavoritesUseCase extends AuthedUseCase {
  static const _defaultTypes = 'Movie,Series,Episode';

  GetAggregatedFavoritesUseCase({
    required super.sessionRepository,
    required super.serverRepository,
    required super.embyGateway,
  });

  Stream<GlobalSearchServerResult> executeStream({
    String includeItemTypes = _defaultTypes,
    int? limitPerServer,
  }) {
    final types = includeItemTypes.trim().isEmpty
        ? _defaultTypes
        : includeItemTypes;
    return _fanOutPerServer(
      sessionRepository: sessionRepository,
      serverRepository: serverRepository,
      logTag: 'AggregatedFavorites',
      fetchItems: (context) async {
        final items = await embyGateway.getFavoriteItems(
          ctx: context,
          includeItemTypes: types,
          sortBy: 'SortName',
          sortOrder: SortOrder.ascending,
        );
        return limitPerServer == null
            ? items
            : items.take(limitPerServer).toList(growable: false);
      },
    );
  }
}

class GetAggregatedRecentUseCase extends AuthedUseCase {
  static const _defaultTypes = 'Movie,Series';

  GetAggregatedRecentUseCase({
    required super.sessionRepository,
    required super.serverRepository,
    required super.embyGateway,
  });

  Stream<GlobalSearchServerResult> executeStream({
    String includeItemTypes = _defaultTypes,
    int? limitPerServer,
  }) {
    return _fanOutPerServer(
      sessionRepository: sessionRepository,
      serverRepository: serverRepository,
      logTag: 'AggregatedRecent',
      fetchItems: (context) async {
        return embyGateway.getLibraryItems(
          ctx: context,
          includeItemTypes: includeItemTypes,
          fields:
              'BasicSyncInfo,CollectionType,PrimaryImageAspectRatio,UserData,'
              'CommunityRating,ProviderIds,ProductionYear,ChildCount,Container,'
              'CanDelete,DateCreated',
          sortBy: 'DateCreated',
          sortOrder: SortOrder.descending,
          recursive: true,
          limit: limitPerServer ?? 20,
        );
      },
    );
  }
}