planes return to base after attacking

OpenRa.Game/Traits/Activities/FlyAttack.cs

@@ -14,7 +14,8 @@ namespace OpenRa.Game.Traits.Activities
 
 		public IActivity Tick(Actor self)
 		{
-			if (Target == null || Target.IsDead) return NextActivity;
+			if (Target == null || Target.IsDead) 
+				return NextActivity;
 
 			var limitedAmmo = self.traits.GetOrDefault<LimitedAmmo>();
 			if (limitedAmmo != null && !limitedAmmo.HasAmmo())

OpenRa.Game/Traits/Activities/ReturnToBase.cs

@@ -7,14 +7,37 @@ namespace OpenRa.Game.Traits.Activities
 {
 	class ReturnToBase : IActivity
 	{
+		// todo: defer decision-making until we are first scheduled!
 		public IActivity NextActivity { get; set; }
 		bool isCanceled;
 
 		readonly float2 w1, w2, w3;	/* tangent points to turn circles */
 		readonly float2 landPoint;
 
-		public ReturnToBase(Actor self, float2 landPos)
+		public ReturnToBase(Actor self)
+			: this( self, null ) {}
+
+		Actor ChooseAirfield(Actor self)
 		{
+			// todo: handle reservations
+
+			var airfield = Game.world.Actors
+				.Where(a => a.Info == Rules.UnitInfo["AFLD"]
+					&& a.Owner == self.Owner)
+				.FirstOrDefault();
+
+			if (airfield == null)
+				throw new NotImplementedException("nowhere to land; what to do?");
+
+			return airfield;
+		}
+
+		public ReturnToBase(Actor self, Actor dest)
+		{
+			if (dest == null)
+				dest = ChooseAirfield(self);
+
+			var landPos = dest.CenterLocation;
 			var unit = self.traits.Get<Unit>();
 			var speed = .2f * Util.GetEffectiveSpeed(self);
 			var approachStart = landPos - new float2(unit.Altitude * speed, 0);

OpenRa.Game/Traits/AttackPlane.cs

@@ -31,8 +31,10 @@ namespace OpenRa.Game.Traits
 
 		protected override void QueueAttack(Actor self, Order order)
 		{
-			self.QueueActivity(new FlyAttack(order.TargetActor));
+			self.CancelActivity();
 			target = order.TargetActor;
+			self.QueueActivity(new FlyAttack(order.TargetActor));
+			self.QueueActivity(new ReturnToBase(self));
 		}
 	}
 }

OpenRa.Game/Traits/Plane.cs

@@ -36,7 +36,7 @@ namespace OpenRa.Game.Traits
 			if (order.OrderString == "Enter")
 			{
 				self.CancelActivity();
-				self.QueueActivity(new ReturnToBase(self, order.TargetActor.CenterLocation));
+				self.QueueActivity(new ReturnToBase(self, order.TargetActor));
 			}
 		}
 

OpenRa.Game/Traits/Util.cs

@@ -139,7 +139,7 @@ namespace OpenRa.Game.Traits
 
 		public static IActivity SequenceActivities(params IActivity[] acts)
 		{
-			return acts.Reverse().Aggregate((IActivity)null,
+			return acts.Reverse().Aggregate(
 				(next, a) => { a.NextActivity = next; return a; });
 		}
 	}