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fullenifulleni
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feat: add sources filter bloc
- Implemented bloc for source filtering - Added events and states - Handles fetching and pagination
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‎lib/headlines-feed/bloc/sources_filter_bloc.dart

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import 'dart:async';
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import 'package:bloc/bloc.dart';
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import 'package:bloc_concurrency/bloc_concurrency.dart'; // For transformers
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import 'package:equatable/equatable.dart';
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import 'package:ht_shared/ht_shared.dart'; // For PaginatedResponse
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import 'package:ht_sources_client/ht_sources_client.dart'; // Keep existing, also for Source model
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import 'package:ht_sources_repository/ht_sources_repository.dart';
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part 'sources_filter_event.dart';
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part 'sources_filter_state.dart';
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/// {@template sources_filter_bloc}
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/// Manages the state for fetching and displaying sources for filtering.
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///
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/// Handles initial fetching and pagination of sources using the
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/// provided [HtSourcesRepository].
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/// {@endtemplate}
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class SourcesFilterBloc extends Bloc<SourcesFilterEvent, SourcesFilterState> {
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/// {@macro sources_filter_bloc}
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///
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/// Requires a [HtSourcesRepository] to interact with the data layer.
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SourcesFilterBloc({required HtSourcesRepository sourcesRepository})
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: _sourcesRepository = sourcesRepository,
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super(const SourcesFilterState()) {
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on<SourcesFilterRequested>(
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_onSourcesFilterRequested,
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transformer: restartable(), // Only process the latest request
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);
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on<SourcesFilterLoadMoreRequested>(
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_onSourcesFilterLoadMoreRequested,
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transformer: droppable(), // Ignore new requests while one is processing
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);
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}
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final HtSourcesRepository _sourcesRepository;
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/// Number of sources to fetch per page.
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static const _sourcesLimit = 20;
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/// Handles the initial request to fetch sources.
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Future<void> _onSourcesFilterRequested(
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SourcesFilterRequested event,
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Emitter<SourcesFilterState> emit,
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) async {
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// Prevent fetching if already loading or successful
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if (state.status == SourcesFilterStatus.loading ||
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state.status == SourcesFilterStatus.success) {
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return;
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}
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emit(state.copyWith(status: SourcesFilterStatus.loading));
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try {
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final response = await _sourcesRepository.getSources(
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limit: _sourcesLimit,
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);
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emit(
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state.copyWith(
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status: SourcesFilterStatus.success,
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sources: response.items,
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hasMore: response.hasMore,
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cursor: response.cursor,
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clearError: true, // Clear any previous error
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),
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);
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} on SourceFetchFailure catch (e) {
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emit(
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state.copyWith(
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status: SourcesFilterStatus.failure,
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error: e,
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),
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);
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} catch (e) {
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// Catch unexpected errors
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emit(
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state.copyWith(
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status: SourcesFilterStatus.failure,
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error: e,
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),
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);
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}
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}
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/// Handles the request to load more sources for pagination.
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Future<void> _onSourcesFilterLoadMoreRequested(
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SourcesFilterLoadMoreRequested event,
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Emitter<SourcesFilterState> emit,
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) async {
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// Only proceed if currently successful and has more items
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if (state.status != SourcesFilterStatus.success || !state.hasMore) {
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return;
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}
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emit(state.copyWith(status: SourcesFilterStatus.loadingMore));
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try {
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final response = await _sourcesRepository.getSources(
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limit: _sourcesLimit,
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startAfterId: state.cursor, // Use the cursor from the current state
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);
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emit(
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state.copyWith(
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status: SourcesFilterStatus.success,
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// Append new sources to the existing list
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sources: List.of(state.sources)..addAll(response.items),
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hasMore: response.hasMore,
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cursor: response.cursor,
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),
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);
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} on SourceFetchFailure catch (e) {
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// Keep existing data but indicate failure
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emit(
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state.copyWith(
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status: SourcesFilterStatus.failure,
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error: e,
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),
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);
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} catch (e) {
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// Catch unexpected errors
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emit(
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state.copyWith(
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status: SourcesFilterStatus.failure,
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error: e,
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),
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);
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}
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}
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}

‎lib/headlines-feed/bloc/sources_filter_event.dart

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part of 'sources_filter_bloc.dart';
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/// {@template sources_filter_event}
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/// Base class for events related to fetching and managing source filters.
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/// {@endtemplate}
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sealed class SourcesFilterEvent extends Equatable {
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/// {@macro sources_filter_event}
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const SourcesFilterEvent();
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@override
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List<Object> get props => [];
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}
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/// {@template sources_filter_requested}
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/// Event triggered to request the initial list of sources.
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/// {@endtemplate}
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final class SourcesFilterRequested extends SourcesFilterEvent {}
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/// {@template sources_filter_load_more_requested}
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/// Event triggered to request the next page of sources for pagination.
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/// {@endtemplate}
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final class SourcesFilterLoadMoreRequested extends SourcesFilterEvent {}

‎lib/headlines-feed/bloc/sources_filter_state.dart

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part of 'sources_filter_bloc.dart';
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/// Enum representing the different statuses of the source filter data fetching.
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enum SourcesFilterStatus {
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/// Initial state, no data loaded yet.
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initial,
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/// Currently fetching the first page of sources.
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loading,
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/// Successfully loaded sources. May be loading more in the background.
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success,
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/// An error occurred while fetching sources.
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failure,
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/// Loading more sources for pagination (infinity scroll).
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loadingMore,
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}
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/// {@template sources_filter_state}
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/// Represents the state for the source filter feature.
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///
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/// Contains the list of fetched sources, pagination information,
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/// loading/error status.
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/// {@endtemplate}
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final class SourcesFilterState extends Equatable {
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/// {@macro sources_filter_state}
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const SourcesFilterState({
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this.status = SourcesFilterStatus.initial,
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this.sources = const [],
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this.hasMore = true,
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this.cursor,
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this.error,
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});
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/// The current status of fetching sources.
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final SourcesFilterStatus status;
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/// The list of [Source] objects fetched so far.
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final List<Source> sources;
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/// Flag indicating if there are more sources available to fetch.
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final bool hasMore;
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/// The cursor string to fetch the next page of sources.
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/// This is typically the ID of the last fetched source.
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final String? cursor;
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/// An optional error object if the status is [SourcesFilterStatus.failure].
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final Object? error;
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/// Creates a copy of this state with the given fields replaced.
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SourcesFilterState copyWith({
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SourcesFilterStatus? status,
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List<Source>? sources,
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bool? hasMore,
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String? cursor,
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Object? error,
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bool clearError = false, // Flag to explicitly clear the error
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bool clearCursor = false, // Flag to explicitly clear the cursor
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}) {
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return SourcesFilterState(
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status: status ?? this.status,
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sources: sources ?? this.sources,
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hasMore: hasMore ?? this.hasMore,
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// Allow explicitly setting cursor to null or clearing it
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cursor: clearCursor ? null : (cursor ?? this.cursor),
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// Clear error if requested, otherwise keep existing or use new one
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error: clearError ? null : error ?? this.error,
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);
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}
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@override
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List<Object?> get props => [status, sources, hasMore, cursor, error];
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}

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