Fix ResupplyAircraft being cancelable by Stop command

It is now immediately queued again, as long as the actor
has not finished rearming/repairing yet.

OpenRA.Mods.Common/Traits/Air/Aircraft.cs

@@ -171,8 +171,8 @@ namespace OpenRA.Mods.Common.Traits
 		public readonly AircraftInfo Info;
 		readonly Actor self;
 
-		RepairableInfo repairableInfo;
+		Repairable repairable;
-		RearmableInfo rearmableInfo;
+		Rearmable rearmable;
 		ConditionManager conditionManager;
 		IDisposable reservation;
 		IEnumerable<int> speedModifiers;
@@ -228,8 +228,8 @@ namespace OpenRA.Mods.Common.Traits
 
 		protected virtual void Created(Actor self)
 		{
-			repairableInfo = self.Info.TraitInfoOrDefault<RepairableInfo>();
+			repairable = self.TraitOrDefault<Repairable>();
-			rearmableInfo = self.Info.TraitInfoOrDefault<RearmableInfo>();
+			rearmable = self.TraitOrDefault<Rearmable>();
 			conditionManager = self.TraitOrDefault<ConditionManager>();
 			speedModifiers = self.TraitsImplementing<ISpeedModifier>().ToArray().Select(sm => sm.GetSpeedModifier());
 			cachedPosition = self.CenterPosition;
@@ -469,8 +469,8 @@ namespace OpenRA.Mods.Common.Traits
 			if (self.AppearsHostileTo(a))
 				return false;
 
-			return (rearmableInfo != null && rearmableInfo.RearmActors.Contains(a.Info.Name))
+			return (rearmable != null && rearmable.Info.RearmActors.Contains(a.Info.Name))
-				|| (repairableInfo != null && repairableInfo.RepairActors.Contains(a.Info.Name));
+				|| (repairable != null && repairable.Info.RepairActors.Contains(a.Info.Name));
 		}
 
 		public int MovementSpeed
@@ -503,14 +503,23 @@ namespace OpenRA.Mods.Common.Traits
 			return Info.LandableTerrainTypes.Contains(type);
 		}
 
+		public bool CanRearmAt(Actor host)
+		{
+			return rearmable != null && rearmable.Info.RearmActors.Contains(host.Info.Name) && rearmable.RearmableAmmoPools.Any(p => !p.FullAmmo());
+		}
+
+		public bool CanRepairAt(Actor host)
+		{
+			return repairable != null && repairable.Info.RepairActors.Contains(host.Info.Name) && self.GetDamageState() != DamageState.Undamaged;
+		}
+
 		public virtual IEnumerable<Activity> GetResupplyActivities(Actor a)
 		{
-			var name = a.Info.Name;
+			// The ResupplyAircraft activity guarantees that we're on the helipad/repair depot
-			if (rearmableInfo != null && rearmableInfo.RearmActors.Contains(name))
+			if (CanRearmAt(a))
 				yield return new Rearm(self, a, WDist.Zero);
 
-			// The ResupplyAircraft activity guarantees that we're on the helipad
+			if (CanRepairAt(a))
-			if (repairableInfo != null && repairableInfo.RepairActors.Contains(name))
 				yield return new Repair(self, a, WDist.Zero);
 		}
 
@@ -521,21 +530,45 @@ namespace OpenRA.Mods.Common.Traits
 
 		void INotifyBecomingIdle.OnBecomingIdle(Actor self)
 		{
-			if (Info.VTOL && Info.LandWhenIdle)
+			OnBecomingIdle(self);
+		}
+
+		protected virtual void OnBecomingIdle(Actor self)
+		{
+			var atLandAltitude = self.World.Map.DistanceAboveTerrain(CenterPosition) == Info.LandAltitude;
+
+			// Work-around to prevent players from accidentally canceling resupply by pressing 'Stop',
+			// by re-queueing ResupplyAircraft as long as resupply hasn't finished and aircraft is still on resupplier.
+			// TODO: Investigate moving this back to ResolveOrder's "Stop" handling,
+			// once conflicts with other traits' "Stop" orders have been fixed.
+			if (atLandAltitude)
+			{
+				var host = GetActorBelow();
+				if (host != null && (CanRearmAt(host) || CanRepairAt(host)))
+				{
+					self.QueueActivity(new ResupplyAircraft(self));
+					return;
+				}
+			}
+
+			if (!atLandAltitude && Info.VTOL && Info.LandWhenIdle)
 			{
 				if (Info.TurnToLand)
 					self.QueueActivity(new Turn(self, Info.InitialFacing));
 
 				self.QueueActivity(new HeliLand(self, true));
 			}
-			else if (!Info.CanHover && (Info.TakeOffOnResupply || ReservedActor == null || self.World.Map.DistanceAboveTerrain(CenterPosition) != Info.LandAltitude))
+			else if (!Info.CanHover && !atLandAltitude)
 				self.QueueActivity(new FlyCircle(self, -1, Info.IdleTurnSpeed > -1 ? Info.IdleTurnSpeed : TurnSpeed));
-
+			else if (atLandAltitude && (Info.TakeOffOnResupply || ReservedActor == null))
+				self.QueueActivity(new TakeOff(self));
+			else if (Info.CanHover && self.Info.HasTraitInfo<AutoCarryallInfo>() && Info.IdleTurnSpeed > -1)
+			{
 				// Temporary HACK for the AutoCarryall special case (needs CanHover, but also HeliFlyCircle on idle).
 				// Will go away soon (in a separate PR) with the arrival of ActionsWhenIdle.
-			else if (Info.CanHover && self.Info.HasTraitInfo<AutoCarryallInfo>() && Info.IdleTurnSpeed > -1)
 				self.QueueActivity(new HeliFlyCircle(self, Info.IdleTurnSpeed > -1 ? Info.IdleTurnSpeed : TurnSpeed));
 			}
+		}
 
 		#region Implement IPositionable
 
@@ -717,13 +750,13 @@ namespace OpenRA.Mods.Common.Traits
 
 		Order IIssueDeployOrder.IssueDeployOrder(Actor self, bool queued)
 		{
-			if (rearmableInfo == null || !rearmableInfo.RearmActors.Any())
+			if (rearmable == null || !rearmable.Info.RearmActors.Any())
 				return null;
 
 			return new Order("ReturnToBase", self, queued);
 		}
 
-		bool IIssueDeployOrder.CanIssueDeployOrder(Actor self) { return rearmableInfo != null && rearmableInfo.RearmActors.Any(); }
+		bool IIssueDeployOrder.CanIssueDeployOrder(Actor self) { return rearmable != null && rearmable.Info.RearmActors.Any(); }
 
 		public string VoicePhraseForOrder(Actor self, Order order)
 		{
@@ -742,7 +775,7 @@ namespace OpenRA.Mods.Common.Traits
 				case "Stop":
 					return Info.Voice;
 				case "ReturnToBase":
-					return rearmableInfo != null && rearmableInfo.RearmActors.Any() ? Info.Voice : null;
+					return rearmable != null && rearmable.Info.RearmActors.Any() ? Info.Voice : null;
 				default: return null;
 			}
 		}
@@ -791,15 +824,15 @@ namespace OpenRA.Mods.Common.Traits
 			else if (order.OrderString == "Stop")
 			{
 				self.CancelActivity();
+
+				// HACK: If the player accidentally pressed 'Stop', we don't want this to cancel reservation.
+				// If unreserving is actually desired despite an actor below, it should be triggered from OnBecomingIdle.
 				if (GetActorBelow() != null)
-				{
-					self.QueueActivity(new ResupplyAircraft(self));
 					return;
-				}
 
 				UnReserve();
 			}
-			else if (order.OrderString == "ReturnToBase" && rearmableInfo != null && rearmableInfo.RearmActors.Any())
+			else if (order.OrderString == "ReturnToBase" && rearmable != null && rearmable.Info.RearmActors.Any())
 			{
 				if (!order.Queued)
 					UnReserve();