Core/Movement: waypoint movement

Port From (https://github.com/TrinityCore/TrinityCore/commit/97585597f0b1aff93873fe4d757556731bc0c1b2)

Source/Game/Entities/Creature/Creature.cs

@@ -105,6 +105,21 @@ namespace Game.Entities
             ForcedDespawn(0);
         }
 
+        public override void PauseMovement(uint timer = 0, MovementSlot slot = 0)
+        {
+            base.PauseMovement(timer, slot);
+
+            SetHomePosition(GetPosition());
+        }
+
+        public bool IsReturningHome()
+        {
+            if (GetMotionMaster().GetMotionSlotType(MovementSlot.Active) == MovementGeneratorType.Home)
+                return true;
+
+            return false;
+        }
+        
         public void SearchFormation()
         {
             if (IsSummon())
@@ -119,6 +134,33 @@ namespace Game.Entities
                 FormationMgr.AddCreatureToGroup(frmdata.leaderGUID, this);
         }
 
+        public bool IsFormationLeader()
+        {
+            if (m_formation == null)
+                return false;
+
+            return m_formation.IsLeader(this);
+        }
+
+        public void SignalFormationMovement(Position destination, uint id = 0, WaypointMoveType moveType = 0, bool orientation = false)
+        {
+            if (m_formation == null)
+                return;
+
+            if (!m_formation.IsLeader(this))
+                return;
+
+            m_formation.LeaderMoveTo(destination, id, moveType, orientation);
+        }
+
+        public bool IsFormationLeaderMoveAllowed()
+        {
+            if (m_formation == null)
+                return false;
+
+            return m_formation.CanLeaderStartMoving();
+        }
+        
         public void RemoveCorpse(bool setSpawnTime = true, bool destroyForNearbyPlayers = true)
         {
             if (GetDeathState() != DeathState.Corpse)

Source/Game/Entities/Creature/CreatureGroups.cs

@@ -216,7 +216,7 @@ namespace Game.Entities
             m_Formed = !dismiss;
         }
 
-        public void LeaderMoveTo(Position destination, uint id = 0, uint moveType = 0, bool orientation = false)
+        public void LeaderMoveTo(Position destination, uint id = 0, WaypointMoveType moveType = 0, bool orientation = false)
         {
             //! To do: This should probably get its own movement generator or use WaypointMovementGenerator.
             //! If the leader's path is known, member's path can be plotted as well using formation offsets.
@@ -258,11 +258,26 @@ namespace Game.Entities
             }
         }
 
+        public bool CanLeaderStartMoving()
+        {
+            foreach (var itr in m_members)
+            {
+                if (itr.Key != m_leader && itr.Key.IsAlive())
+                {
+                    if (itr.Key.IsEngaged() || itr.Key.IsReturningHome())
+                        return false;
+                }
+            }
+
+            return true;
+        }
+
         public Creature GetLeader() { return m_leader; }
         public uint GetId() { return m_groupID; }
         public bool IsEmpty() { return m_members.Empty(); }
         public bool IsFormed() { return m_Formed; }
-
+        public bool IsLeader(Creature creature) { return m_leader == creature; }
+        
         Creature m_leader;
         Dictionary<Creature, FormationInfo> m_members = new Dictionary<Creature, FormationInfo>();