deleteOldSignals method

@override Future<int> deleteOldSignals(DateTime cutoff)

Deletes signals in terminal states (DELIVERED, EXPIRED) older than cutoff.

Returns the number of signals deleted.

Implementation

@override
Future<int> deleteOldSignals(DateTime cutoff) async {
  final before = _signals.length;
  _signals.removeWhere((s) {
    if (s.status != SignalStatus.delivered &&
        s.status != SignalStatus.expired) {
      return false;
    }
    return DateTime.parse(s.createdAt).isBefore(cutoff);
  });
  return before - _signals.length;
}