Battlegrounds/Buffs: Rework using areatriggers

Port From (https://github.com/TrinityCore/TrinityCore/commit/f5461a1161a5a9dfabe7a142ad84f8c900776c92)

Source/Game/BattleGrounds/BattleGround.cs

@@ -1546,52 +1546,6 @@ namespace Game.BattleGrounds
             SetRemainingTime(0);
         }
 
-        // IMPORTANT NOTICE:
-        // buffs aren't spawned/despawned when players captures anything
-        // buffs are in their positions when Battleground starts
-        public void HandleTriggerBuff(ObjectGuid goGuid)
-        {
-            if (!FindBgMap())
-            {
-                Log.outError(LogFilter.Battleground, $"Battleground::HandleTriggerBuff called with null bg map, {goGuid}");
-                return;
-            }
-
-            GameObject obj = GetBgMap().GetGameObject(goGuid);
-            if (!obj || obj.GetGoType() != GameObjectTypes.Trap || !obj.IsSpawned())
-                return;
-
-            // Change buff type, when buff is used:
-            int index = BgObjects.Length - 1;
-            while (index >= 0 && BgObjects[index] != goGuid)
-                index--;
-            if (index < 0)
-            {
-                Log.outError(LogFilter.Battleground, $"Battleground.HandleTriggerBuff: cannot find buff gameobject ({goGuid}, entry: {obj.GetEntry()}, type: {obj.GetGoType()}) in internal data for BG (map: {GetMapId()}, instance id: {m_InstanceID})!");
-                return;
-            }
-
-            // Randomly select new buff
-            int buff = RandomHelper.IRand(0, 2);
-            uint entry = obj.GetEntry();
-            if (m_BuffChange && entry != Buff_Entries[buff])
-            {
-                // Despawn current buff
-                SpawnBGObject(index, BattlegroundConst.RespawnOneDay);
-                // Set index for new one
-                for (byte currBuffTypeIndex = 0; currBuffTypeIndex < 3; ++currBuffTypeIndex)
-                {
-                    if (entry == Buff_Entries[currBuffTypeIndex])
-                    {
-                        index -= currBuffTypeIndex;
-                        index += buff;
-                    }
-                }
-            }
-
-            SpawnBGObject(index, BattlegroundConst.BuffRespawnTime);
-        }
-
         public virtual void HandleKillPlayer(Player victim, Player killer)
         {
             // Keep in mind that for arena this will have to be changed a bit
@@ -1974,7 +1928,6 @@ namespace Game.BattleGrounds
         // this must be filled inructors!
         public uint[] StartMessageIds = new uint[4];
 
-        public bool m_BuffChange;
         bool m_IsRandom;
 
         public BGHonorMode m_HonorMode;

Source/Game/Entities/GameObject/GameObject.cs

@@ -601,17 +601,9 @@ namespace Game.Entities
 
                             // Type 0 despawns after being triggered, type 1 does not.
                             // @todo This is activation radius. Casting radius must be selected from spell 
-                            float radius;
+                            float radius = goInfo.Trap.radius / 2.0f; // this division seems to date back to when the field was called diameter, don't think it is still relevant.
-                            if (goInfo.Trap.radius == 0f)
+                            if (radius == 0f)
-                            {
+                                break;
-                                // Battlegroundgameobjects have data2 == 0 && data5 == 3
-                                if (goInfo.Trap.cooldown != 3)
-                                    break;
-
-                                radius = 3.0f;
-                            }
-                            else
-                                radius = goInfo.Trap.radius / 2.0f;
 
                             Unit target;
                             // @todo this hack with search required until GO casting not implemented
@@ -753,18 +745,6 @@ namespace Game.Entities
                                     SetLootState(LootState.JustDeactivated);
                                 else if (goInfo.Trap.charges == 0)
                                     SetLootState(LootState.Ready);
-
-                                // Battleground gameobjects have data2 == 0 && data5 == 3
-                                if (goInfo.Trap.radius == 0 && goInfo.Trap.cooldown == 3)
-                                {
-                                    Player player = target.ToPlayer();
-                                    if (player)
-                                    {
-                                        Battleground bg = player.GetBattleground();
-                                        if (bg)
-                                            bg.HandleTriggerBuff(GetGUID());
-                                    }
-                                }
                             }
                             break;
                         }

Source/Game/Entities/Object/WorldObject.cs

@@ -1683,7 +1683,7 @@ namespace Game.Entities
             return searcher.GetTarget();
         }
 
-        GameObject FindNearestGameObjectWithOptions(float range, FindGameObjectOptions options)
+        public GameObject FindNearestGameObjectWithOptions(float range, FindGameObjectOptions options)
         {
             NearestCheckCustomizer checkCustomizer = new(this, range);
             GameObjectWithOptionsInObjectRangeCheck<NearestCheckCustomizer> checker = new(this, checkCustomizer, options);
@@ -4062,13 +4062,13 @@ namespace Game.Entities
         public ObjectGuid? PrivateObjectOwnerGuid;
     }
 
-    class FindGameObjectOptions
+    public class FindGameObjectOptions
     {
         public uint? GameObjectId;
         public string StringId;
 
         public bool? IsSummon;
-        public bool? IsSpawned;
+        public bool? IsSpawned = true; // most searches should be for spawned objects only, to search for "any" just clear this field at call site
 
         public bool IgnorePhases;
         public bool IgnoreNotOwnedPrivateObjects = true;

Source/Scripts/World/AreaTrigger.cs

@@ -109,7 +109,7 @@ namespace Scripts.World.Areatriggers
     }
 
     struct Misc
-    { 
+    {
         //Brewfest
         public const uint AreatriggerTalkCooldown = 5; // In Seconds
 
@@ -396,4 +396,41 @@ namespace Scripts.World.Areatriggers
             player.KilledMonsterCredit(CreatureIds.KillCreditTeleportStormwind);
         }
     }
+
+    [Script]
+    class areatrigger_battleground_buffs : AreaTriggerAI
+    {
+        public areatrigger_battleground_buffs(AreaTrigger areatrigger) : base(areatrigger) { }
+
+        public override void OnUnitEnter(Unit unit)
+        {
+            if (!unit.IsPlayer())
+                return;
+
+            var player = unit.ToPlayer();
+            GameObject buffObject = player.FindNearestGameObjectWithOptions(4.0f, new FindGameObjectOptions() { StringId = "bg_buff_object" });
+            if (buffObject != null)
+            {
+                buffObject.ActivateObject(GameObjectActions.Disturb, 0, player);
+                buffObject.DespawnOrUnsummon();
+            }
+        }
+    }
+
+    [Script]
+    class AreaTrigger_at_battleground_buffs : AreaTriggerScript
+    {
+        public AreaTrigger_at_battleground_buffs() : base("at_battleground_buffs") { }
+
+        public override bool OnTrigger(Player player, AreaTriggerRecord areaTrigger)
+        {
+            GameObject buffObject = player.FindNearestGameObjectWithOptions(4.0f, new FindGameObjectOptions() { StringId = "bg_buff_object" });
+            if (buffObject != null)
+            {
+                buffObject.ActivateObject(GameObjectActions.Disturb, 0, player);
+                buffObject.DespawnOrUnsummon();
+            }
+            return true;
+        }
+    }
 }