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Add conservative ACK timeout

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Janez T
2026-03-06 20:27:05 +01:00
parent 85d0b26c67
commit 43f5702666
5 changed files with 206 additions and 7 deletions
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62
lib/providers/helpers/message_retry_manager.dart
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@@ -1,3 +1,6 @@
import 'dart:convert';
import 'dart:math' as math;
import '../../models/message.dart';
import '../../models/contact.dart';
@@ -22,6 +25,12 @@ class MessageRetryManager {
// These are app-level timeouts, separate from firmware's suggested timeout
// Firmware timeout is for ACK arrival, these are for retry attempts
static const List<int> _timeouts = [4000, 8000, 12000];
static const int _defaultLoRaSf = 10;
static const int _defaultLoRaCr = 5;
static const int _defaultLoRaBwHz = 250000;
static const int _defaultLoRaPreambleSymbols = 8;
static const int _defaultLoRaCrcEnabled = 1;
static const int _defaultLoRaExplicitHeader = 1;
/// Get timeout for a specific retry attempt (0-2)
/// Returns: 4000ms for attempt 0, 8000ms for attempt 1, 12000ms for attempt 2
@@ -32,6 +41,30 @@ class MessageRetryManager {
return _timeouts[attempt];
}
/// Calculate a conservative delivery-ACK timeout when firmware doesn't
/// provide one or returns an invalid value.
int calculateAckTimeoutMs({
required String text,
required Contact? contact,
int? suggestedTimeoutMs,
}) {
if (suggestedTimeoutMs != null && suggestedTimeoutMs > 0) {
return suggestedTimeoutMs;
}
final payloadBytes = utf8.encode(text).length;
final airtimeMs = _estimateLoRaAirtimeMs(payloadBytes);
final hopCount = contact?.hasPath == true
? math.max(contact!.outPathLen, 0)
: -1;
if (hopCount < 0) {
return ((airtimeMs * 10) + 4000).clamp(10000, 30000);
}
return ((airtimeMs * (hopCount + 1) * 2) + 1500).clamp(4000, 20000);
}
/// Check if a message is eligible for retry
///
/// Returns true if:
@@ -67,8 +100,8 @@ class MessageRetryManager {
/// Contacts without paths already use flood mode automatically.
bool shouldUseFloodFallback(Message message, Contact contact) {
return message.retryAttempt >= 3 &&
contact.hasPath && // ✅ FIXED: Flood fallback for failed direct paths
!message.usedFloodFallback;
contact.hasPath && // ✅ FIXED: Flood fallback for failed direct paths
!message.usedFloodFallback;
}
/// Track a retry attempt for a message
@@ -98,4 +131,29 @@ class MessageRetryManager {
DateTime? getLastRetryTime(String messageId) {
return _lastRetryTimes[messageId];
}
int _estimateLoRaAirtimeMs(int payloadLenBytes) {
final sf = _defaultLoRaSf;
final bw = _defaultLoRaBwHz.toDouble();
final cr = (_defaultLoRaCr - 4).clamp(1, 4);
final ih = _defaultLoRaExplicitHeader == 1 ? 0 : 1;
final de = (sf >= 11 && _defaultLoRaBwHz <= 125000) ? 1 : 0;
final symbolMs = ((1 << sf) / bw) * 1000.0;
final preambleMs = (_defaultLoRaPreambleSymbols + 4.25) * symbolMs;
final num =
(8 * payloadLenBytes) -
(4 * sf) +
28 +
(16 * _defaultLoRaCrcEnabled) -
(20 * ih);
final den = 4 * (sf - (2 * de));
final payloadSymCoeff = den <= 0 ? 0 : (num / den).ceil();
final payloadSymbols =
8 + (payloadSymCoeff < 0 ? 0 : payloadSymCoeff) * (cr + 4);
final payloadMs = payloadSymbols * symbolMs;
return (preambleMs + payloadMs).ceil();
}
}