Add retransmission handling

lib/providers/connection_provider.dart

@@ -249,7 +249,10 @@ class ConnectionProvider with ChangeNotifier {
         await Future.delayed(const Duration(milliseconds: 300));
 
         if (pendingOp.messageId != null) {
-          _messageDeliveryTracker.trackPendingMessage(pendingOp.messageId!);
+          _messageDeliveryTracker.trackPendingDirectMessage(
+            pendingOp.messageId!,
+            pendingOp.contactPublicKey,
+          );
         }
 
         await _activeService.sendTextMessage(
@@ -352,7 +355,11 @@ class ConnectionProvider with ChangeNotifier {
 
     service.onMessageSent =
         (expectedAckTag, suggestedTimeoutMs, isFloodMode, contactPublicKey) {
-          final messageId = _messageDeliveryTracker.popPendingMessageId();
+          final messageId = contactPublicKey != null
+              ? _messageDeliveryTracker.popPendingDirectMessageId(
+                  contactPublicKey,
+                )
+              : _messageDeliveryTracker.popPendingMessageId();
           if (messageId != null) {
             _messageDeliveryTracker.mapAckTagToMessageId(
               expectedAckTag,
@@ -1148,7 +1155,10 @@ class ConnectionProvider with ChangeNotifier {
       // The MessagesProvider now uses simple ACK tag → recipientPublicKey mapping.
       // We still track here for the SENT response callback to work.
       if (messageId != null) {
-        _messageDeliveryTracker.trackPendingMessage(messageId);
+        _messageDeliveryTracker.trackPendingDirectMessage(
+          messageId,
+          contactPublicKey,
+        );
         debugPrint('  📝 Tracked pending message: $messageId');
       }
 

lib/providers/helpers/message_delivery_tracker.dart

@@ -1,3 +1,5 @@
+import 'dart:typed_data';
+
 /// Message delivery tracking helper
 ///
 /// Manages message delivery tracking for sent messages, including:
@@ -16,6 +18,9 @@ class MessageDeliveryTracker {
   /// Messages tracked here before sending, popped when RESP_CODE_SENT arrives
   final List<String> _pendingMessageIds = [];
 
+  /// Contact-scoped FIFOs for matching direct-message SENT responses.
+  final Map<String, List<String>> _pendingMessageIdsByContact = {};
+
   /// Map of ACK tag to message ID for delivery confirmation
   final Map<int, String> _ackTagToMessageId = {};
 
@@ -33,6 +38,15 @@ class MessageDeliveryTracker {
     _pendingMessageIds.add(messageId);
   }
 
+  /// Track a pending direct message ID for a specific contact.
+  void trackPendingDirectMessage(String messageId, Uint8List contactPublicKey) {
+    trackPendingMessage(messageId);
+    final contactKey = _contactKey(contactPublicKey);
+    _pendingMessageIdsByContact
+        .putIfAbsent(contactKey, () => [])
+        .add(messageId);
+  }
+
   /// Pop the next pending message ID from FIFO queue
   ///
   /// Called when RESP_CODE_SENT arrives. Returns null if queue empty.
@@ -43,6 +57,24 @@ class MessageDeliveryTracker {
     return _pendingMessageIds.removeAt(0);
   }
 
+  /// Pop the next pending direct message ID for a specific contact.
+  ///
+  /// Falls back to the legacy global FIFO if the contact queue is empty.
+  String? popPendingDirectMessageId(Uint8List contactPublicKey) {
+    final contactKey = _contactKey(contactPublicKey);
+    final queue = _pendingMessageIdsByContact[contactKey];
+    if (queue == null || queue.isEmpty) {
+      return popPendingMessageId();
+    }
+
+    final messageId = queue.removeAt(0);
+    if (queue.isEmpty) {
+      _pendingMessageIdsByContact.remove(contactKey);
+    }
+    _pendingMessageIds.remove(messageId);
+    return messageId;
+  }
+
   /// Map ACK tag to message ID after RESP_CODE_SENT received
   ///
   /// Creates bidirectional mapping for efficient cleanup and tracking.
@@ -86,6 +118,17 @@ class MessageDeliveryTracker {
       _ackTagToMessageId.remove(ackTag);
       _ackTagTimestamps.remove(ackTag);
     }
+    _pendingMessageIds.remove(messageId);
+    final emptyKeys = <String>[];
+    for (final entry in _pendingMessageIdsByContact.entries) {
+      entry.value.remove(messageId);
+      if (entry.value.isEmpty) {
+        emptyKeys.add(entry.key);
+      }
+    }
+    for (final key in emptyKeys) {
+      _pendingMessageIdsByContact.remove(key);
+    }
   }
 
   /// Clean up stale ACK mappings
@@ -114,6 +157,7 @@ class MessageDeliveryTracker {
   /// Clear all tracking state
   void clearTracking() {
     _pendingMessageIds.clear();
+    _pendingMessageIdsByContact.clear();
     _ackTagToMessageId.clear();
     _messageIdToAckTag.clear();
     _ackTagTimestamps.clear();
@@ -133,9 +177,7 @@ class MessageDeliveryTracker {
   /// Get oldest pending ACK timestamp (for debugging)
   DateTime? get oldestPendingTimestamp {
     if (_ackTagTimestamps.isEmpty) return null;
-    return _ackTagTimestamps.values.reduce(
-      (a, b) => a.isBefore(b) ? a : b,
-    );
+    return _ackTagTimestamps.values.reduce((a, b) => a.isBefore(b) ? a : b);
   }
 
   /// Get diagnostic info for debugging
@@ -145,6 +187,15 @@ class MessageDeliveryTracker {
       'shouldRateLimit': shouldRateLimit,
       'oldestPending': oldestPendingTimestamp?.toIso8601String(),
       'ackTags': _ackTagToMessageId.keys.toList(),
+      'pendingByContact': _pendingMessageIdsByContact.map(
+        (key, value) => MapEntry(key, value.length),
+      ),
     };
   }
+
+  String _contactKey(Uint8List contactPublicKey) {
+    return contactPublicKey
+        .map((b) => b.toRadixString(16).padLeft(2, '0'))
+        .join();
+  }
 }

lib/providers/messages_provider.dart

@@ -28,6 +28,9 @@ class MessagesProvider with ChangeNotifier {
   // Key: message ID (not ACK tag, since multiple messages can share same ACK)
   final Map<String, Timer> _timeoutTimers = {};
 
+  // Recently completed ACKs are kept briefly to ignore duplicate confirms.
+  final Map<int, DateTime> _completedAckHistory = {};
+
   // Retry management
   final MessageRetryManager _retryManager = MessageRetryManager();
 
@@ -906,11 +909,13 @@ class MessagesProvider with ChangeNotifier {
       final (groupId, recipientPublicKey) = groupMapping;
       debugPrint('  ✅ This is part of a grouped message: $groupId');
 
-      // Update the recipient status to "sent" in the grouped message
+      // ACK-tracked recipients stay pending until the delivery confirm arrives.
       updateGroupedMessageRecipientStatus(
         groupId,
         recipientPublicKey,
-        MessageDeliveryStatus.sent,
+        expectedAckTag > 0
+            ? MessageDeliveryStatus.sending
+            : MessageDeliveryStatus.sent,
       );
 
       // Track the ACK for this specific recipient
@@ -1022,7 +1027,9 @@ class MessagesProvider with ChangeNotifier {
       );
 
       final updatedMessage = message.copyWith(
-        deliveryStatus: MessageDeliveryStatus.sent,
+        deliveryStatus: expectedAckTag > 0
+            ? MessageDeliveryStatus.sending
+            : MessageDeliveryStatus.sent,
         expectedAckTag: expectedAckTag > 0 ? expectedAckTag : null,
         suggestedTimeoutMs: suggestedTimeoutMs > 0 ? suggestedTimeoutMs : null,
       );
@@ -1245,6 +1252,7 @@ class MessagesProvider with ChangeNotifier {
 
   /// Update message status to delivered with RTT
   void markMessageDelivered(int ackCode, int roundTripTimeMs) {
+    _cleanupCompletedAckHistory();
     debugPrint(
       '🔍 [MessagesProvider] markMessageDelivered called with ACK: $ackCode, RTT: ${roundTripTimeMs}ms',
     );
@@ -1296,6 +1304,7 @@ class MessagesProvider with ChangeNotifier {
         );
         _ackTagToRecipients.remove(ackCode);
         _pendingSentMessages.remove(ackCode);
+        _rememberCompletedAck(ackCode);
       }
 
       debugPrint(
@@ -1339,6 +1348,7 @@ class MessagesProvider with ChangeNotifier {
 
         // Remove from pending
         _pendingSentMessages.remove(ackCode);
+        _rememberCompletedAck(ackCode);
 
         // Clear retry tracking on successful delivery
         _retryManager.clearRetry(message.id);
@@ -1362,6 +1372,12 @@ class MessagesProvider with ChangeNotifier {
         );
       }
     } else {
+      if (_completedAckHistory.containsKey(ackCode)) {
+        debugPrint(
+          'ℹ️ [MessagesProvider] Duplicate/late ACK $ackCode ignored (already completed)',
+        );
+        return;
+      }
       debugPrint(
         '⚠️ [MessagesProvider] No pending message found for ACK code: $ackCode',
       );
@@ -1482,18 +1498,31 @@ class MessagesProvider with ChangeNotifier {
         debugPrint(
           '⏰ [MessagesProvider] Executing retry $nextAttempt for message $messageId',
         );
+        final currentIndex = _messages.indexWhere((m) => m.id == messageId);
+        if (currentIndex == -1) {
+          return;
+        }
+        final currentMessage = _messages[currentIndex];
+        if (currentMessage.deliveryStatus == MessageDeliveryStatus.delivered) {
+          return;
+        }
+
         if (sendMessageCallback != null) {
-          await sendMessageCallback!(
+          final queued = await sendMessageCallback!(
             contactPublicKey: contact.publicKey,
             text: message.text,
             messageId: messageId,
             contact: contact,
             retryAttempt: nextAttempt,
           );
+          if (!queued) {
+            _markAsPermanentlyFailed(messageId, currentMessage);
+          }
         } else {
           debugPrint(
             '⚠️ [MessagesProvider] sendMessageCallback not set, cannot retry',
           );
+          _markAsPermanentlyFailed(messageId, currentMessage);
         }
       });
 
@@ -1529,17 +1558,21 @@ class MessagesProvider with ChangeNotifier {
 
       // Send with flood mode (no retry after this)
       if (sendMessageCallback != null) {
-        await sendMessageCallback!(
+        final queued = await sendMessageCallback!(
           contactPublicKey: contact.publicKey,
           text: message.text,
           messageId: messageId,
           contact: contact,
           retryAttempt: 0, // Reset attempt for flood
         );
+        if (!queued) {
+          _markAsPermanentlyFailed(messageId, _messages[index]);
+        }
       } else {
         debugPrint(
           '⚠️ [MessagesProvider] sendMessageCallback not set, cannot send flood',
         );
+        _markAsPermanentlyFailed(messageId, _messages[index]);
       }
 
       _persistMessages();
@@ -1608,17 +1641,21 @@ class MessagesProvider with ChangeNotifier {
 
     // Send again
     if (sendMessageCallback != null) {
-      await sendMessageCallback!(
+      final queued = await sendMessageCallback!(
         contactPublicKey: contact.publicKey,
         text: message.text,
         messageId: messageId,
         contact: contact,
         retryAttempt: 0,
       );
+      if (!queued) {
+        _markAsPermanentlyFailed(messageId, _messages[index]);
+      }
     } else {
       debugPrint(
         '⚠️ [MessagesProvider] sendMessageCallback not set, cannot resend',
       );
+      _markAsPermanentlyFailed(messageId, _messages[index]);
     }
 
     _persistMessages();
@@ -1631,10 +1668,29 @@ class MessagesProvider with ChangeNotifier {
       timer.cancel();
     }
     _timeoutTimers.clear();
+    _completedAckHistory.clear();
 
     // Clear retry manager
     _retryManager.clearAll();
 
     super.dispose();
   }
+
+  void _rememberCompletedAck(int ackCode) {
+    _completedAckHistory[ackCode] = DateTime.now();
+    _cleanupCompletedAckHistory();
+  }
+
+  void _cleanupCompletedAckHistory({
+    Duration maxAge = const Duration(minutes: 15),
+  }) {
+    final cutoff = DateTime.now().subtract(maxAge);
+    final staleAcks = _completedAckHistory.entries
+        .where((entry) => entry.value.isBefore(cutoff))
+        .map((entry) => entry.key)
+        .toList();
+    for (final ack in staleAcks) {
+      _completedAckHistory.remove(ack);
+    }
+  }
 }