fix(ai): restore pre-AOS berserk energy vortexes and blade spirits (#2666)

#2132 let a player's energy vortex or blade spirits in pre-AOS Felucca target their own caster, gated by `FollowsAcquireRules`. #2232's AI overhaul moved the summon checks into `IsInvalidSummonTarget`, which excluded the caster in every era, and dropped the gate. Since then `FollowsAcquireRules` has had no readers and summons have never turned on their caster.

## Changes

- `IsInvalidSummonTarget` reads `FollowsAcquireRules` again. A summon that follows the acquire rules spares its caster and anyone the caster's harmful spells would spare. The vortex and blade spirits don't follow them in pre-AOS Felucca when a player summoned them.
- The animated-dead restrictions (no players, no other animated dead, no pets) apply to every animated summon regardless of that setting.
- `AcquireNewFocusMob` sets a berserk summon's caster aside and targets them only when nobody else is available. #2132 meant to prefer others, but its check only worked when the caster was scanned before the other candidates, and the vortex's Int-plus-Magery ranking usually puts a nearby caster first.
- The AOS summon-target check no longer dereferences a missing `SummonMaster`. A summon whose caster was deleted before a reload comes back without one.

Controlled summons are unaffected: since #2665 they target through `HandleControlled` and never reach this scan.

## Tests

`SummonAcquireRulesTests` has 6 cases, skipped without client map data. Pre-AOS Felucca: a vortex and blade spirits each target their caster when the caster is alone, and a vortex targets a bystander even when the caster ranks higher. Pre-AOS Trammel and AOS Felucca: the caster is still spared. An AOS scan next to a summon with no master doesn't throw. `UOContent.Tests`: 1148 passed, 2 skipped, 0 failed on Windows.

Projects/UOContent.Tests/Tests/Mobiles/AI/SummonAcquireRulesTests.cs

@@ -0,0 +1,113 @@
+using System;
+using System.Collections.Generic;
+using Server;
+using Server.Mobiles;
+using Xunit;
+
+namespace UOContent.Tests.Mobiles.AI;
+
+[Collection("Sequential UOContent Tests")]
+public class SummonAcquireRulesTests : IDisposable
+{
+    private readonly List<Mobile> _created = [];
+    private readonly Expansion _previous = Core.Expansion;
+
+    private PlayerMobile Player(Map map, int x, int intel)
+    {
+        var player = new PlayerMobile { Player = true, RawInt = intel };
+        player.MoveToWorld(new Point3D(x, 1600, map.GetAverageZ(x, 1600)), map);
+        _created.Add(player);
+        return player;
+    }
+
+    private BaseCreature Summon(BaseCreature summon, Mobile caster, int x)
+    {
+        _created.Add(summon);
+        summon.Summoned = true;
+        summon.SummonMaster = caster;
+        summon.MoveToWorld(new Point3D(x, 1600, caster.Map.GetAverageZ(x, 1600)), caster.Map);
+        summon.AIObject.AITimer.Stop();
+        return summon;
+    }
+
+    private static bool Acquire(BaseCreature creature)
+    {
+        creature.NextReacquireTime = Core.TickCount - 1;
+        return creature.AIObject.AcquireFocusMob(creature.RangePerception, creature.FightMode, false, false, true);
+    }
+
+    [SkippableTheory]
+    [InlineData(true)]
+    [InlineData(false)]
+    public void PreAosFeluccaVortexTurnsOnItsCaster(bool bladeSpirits)
+    {
+        Skip.If(!Server.Tests.TestServerInitializer.TileDataLoaded, "Requires UO client map data.");
+        Core.Expansion = Expansion.UOR;
+
+        var caster = Player(Map.Felucca, 1500, 100);
+        var summon = Summon(bladeSpirits ? new BladeSpirits() : new EnergyVortex(), caster, 1499);
+
+        Assert.True(Acquire(summon));
+        Assert.Same(caster, summon.FocusMob);
+    }
+
+    [SkippableFact]
+    public void PreAosFeluccaVortexPrefersAnyoneOverItsCaster()
+    {
+        Skip.If(!Server.Tests.TestServerInitializer.TileDataLoaded, "Requires UO client map data.");
+        Core.Expansion = Expansion.UOR;
+
+        // The caster outranks the bystander on the vortex's int-over-distance ranking.
+        var caster = Player(Map.Felucca, 1500, 100);
+        var bystander = Player(Map.Felucca, 1496, 10);
+        var vortex = Summon(new EnergyVortex(), caster, 1499);
+
+        Assert.True(Acquire(vortex));
+        Assert.Same(bystander, vortex.FocusMob);
+    }
+
+    [SkippableTheory]
+    [InlineData(Expansion.UOR, 1)] // Trammel
+    [InlineData(Expansion.AOS, 0)] // Felucca
+    public void VortexSparesItsCasterOutsidePreAosFelucca(Expansion expansion, int mapIndex)
+    {
+        Skip.If(!Server.Tests.TestServerInitializer.TileDataLoaded, "Requires UO client map data.");
+        Core.Expansion = expansion;
+
+        var caster = Player(Map.Maps[mapIndex], 1500, 100);
+        var vortex = Summon(new EnergyVortex(), caster, 1499);
+
+        Assert.False(Acquire(vortex));
+        Assert.Null(vortex.FocusMob);
+    }
+
+    [SkippableFact]
+    public void MasterlessSummonDoesNotBreakAcquisition()
+    {
+        Skip.If(!Server.Tests.TestServerInitializer.TileDataLoaded, "Requires UO client map data.");
+        Core.Expansion = Expansion.AOS;
+
+        var player = Player(Map.Felucca, 1500, 100);
+        var hunter = new PetTestStub();
+        _created.Add(hunter);
+        hunter.MoveToWorld(new Point3D(1499, 1600, player.Z), player.Map);
+        hunter.AIObject.AITimer.Stop();
+
+        var masterless = new PetTestStub { Summoned = true };
+        _created.Add(masterless);
+        masterless.MoveToWorld(new Point3D(1498, 1600, player.Z), player.Map);
+        masterless.AIObject.AITimer.Stop();
+
+        Assert.True(Acquire(hunter));
+    }
+
+    public void Dispose()
+    {
+        Core.Expansion = _previous;
+
+        foreach (var mobile in _created)
+        {
+            mobile.Delete();
+        }
+    }
+}

Projects/UOContent/Mobiles/AI/BaseAI/BaseAI.cs

@@ -996,6 +996,7 @@ public abstract partial class BaseAI
         Mobile enemySummonMob = null;
         var val = double.MinValue;
         var enemySummonVal = double.MinValue;
+        Mobile summonMaster = null;
 
         foreach (var m in map.GetMobilesInRange(Mobile.Location, iRange))
         {
@@ -1005,14 +1006,24 @@ public abstract partial class BaseAI
             }
 
             var bc = m as BaseCreature;
-            var pm = m as PlayerMobile;
 
-            if (IsInvalidSummonTarget(m, bc, pm) || IsInvalidFactionTarget(m, bFacFriend, bFacFoe)
+            if (IsInvalidSummonTarget(m, bc) || IsInvalidFactionTarget(m, bFacFriend, bFacFoe)
-                                                 || IsInvalidFightModeTarget(m, acqType, bc))
+                                             || IsInvalidFightModeTarget(m, acqType, bc))
             {
                 continue;
             }
 
+            // Only a summon that ignores the acquire rules gets here with its caster; anyone else comes first.
+            if (m == Mobile.SummonMaster)
+            {
+                if (Mobile.InLOS(m))
+                {
+                    summonMaster = m;
+                }
+
+                continue;
+            }
+
             var theirVal = Mobile.GetFightModeRanking(m, acqType, bPlayerOnly);
 
             if (theirVal > val && Mobile.InLOS(m))
@@ -1020,15 +1031,14 @@ public abstract partial class BaseAI
                 newFocusMob = m;
                 val = theirVal;
             }
-            else if (Core.AOS && theirVal > enemySummonVal
+            else if (Core.AOS && theirVal > enemySummonVal && Mobile.InLOS(m) && bc is { Summoned: true, Controlled: false })
-                              && Mobile.InLOS(m) && bc?.Summoned == true && bc.Controlled != true)
             {
                 enemySummonMob = m;
                 enemySummonVal = theirVal;
             }
         }
 
-        Mobile.FocusMob = newFocusMob ?? enemySummonMob;
+        Mobile.FocusMob = newFocusMob ?? enemySummonMob ?? summonMaster;
         return Mobile.FocusMob != null;
     }
 
@@ -1036,21 +1046,28 @@ public abstract partial class BaseAI
         m.Deleted || m.Blessed || m == Mobile || m is BaseFamiliar || !m.Alive || m.IsDeadBondedPet ||
         m.AccessLevel > AccessLevel.Player || bPlayerOnly && !m.Player || !Mobile.CanSee(m);
 
-    private bool IsInvalidSummonTarget(Mobile m, BaseCreature bc, PlayerMobile pm)
+    private bool IsInvalidSummonTarget(Mobile m, BaseCreature bc)
     {
+        // A summon whose caster was deleted before a reload comes back with no master.
         if (Core.AOS && bc?.Summoned == true &&
-            (bc.SummonMaster == Mobile || !bc.SummonMaster.Player && IsHostile(bc.SummonMaster)))
+            (bc.SummonMaster == Mobile || bc.SummonMaster is { Player: false } summonMaster && IsHostile(summonMaster)))
         {
             return true;
         }
 
-        if (!Mobile.Summoned || Mobile.SummonMaster == null)
+        var master = Mobile.SummonMaster;
+
+        if (!Mobile.Summoned || master == null)
         {
             return false;
         }
 
-        return m == Mobile.SummonMaster || !SpellHelper.ValidIndirectTarget(Mobile.SummonMaster, m) ||
+        if (Mobile.IsAnimatedDead && (m.Player || bc?.IsAnimatedDead == true || bc?.Controlled == true))
-               Mobile.IsAnimatedDead && (pm != null || bc?.IsAnimatedDead == true || bc?.Controlled == true);
+        {
+            return true;
+        }
+
+        return Mobile.FollowsAcquireRules && (m == master || !SpellHelper.ValidIndirectTarget(master, m));
     }
 
     private bool IsInvalidFactionTarget(Mobile m, bool bFacFriend, bool bFacFoe) =>

Projects/UOContent/Mobiles/BaseCreature.cs

@@ -920,6 +920,10 @@ namespace Server.Mobiles
         [CommandProperty(AccessLevel.GameMaster)]
         public bool IsPrisoner { get; set; }
 
+        /// <summary>
+        /// When false, a summon may target its own caster and anyone the caster's harmful spells would spare.
+        /// It still prefers any other target over the caster.
+        /// </summary>
         public virtual bool FollowsAcquireRules => true;
 
         public virtual Faction FactionAllegiance => null;

Projects/UOContent/Mobiles/Monsters/Misc/Melee/BladeSpirits.cs

@@ -55,7 +55,8 @@ namespace Server.Mobiles
         public override bool BleedImmune => true;
         public override Poison PoisonImmune => Poison.Lethal;
 
-        public override bool FollowsAcquireRules => Core.AOS || !Summoned || SummonMaster?.Player != true || Map != Map.Felucca;
+        public override bool FollowsAcquireRules => Core.AOS || !Summoned || SummonMaster?.Player != true ||
+                                                    (Map?.Rules & MapRules.HarmfulRestrictions) != 0;
 
         public override double GetFightModeRanking(Mobile m, FightMode acqType, bool bPlayerOnly) =>
             (m.Str + m.Skills.Tactics.Value) / Math.Max(this.GetDistanceToSqrt(m), 1.0);

Projects/UOContent/Mobiles/Monsters/Misc/Melee/EnergyVortex.cs

@@ -63,7 +63,8 @@ namespace Server.Mobiles
         public override bool BleedImmune => true;
         public override Poison PoisonImmune => Poison.Lethal;
 
-        public override bool FollowsAcquireRules => Core.AOS || !Summoned || SummonMaster?.Player != true || Map != Map.Felucca;
+        public override bool FollowsAcquireRules => Core.AOS || !Summoned || SummonMaster?.Player != true ||
+                                                    (Map?.Rules & MapRules.HarmfulRestrictions) != 0;
 
         public override double GetFightModeRanking(Mobile m, FightMode acqType, bool bPlayerOnly) =>
             (m.Int + m.Skills.Magery.Value) / Math.Max(this.GetDistanceToSqrt(m), 1.0);