Regions discovery from nearby repeaters

lib/connector/meshcore_connector.dart

@@ -264,6 +264,10 @@ class MeshCoreConnector extends ChangeNotifier {
   // Serializes path operations (setContactPath/clearContactPath) to prevent
   // interleaved async calls from leaving in-memory state inconsistent with device.
   Future<void> _pathOpLock = Future.value();
+  // Flood scope is a global firmware setting, so scoped channel sends must not
+  // overlap or a message may inherit another channel's region.
+  Future<void> _channelScopedSendLock = Future.value();
+  static const Duration _commandAckTimeout = Duration(seconds: 5);
   Map<String, String>? _currentCustomVars;
 
   /// Maps repeater pubkey-prefix hex (12 hex chars = first 6 bytes) → the
@@ -679,7 +683,7 @@ class MeshCoreConnector extends ChangeNotifier {
   }
 
   bool hasChannelRegion(int channelIndex) {
-    return _channelRegions[channelIndex] != '';
+    return (_channelRegions[channelIndex] ?? '').isNotEmpty;
   }
 
   Region getChannelRegion(int channelIndex) {
@@ -3217,19 +3221,14 @@ class MeshCoreConnector extends ChangeNotifier {
       // Send the reaction to the device (don't add as a visible message)
       final reactionQueueId = _nextReactionSendQueueId();
       _pendingChannelSentQueue.add(reactionQueueId);
-      try {
-        await sendFrame(
-          buildSetFloodScopeFrame(getChannelRegion(channel.index)),
-        );
+      await _runScopedChannelSend(() async {
         await _waitForRadioQuiet(lastInboundRxTime: _lastChannelMsgRxTime);
-        await sendFrame(
+        await _sendFrameAndWaitForCommandAck(
           buildSendChannelTextMsgFrame(channel.index, text),
           channelSendQueueId: reactionQueueId,
           expectsGenericAck: true,
         );
-      } finally {
-        await sendFrame(buildSetFloodScopeFrame(''));
-      }
+      }, region: getChannelRegion(channel.index));
       return;
     }
 
@@ -3246,16 +3245,80 @@ class MeshCoreConnector extends ChangeNotifier {
     notifyListeners();
 
     final outboundText = prepareChannelOutboundText(channel.index, text);
-    try {
-      await sendFrame(buildSetFloodScopeFrame(getChannelRegion(channel.index)));
+    await _runScopedChannelSend(() async {
       await _waitForRadioQuiet(lastInboundRxTime: _lastChannelMsgRxTime);
-      await sendFrame(
+      await _sendFrameAndWaitForCommandAck(
         buildSendChannelTextMsgFrame(channel.index, outboundText),
         channelSendQueueId: message.messageId,
         expectsGenericAck: true,
       );
+    }, region: getChannelRegion(channel.index));
+  }
+
+  Future<void> _runScopedChannelSend(
+    Future<void> Function() action, {
+    required String region,
+  }) async {
+    final prev = _channelScopedSendLock;
+    final completer = Completer<void>();
+    _channelScopedSendLock = completer.future;
+    await prev;
+
+    try {
+      await _sendFrameAndWaitForCommandAck(buildSetFloodScopeFrame(region));
+      try {
+        await action();
+      } finally {
+        if (isConnected) {
+          await _sendFrameAndWaitForCommandAck(buildSetFloodScopeFrame(''));
+        }
+      }
     } finally {
-      await sendFrame(buildSetFloodScopeFrame(''));
+      completer.complete();
+    }
+  }
+
+  Future<void> _sendFrameAndWaitForCommandAck(
+    Uint8List data, {
+    String? channelSendQueueId,
+    bool expectsGenericAck = false,
+  }) async {
+    final completer = Completer<void>();
+    late final StreamSubscription<Uint8List> subscription;
+    late final Timer timeout;
+
+    void complete() {
+      if (!completer.isCompleted) completer.complete();
+    }
+
+    void completeError(Object error) {
+      if (!completer.isCompleted) completer.completeError(error);
+    }
+
+    subscription = receivedFrames.listen((frame) {
+      if (frame.isEmpty) return;
+      if (frame[0] == respCodeOk) {
+        complete();
+      } else if (frame[0] == respCodeErr) {
+        final errCode = frame.length > 1 ? frame[1] : -1;
+        completeError(Exception('Command failed with error code $errCode'));
+      }
+    });
+
+    timeout = Timer(_commandAckTimeout, () {
+      completeError(TimeoutException('Command ACK timed out'));
+    });
+
+    try {
+      await sendFrame(
+        data,
+        channelSendQueueId: channelSendQueueId,
+        expectsGenericAck: expectsGenericAck,
+      );
+      await completer.future;
+    } finally {
+      timeout.cancel();
+      await subscription.cancel();
     }
   }
 
@@ -3858,6 +3921,9 @@ class MeshCoreConnector extends ChangeNotifier {
       case pushCodePathUpdated:
         _handlePathUpdated(frame);
         break;
+      case pushCodeControlData:
+        // Optional feature-specific services listen to receivedFrames directly.
+        break;
       case pushCodeLoginSuccess:
         _handleLoginSuccess(frame);
         break;

lib/connector/meshcore_protocol.dart

@@ -207,6 +207,7 @@ const int cmdSendTelemetryReq = 39;
 const int cmdGetCustomVar = 40;
 const int cmdSetCustomVar = 41;
 const int cmdSendBinaryReq = 50;
+const int cmdSendControlData = 55;
 const int cmdGetStats = 56;
 const int cmdSendAnonReq = 57;
 const int cmdSetAutoAddConfig = 58;
@@ -226,6 +227,12 @@ const int reqTypeGetTelemetry = 0x03;
 const int reqTypeGetAccessList = 0x05;
 const int reqTypeGetNeighbors = 0x06;
 
+const int anonReqTypeRegions = 0x01;
+
+// Control data sub-types used by MeshCore discovery packets.
+const int controlSubtypeDiscoverReq = 0x08;
+const int controlSubtypeDiscoverResp = 0x09;
+
 // Repeater response codes
 const int respServerLoginOk = 0;
 
@@ -268,6 +275,7 @@ const int pushCodeTraceData = 0x89;
 const int pushCodeNewAdvert = 0x8A;
 const int pushCodeTelemetryResponse = 0x8B;
 const int pushCodeBinaryResponse = 0x8C;
+const int pushCodeControlData = 0x8E;
 
 // Contact/advertisement types
 const int advTypeChat = 1;
@@ -857,6 +865,67 @@ Uint8List buildSendBinaryReq(Uint8List repeaterPubKey, {Uint8List? payload}) {
   return writer.toBytes();
 }
 
+Uint8List buildSendControlDataFrame(Uint8List payload) {
+  final writer = BufferWriter();
+  writer.writeByte(cmdSendControlData);
+  writer.writeBytes(payload);
+  return writer.toBytes();
+}
+
+Uint8List buildDiscoveryRequestPayload(
+  int tag, {
+  bool prefixOnly = false,
+  int typeMask = 1 << advTypeRepeater,
+}) {
+  final writer = BufferWriter();
+  // The high bit must be set for CMD_SEND_CONTROL_DATA; DISCOVER_REQ uses
+  // subtype 0x8, with the low bit selecting short/full public keys in replies.
+  writer.writeByte(
+    (controlSubtypeDiscoverReq << 4) | (prefixOnly ? 0x01 : 0x00),
+  );
+  writer.writeByte(typeMask);
+  writer.writeUInt32LE(tag);
+  writer.writeUInt32LE(0); // since=0 asks nearby nodes for any recent advert.
+  return writer.toBytes();
+}
+
+Uint8List _reversePathByHop(Uint8List path, int pathHashWidth) {
+  if (path.isEmpty) return Uint8List(0);
+  final width = pathHashWidth.clamp(1, 4).toInt();
+  if (path.length % width != 0) {
+    return Uint8List.fromList(path.reversed.toList());
+  }
+
+  final reversed = Uint8List(path.length);
+  final hops = path.length ~/ width;
+  for (var i = 0; i < hops; i++) {
+    final from = (hops - 1 - i) * width;
+    reversed.setRange(i * width, (i + 1) * width, path, from);
+  }
+  return reversed;
+}
+
+// Build CMD_SEND_ANON_REQ frame.
+// Payload format for regions: [anon_req_type][reply_path_len][reply_path...].
+Uint8List buildSendAnonReqFrame(
+  Uint8List repeaterPubKey, {
+  required int requestType,
+  Uint8List? replyPath,
+  int replyHopCount = 0,
+  int pathHashWidth = pathHashSize,
+}) {
+  final width = pathHashWidth.clamp(1, 4).toInt();
+  final path = replyPath ?? Uint8List(0);
+  final encodedPathLen = ((width - 1) << 6) | (replyHopCount & 0x3F);
+  final writer = BufferWriter();
+  writer.writeByte(cmdSendAnonReq);
+  writer.writeBytes(repeaterPubKey);
+  writer.writeByte(requestType);
+  writer.writeByte(encodedPathLen);
+  writer.writeBytes(_reversePathByHop(path, width));
+  return writer.toBytes();
+}
+
 //Build a trace request frame
 //[cmd][tag x4][auth x4][flag][payload]
 Uint8List buildTraceReq(int tag, int auth, int flag, {Uint8List? payload}) {

lib/l10n/app_en.arb

@@ -154,6 +154,9 @@
   "settings_regionManagement_screenTitle": "Region Management",
   "settings_regionNameHint": "Enter region name",
   "settings_regionAddRegion": "Add region",
+  "settings_regionFetchRegions": "Fetch regions from repeaters",
+  "settings_regionFetchRegionsFail": "No regions were found",
+  "settings_regionFetchRegionsAlreadyExists": "This region has already been added",
   "settings_regionName": "Region Name",
   "settings_regionDeleted": "Region deleted",
   "settings_deleteRegion": "Delete Region",

lib/l10n/app_localizations.dart

@@ -760,6 +760,24 @@ abstract class AppLocalizations {
   /// **'Add region'**
   String get settings_regionAddRegion;
 
+  /// No description provided for @settings_regionFetchRegions.
+  ///
+  /// In en, this message translates to:
+  /// **'Fetch regions from repeaters'**
+  String get settings_regionFetchRegions;
+
+  /// No description provided for @settings_regionFetchRegionsFail.
+  ///
+  /// In en, this message translates to:
+  /// **'No regions were found'**
+  String get settings_regionFetchRegionsFail;
+
+  /// No description provided for @settings_regionFetchRegionsAlreadyExists.
+  ///
+  /// In en, this message translates to:
+  /// **'This region has already been added'**
+  String get settings_regionFetchRegionsAlreadyExists;
+
   /// No description provided for @settings_regionName.
   ///
   /// In en, this message translates to:

lib/l10n/app_localizations_bg.dart

@@ -354,6 +354,16 @@ class AppLocalizationsBg extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Add region';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Region Name';
 

lib/l10n/app_localizations_de.dart

@@ -357,6 +357,16 @@ class AppLocalizationsDe extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Region hinzufügen';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Regions-Name';
 

lib/l10n/app_localizations_en.dart

@@ -350,6 +350,16 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Add region';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Region Name';
 

lib/l10n/app_localizations_es.dart

@@ -354,6 +354,16 @@ class AppLocalizationsEs extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Add region';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Region Name';
 

lib/l10n/app_localizations_fr.dart

@@ -356,6 +356,16 @@ class AppLocalizationsFr extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Add region';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Region Name';
 

lib/l10n/app_localizations_hu.dart

@@ -353,6 +353,16 @@ class AppLocalizationsHu extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Add region';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Region Name';
 

lib/l10n/app_localizations_it.dart

@@ -356,6 +356,16 @@ class AppLocalizationsIt extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Add region';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Region Name';
 

lib/l10n/app_localizations_ja.dart

@@ -341,6 +341,16 @@ class AppLocalizationsJa extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Add region';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Region Name';
 

lib/l10n/app_localizations_ko.dart

@@ -340,6 +340,16 @@ class AppLocalizationsKo extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Add region';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Region Name';
 

lib/l10n/app_localizations_nl.dart

@@ -352,6 +352,16 @@ class AppLocalizationsNl extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Add region';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Region Name';
 

lib/l10n/app_localizations_pl.dart

@@ -358,6 +358,16 @@ class AppLocalizationsPl extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Add region';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Region Name';
 

lib/l10n/app_localizations_pt.dart

@@ -356,6 +356,16 @@ class AppLocalizationsPt extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Add region';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Region Name';
 

lib/l10n/app_localizations_ru.dart

@@ -355,6 +355,16 @@ class AppLocalizationsRu extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Add region';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Region Name';
 

lib/l10n/app_localizations_sk.dart

@@ -354,6 +354,16 @@ class AppLocalizationsSk extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Add region';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Region Name';
 

lib/l10n/app_localizations_sl.dart

@@ -352,6 +352,16 @@ class AppLocalizationsSl extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Add region';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Region Name';
 

lib/l10n/app_localizations_sv.dart

@@ -352,6 +352,16 @@ class AppLocalizationsSv extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Add region';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Region Name';
 

lib/l10n/app_localizations_uk.dart

@@ -354,6 +354,16 @@ class AppLocalizationsUk extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Add region';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Region Name';
 

lib/l10n/app_localizations_zh.dart

@@ -338,6 +338,16 @@ class AppLocalizationsZh extends AppLocalizations {
   @override
   String get settings_regionAddRegion => 'Add region';
 
+  @override
+  String get settings_regionFetchRegions => 'Fetch regions from repeaters';
+
+  @override
+  String get settings_regionFetchRegionsFail => 'No regions were found';
+
+  @override
+  String get settings_regionFetchRegionsAlreadyExists =>
+      'This region has already been added';
+
   @override
   String get settings_regionName => 'Region Name';
 

lib/screens/region_management_screen.dart

@@ -1,7 +1,12 @@
+import 'dart:async';
+import 'dart:convert';
+
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:meshcore_open/connector/meshcore_connector.dart';
+import 'package:meshcore_open/connector/meshcore_protocol.dart';
 import 'package:meshcore_open/l10n/l10n.dart';
+import 'package:meshcore_open/models/contact.dart';
 import 'package:meshcore_open/storage/region_store.dart';
 import 'package:provider/provider.dart';
 
@@ -22,8 +27,11 @@ class RegionManagementScreen extends StatefulWidget {
 }
 
 class _RegionManagementScreenState extends State<RegionManagementScreen> {
+  static final RegExp _validFetchedRegion = RegExp(r'^[a-z0-9-]{1,30}$');
+
   final RegionStore _regionStore = RegionStore();
   List<Region> _regions = [];
+  bool _isFetchingRegions = false;
 
   String region = '';
 
@@ -59,6 +67,17 @@ class _RegionManagementScreenState extends State<RegionManagementScreen> {
             icon: const Icon(Icons.add),
             onPressed: () => _showAddRegionDialog(context),
           ),
+          IconButton(
+            tooltip: l10n.settings_regionFetchRegions,
+            icon: _isFetchingRegions
+                ? const SizedBox(
+                    width: 20,
+                    height: 20,
+                    child: CircularProgressIndicator(strokeWidth: 2),
+                  )
+                : const Icon(Icons.travel_explore),
+            onPressed: _isFetchingRegions ? null : _showFetchRegionsDialog,
+          ),
         ],
       ),
       body: ListView.builder(
@@ -107,6 +126,321 @@ class _RegionManagementScreenState extends State<RegionManagementScreen> {
     );
   }
 
+  Future<void> _showFetchRegionsDialog() async {
+    if (_isFetchingRegions) return;
+
+    setState(() {
+      _isFetchingRegions = true;
+    });
+
+    Set<Region> fetchedRegions = {};
+    try {
+      fetchedRegions = await _fetchRegionsFromRepeaters();
+    } finally {
+      if (mounted) {
+        setState(() {
+          _isFetchingRegions = false;
+        });
+      }
+    }
+
+    if (!mounted) return;
+    final l10n = context.l10n;
+    final sortedRegions = fetchedRegions.toList()..sort();
+    await showDialog<void>(
+      context: context,
+      builder: (dialogContext) => AlertDialog(
+        title: Text(l10n.settings_regionFetchRegions),
+        content: sortedRegions.isEmpty
+            ? Text(l10n.settings_regionFetchRegionsFail)
+            : StatefulBuilder(
+                builder: (context, setDialogState) {
+                  return SizedBox(
+                    width: double.maxFinite,
+                    child: ListView.builder(
+                      shrinkWrap: true,
+                      itemCount: sortedRegions.length,
+                      itemBuilder: (context, index) {
+                        final fetchedRegion = sortedRegions[index];
+                        final alreadyExists = _regions.contains(fetchedRegion);
+                        return Card(
+                          child: ListTile(
+                            title: Text(fetchedRegion),
+                            trailing: TextButton(
+                              style: alreadyExists
+                                  ? TextButton.styleFrom(
+                                      foregroundColor: Theme.of(
+                                        context,
+                                      ).disabledColor,
+                                    )
+                                  : null,
+                              onPressed: () {
+                                if (alreadyExists) {
+                                  _showDialogSnackBar(
+                                    context,
+                                    l10n.settings_regionFetchRegionsAlreadyExists,
+                                  );
+                                  return;
+                                }
+
+                                _regionStore.addRegion(fetchedRegion);
+                                _loadRegions();
+                                setDialogState(() {});
+                              },
+                              child: Text(l10n.common_add),
+                            ),
+                          ),
+                        );
+                      },
+                    ),
+                  );
+                },
+              ),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(dialogContext),
+            child: Text(l10n.common_close),
+          ),
+        ],
+      ),
+    );
+  }
+
+  void _showDialogSnackBar(BuildContext context, String message) {
+    final overlay = Overlay.maybeOf(context);
+    if (overlay == null) return;
+
+    final theme = Theme.of(context);
+    final entry = OverlayEntry(
+      builder: (context) => Positioned(
+        left: 16,
+        right: 16,
+        bottom: 32,
+        child: SafeArea(
+          child: Material(
+            color: theme.colorScheme.inverseSurface,
+            elevation: 6,
+            borderRadius: BorderRadius.circular(4),
+            child: Padding(
+              padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 14),
+              child: Text(
+                message,
+                style: theme.textTheme.bodyMedium?.copyWith(
+                  color: theme.colorScheme.onInverseSurface,
+                ),
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    overlay.insert(entry);
+    Timer(const Duration(seconds: 3), entry.remove);
+  }
+
+  Future<Set<Region>> _fetchRegionsFromRepeaters() async {
+    final connector = context.read<MeshCoreConnector>();
+    final repeaters = await _discoverNearbyRepeaters(connector);
+    final regions = <Region>{};
+
+    for (final repeater in repeaters) {
+      if (!mounted || !connector.isConnected) break;
+      regions.addAll(await _requestRegionsFromRepeater(connector, repeater));
+    }
+
+    return regions;
+  }
+
+  Future<List<Contact>> _discoverNearbyRepeaters(
+    MeshCoreConnector connector,
+  ) async {
+    final repeaters = connector.contacts
+        .where((contact) => contact.type == advTypeRepeater)
+        .toList();
+    if (repeaters.isEmpty || !connector.isConnected) return <Contact>[];
+
+    StreamSubscription<Uint8List>? subscription;
+    Timer? timeout;
+    final completer = Completer<Set<String>>();
+    final respondingPrefixes = <String>{};
+    final tag = DateTime.now().microsecondsSinceEpoch & 0xFFFFFFFF;
+
+    void complete() {
+      if (completer.isCompleted) return;
+      timeout?.cancel();
+      subscription?.cancel();
+      completer.complete(respondingPrefixes);
+    }
+
+    subscription = connector.receivedFrames.listen((frame) {
+      if (frame.isEmpty || completer.isCompleted) return;
+
+      final reader = BufferReader(frame);
+      try {
+        if (reader.readByte() != pushCodeControlData) return;
+        if (reader.remaining < 9) return;
+        reader.skipBytes(3); // SNR, RSSI, path_len from companion firmware.
+
+        final payloadType = reader.readByte();
+        if (((payloadType >> 4) & 0x0F) != controlSubtypeDiscoverResp ||
+            (payloadType & 0x0F) != advTypeRepeater) {
+          return;
+        }
+
+        reader.skipBytes(1); // Inbound SNR reported by the responding repeater.
+        if (reader.readUInt32LE() != tag) return;
+
+        final publicKeyPrefix = reader.readRemainingBytes();
+        if (publicKeyPrefix.isEmpty) return;
+        respondingPrefixes.add(pubKeyToHex(publicKeyPrefix));
+      } catch (_) {
+        // Ignore malformed discovery frames; another response may still arrive.
+      }
+    });
+
+    try {
+      final payload = buildDiscoveryRequestPayload(tag, prefixOnly: true);
+      await connector.sendFrame(buildSendControlDataFrame(payload));
+      timeout = Timer(const Duration(seconds: 10), complete);
+      final prefixes = await completer.future;
+      return repeaters.where((contact) {
+        final contactKey = contact.publicKeyHex.toLowerCase();
+        return prefixes.any((prefix) => contactKey.startsWith(prefix));
+      }).toList();
+    } catch (_) {
+      timeout?.cancel();
+      await subscription.cancel();
+      return <Contact>[];
+    }
+  }
+
+  Future<Set<Region>> _requestRegionsFromRepeater(
+    MeshCoreConnector connector,
+    Contact repeater,
+  ) async {
+    StreamSubscription<Uint8List>? subscription;
+    Timer? timeout;
+    final completer = Completer<Set<Region>>();
+    int? expectedTag;
+    final originalPath = Uint8List.fromList(repeater.path);
+    final originalPathLength = repeater.pathLength;
+    var pathChangedForRequest = false;
+
+    void complete(Set<Region> regions) {
+      if (completer.isCompleted) return;
+      timeout?.cancel();
+      subscription?.cancel();
+      completer.complete(regions);
+    }
+
+    void restartTimeout(Duration duration) {
+      timeout?.cancel();
+      timeout = Timer(duration, () => complete(<Region>{}));
+    }
+
+    try {
+      final replyPath = Uint8List(0);
+      const replyHopCount = 0;
+      await connector.setContactPath(repeater, replyPath, replyHopCount);
+      pathChangedForRequest = true;
+
+      subscription = connector.receivedFrames.listen((frame) {
+        if (frame.isEmpty || completer.isCompleted) return;
+
+        final reader = BufferReader(frame);
+        try {
+          final cmd = reader.readByte();
+          if (cmd == respCodeSent) {
+            reader.skipBytes(1);
+            expectedTag = reader.readUInt32LE();
+            final estimatedTimeoutMs = reader.readUInt32LE();
+            restartTimeout(
+              Duration(
+                milliseconds: estimatedTimeoutMs > 0
+                    ? estimatedTimeoutMs + 2000
+                    : 10000,
+              ),
+            );
+            return;
+          }
+
+          if (cmd == respCodeErr) {
+            complete(<Region>{});
+            return;
+          }
+
+          if (cmd != pushCodeBinaryResponse || expectedTag == null) return;
+
+          reader.skipBytes(1);
+          final tag = reader.readUInt32LE();
+          if (tag != expectedTag) return;
+
+          complete(_parseRegionsResponse(reader.readRemainingBytes()));
+        } catch (_) {
+          complete(<Region>{});
+        }
+      });
+
+      restartTimeout(const Duration(seconds: 10));
+      final frame = buildSendAnonReqFrame(
+        repeater.publicKey,
+        requestType: anonReqTypeRegions,
+        replyPath: replyPath,
+        replyHopCount: replyHopCount,
+        pathHashWidth: connector.pathHashByteWidth,
+      );
+      await connector.sendFrame(frame);
+      final regions = await completer.future;
+      if (pathChangedForRequest && connector.isConnected) {
+        await _restoreRepeaterPath(
+          connector,
+          repeater,
+          originalPathLength,
+          originalPath,
+        );
+      }
+      return regions;
+    } catch (_) {
+      timeout?.cancel();
+      subscription?.cancel();
+      if (pathChangedForRequest && connector.isConnected) {
+        await _restoreRepeaterPath(
+          connector,
+          repeater,
+          originalPathLength,
+          originalPath,
+        );
+      }
+      return <Region>{};
+    }
+  }
+
+  Future<void> _restoreRepeaterPath(
+    MeshCoreConnector connector,
+    Contact repeater,
+    int originalPathLength,
+    Uint8List originalPath,
+  ) async {
+    if (originalPathLength < 0) {
+      await connector.clearContactPath(repeater);
+      return;
+    }
+    await connector.setContactPath(repeater, originalPath, originalPathLength);
+  }
+
+  Set<Region> _parseRegionsResponse(Uint8List frame) {
+    if (frame.length <= 4) return <Region>{};
+    final names = utf8
+        .decode(frame.sublist(4), allowMalformed: true)
+        .replaceAll('\x00', '')
+        .split(',');
+    return names
+        .map((name) => name.trim())
+        .where((name) => _validFetchedRegion.hasMatch(name))
+        .toSet();
+  }
+
   void _handleAddRegion(Region region, BuildContext context) {
     Navigator.pop(context);
     _regionStore.addRegion(region);