Improved BACK action appliable detection

transition_machine/include/Config.hpp

@@ -138,7 +138,7 @@ class Config
 
   private :
 
-  const unsigned int HISTORY_SIZE = 1000;
+  const unsigned int HISTORY_SIZE = 2000;
   /// @brief The name of the current state of the TransitionMachine.
   std::string currentStateName;
   /// @brief For each state of the TransitionMachine, an history of the Action that have been applied to this Config.

transition_machine/src/ActionBank.cpp

@@ -564,16 +564,37 @@ std::vector<Action::BasicAction> ActionBank::str2sequence(const std::string & na
         };
       auto appliable = [dist](Config & c, Action::BasicAction)
         {
-          std::string classifierName = c.pastActions.top().first;
-          int stateHistorySize = c.getStateHistory(classifierName).size();
-
-          if (c.getCurrentStateHistory().size() >= 2 && (c.getCurrentStateHistory().top() == "BACK" || c.getCurrentStateHistory().getElem(1) == "BACK"))
+          if (c.pastActions.size() == 0)
             return false;
 
+          const std::string & classifierName = c.pastActions.top().first;
+
           if (c.hashHistory.contains(c.computeHash()))
             return false;
 
-          if (stateHistorySize <= dist)
+          unsigned int topIndex = 0;
+
+          static auto undoOneTime = [](Config & c, const std::string & classifierName, unsigned int & topIndex)
+          {
+            while (true)
+            {
+              topIndex++;
+
+              if (topIndex >= c.pastActions.size())
+                return;
+
+              if (c.pastActions.getElem(topIndex).first == classifierName)
+                return;
+            }
+          };
+
+          undoOneTime(c, classifierName, topIndex);
+          for (int i = 0; i < dist-1; i++)
+            undoOneTime(c, classifierName, topIndex);
+
+          undoOneTime(c, classifierName, topIndex);
+
+          if (topIndex >= c.pastActions.size())
             return false;
 
           return true;