From d693bdb95dfd7a4c84f3c04813aaa713ece24dfd Mon Sep 17 00:00:00 2001
From: Rushor <Rushor@users.noreply.github.com>
Date: Sun, 25 Jun 2017 12:29:05 +0200
Subject: [PATCH] Core/Creature: Implement Mangos GroupAI flags (allows
 formation without following) (#18733)

---
 sql/updates/world/3.3.5/2017_12_18_00_world.sql      | 4 ++++
 src/server/game/Entities/Creature/CreatureGroups.cpp | 8 +++-----
 src/server/game/Entities/Creature/CreatureGroups.h   | 8 ++++++++
 3 files changed, 15 insertions(+), 5 deletions(-)
 create mode 100644 sql/updates/world/3.3.5/2017_12_18_00_world.sql

diff --git a/sql/updates/world/3.3.5/2017_12_18_00_world.sql b/sql/updates/world/3.3.5/2017_12_18_00_world.sql
new file mode 100644
index 00000000000..6741d0c96bc
--- /dev/null
+++ b/sql/updates/world/3.3.5/2017_12_18_00_world.sql
@@ -0,0 +1,4 @@
+-- 
+UPDATE `creature_formations` SET `groupAI`=7 WHERE `groupAI`=2; -- members attack and members follow the leader
+UPDATE `creature_formations` SET `groupAI`=4 WHERE `groupAI`=0; -- members follow the leader
+UPDATE `creature_formations` SET `groupAI`=5 WHERE `groupAI`=1; -- The members aggroes if the leader aggroes and  members follow the leader
diff --git a/src/server/game/Entities/Creature/CreatureGroups.cpp b/src/server/game/Entities/Creature/CreatureGroups.cpp
index 1abbd1c6f6e..fc60d3b3bec 100644
--- a/src/server/game/Entities/Creature/CreatureGroups.cpp
+++ b/src/server/game/Entities/Creature/CreatureGroups.cpp
@@ -176,9 +176,6 @@ void CreatureGroup::MemberAttackStart(Creature* member, Unit* target)
     if (!groupAI)
         return;
 
-    if (groupAI == 1 && member != m_leader)
-        return;
-
     for (CreatureGroupMemberType::iterator itr = m_members.begin(); itr != m_members.end(); ++itr)
     {
         if (m_leader) // avoid crash if leader was killed and reset.
@@ -196,7 +193,7 @@ void CreatureGroup::MemberAttackStart(Creature* member, Unit* target)
         if (other->GetVictim())
             continue;
 
-        if (other->IsValidAttackTarget(target))
+        if (((other != m_leader && groupAI & FLAG_AGGRO_ON_AGGRO) || (other == m_leader && groupAI & FLAG_TO_AGGRO_ON_AGGRO)) && other->IsValidAttackTarget(target))
             other->AI()->AttackStart(target);
     }
 }
@@ -229,7 +226,8 @@ void CreatureGroup::LeaderMoveTo(float x, float y, float z)
     for (CreatureGroupMemberType::iterator itr = m_members.begin(); itr != m_members.end(); ++itr)
     {
         Creature* member = itr->first;
-        if (member == m_leader || !member->IsAlive() || member->GetVictim())
+        uint8 groupAI = sFormationMgr->CreatureGroupMap[member->GetSpawnId()]->groupAI;
+        if (member == m_leader || !member->IsAlive() || member->GetVictim() || !(groupAI & FLAG_FOLLOW))
             continue;
 
         if (itr->second->point_1)
diff --git a/src/server/game/Entities/Creature/CreatureGroups.h b/src/server/game/Entities/Creature/CreatureGroups.h
index 67164cee91c..0de06e11c2b 100644
--- a/src/server/game/Entities/Creature/CreatureGroups.h
+++ b/src/server/game/Entities/Creature/CreatureGroups.h
@@ -23,6 +23,14 @@
 #include <unordered_map>
 #include <map>
 
+enum GroupAIFlags
+{
+    FLAG_AGGRO_NONE        = 0,          // If any creature from group is attacked, members won't assist and won't follow
+    FLAG_AGGRO_ON_AGGRO    = 0x00000001, // The member aggroes if the leader aggroes
+    FLAG_TO_AGGRO_ON_AGGRO = 0x00000002, // The leader aggroes if the member aggroes
+    FLAG_FOLLOW            = 0x00000004, // The member will follow the leader
+};
+
 class Creature;
 class CreatureGroup;