Core/SAI: Implement SMART_TARGET_ACTION_INVOKER in SMART_EVENT_FRIENDLY_HEALTH_PCT

Port From (https://github.com/TrinityCore/TrinityCore/commit/902ed74c2adaf2dadcd38f1fb96963f7ec46df07)

Source/Game/AI/SmartScripts/SmartAIManager.cs

@@ -818,6 +818,10 @@ namespace Game.AI
                             case SmartTargets.PlayerRange:
                             case SmartTargets.PlayerDistance:
                                 break;
+                            case SmartTargets.ActionInvoker:
+                                if (!NotNULL(e, e.Event.friendlyHealthPct.radius))
+                                    return false;
+                                break;
                             default:
                                 Log.outError(LogFilter.Sql, $"SmartAIMgr: {e} uses invalid target_type {e.GetTargetType()}, skipped.");
                                 return false;
@@ -2303,6 +2307,7 @@ namespace Game.AI
             public uint maxHpPct;
             public uint repeatMin;
             public uint repeatMax;
+            public uint radius;
         }
         public struct Distance
         {

Source/Game/AI/SmartScripts/SmartScript.cs

@@ -3614,7 +3614,7 @@ namespace Game.AI
                     if (_me == null || !_me.IsEngaged())
                         return;
 
-                    List<WorldObject> targets;
+                    Unit unitTarget = null;
 
                     switch (e.GetTargetType())
                     {
@@ -3625,22 +3625,13 @@ namespace Game.AI
                         case SmartTargets.ClosestPlayer:
                         case SmartTargets.PlayerRange:
                         case SmartTargets.PlayerDistance:
-                            targets = GetTargets(e);
+                        {
-                            break;
+                            var targets = GetTargets(e);
-                        default:
+                            foreach (WorldObject target in targets)
-                            return;
-                    }
-
-                    if (targets == null)
-                        return;
-
-                    Unit unitTarget = null;
-                    foreach (var target in targets)
                             {
                                 if (IsUnit(target) && _me.IsFriendlyTo(target.ToUnit()) && target.ToUnit().IsAlive() && target.ToUnit().IsInCombat())
                                 {
                                     uint healthPct = (uint)target.ToUnit().GetHealthPct();
-
                                     if (healthPct > e.Event.friendlyHealthPct.maxHpPct || healthPct < e.Event.friendlyHealthPct.minHpPct)
                                         continue;
 
@@ -3648,6 +3639,14 @@ namespace Game.AI
                                     break;
                                 }
                             }
+                        }
+                        break;
+                        case SmartTargets.ActionInvoker:
+                            unitTarget = DoSelectLowestHpPercentFriendly((float)e.Event.friendlyHealthPct.radius, e.Event.friendlyHealthPct.minHpPct, e.Event.friendlyHealthPct.maxHpPct);
+                            break;
+                        default:
+                            return;
+                    }
 
                     if (unitTarget == null)
                         return;
@@ -4180,6 +4179,17 @@ namespace Game.AI
             return searcher.GetTarget();
         }
 
+        Unit DoSelectLowestHpPercentFriendly(float range, uint minHpPct, uint maxHpPct)
+        {
+            if (_me == null)
+                return null;
+
+            MostHPPercentMissingInRange u_check = new(_me, range, minHpPct, maxHpPct);
+            UnitLastSearcher searcher = new(_me, u_check);
+            Cell.VisitGridObjects(_me, searcher, range);
+            return searcher.GetTarget();
+        }
+        
         void DoFindFriendlyCC(List<Creature> creatures, float range)
         {
             if (_me == null)

Source/Game/Maps/GridNotifiers.cs

@@ -1859,6 +1859,34 @@ namespace Game.Maps
         ulong i_hp;
     }
 
+    class MostHPPercentMissingInRange : ICheck<Unit>
+    {
+        Unit _obj;
+        float _range;
+        float _minHpPct;
+        float _maxHpPct;
+        float _hpPct;
+
+        public MostHPPercentMissingInRange(Unit obj, float range, uint minHpPct, uint maxHpPct)
+        {
+            _obj = obj;
+            _range = range;
+            _minHpPct = minHpPct;
+            _maxHpPct = maxHpPct;
+            _hpPct = 101.0f;
+        }
+
+        public bool Invoke(Unit u)
+        {
+            if (u.IsAlive() && u.IsInCombat() && !_obj.IsHostileTo(u) && _obj.IsWithinDistInMap(u, _range) && _minHpPct <= u.GetHealthPct() && u.GetHealthPct() <= _maxHpPct && u.GetHealthPct() < _hpPct)
+            {
+                _hpPct = u.GetHealthPct();
+                return true;
+            }
+            return false;
+        }
+    }
+    
     public class FriendlyBelowHpPctEntryInRange : ICheck<Unit>
     {
         public FriendlyBelowHpPctEntryInRange(Unit obj, uint entry, float range, byte pct, bool excludeSelf)