From 2f1a6e88073742ac795ac997a1c4f67bc1fb2a42 Mon Sep 17 00:00:00 2001
From: reaperrr <thereaperrr@aol.com>
Date: Thu, 16 Jun 2016 15:22:38 +0200
Subject: [PATCH] Add maximum and minimum range vs. target checks

This adresses the issue that actors would ignore the validity of weapons when deciding the attack distance versus a target. This could result in actors staying out of range of a weapon valid versus target if they carried a weapon with higher range but invalid versus target.
---
 .../Activities/Air/HeliAttack.cs              |  4 +-
 .../Traits/Attack/AttackBase.cs               | 48 ++++++++++++++++++-
 2 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/OpenRA.Mods.Common/Activities/Air/HeliAttack.cs b/OpenRA.Mods.Common/Activities/Air/HeliAttack.cs
index c389c2f4ad..1cfc95144d 100644
--- a/OpenRA.Mods.Common/Activities/Air/HeliAttack.cs
+++ b/OpenRA.Mods.Common/Activities/Air/HeliAttack.cs
@@ -82,12 +82,12 @@ namespace OpenRA.Mods.Common.Activities
 			// Fly towards the target
 			// TODO: Fix that the helicopter won't do anything if it has multiple weapons with different ranges
 			// and the weapon with the longest range is out of ammo
-			if (!target.IsInRange(self.CenterPosition, attackHeli.GetMaximumRange()))
+			if (!target.IsInRange(self.CenterPosition, attackHeli.GetMaximumRangeVersusTarget(target)))
 				helicopter.SetPosition(self, helicopter.CenterPosition + helicopter.FlyStep(desiredFacing));
 
 			// Fly backwards from the target
 			// TODO: Same problem as with MaximumRange
-			if (target.IsInRange(self.CenterPosition, attackHeli.GetMinimumRange()))
+			if (target.IsInRange(self.CenterPosition, attackHeli.GetMinimumRangeVersusTarget(target)))
 			{
 				// Facing 0 doesn't work with the following position change
 				var facing = 1;
diff --git a/OpenRA.Mods.Common/Traits/Attack/AttackBase.cs b/OpenRA.Mods.Common/Traits/Attack/AttackBase.cs
index a50e61a309..bbceaae98c 100644
--- a/OpenRA.Mods.Common/Traits/Attack/AttackBase.cs
+++ b/OpenRA.Mods.Common/Traits/Attack/AttackBase.cs
@@ -230,6 +230,52 @@ namespace OpenRA.Mods.Common.Traits
 			return max;
 		}
 
+		public WDist GetMinimumRangeVersusTarget(Target target)
+		{
+			if (IsTraitDisabled)
+				return WDist.Zero;
+
+			// PERF: Avoid LINQ.
+			var min = WDist.MaxValue;
+			foreach (var armament in Armaments)
+			{
+				if (armament.IsTraitDisabled)
+					continue;
+
+				if (!armament.Weapon.IsValidAgainst(target, self.World, self))
+					continue;
+
+				var range = armament.Weapon.MinRange;
+				if (min > range)
+					min = range;
+			}
+
+			return min != WDist.MaxValue ? min : WDist.Zero;
+		}
+
+		public WDist GetMaximumRangeVersusTarget(Target target)
+		{
+			if (IsTraitDisabled)
+				return WDist.Zero;
+
+			// PERF: Avoid LINQ.
+			var max = WDist.Zero;
+			foreach (var armament in Armaments)
+			{
+				if (armament.IsTraitDisabled)
+					continue;
+
+				if (!armament.Weapon.IsValidAgainst(target, self.World, self))
+					continue;
+
+				var range = armament.MaxRange();
+				if (max < range)
+					max = range;
+			}
+
+			return max;
+		}
+
 		// Enumerates all armaments, that this actor possesses, that can be used against Target t
 		public IEnumerable<Armament> ChooseArmamentsForTarget(Target t, bool forceAttack)
 		{
@@ -282,7 +328,7 @@ namespace OpenRA.Mods.Common.Traits
 		public bool IsReachableTarget(Target target, bool allowMove)
 		{
 			return HasAnyValidWeapons(target)
-				&& (target.IsInRange(self.CenterPosition, GetMaximumRange()) || (allowMove && self.Info.HasTraitInfo<IMoveInfo>()));
+				&& (target.IsInRange(self.CenterPosition, GetMaximumRangeVersusTarget(target)) || (allowMove && self.Info.HasTraitInfo<IMoveInfo>()));
 		}
 
 		public Stance UnforcedAttackTargetStances()