Core/Instances: New ZoneScript hook - OnCreatureGroupDepleted

Port From (https://github.com/TrinityCore/TrinityCore/commit/ec2631eca3a397dffd2e525b34c131c283beb167)

Source/Game/Entities/Creature/Creature.cs

@@ -2028,8 +2028,15 @@ namespace Game.Entities
                 SetNoSearchAssistance(false);
 
                 //Dismiss group if is leader
-                if (m_formation != null && m_formation.GetLeader() == this)
-                    m_formation.FormationReset(true);
+                if (m_formation != null)
+                {
+                    if (m_formation.GetLeader() == this)
+                        m_formation.FormationReset(true);
+
+                    ZoneScript script = GetZoneScript();
+                    if (script != null && !m_formation.HasAliveMembers())
+                        script.OnCreatureGroupDepleted(m_formation);
+                }
 
                 bool needsFalling = (IsFlying() || IsHovering()) && !IsUnderWater() && !HasUnitState(UnitState.Root);
                 SetHover(false, false);

Source/Game/Entities/Creature/CreatureGroups.cs

@@ -55,6 +55,12 @@ namespace Game.Entities
             Log.outDebug(LogFilter.Unit, $"Deleting member GUID: {leaderSpawnId} from group {member.GetSpawnId()}");
             group.RemoveMember(member);
 
+            // If removed member was alive we need to check if we have any other alive members
+            // if not - fire OnCreatureGroupDepleted
+            ZoneScript script = member.GetZoneScript();
+            if (script != null && member.IsAlive() && !group.HasAliveMembers())
+                script.OnCreatureGroupDepleted(group);
+
             if (group.IsEmpty())
             {
                 if (leaderSpawnId != 0)
@@ -299,6 +305,29 @@ namespace Game.Entities
             return true;
         }
 
+        public bool HasAliveMembers()
+        {
+            return _members.Any(pair => pair.Key.IsAlive());
+        }
+
+        public bool LeaderHasStringId(string id)
+        {
+            if (_leader != null)
+                return _leader.HasStringId(id);
+
+            CreatureData leaderCreatureData = Global.ObjectMgr.GetCreatureData(_leaderSpawnId);
+            if (leaderCreatureData != null)
+            {
+                if (leaderCreatureData.StringId == id)
+                    return true;
+
+                if (Global.ObjectMgr.GetCreatureTemplate(leaderCreatureData.Id).StringId == id)
+                    return true;
+            }
+
+            return false;
+        }
+
         public Creature GetLeader() { return _leader; }
         public ulong GetLeaderSpawnId() { return _leaderSpawnId; }
         public bool IsEmpty() { return _members.Empty(); }