82 lines
2.6 KiB
Dart
82 lines
2.6 KiB
Dart
import 'package:flutter_bloc/flutter_bloc.dart';
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import 'package:hl_lieferservice/widget/operations/bloc/operation_event.dart';
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import 'package:hl_lieferservice/widget/operations/bloc/operation_state.dart';
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class OperationBloc extends Bloc<OperationEvent, OperationState> {
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/// Counts how many in-flight mutations want to show the blocking overlay.
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/// Allows multiple parallel mutations without one prematurely closing the
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/// overlay before the others complete.
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int _inFlightCount = 0;
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/// When the current overlay session began (set when [_inFlightCount]
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/// transitions 0 → 1). Used to enforce [_minimumDisplayDuration].
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DateTime? _overlayStartedAt;
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/// Minimum time the overlay stays visible, even if the underlying request
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/// completes faster. Prevents a "did anything happen?" UX where a sub-100 ms
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/// roundtrip flashes the overlay for one frame.
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static const Duration _minimumDisplayDuration = Duration(milliseconds: 350);
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OperationBloc() : super(OperationIdle()) {
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on<StartOperation>(_startOperation);
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on<FailOperation>(_failOperation);
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on<FinishOperation>(_finishOperation);
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}
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Future<void> _startOperation(
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StartOperation event,
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Emitter<OperationState> emit,
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) async {
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if (_inFlightCount == 0) {
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_overlayStartedAt = DateTime.now();
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}
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_inFlightCount += 1;
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emit(OperationInProgress(message: event.message));
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}
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Future<void> _finishOperation(
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FinishOperation event,
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Emitter<OperationState> emit,
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) async {
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_inFlightCount = (_inFlightCount - 1).clamp(0, 1 << 30);
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if (event.message != null) {
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emit(OperationFinished(message: event.message));
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await Future.delayed(const Duration(seconds: 5));
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}
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if (_inFlightCount > 0) {
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emit(OperationInProgress());
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} else {
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await _awaitMinimumOverlayDuration();
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_overlayStartedAt = null;
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emit(OperationIdle());
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}
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}
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Future<void> _failOperation(
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FailOperation event,
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Emitter<OperationState> emit,
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) async {
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_inFlightCount = (_inFlightCount - 1).clamp(0, 1 << 30);
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emit(OperationFailed(message: event.message));
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await Future.delayed(const Duration(seconds: 5));
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if (_inFlightCount > 0) {
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emit(OperationInProgress());
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} else {
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_overlayStartedAt = null;
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emit(OperationIdle());
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}
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}
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Future<void> _awaitMinimumOverlayDuration() async {
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final startedAt = _overlayStartedAt;
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if (startedAt == null) return;
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final elapsed = DateTime.now().difference(startedAt);
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if (elapsed < _minimumDisplayDuration) {
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await Future.delayed(_minimumDisplayDuration - elapsed);
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}
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}
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}
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