Battlegrounds/Buffs: Rework using areatriggers (#29171)

* Rework GameObject trap handling for buffs (removed radius hack)
* Add script for Old AreaTriggers
* Add script for new AreaTriggers
* Spawn AreaTriggers in Arathi Basin

7 files changed, 40 insertions, 69 deletions

diff --git a/src/server/game/Battlegrounds/Battleground.cpp b/src/server/game/Battlegrounds/Battleground.cpp
index 473e1124412..06d0b381b4d 100644
--- a/src/server/game/Battlegrounds/Battleground.cpp
+++ b/src/server/game/Battlegrounds/Battleground.cpp
@@ -75,7 +75,6 @@ Battleground::Battleground(BattlegroundTemplate const* battlegroundTemplate) : _
     m_Events            = 0;
     m_StartDelayTime    = 0;
     m_IsRated           = false;
-    m_BuffChange        = false;
     m_IsRandom          = false;
     m_InBGFreeSlotQueue = false;
     m_SetDeleteThis     = false;
@@ -1647,51 +1646,6 @@ void Battleground::EndNow()
     SetRemainingTime(0);
 }
 
-// IMPORTANT NOTICE:
-// buffs aren't spawned/despawned when players captures anything
-// buffs are in their positions when battleground starts
-void Battleground::HandleTriggerBuff(ObjectGuid go_guid)
-{
-    if (!FindBgMap())
-    {
-        TC_LOG_ERROR("bg.battleground", "Battleground::HandleTriggerBuff called with null bg map, {}", go_guid.ToString());
-        return;
-    }
-
-    GameObject* obj = GetBgMap()->GetGameObject(go_guid);
-    if (!obj || obj->GetGoType() != GAMEOBJECT_TYPE_TRAP || !obj->isSpawned())
-        return;
-
-    // Change buff type, when buff is used:
-    int32 index = BgObjects.size() - 1;
-    while (index >= 0 && BgObjects[index] != go_guid)
-        index--;
-    if (index < 0)
-    {
-        TC_LOG_ERROR("bg.battleground", "Battleground::HandleTriggerBuff: cannot find buff gameobject ({}, entry: {}, type: {}) in internal data for BG (map: {}, instance id: {})!",
-            go_guid.ToString(), obj->GetEntry(), obj->GetGoType(), GetMapId(), m_InstanceID);
-        return;
-    }
-
-    // Randomly select new buff
-    uint8 buff = urand(0, 2);
-    uint32 entry = obj->GetEntry();
-    if (m_BuffChange && entry != Buff_Entries[buff])
-    {
-        // Despawn current buff
-        SpawnBGObject(index, RESPAWN_ONE_DAY);
-        // Set index for new one
-        for (uint8 currBuffTypeIndex = 0; currBuffTypeIndex < 3; ++currBuffTypeIndex)
-            if (entry == Buff_Entries[currBuffTypeIndex])
-            {
-                index -= currBuffTypeIndex;
-                index += buff;
-            }
-    }
-
-    SpawnBGObject(index, BUFF_RESPAWN_TIME);
-}
-
 void Battleground::HandleKillPlayer(Player* victim, Player* killer)
 {
     // Keep in mind that for arena this will have to be changed a bit
diff --git a/src/server/game/Battlegrounds/Battleground.h b/src/server/game/Battlegrounds/Battleground.h
index 1bca27efc86..d589c1e33d7 100644
--- a/src/server/game/Battlegrounds/Battleground.h
+++ b/src/server/game/Battlegrounds/Battleground.h
@@ -445,7 +445,6 @@ class TC_GAME_API Battleground : public ZoneScript
         virtual void RemovePlayerAtLeave(ObjectGuid guid, bool Transport, bool SendPacket);
                                                             // can be extended in in BG subclass
 
-        void HandleTriggerBuff(ObjectGuid go_guid);
         void SetHoliday(bool is_holiday);
 
         /// @todo make this protected:
@@ -556,7 +555,6 @@ class TC_GAME_API Battleground : public ZoneScript
         // this must be filled in constructors!
         uint32 StartMessageIds[BG_STARTING_EVENT_COUNT];
 
-        bool   m_BuffChange;
         bool   m_IsRandom;
 
         BGHonorMode m_HonorMode;
diff --git a/src/server/game/Battlegrounds/Zones/BattlegroundAB.cpp b/src/server/game/Battlegrounds/Zones/BattlegroundAB.cpp
index adec4dcdca8..07aeb6ef5d8 100644
--- a/src/server/game/Battlegrounds/Zones/BattlegroundAB.cpp
+++ b/src/server/game/Battlegrounds/Zones/BattlegroundAB.cpp
@@ -23,13 +23,11 @@
 #include "Map.h"
 #include "ObjectMgr.h"
 #include "Player.h"
-#include "Random.h"
 #include "SpellInfo.h"
 
 BattlegroundAB::BattlegroundAB(BattlegroundTemplate const* battlegroundTemplate) : Battleground(battlegroundTemplate)
 {
     m_IsInformedNearVictory = false;
-    m_BuffChange = true;
     BgObjects.resize(0);
     BgCreatures.resize(0);
     m_lastTick = 0;
diff --git a/src/server/game/Battlegrounds/Zones/BattlegroundEY.cpp b/src/server/game/Battlegrounds/Zones/BattlegroundEY.cpp
index 250857dacb0..f33ae2b444d 100644
--- a/src/server/game/Battlegrounds/Zones/BattlegroundEY.cpp
+++ b/src/server/game/Battlegrounds/Zones/BattlegroundEY.cpp
@@ -38,7 +38,6 @@ uint32 BG_EY_HonorScoreTicks[BG_HONOR_MODE_NUM] =
 
 BattlegroundEY::BattlegroundEY(BattlegroundTemplate const* battlegroundTemplate) : Battleground(battlegroundTemplate)
 {
-    m_BuffChange = true;
     BgObjects.resize(BG_EY_OBJECT_MAX);
     BgCreatures.resize(BG_EY_CREATURES_MAX);
     m_Points_Trigger[FEL_REAVER] = TR_FEL_REAVER_BUFF;
diff --git a/src/server/game/Entities/GameObject/GameObject.cpp b/src/server/game/Entities/GameObject/GameObject.cpp
index df5c39ecffa..b7d77cad622 100644
--- a/src/server/game/Entities/GameObject/GameObject.cpp
+++ b/src/server/game/Entities/GameObject/GameObject.cpp
@@ -1150,17 +1150,9 @@ void GameObject::Update(uint32 diff)
 
                     // Type 0 despawns after being triggered, type 1 does not.
                     /// @todo This is activation radius. Casting radius must be selected from spell data.
-                    float radius;
-                    if (!goInfo->trap.radius)
-                    {
-                        // Battleground traps: data2 == 0 && data5 == 3
-                        if (goInfo->trap.cooldown != 3)
-                            break;
-
-                        radius = 3.f;
-                    }
-                    else
-                        radius = goInfo->trap.radius / 2.f;
+                    float radius = goInfo->trap.radius / 2.f; // this division seems to date back to when the field was called diameter, don't think it is still relevant.
+                    if (!radius)
+                        break;
 
                     // Pointer to appropriate target if found any
                     Unit* target = nullptr;
@@ -1301,12 +1293,6 @@ void GameObject::Update(uint32 diff)
                             SetLootState(GO_JUST_DEACTIVATED);
                         else if (!goInfo->trap.charges)
                             SetLootState(GO_READY);
-
-                        // Battleground gameobjects have data2 == 0 && data5 == 3
-                        if (!goInfo->trap.radius && goInfo->trap.cooldown == 3)
-                            if (Player* player = target->ToPlayer())
-                                if (Battleground* bg = player->GetBattleground())
-                                    bg->HandleTriggerBuff(GetGUID());
                     }
                     break;
                 }
diff --git a/src/server/game/Entities/Object/Object.h b/src/server/game/Entities/Object/Object.h
index 4bc8fc28896..629367079a8 100644
--- a/src/server/game/Entities/Object/Object.h
+++ b/src/server/game/Entities/Object/Object.h
@@ -459,7 +459,7 @@ struct FindGameObjectOptions
     Optional<std::string_view> StringId;
 
     Optional<bool> IsSummon;
-    Optional<bool> IsSpawned;
+    Optional<bool> IsSpawned = true; // most searches should be for spawned objects only, to search for "any" just clear this field at call site
 
     bool IgnorePhases = false;
     bool IgnoreNotOwnedPrivateObjects = true;
diff --git a/src/server/scripts/World/areatrigger_scripts.cpp b/src/server/scripts/World/areatrigger_scripts.cpp
index 71f1f89ae3e..8bf43d076ac 100644
--- a/src/server/scripts/World/areatrigger_scripts.cpp
+++ b/src/server/scripts/World/areatrigger_scripts.cpp
@@ -407,6 +407,40 @@ struct areatrigger_stormwind_teleport_unit : AreaTriggerAI
     }
 };
 
+void HandleBuffAreaTrigger(Player* player)
+{
+    if (GameObject* buffObject = player->FindNearestGameObjectWithOptions(4.0f, { .StringId = "bg_buff_object" }))
+    {
+        buffObject->ActivateObject(GameObjectActions::Disturb, 0, player);
+        buffObject->DespawnOrUnsummon();
+    }
+}
+
+struct areatrigger_battleground_buffs : AreaTriggerAI
+{
+    areatrigger_battleground_buffs(AreaTrigger* areatrigger) : AreaTriggerAI(areatrigger) { }
+
+    void OnUnitEnter(Unit* unit) override
+    {
+        if (!unit->IsPlayer())
+            return;
+
+        HandleBuffAreaTrigger(unit->ToPlayer());
+    }
+};
+
+class AreaTrigger_at_battleground_buffs : public AreaTriggerScript
+{
+public:
+    AreaTrigger_at_battleground_buffs() : AreaTriggerScript("at_battleground_buffs") { }
+
+    bool OnTrigger(Player* player, AreaTriggerEntry const* /*areaTrigger*/) override
+    {
+        HandleBuffAreaTrigger(player);
+        return true;
+    }
+};
+
 void AddSC_areatrigger_scripts()
 {
     new AreaTrigger_at_coilfang_waterfall();
@@ -418,4 +452,6 @@ void AddSC_areatrigger_scripts()
     new AreaTrigger_at_area_52_entrance();
     new AreaTrigger_at_frostgrips_hollow();
     RegisterAreaTriggerAI(areatrigger_stormwind_teleport_unit);
+    RegisterAreaTriggerAI(areatrigger_battleground_buffs);
+    new AreaTrigger_at_battleground_buffs();
 }