From 67d8e1c90649e888b2a4682f589c92a4ab0c4cab Mon Sep 17 00:00:00 2001
From: Janez T <hey@dz0ny.dev>
Date: Wed, 18 Mar 2026 14:24:38 +0100
Subject: [PATCH] fix: Deduplicate telemetry from 0x8B + 0x8C double delivery

When firmware sends telemetry via both pushTelemetryResponse (0x8B)
and pushBinaryResponse (0x8C), the same LPP data was parsed and
applied twice, causing duplicate sensor entries.

Added hash-based dedup: same payload for same contact within 2s is
skipped. Also added minimum length check for binary responses.
---
 lib/providers/app_provider.dart      | 11 +++++++----
 lib/providers/contacts_provider.dart | 19 +++++++++++++++++++
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/lib/providers/app_provider.dart b/lib/providers/app_provider.dart
index 6e536b6..80ae80c 100644
--- a/lib/providers/app_provider.dart
+++ b/lib/providers/app_provider.dart
@@ -1338,11 +1338,14 @@ class AppProvider with ChangeNotifier {
         return;
       }
       debugPrint(
-        '📊 [AppProvider] Binary response (0x8C) received - updating contact telemetry',
+        '📊 [AppProvider] Binary response (0x8C tag=$tag) received',
       );
-      // Binary response tag 0 = telemetry data (Cayenne LPP format)
-      // Other tags may be used for different data types in the future
-      contactsProvider.updateTelemetry(publicKeyPrefix, responseData);
+      // Binary responses carry Cayenne LPP telemetry data.
+      // The data starts with a channel byte — valid LPP always has at least
+      // 3 bytes (channel + type + value). Skip clearly non-telemetry payloads.
+      if (responseData.length >= 3) {
+        contactsProvider.updateTelemetry(publicKeyPrefix, responseData);
+      }
     };
 
     // When raw binary data is received (PUSH_CODE_RAW_DATA 0x84)
diff --git a/lib/providers/contacts_provider.dart b/lib/providers/contacts_provider.dart
index 15039f0..c43af78 100644
--- a/lib/providers/contacts_provider.dart
+++ b/lib/providers/contacts_provider.dart
@@ -926,6 +926,10 @@ class ContactsProvider with ChangeNotifier {
   }
 
   /// Update contact telemetry
+  // Dedup: track last telemetry data hash per contact to avoid processing
+  // the same payload twice (0x8B + 0x8C can both fire for the same data).
+  final Map<String, (int, DateTime)> _lastTelemetryHash = {};
+
   void updateTelemetry(Uint8List publicKeyPrefix, Uint8List lppData) {
     debugPrint('📊 [ContactsProvider] updateTelemetry() called');
     debugPrint(
@@ -933,6 +937,21 @@ class ContactsProvider with ChangeNotifier {
     );
     debugPrint('  LPP data size: ${lppData.length} bytes');
 
+    // Deduplicate: same data for same contact within 2 seconds = skip
+    final prefixHex = publicKeyPrefix
+        .map((b) => b.toRadixString(16).padLeft(2, '0'))
+        .join();
+    final dataHash = lppData.fold<int>(0, (h, b) => h * 31 + b);
+    final now = DateTime.now();
+    final last = _lastTelemetryHash[prefixHex];
+    if (last != null &&
+        last.$1 == dataHash &&
+        now.difference(last.$2).inSeconds < 2) {
+      debugPrint('  ⏭️ Duplicate telemetry payload, skipping');
+      return;
+    }
+    _lastTelemetryHash[prefixHex] = (dataHash, now);
+
     // Find contact by public key prefix
     final contact = _findContactByPrefix(publicKeyPrefix);
     if (contact == null) {