Don't run RCS in Node Executor when IDLE

We can be enabled and hammering on DoRCS every tick but not be doing
anything.

Added more initializion paranoia around resetting back to Idle as well.

Also bonus fixed that it doesn't rely on VesselState any more for doing
its own reflection poking around.

Signed-off-by: Lamont Granquist <lamont@scriptkiddie.org>

MechJeb2/MechJebModuleNodeExecutor.cs

@@ -9,11 +9,13 @@ namespace MuMech
 {
     public class MechJebModuleNodeExecutor : ComputerModule
     {
-        private static readonly bool realfuelsLoaded;
+        private static readonly bool _isLoadedRealFuels;
+        private static readonly bool _isLoadedPrincipia;
 
         static MechJebModuleNodeExecutor()
         {
-            realfuelsLoaded = ReflectionUtils.IsAssemblyLoaded("RealFuels");
+            _isLoadedRealFuels = ReflectionUtils.IsAssemblyLoaded("RealFuels");
+            _isLoadedPrincipia = ReflectionUtils.IsAssemblyLoaded("principia.ksp_plugin_adapter");
         }
 
         // whether to auto-warp to nodes
@@ -35,7 +37,7 @@ public string NextNodeBurnTime()
                 return "-";
 
             double dV;
-            if (VesselState.isLoadedPrincipia && _dvLeft > 0)
+            if (_isLoadedPrincipia && _dvLeft > 0)
             {
                 dV = _dvLeft;
             }
@@ -103,13 +105,15 @@ protected override void OnModuleEnabled()
         {
             Core.Attitude.Users.Add(this);
             Core.Thrust.Users.Add(this);
+            State = States.IDLE;
         }
 
         protected override void OnModuleDisabled()
         {
             Core.Attitude.attitudeDeactivate();
             Core.Thrust.ThrustOff();
             Core.Thrust.Users.Remove(this);
+            State   = States.IDLE;
             _dvLeft = 0;
         }
 
@@ -120,18 +124,20 @@ public enum States { WARPALIGN, LEAD, BURN, IDLE }
         private Mode   _mode = Mode.ONE_NODE;
         public  States State = States.IDLE;
 
-        private        double   _dvLeft;    // for Principia
-        private        Vector3d _direction; // de-rotated world vector
-        private        Vector3d _worldDirection => Planetarium.fetch.rotation * _direction;
-        private        double   _ignitionUT;
-        private static bool     _isLoadedPrincipia => VesselState.isLoadedPrincipia;
-        private        bool     _hasNodes          => Vessel.patchedConicSolver.maneuverNodes.Count > 0;
-        private        double   _ullageUntil;
+        private double   _dvLeft;    // for Principia
+        private Vector3d _direction; // de-rotated world vector
+        private Vector3d _worldDirection => Planetarium.fetch.rotation * _direction;
+        private double   _ignitionUT;
+        private bool     _hasNodes => Vessel.patchedConicSolver.maneuverNodes.Count > 0;
+        private double   _ullageUntil;
 
         public override void Drive(FlightCtrlState s) => DoRCS(s);
 
         private void DoRCS(FlightCtrlState s)
         {
+            if (State == States.IDLE)
+                return;
+
             // seconds to continue to apply RCS after ullage has settled to VeryStable
             const double MIN_RCS_TIME = 0.25;
 
@@ -145,7 +151,7 @@ private void DoRCS(FlightCtrlState s)
             if (State != States.LEAD || RCSOnly)
                 return;
 
-            if (!Core.Thrust.AutoRCSUllaging || !realfuelsLoaded)
+            if (!Core.Thrust.AutoRCSUllaging || !_isLoadedRealFuels)
                 return;
 
             // always apply MIN_RCS_TIME of ullage right before the ignition time