AppFlowy/frontend/app_flowy/lib/plugins/grid/application/row/row_bloc.dart

import 'dart:collection';
import 'package:app_flowy/plugins/grid/application/cell/cell_service/cell_service.dart';
import 'package:equatable/equatable.dart';
import 'package:flowy_sdk/protobuf/flowy-grid/field_entities.pb.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:freezed_annotation/freezed_annotation.dart';
import 'dart:async';
import 'row_service.dart';

part 'row_bloc.freezed.dart';

class RowBloc extends Bloc<RowEvent, RowState> {
  final RowService _rowService;
  final GridRowCache _rowCache;
  void Function()? _rowListenFn;

  RowBloc({
    required GridRowInfo rowInfo,
    required GridRowCache rowCache,
  })  : _rowService = RowService(
          gridId: rowInfo.gridId,
          blockId: rowInfo.blockId,
          rowId: rowInfo.id,
        ),
        _rowCache = rowCache,
        super(RowState.initial(rowInfo, rowCache.loadGridCells(rowInfo.id))) {
    on<RowEvent>(
      (event, emit) async {
        await event.map(
          initial: (_InitialRow value) async {
            await _startListening();
          },
          createRow: (_CreateRow value) {
            _rowService.createRow();
          },
          didReceiveCellDatas: (_DidReceiveCellDatas value) async {
            final fields = value.gridCellMap.values
                .map((e) => GridCellEquatable(e.field))
                .toList();
            final snapshots = UnmodifiableListView(fields);
            emit(state.copyWith(
              gridCellMap: value.gridCellMap,
              snapshots: snapshots,
              changeReason: value.reason,
            ));
          },
        );
      },
    );
  }

  @override
  Future<void> close() async {
    if (_rowListenFn != null) {
      _rowCache.removeRowListener(_rowListenFn!);
    }

    return super.close();
  }

  Future<void> _startListening() async {
    _rowListenFn = _rowCache.addListener(
      rowId: state.rowInfo.id,
      onCellUpdated: (cellDatas, reason) =>
          add(RowEvent.didReceiveCellDatas(cellDatas, reason)),
      listenWhen: () => !isClosed,
    );
  }
}

@freezed
class RowEvent with _$RowEvent {
  const factory RowEvent.initial() = _InitialRow;
  const factory RowEvent.createRow() = _CreateRow;
  const factory RowEvent.didReceiveCellDatas(
          GridCellMap gridCellMap, GridRowChangeReason reason) =
      _DidReceiveCellDatas;
}

@freezed
class RowState with _$RowState {
  const factory RowState({
    required GridRowInfo rowInfo,
    required GridCellMap gridCellMap,
    required UnmodifiableListView<GridCellEquatable> snapshots,
    GridRowChangeReason? changeReason,
  }) = _RowState;

  factory RowState.initial(GridRowInfo rowInfo, GridCellMap cellDataMap) =>
      RowState(
        rowInfo: rowInfo,
        gridCellMap: cellDataMap,
        snapshots: UnmodifiableListView(
            cellDataMap.values.map((e) => GridCellEquatable(e.field)).toList()),
      );
}

class GridCellEquatable extends Equatable {
  final GridFieldPB _field;

  const GridCellEquatable(GridFieldPB field) : _field = field;

  @override
  List<Object?> get props => [
        _field.id,
        _field.fieldType,
        _field.visibility,
        _field.width,
      ];
}