Core/Gameobjects: Improve stealth detection

Port From (https://github.com/TrinityCore/TrinityCore/commit/60e66621dae44cb832ebb0bdb5e168f9ab114ecb)

Source/Game/Entities/GameObject/GameObject.cs

@@ -663,7 +663,7 @@ namespace Game.Entities
                             if (owner)
                             {
                                 // Hunter trap: Search units which are unfriendly to the trap's owner
-                                var checker = new NearestAttackableNoTotemUnitInObjectRangeCheck(this, owner, radius);
+                                var checker = new NearestAttackableNoTotemUnitInObjectRangeCheck(this, radius);
                                 var searcher = new UnitLastSearcher(this, checker);
                                 Cell.VisitAllObjects(this, searcher, radius);
                                 target = searcher.GetTarget();

Source/Game/Entities/Object/WorldObject.cs

@@ -1248,10 +1248,17 @@ namespace Game.Entities
             if (distance < combatReach)
                 return true;
 
-            if (!HasInArc(MathFunctions.PI, obj))
+            // Only check back for units, it does not make sense for gameobjects
+            if (unit && !HasInArc(MathF.PI, obj))
                 return false;
 
-            GameObject go = obj.ToGameObject();
+            // Traps should detect stealth always
+            GameObject go = ToGameObject();
+            if (go != null)
+                if (go.GetGoType() == GameObjectTypes.Trap)
+                    return true;
+
+            go = obj.ToGameObject();
             for (int i = 0; i < (int)StealthType.Max; ++i)
             {
                 if (!Convert.ToBoolean(obj.m_stealth.GetFlags() & (1 << i)))
@@ -2056,8 +2063,8 @@ namespace Game.Entities
                 }
             }
 
-            Unit unit = ToUnit();
+            Unit unit = ToUnit() ?? selfPlayerOwner;
-            Unit targetUnit = target.ToUnit();
+            Unit targetUnit = target.ToUnit() ?? targetPlayerOwner;
             if (unit && unit.HasUnitFlag(UnitFlags.PlayerControlled))
             {
                 if (targetUnit && targetUnit.HasUnitFlag(UnitFlags.PlayerControlled))
@@ -2452,7 +2459,7 @@ namespace Game.Entities
             if (IsFriendlyTo(target) || target.IsFriendlyTo(this))
                 return false;
 
-            Player playerAffectingAttacker = unit != null && unit.HasUnitFlag(UnitFlags.PlayerControlled) ? GetAffectingPlayer() : null;
+            Player playerAffectingAttacker = unit != null && unit.HasUnitFlag(UnitFlags.PlayerControlled) ? GetAffectingPlayer() : IsGameObject() ? GetAffectingPlayer() : null;
             Player playerAffectingTarget = unitTarget != null && unitTarget.HasUnitFlag(UnitFlags.PlayerControlled) ? target.GetAffectingPlayer() : null;
 
             // Not all neutral creatures can be attacked (even some unfriendly faction does not react aggresive to you, like Sporaggar)
@@ -2500,14 +2507,14 @@ namespace Game.Entities
             // additional checks - only PvP case
             if (playerAffectingAttacker && playerAffectingTarget)
             {
-                if (unitTarget.IsPvP())
+                if (playerAffectingTarget.IsPvP())
                     return true;
 
-                if (unit.IsFFAPvP() && unitTarget.IsFFAPvP())
+                if (playerAffectingAttacker.IsFFAPvP() && playerAffectingTarget.IsFFAPvP())
                     return true;
 
-                return unit.HasPvpFlag(UnitPVPStateFlags.Unk1) ||
+                return playerAffectingAttacker.HasPvpFlag(UnitPVPStateFlags.Unk1) ||
-                    unitTarget.HasPvpFlag(UnitPVPStateFlags.Unk1);
+                    playerAffectingTarget.HasPvpFlag(UnitPVPStateFlags.Unk1);
             }
 
             return true;

Source/Game/Maps/GridNotifiers.cs

@@ -1962,10 +1962,9 @@ namespace Game.Maps
 
     public class NearestAttackableNoTotemUnitInObjectRangeCheck : ICheck<Unit>
     {
-        public NearestAttackableNoTotemUnitInObjectRangeCheck(WorldObject obj, Unit funit, float range)
+        public NearestAttackableNoTotemUnitInObjectRangeCheck(WorldObject obj, float range)
         {
             i_obj = obj;
-            i_funit = funit;
             i_range = range;
         }
 
@@ -1983,7 +1982,7 @@ namespace Game.Maps
             if (!u.IsTargetableForAttack(false))
                 return false;
 
-            if (!i_obj.IsWithinDistInMap(u, i_range) || i_funit.IsValidAttackTarget(u))
+            if (!i_obj.IsWithinDistInMap(u, i_range) || i_obj.IsValidAttackTarget(u))
                 return false;
 
             i_range = i_obj.GetDistance(u);
@@ -1991,7 +1990,6 @@ namespace Game.Maps
         }
 
         WorldObject i_obj;
-        Unit i_funit;
         float i_range;
     }
 

Source/Game/Spells/Spell.cs

@@ -4639,7 +4639,9 @@ namespace Game.Spells
             {
                 // Check explicit target for m_originalCaster - todo: get rid of such workarounds
                 WorldObject caster = m_caster;
-                if (m_originalCaster != null)
+                // in case of gameobjects like traps, we need the gameobject itself to check target validity
+                // otherwise, if originalCaster is far away and cannot detect the target, the trap would not hit the target
+                if (m_originalCaster != null && !caster.IsGameObject())
                     caster = m_originalCaster;
 
                 castResult = m_spellInfo.CheckExplicitTarget(caster, m_targets.GetObjectTarget(), m_targets.GetItemTarget());