resolved conflict and update doc

lib/connector/meshcore_connector.dart

@@ -162,6 +162,12 @@ class MeshCoreConnector extends ChangeNotifier {
   // Message windowing to limit memory usage
   static const int _messageWindowSize = 200;
 
+  // Cap on discovered (non-contact) nodes retained in memory. Adverts arrive
+  // continuously from the whole mesh, so without a bound this list grows for
+  // as long as the app stays connected. When full, the stalest node (oldest
+  // lastSeen) is evicted to make room for a newly heard one.
+  static const int _maxDiscoveredContacts = 500;
+
   MeshCoreConnectionState _state = MeshCoreConnectionState.disconnected;
   BluetoothDevice? _device;
   BluetoothCharacteristic? _rxCharacteristic;
@@ -251,6 +257,9 @@ class MeshCoreConnector extends ChangeNotifier {
   DateTime _lastRadioRxTime = DateTime.fromMillisecondsSinceEpoch(0);
   DateTime _lastContactMsgRxTime = DateTime.fromMillisecondsSinceEpoch(0);
   DateTime _lastChannelMsgRxTime = DateTime.fromMillisecondsSinceEpoch(0);
+  DateTime _lastZeroHopAdvertAt = DateTime.fromMillisecondsSinceEpoch(0);
+  double? _lastZeroHopAdvertLatitude;
+  double? _lastZeroHopAdvertLongitude;
   static const int _radioQuietMs = 3000;
   static const int _radioQuietMaxWaitMs = 3000;
 
@@ -1066,6 +1075,13 @@ class MeshCoreConnector extends ChangeNotifier {
 
   Future<void> _loadDiscoveredContactCache() async {
     final cached = await _discoveryContactStore.loadContacts();
+    // Trim a previously-saved oversized list down to the freshest entries so a
+    // device that grew unbounded before the cap existed recovers on load.
+    if (cached.length > _maxDiscoveredContacts) {
+      cached.sort((a, b) => b.lastSeen.compareTo(a.lastSeen));
+      cached.removeRange(_maxDiscoveredContacts, cached.length);
+      unawaited(_discoveryContactStore.saveContacts(cached));
+    }
     _discoveredContacts
       ..clear()
       ..addAll(cached);
@@ -2558,6 +2574,8 @@ class MeshCoreConnector extends ChangeNotifier {
     _selfName = null;
     _selfLatitude = null;
     _selfLongitude = null;
+    _lastZeroHopAdvertLatitude = null;
+    _lastZeroHopAdvertLongitude = null;
     _awaitingSelfInfo = false;
     _webInitialHandshakeRequestSent = false;
     _selfInfoRetryTimer?.cancel();
@@ -2724,6 +2742,8 @@ class MeshCoreConnector extends ChangeNotifier {
     _selfName = null;
     _selfLatitude = null;
     _selfLongitude = null;
+    _lastZeroHopAdvertLatitude = null;
+    _lastZeroHopAdvertLongitude = null;
     _clientRepeat = null;
     _rememberedNonRepeatRadioState = null;
     _firmwareVerCode = null;
@@ -3883,6 +3903,11 @@ class MeshCoreConnector extends ChangeNotifier {
   Future<void> sendSelfAdvert({bool flood = true}) async {
     if (!isConnected) return;
     await sendFrame(buildSendSelfAdvertFrame(flood: flood));
+    if (!flood) {
+      _lastZeroHopAdvertAt = DateTime.now();
+      _lastZeroHopAdvertLatitude = _selfLatitude;
+      _lastZeroHopAdvertLongitude = _selfLongitude;
+    }
   }
 
   Future<void> rebootDevice() async {
@@ -4346,6 +4371,42 @@ class MeshCoreConnector extends ChangeNotifier {
         tag: 'Connector',
       );
     }
+
+    const locationChangeEpsilon = 2.25e-4; // ~25 meters in degrees.
+    final lastAdvertLatitude = _lastZeroHopAdvertLatitude;
+    final lastAdvertLongitude = _lastZeroHopAdvertLongitude;
+    final currentLatitude = _selfLatitude;
+    final currentLongitude = _selfLongitude;
+    final latChanged =
+        lastAdvertLatitude != null &&
+        currentLatitude != null &&
+        (currentLatitude - lastAdvertLatitude).abs() >= locationChangeEpsilon;
+    final lonChanged =
+        lastAdvertLongitude != null &&
+        currentLongitude != null &&
+        (currentLongitude - lastAdvertLongitude).abs() >= locationChangeEpsilon;
+    final gpsSampleChanged =
+        hasValidLocation(currentLatitude, currentLongitude) &&
+        (!hasValidLocation(lastAdvertLatitude, lastAdvertLongitude) ||
+            latChanged ||
+            lonChanged);
+    final effectiveGpsIntervalSeconds =
+        _appSettingsService?.resolvedGpsIntervalSeconds(_currentCustomVars) ??
+        0;
+    final timeSinceLastZeroHopAdvert = DateTime.now().difference(
+      _lastZeroHopAdvertAt,
+    );
+    final shouldAutoSendZeroHopAdvert =
+        (gpsSampleChanged || (_clientRepeat ?? false)) &&
+        _advertLocPolicy == 1 &&
+        (_appSettingsService?.settings.autoSendZeroHopAdvertOnGpsUpdate ??
+            false) &&
+        effectiveGpsIntervalSeconds > 0 &&
+        timeSinceLastZeroHopAdvert.inSeconds >= effectiveGpsIntervalSeconds;
+    if (shouldAutoSendZeroHopAdvert) {
+      unawaited(sendSelfAdvert(flood: false));
+    }
+
     final selfName = _selfName?.trim();
     if (_activeTransport == MeshCoreTransportType.usb &&
         selfName != null &&
@@ -7139,6 +7200,10 @@ class MeshCoreConnector extends ChangeNotifier {
       isActive: addActive,
       flags: 0,
     );
+
+    if (_discoveredContacts.length >= _maxDiscoveredContacts) {
+      _evictStalestDiscoveredContact();
+    }
     _discoveredContacts.add(disContact);
 
     unawaited(_persistDiscoveredContacts());
@@ -7156,6 +7221,19 @@ class MeshCoreConnector extends ChangeNotifier {
     }
   }
 
+  void _evictStalestDiscoveredContact() {
+    if (_discoveredContacts.isEmpty) return;
+    var stalestIndex = 0;
+    for (int i = 1; i < _discoveredContacts.length; i++) {
+      if (_discoveredContacts[i].lastSeen.isBefore(
+        _discoveredContacts[stalestIndex].lastSeen,
+      )) {
+        stalestIndex = i;
+      }
+    }
+    _discoveredContacts.removeAt(stalestIndex);
+  }
+
   void removeAllDiscoveredContacts() {
     _discoveredContacts.clear();
     unawaited(_persistDiscoveredContacts());