Core/Instances: New ZoneScript hook - OnCreatureGroupDepleted

* Triggers when the CreatureGroup no longer has any alive members (either last alive member dies or is removed from the group)

3 files changed, 46 insertions, 4 deletions

diff --git a/src/server/game/Entities/Creature/Creature.cpp b/src/server/game/Entities/Creature/Creature.cpp
index d466920c81f..9b3a159e2f7 100644
--- a/src/server/game/Entities/Creature/Creature.cpp
+++ b/src/server/game/Entities/Creature/Creature.cpp
@@ -362,7 +362,7 @@ void Creature::RemoveFromWorld()
             GetZoneScript()->OnCreatureRemove(this);
 
         if (m_formation)
-            sFormationMgr->RemoveCreatureFromGroup(m_formation, this);
+            FormationMgr::RemoveCreatureFromGroup(m_formation, this);
 
         Unit::RemoveFromWorld();
 
@@ -2216,8 +2216,15 @@ void Creature::setDeathState(DeathState s)
         SetNoSearchAssistance(false);
 
         //Dismiss group if is leader
-        if (m_formation && m_formation->GetLeader() == this)
-            m_formation->FormationReset(true);
+        if (m_formation)
+        {
+            if (m_formation->GetLeader() == this)
+                m_formation->FormationReset(true);
+
+            if (ZoneScript* script = GetZoneScript())
+                if (!m_formation->HasAliveMembers())
+                    script->OnCreatureGroupDepleted(m_formation);
+        }
 
         bool needsFalling = (IsFlying() || IsHovering()) && !IsUnderWater() && !HasUnitState(UNIT_STATE_ROOT);
         SetHover(false, false);
diff --git a/src/server/game/Entities/Creature/CreatureGroups.cpp b/src/server/game/Entities/Creature/CreatureGroups.cpp
index 4f04f26ea90..179e3c5179f 100644
--- a/src/server/game/Entities/Creature/CreatureGroups.cpp
+++ b/src/server/game/Entities/Creature/CreatureGroups.cpp
@@ -25,6 +25,7 @@
 #include "MotionMaster.h"
 #include "MovementGenerator.h"
 #include "ObjectMgr.h"
+#include "ZoneScript.h"
 
 FormationMgr::FormationMgr() = default;
 FormationMgr::~FormationMgr() = default;
@@ -74,6 +75,12 @@ void FormationMgr::RemoveCreatureFromGroup(CreatureGroup* group, Creature* membe
     TC_LOG_DEBUG("entities.unit", "Deleting member pointer to GUID: {} from group {}", leaderSpawnId, 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
+    if (ZoneScript* script = member->GetZoneScript())
+        if (member->IsAlive() && !group->HasAliveMembers())
+            script->OnCreatureGroupDepleted(group);
+
     if (group->IsEmpty())
     {
         if (leaderSpawnId)
@@ -302,3 +309,25 @@ bool CreatureGroup::CanLeaderStartMoving() const
 
     return true;
 }
+
+bool CreatureGroup::HasAliveMembers() const
+{
+    return std::ranges::any_of(_members, [](Creature const* member) { return member->IsAlive(); }, &MembersMap::value_type::first);
+}
+
+bool CreatureGroup::LeaderHasStringId(std::string_view id) const
+{
+    if (_leader)
+        return _leader->HasStringId(id);
+
+    if (CreatureData const* leaderCreatureData = sObjectMgr->GetCreatureData(_leaderSpawnId))
+    {
+        if (leaderCreatureData->StringId == id)
+            return true;
+
+        if (ASSERT_NOTNULL(sObjectMgr->GetCreatureTemplate(leaderCreatureData->id))->StringId == id)
+            return true;
+    }
+
+    return false;
+}
diff --git a/src/server/game/Entities/Creature/CreatureGroups.h b/src/server/game/Entities/Creature/CreatureGroups.h
index be8a9967bf5..c7afaa1cedd 100644
--- a/src/server/game/Entities/Creature/CreatureGroups.h
+++ b/src/server/game/Entities/Creature/CreatureGroups.h
@@ -74,7 +74,9 @@ class TC_GAME_API CreatureGroup
 {
     private:
         Creature* _leader;
-        std::unordered_map<Creature*, FormationInfo*> _members;
+
+        using MembersMap = std::unordered_map<Creature*, FormationInfo*>;
+        MembersMap _members;
 
         ObjectGuid::LowType _leaderSpawnId;
         bool _formed;
@@ -103,6 +105,10 @@ class TC_GAME_API CreatureGroup
         void LeaderStartedMoving();
         void MemberEngagingTarget(Creature* member, Unit* target);
         bool CanLeaderStartMoving() const;
+
+        bool HasAliveMembers() const;
+
+        bool LeaderHasStringId(std::string_view id) const;
 };
 
 #define sFormationMgr FormationMgr::instance()