import 'dart:async';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:finlytic_app/features/search/repositories/search_repository.dart';
import 'search_event.dart';
import 'search_state.dart';

export 'search_event.dart';
export 'search_state.dart';

EventTransformer<Event> debounce<Event>(Duration duration) {
  return (events, mapper) => events.switchMap((event) => Stream.value(event).asyncExpand(mapper));
}

extension SwitchMapExtension<T> on Stream<T> {
  Stream<R> switchMap<R>(Stream<R> Function(T event) mapper) {
    StreamController<R>? controller;
    StreamSubscription<T>? inputSub;
    StreamSubscription<R>? outputSub;

    controller = StreamController<R>(
      onListen: () {
        inputSub = listen((event) {
          outputSub?.cancel();
          outputSub = mapper(event).listen(
            controller?.add,
            onError: controller?.addError,
          );
        }, onDone: () {
          // Wait for last sub to finish or close
        });
      },
      onCancel: () {
        outputSub?.cancel();
        inputSub?.cancel();
      },
    );
    return controller.stream;
  }
}

class SearchBloc extends Bloc<SearchEvent, SearchState> {
  final SearchRepository repository;

  SearchBloc({required this.repository}) : super(SearchInitial()) {
    on<SearchQueryChanged>(_onSearchQueryChanged);
  }

  Future<void> _onSearchQueryChanged(SearchQueryChanged event, Emitter<SearchState> emit) async {
    emit(SearchLoading());
    try {
      final results = await repository.searchAssets(event.query);
      emit(SearchLoaded(results));
    } catch (e) {
      emit(const SearchError("Fehler bei der Suche."));
    }
  }
}