feat: add Codec2 voice messages over LoRa mesh (iOS/macOS only)

Push-to-talk voice messaging using the Codec2 ultra-low-bitrate speech
codec, transmitted as V: prefixed packets over the existing MeshCore
LoRa mesh pipeline.

Voice recording UI (long-press send button or + menu) is gated behind
Platform.isIOS || Platform.isMacOS since the `record` package only
supports microphone capture on those platforms in this build.

Key changes:
- VoiceRecorderService: streams 8kHz mono PCM chunks via `record` package
- VoicePlayerService: decodes Codec2 bytes to WAV and plays via audioplayers
- VoiceCodecService: async Codec2 encode/decode in background isolates
- VoiceProvider: reassembles multi-packet sessions, drives playback
- VoiceMessageBubble: shows packet progress, play/stop controls
- MessagesProvider: detects V: prefix, routes to VoiceProvider
- MessagesTab: PTT long-press gesture + recording indicator (iOS/macOS)
- Message model: isVoice + voiceId fields for session tracking
- Auto-selects codec mode from radio bandwidth (700C/1200/1300 bps)
- codec2_flutter + meshcore_client switched from path to git deps

lib/providers/app_provider.dart

@@ -6,11 +6,13 @@ import 'contacts_provider.dart';
 import 'messages_provider.dart';
 import 'drawing_provider.dart';
 import 'channels_provider.dart';
+import 'voice_provider.dart';
 import '../services/tile_cache_service.dart';
 import '../services/location_tracking_service.dart';
 import '../models/contact.dart';
 import '../models/message.dart';
 import '../utils/drawing_message_parser.dart';
+import '../utils/voice_message_parser.dart';
 
 /// Main App Provider - coordinates all other providers
 class AppProvider with ChangeNotifier {
@@ -19,6 +21,7 @@ class AppProvider with ChangeNotifier {
   final MessagesProvider messagesProvider;
   final DrawingProvider drawingProvider;
   final ChannelsProvider channelsProvider;
+  final VoiceProvider voiceProvider;
   final TileCacheService tileCacheService;
   final LocationTrackingService locationTrackingService =
       LocationTrackingService();
@@ -38,6 +41,7 @@ class AppProvider with ChangeNotifier {
     required this.messagesProvider,
     required this.drawingProvider,
     required this.channelsProvider,
+    required this.voiceProvider,
     required this.tileCacheService,
   }) {
     _setupCallbacks();
@@ -335,6 +339,19 @@ class AppProvider with ChangeNotifier {
         return;
       }
 
+      // If it's a text-format voice packet, feed it to VoiceProvider
+      if (VoicePacket.isVoiceText(enrichedMessage.text)) {
+        final pkt = VoicePacket.tryParseText(enrichedMessage.text);
+        if (pkt != null) {
+          voiceProvider.addPacket(pkt);
+          // Mark the message with voice metadata before adding to chat
+          enrichedMessage = enrichedMessage.copyWith(
+            isVoice: true,
+            voiceId: pkt.sessionId,
+          );
+        }
+      }
+
       // Pass contact lookup function to link channel messages with contacts
       messagesProvider.addMessage(
         enrichedMessage,
@@ -380,6 +397,18 @@ class AppProvider with ChangeNotifier {
       contactsProvider.updateTelemetry(publicKeyPrefix, responseData);
     };
 
+    // When raw binary data is received (PUSH_CODE_RAW_DATA 0x84)
+    // Used for direct binary voice packets (VoicePacket binary format, magic 0x56 'V')
+    connectionProvider.onRawDataReceived = (payload, snrRaw, rssiDbm) {
+      if (!VoicePacket.isVoiceBinary(payload)) return;
+      final pkt = VoicePacket.tryParseBinary(payload);
+      if (pkt == null) return;
+      debugPrint('🎙️ [AppProvider] Binary voice packet received: $pkt');
+      final justComplete = voiceProvider.addPacket(pkt);
+      // Insert or update the placeholder message in the chat list
+      _handleIncomingVoicePacket(pkt, justComplete: justComplete);
+    };
+
     // When a contact's routing path is updated in the mesh network
     connectionProvider.onPathUpdated = (publicKey) {
       debugPrint(
@@ -693,6 +722,41 @@ class AppProvider with ChangeNotifier {
     }
   }
 
+  /// Insert or update a voice placeholder message for binary raw-data packets.
+  ///
+  /// Binary voice packets arrive without a chat message, so we synthesise one
+  /// to give the user a playable bubble in the message list.
+  void _handleIncomingVoicePacket(VoicePacket pkt, {required bool justComplete}) {
+    final sessionId = pkt.sessionId;
+
+    // Check if a placeholder for this session already exists
+    final existing = messagesProvider.messages.where(
+      (m) => m.isVoice && m.voiceId == sessionId,
+    ).firstOrNull;
+
+    if (existing != null) {
+      // Already have a placeholder — no need to add another
+      return;
+    }
+
+    // First packet of a new session: insert placeholder message
+    final msgId = 'voice_$sessionId';
+    final placeholder = Message(
+      id: msgId,
+      messageType: MessageType.contact, // direct contact (binary only)
+      senderPublicKeyPrefix: null,
+      pathLen: 0,
+      textType: MessageTextType.plain,
+      senderTimestamp: DateTime.now().millisecondsSinceEpoch ~/ 1000,
+      text: '', // no text — displayed as VoiceMessageBubble
+      receivedAt: DateTime.now(),
+      deliveryStatus: MessageDeliveryStatus.received,
+      isVoice: true,
+      voiceId: sessionId,
+    );
+    messagesProvider.addMessage(placeholder, contactLookup: (_) => '');
+  }
+
   // Removed _syncMessages() - messages are automatically synced via PUSH_CODE_MSG_WAITING events
   // The ConnectionProvider's onMessageWaiting callback handles automatic message fetching
 

lib/providers/connection_provider.dart

@@ -167,6 +167,7 @@ class ConnectionProvider with ChangeNotifier {
   Function(String messageId, int echoCount, int snrRaw, int rssiDbm)?
   onMessageEchoDetected;
   Function(Uint8List publicKeyPrefix, Uint8List statusData)? onStatusResponse;
+  Function(Uint8List payload, int snrRaw, int rssiDbm)? onRawDataReceived;
 
   // Track pending send operations for auto-recovery
   final Map<String, _PendingSendOperation> _pendingSendOperations = {};
@@ -498,6 +499,10 @@ class ConnectionProvider with ChangeNotifier {
       onStatusResponse?.call(publicKeyPrefix, statusData);
     };
 
+    _bleService.onRawDataReceived = (payload, snrRaw, rssiDbm) {
+      onRawDataReceived?.call(payload, snrRaw, rssiDbm);
+    };
+
     _bleService.onDeviceInfoReceived = (deviceInfo) {
       debugPrint('📥 [Provider] Received DeviceInfo:');
       debugPrint('  Firmware Version: ${deviceInfo['firmwareVersion']}');
@@ -1318,6 +1323,21 @@ class ConnectionProvider with ChangeNotifier {
     }
   }
 
+  /// Send a raw binary voice packet directly to a contact (cmdSendRawData, code 25).
+  /// Only works for contacts with a known direct route (outPathLen >= 0).
+  Future<void> sendRawVoicePacket({
+    required Uint8List contactPath,
+    required int contactPathLen,
+    required Uint8List payload,
+  }) async {
+    if (!_bleService.isConnected) return;
+    await _bleService.sendRawVoicePacket(
+      contactPathLen: contactPathLen,
+      contactPath: contactPath,
+      payload: payload,
+    );
+  }
+
   /// Request telemetry from contact
   ///
   /// COMPATIBILITY NOTE: This method sends CMD_SEND_TELEMETRY_REQ (39).

lib/providers/messages_provider.dart

@@ -8,6 +8,7 @@ import '../services/message_storage_service.dart';
 import '../services/notification_service.dart';
 import '../utils/sar_message_parser.dart';
 import '../utils/drawing_message_parser.dart';
+import '../utils/voice_message_parser.dart';
 import '../l10n/app_localizations.dart';
 import 'helpers/message_retry_manager.dart';
 
@@ -277,6 +278,17 @@ class MessagesProvider with ChangeNotifier {
       );
     }
 
+    // Check if it's a voice message (V:...) and not already marked
+    if (VoicePacket.isVoiceText(enhancedMessage.text) && !enhancedMessage.isVoice) {
+      final pkt = VoicePacket.tryParseText(enhancedMessage.text);
+      if (pkt != null) {
+        enhancedMessage = enhancedMessage.copyWith(
+          isVoice: true,
+          voiceId: pkt.sessionId,
+        );
+      }
+    }
+
     // For channel messages with sender name, try to link with contact
     Message finalMessage = enhancedMessage;
     if (enhancedMessage.isChannelMessage &&

lib/providers/voice_provider.dart

@@ -0,0 +1,121 @@
+import 'dart:async';
+import 'package:flutter/foundation.dart';
+import '../utils/voice_message_parser.dart';
+import '../services/voice_codec_service.dart';
+import '../services/voice_player_service.dart';
+
+/// Reassembly state for one voice session.
+class VoiceSession {
+  final String sessionId;
+  final VoicePacketMode mode;
+  final int total;
+  final List<VoicePacket?> packets; // indexed by packet.index
+
+  VoiceSession({
+    required this.sessionId,
+    required this.mode,
+    required this.total,
+  }) : packets = List.filled(total, null);
+
+  int get receivedCount => packets.where((p) => p != null).length;
+  bool get isComplete => receivedCount == total;
+
+  /// Total estimated audio duration in seconds (sum of all received packets).
+  double get estimatedDurationSeconds {
+    var ms = 0;
+    for (final p in packets) {
+      if (p != null) ms += p.durationMs;
+    }
+    return ms / 1000.0;
+  }
+}
+
+/// Manages incoming voice packet sessions and coordinates playback.
+class VoiceProvider with ChangeNotifier {
+  final VoiceCodecService _codec;
+  final VoicePlayerService _player;
+
+  /// Active sessions keyed by sessionId.
+  final Map<String, VoiceSession> _sessions = {};
+
+  /// Currently playing session ID, or null.
+  String? _playingSessionId;
+
+  VoiceProvider({
+    required VoiceCodecService codec,
+    required VoicePlayerService player,
+  })  : _codec = codec,
+        _player = player;
+
+  // ── Session accessors ────────────────────────────────────────────────────
+
+  VoiceSession? session(String sessionId) => _sessions[sessionId];
+  bool isComplete(String sessionId) => _sessions[sessionId]?.isComplete ?? false;
+  bool isPlaying(String sessionId) =>
+      _playingSessionId == sessionId && _player.isPlaying;
+
+  // ── Packet reception ─────────────────────────────────────────────────────
+
+  /// Add an incoming [packet] to its session.  Creates the session on first packet.
+  /// Returns true if the session just became complete.
+  bool addPacket(VoicePacket packet) {
+    _sessions.putIfAbsent(
+      packet.sessionId,
+      () => VoiceSession(
+        sessionId: packet.sessionId,
+        mode: packet.mode,
+        total: packet.total,
+      ),
+    );
+
+    final session = _sessions[packet.sessionId]!;
+    if (packet.index < session.total) {
+      session.packets[packet.index] = packet;
+    }
+
+    final justComplete = session.isComplete;
+    notifyListeners();
+    return justComplete;
+  }
+
+  // ── Playback ─────────────────────────────────────────────────────────────
+
+  /// Decode and play the voice session with [sessionId].
+  /// Plays whatever packets are available (handles partial reception gracefully).
+  Future<void> play(String sessionId) async {
+    final session = _sessions[sessionId];
+    if (session == null) {
+      debugPrint('❌ [VoiceProvider] play($sessionId) — session not found, known: ${_sessions.keys.toList()}');
+      return;
+    }
+
+    debugPrint('🎙️ [VoiceProvider] play($sessionId): ${session.receivedCount}/${session.total} packets, mode=${session.mode.label}');
+
+    try {
+      final pcm = await _codec.decodePackets(session.packets, session.mode);
+      debugPrint('🎙️ [VoiceProvider] decoded ${pcm.length} PCM samples');
+      _playingSessionId = sessionId;
+      notifyListeners();
+      await _player.play(pcm);
+    } catch (e, st) {
+      debugPrint('❌ [VoiceProvider] Playback error: $e\n$st');
+    } finally {
+      if (_playingSessionId == sessionId) {
+        _playingSessionId = null;
+        notifyListeners();
+      }
+    }
+  }
+
+  Future<void> stop() async {
+    await _player.stop();
+    _playingSessionId = null;
+    notifyListeners();
+  }
+
+  @override
+  void dispose() {
+    _player.dispose();
+    super.dispose();
+  }
+}