syncrow-web/lib/pages/access_management/booking_system/domain/services/DebouncedBookingSystemService.dart

import 'dart:async';
import 'package:syncrow_web/pages/access_management/booking_system/domain/load_bookable_spaces_param.dart';
import 'package:syncrow_web/pages/access_management/booking_system/domain/models/paginated_bookable_spaces.dart';
import 'package:syncrow_web/pages/access_management/booking_system/domain/services/bookable_system_service.dart';

class DebouncedBookingSystemService implements BookableSystemService {
  final BookableSystemService _inner;
  final Duration debounceDuration;

  Timer? _debounceTimer;
  Completer<PaginatedBookableSpaces>? _lastCompleter;

  DebouncedBookingSystemService(
    this._inner, {
    this.debounceDuration = const Duration(milliseconds: 500),
  });

  @override
  Future<PaginatedBookableSpaces> getBookableSpaces({
    required LoadBookableSpacesParam param,
  }) {
    _debounceTimer?.cancel();
    if (_lastCompleter != null && !_lastCompleter!.isCompleted) {
      _lastCompleter!.completeError(StateError("Cancelled by new search"));
    }

    final completer = Completer<PaginatedBookableSpaces>();
    _lastCompleter = completer;

    _debounceTimer = Timer(debounceDuration, () async {
      try {
        final result = await _inner.getBookableSpaces(param: param);
        if (!completer.isCompleted) {
          completer.complete(result);
        }
      } catch (e, st) {
        if (!completer.isCompleted) {
          completer.completeError(e, st);
        }
      }
    });

    return completer.future;
  }
}