import '../../../../../api/errors/error_mapper.dart';
import '../../../../../api/marianumcloud/talk/chat/getChatResponse.dart';
import '../../../infrastructure/loadableState/loading_error.dart';
import '../../../infrastructure/utilityWidgets/loadableHydratedBloc/loadable_hydrated_bloc.dart';
import '../../../infrastructure/utilityWidgets/loadableHydratedBloc/loadable_hydrated_bloc_event.dart';
import '../repository/chat_repository.dart';
import 'chat_event.dart';
import 'chat_state.dart';

class ChatBloc extends LoadableHydratedBloc<ChatEvent, ChatState, ChatRepository> {
  DateTime _lastTokenSet = DateTime.fromMillisecondsSinceEpoch(0);

  @override
  ChatRepository repository() => ChatRepository();

  @override
  ChatState fromNothing() => const ChatState();

  @override
  ChatState fromStorage(Map<String, dynamic> json) => ChatState.fromJson(json);

  @override
  Map<String, dynamic>? toStorage(ChatState state) => state.toJson();

  @override
  Future<void> gatherData() async {
    final token = innerState?.currentToken ?? '';
    if (token.isEmpty) {
      add(DataGathered((s) => s));
      return;
    }
    await _loadChat(token);
  }

  void setToken(String token) {
    if (token == (innerState?.currentToken ?? '')) {
      refresh();
      return;
    }
    add(Emit((s) => s.copyWith(currentToken: token, chatResponse: null)));
    add(RefetchStarted<ChatState>());
    _loadChat(token);
  }

  void setReferenceMessageId(int? messageId) {
    add(Emit((s) => s.copyWith(referenceMessageId: messageId)));
  }

  void refresh() {
    final token = innerState?.currentToken ?? '';
    if (token.isEmpty) return;
    add(RefetchStarted<ChatState>());
    _loadChat(token);
  }

  Future<void> _loadChat(String token) async {
    final requestStart = DateTime.now();
    _lastTokenSet = requestStart;

    Object? capturedError;
    GetChatResponse? response;
    try {
      response = await repo.data.getChat(
        token: token,
        onError: (e) => capturedError = e,
      );
    } catch (e) {
      capturedError = e;
    }

    if (_lastTokenSet.isAfter(requestStart)) return;
    if ((innerState?.currentToken ?? '') != token) return;

    if (response != null) {
      add(DataGathered((s) => s.copyWith(chatResponse: response)));
    }
    if (capturedError != null) {
      add(Error(LoadingError(
        message: errorToUserMessage(capturedError),
        technicalDetails: errorToTechnicalDetails(capturedError),
        allowRetry: errorAllowsRetry(capturedError),
      )));
    }
  }
}