mobile-app/lib/presentation/screens/plot_detail/bloc/plot_detail_bloc.dart

import 'dart:async';

import 'package:bloc/bloc.dart';
import 'package:equatable/equatable.dart';
import 'package:farm_tpf/custom_model/CropPlot.dart';
import 'package:farm_tpf/data/api/app_exception.dart';
import 'package:farm_tpf/data/repository/repository.dart';
import 'package:meta/meta.dart';

part 'plot_detail_event.dart';
part 'plot_detail_state.dart';

class PlotDetailBloc extends Bloc<PlotDetailEvent, PlotDetailState> {
  final Repository repository;
  PlotDetailBloc({@required this.repository}) : super(PlotDetailInitial());
  static int pageSize = 20;

  @override
  Stream<PlotDetailState> mapEventToState(
    PlotDetailEvent event,
  ) async* {
    if (event is DataFetched &&
        !(state is PlotDetailSuccess &&
            (state as PlotDetailSuccess).hasReachedMax)) {
      try {
        if (state is PlotDetailInitial) {
          yield PlotDetailLoading();
          var response;
          if (event.cropId != null) {
            response = await repository.getPlotDetail(event.cropId,
                page: 0, size: pageSize);
            yield PlotDetailSuccess(
                items: response.activities,
                page: 0,
                hasReachedMax:
                    response.activities.length < pageSize ? true : false);
          } else {
            CropPlot response = await repository
                .getPlotDetailByCode(event.cropCode, page: 0, size: pageSize);

            yield PlotDetailSuccess(
                ownerItem: response,
                items: response.activities,
                page: 0,
                hasReachedMax: true);
          }
        }
        if (state is PlotDetailSuccess) {
          final currentState = state as PlotDetailSuccess;
          int page = currentState.page + 1;
          var response;
          if (event.cropId != null) {
            response = await repository.getPlotDetail(event.cropId,
                page: page, size: pageSize);
            yield response.activities.isEmpty
                ? currentState.copyWith(hasReachedMax: true)
                : PlotDetailSuccess(
                    items: currentState.items + response.activities,
                    page: currentState.page + 1,
                    hasReachedMax: false);
          } else {
            CropPlot response = await repository.getPlotDetailByCode(
                event.cropCode,
                page: page,
                size: pageSize);
            yield PlotDetailSuccess(
                ownerItem: response,
                items: response.activities,
                page: 0,
                hasReachedMax: true);
          }
        }
      } catch (e) {
        var errorString = AppException.handleError(e);
        yield PlotDetailFailure(errorString: errorString);
      }
    }
    if (event is OnRefresh) {
      try {
        yield PlotDetailLoading();
        var response;
        if (event.cropId != null) {
          response = await repository.getPlotDetail(event.cropId,
              page: 0, size: pageSize);
        } else {
          response = await repository.getPlotDetailByCode(event.cropCode,
              page: 0, size: pageSize);
        }
        yield PlotDetailSuccess(
            items: response.activities,
            page: 0,
            hasReachedMax:
                response.activities.length < pageSize ? true : false);
      } catch (e) {
        yield PlotDetailFailure(errorString: AppException.handleError(e));
      }
    }
  }
}