AppFlowy/frontend/appflowy_flutter/lib/plugins/trash/application/trash_bloc.dart

import 'package:dartz/dartz.dart';
import 'package:appflowy_backend/log.dart';
import 'package:appflowy_backend/protobuf/flowy-folder/trash.pb.dart';
import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:freezed_annotation/freezed_annotation.dart';
import 'package:appflowy/plugins/trash/application/trash_service.dart';
import 'package:appflowy/plugins/trash/application/trash_listener.dart';

part 'trash_bloc.freezed.dart';

class TrashBloc extends Bloc<TrashEvent, TrashState> {
  final TrashService _service;
  final TrashListener _listener;
  TrashBloc()
      : _service = TrashService(),
        _listener = TrashListener(),
        super(TrashState.init()) {
    on<TrashEvent>((event, emit) async {
      await event.map(initial: (e) async {
        _listener.start(trashUpdated: _listenTrashUpdated);
        final result = await _service.readTrash();
        emit(result.fold(
          (object) => state.copyWith(
              objects: object.items, successOrFailure: left(unit)),
          (error) => state.copyWith(successOrFailure: right(error)),
        ));
      }, didReceiveTrash: (e) async {
        emit(state.copyWith(objects: e.trash));
      }, putback: (e) async {
        final result = await _service.putback(e.trashId);
        await _handleResult(result, emit);
      }, delete: (e) async {
        final result =
            await _service.deleteViews([Tuple2(e.trash.id, e.trash.ty)]);
        await _handleResult(result, emit);
      }, deleteAll: (e) async {
        final result = await _service.deleteAll();
        await _handleResult(result, emit);
      }, restoreAll: (e) async {
        final result = await _service.restoreAll();
        await _handleResult(result, emit);
      });
    });
  }

  Future<void> _handleResult(
      Either<dynamic, FlowyError> result, Emitter<TrashState> emit) async {
    emit(result.fold(
      (l) => state.copyWith(successOrFailure: left(unit)),
      (error) => state.copyWith(successOrFailure: right(error)),
    ));
  }

  void _listenTrashUpdated(Either<List<TrashPB>, FlowyError> trashOrFailed) {
    trashOrFailed.fold(
      (trash) {
        add(TrashEvent.didReceiveTrash(trash));
      },
      (error) {
        Log.error(error);
      },
    );
  }

  @override
  Future<void> close() async {
    await _listener.close();
    return super.close();
  }
}

@freezed
class TrashEvent with _$TrashEvent {
  const factory TrashEvent.initial() = Initial;
  const factory TrashEvent.didReceiveTrash(List<TrashPB> trash) = ReceiveTrash;
  const factory TrashEvent.putback(String trashId) = Putback;
  const factory TrashEvent.delete(TrashPB trash) = Delete;
  const factory TrashEvent.restoreAll() = RestoreAll;
  const factory TrashEvent.deleteAll() = DeleteAll;
}

@freezed
class TrashState with _$TrashState {
  const factory TrashState({
    required List<TrashPB> objects,
    required Either<Unit, FlowyError> successOrFailure,
  }) = _TrashState;

  factory TrashState.init() => TrashState(
        objects: [],
        successOrFailure: left(unit),
      );
}