From 56a4378a633b2b1afcef089b7a21a91c33f9cc4d Mon Sep 17 00:00:00 2001
From: Robin Mueller <muellerr@irs.uni-stuttgart.de>
Date: Thu, 16 Mar 2023 18:05:23 +0100
Subject: [PATCH] that should be transition safe

---
 mission/system/objects/ComSubsystem.cpp | 25 +++++++++++++++++++++----
 mission/system/objects/ComSubsystem.h   |  2 ++
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/mission/system/objects/ComSubsystem.cpp b/mission/system/objects/ComSubsystem.cpp
index 1d0d9b32..c6a8cfc9 100644
--- a/mission/system/objects/ComSubsystem.cpp
+++ b/mission/system/objects/ComSubsystem.cpp
@@ -24,6 +24,11 @@ ComSubsystem::ComSubsystem(object_id_t setObjectId, uint32_t maxNumberOfSequence
 
 void ComSubsystem::performChildOperation() {
   readEventQueue();
+  if (performRecoveryToRxOnly and not isInTransition) {
+    startRxOnlyRecovery(true);
+    // To avoid immediately enabling TX after falling back.
+    rememberBitLock = false;
+  }
   // Execute default rate sequence after transition has been completed
   if (rememberBitLock and not isInTransition) {
     startRxAndTxLowRateSeq();
@@ -151,10 +156,16 @@ void ComSubsystem::handleEventMessage(EventMessage *eventMessage) {
   Event event = eventMessage->getEvent();
   switch (event) {
     case tcsCtrl::SYRLINKS_OVERHEATING: {
-      // TODO: To prevent simply overwriting/cancelling on-going transitions, set flag here and
-      // execute transition at a later stage.
-      modeHelper.setForced(true);
-      startTransition(com::RX_ONLY, 0);
+      // This event overrides the bit lock.
+      rememberBitLock = false;
+      if (mode == com::RX_ONLY) {
+        return;
+      }
+      if (isInTransition) {
+        performRecoveryToRxOnly = true;
+        return;
+      }
+      startRxOnlyRecovery(true);
       break;
     }
     case PdecHandler::BIT_LOCK_PDEC: {
@@ -204,6 +215,12 @@ void ComSubsystem::checkTransmitterCountdown() {
   }
 }
 
+void ComSubsystem::startRxOnlyRecovery(bool forced) {
+  modeHelper.setForced(forced);
+  startTransition(com::RX_ONLY, 0);
+  performRecoveryToRxOnly = false;
+}
+
 bool ComSubsystem::isTxMode(Mode_t mode) {
   if ((mode == com::Submode::RX_AND_TX_DEFAULT_DATARATE) ||
       (mode == com::Submode::RX_AND_TX_LOW_DATARATE) ||
diff --git a/mission/system/objects/ComSubsystem.h b/mission/system/objects/ComSubsystem.h
index 854a877b..dbc8eda8 100644
--- a/mission/system/objects/ComSubsystem.h
+++ b/mission/system/objects/ComSubsystem.h
@@ -57,6 +57,7 @@ class ComSubsystem : public Subsystem, public ReceivesParameterMessagesIF {
    * @brief	Enables transmitter in low rate mode
    */
   void startRxAndTxLowRateSeq();
+  void startRxOnlyRecovery(bool forced);
 
   /**
    * @brief	Returns true if mode is a mode where the transmitter is on
@@ -73,6 +74,7 @@ class ComSubsystem : public Subsystem, public ReceivesParameterMessagesIF {
   MessageQueueIF *eventQueue = nullptr;
 
   bool enableTxWhenCarrierLock = false;
+  bool performRecoveryToRxOnly = false;
 
   // Countdown will be started as soon as the transmitter was enabled
   Countdown transmitterCountdown;