feat(Core/BG): allow MinPlayersPerTeam override for low-levels (#20083)

src/server/apps/worldserver/worldserver.conf.dist

@@ -3675,6 +3675,13 @@ Battleground.BerserkingBuffRespawn = 120
 
 Battleground.SpeedBuffRespawn = 150
 
+#
+#    Battleground.Override.LowLevels.MinPlayers
+#        Description: Overrides the minimum number of required players per team for all levels < MaxPlayerLevel
+#        Default:     0 (Disabled)
+
+Battleground.Override.LowLevels.MinPlayers = 0
+
 #
 ###################################################################################################
 

src/server/game/Battlegrounds/Battleground.cpp

@@ -146,6 +146,7 @@ Battleground::Battleground()
     m_LastResurrectTime = 0;
     m_ArenaType         = 0;
     m_IsArena           = false;
+    m_IsTemplate        = true;
     m_WinnerId          = PVP_TEAM_NEUTRAL;
     m_StartTime         = 0;
     m_ResetStatTimer    = 0;
@@ -1822,6 +1823,7 @@ GraveyardStruct const* Battleground::GetClosestGraveyard(Player* player)
 
 void Battleground::SetBracket(PvPDifficultyEntry const* bracketEntry)
 {
+    m_IsTemplate = false;
     m_BracketId = bracketEntry->GetBracketId();
     SetLevelRange(bracketEntry->minLevel, bracketEntry->maxLevel);
 }

src/server/game/Battlegrounds/Battleground.h

@@ -23,6 +23,7 @@
 #include "DBCEnums.h"
 #include "GameObject.h"
 #include "SharedDefines.h"
+#include "World.h"
 
 class Creature;
 class GameObject;
@@ -337,8 +338,20 @@ public:
     [[nodiscard]] uint32 GetMinLevel() const          { return m_LevelMin; }
     [[nodiscard]] uint32 GetMaxLevel() const          { return m_LevelMax; }
 
+    [[nodiscard]] bool isTemplate() const             { return m_IsTemplate; }
+    [[nodiscard]] bool isMaxLevel() const
+    {
+        // NOTE: this only works when the BG is not a template but the real BG
+        auto maxPlayerLevel = sWorld->getIntConfig(CONFIG_MAX_PLAYER_LEVEL);
+        return GetMinLevel() <= maxPlayerLevel && maxPlayerLevel <= GetMaxLevel();
+    }
+
     [[nodiscard]] uint32 GetMaxPlayersPerTeam() const { return m_MaxPlayersPerTeam; }
-    [[nodiscard]] uint32 GetMinPlayersPerTeam() const { return m_MinPlayersPerTeam; }
+    [[nodiscard]] uint32 GetMinPlayersPerTeam() const
+    {
+        auto lowLevelsOverride = sWorld->getIntConfig(CONFIG_BATTLEGROUND_OVERRIDE_LOWLEVELS_MINPLAYERS);
+        return (lowLevelsOverride && !isTemplate() && !isMaxLevel() && !isArena()) ? lowLevelsOverride : m_MinPlayersPerTeam;
+    }
 
     [[nodiscard]] int32 GetStartDelayTime() const     { return m_StartDelayTime; }
     [[nodiscard]] uint8 GetArenaType() const          { return m_ArenaType; }
@@ -658,6 +671,7 @@ private:
     bool   _InBGFreeSlotQueue{ false };                // used to make sure that BG is only once inserted into the BattlegroundMgr.BGFreeSlotQueue[bgTypeId] deque
     bool   m_SetDeleteThis;                             // used for safe deletion of the bg after end / all players leave
     bool   m_IsArena;
+    bool   m_IsTemplate;
     PvPTeamId m_WinnerId;
     int32  m_StartDelayTime;
     bool   m_IsRated;                                   // is this battle rated?

src/server/game/Battlegrounds/BattlegroundQueue.cpp

@@ -31,6 +31,8 @@
 #include "ScriptMgr.h"
 #include <unordered_map>
 
+#include "BattlegroundUtils.h"
+
 /*********************************************************/
 /***            BATTLEGROUND QUEUE SYSTEM              ***/
 /*********************************************************/
@@ -760,7 +762,7 @@ void BattlegroundQueue::BattlegroundQueueUpdate(uint32 diff, BattlegroundTypeId
     }
 
     // get min and max players per team
-    uint32 MinPlayersPerTeam = bg_template->GetMinPlayersPerTeam();
+    uint32 MinPlayersPerTeam = GetMinPlayersPerTeam(bg_template, bracketEntry);
     uint32 MaxPlayersPerTeam = bg_template->GetMaxPlayersPerTeam();
 
     if (bg_template->isArena())
@@ -996,7 +998,7 @@ void BattlegroundQueue::BattlegroundQueueAnnouncerUpdate(uint32 diff, Battlegrou
                 _queueAnnouncementTimer[bracket_id] = -1;
 
                 auto bgName = bg_template->GetName();
-                uint32 MaxPlayers = bg_template->GetMinPlayersPerTeam() * 2;
+                uint32 MaxPlayers = GetMinPlayersPerTeam(bg_template, bracketEntry) * 2;
                 uint32 q_min_level = std::min(bracketEntry->minLevel, (uint32) 80);
                 uint32 q_max_level = std::min(bracketEntry->maxLevel, (uint32) 80);
 
@@ -1047,7 +1049,7 @@ void BattlegroundQueue::SendMessageBGQueue(Player* leader, Battleground* bg, PvP
 
     BattlegroundBracketId bracketId = bracketEntry->GetBracketId();
     auto bgName = bg->GetName();
-    uint32 MinPlayers = bg->GetMinPlayersPerTeam();
+    uint32 MinPlayers = GetMinPlayersPerTeam(bg, bracketEntry);
     uint32 MaxPlayers = MinPlayers * 2;
     uint32 q_min_level = std::min(bracketEntry->minLevel, (uint32)80);
     uint32 q_max_level = std::min(bracketEntry->maxLevel, (uint32)80);

src/server/game/Battlegrounds/BattlegroundUtils.cpp

@@ -0,0 +1,20 @@
+#include "BattlegroundUtils.h"
+#include "World.h"
+
+uint32 GetMinPlayersPerTeam(Battleground* bg, PvPDifficultyEntry const* bracketEntry)
+{
+    // The problem addressed here is that methods such as bg->GetMinLevel() and bg->GetMaxLevel() have a different meaning
+    // according to whether the BG is a template (then it's the value from the `battleground_template` table)
+    // or if it's the real BG (then it's the specific bracket minimum level, e.g. "60" for "60-69").
+
+    if (!bg->isTemplate() || bg->isArena())
+    {
+        return bg->GetMinPlayersPerTeam();
+    }
+
+    auto maxPlayerLevel = sWorld->getIntConfig(CONFIG_MAX_PLAYER_LEVEL);
+    auto isMaxLevel = bracketEntry->minLevel <= maxPlayerLevel && maxPlayerLevel <= bracketEntry->maxLevel;
+    auto lowLevelsOverride = sWorld->getIntConfig(CONFIG_BATTLEGROUND_OVERRIDE_LOWLEVELS_MINPLAYERS);
+
+    return (lowLevelsOverride && !isMaxLevel) ? lowLevelsOverride : bg->GetMinPlayersPerTeam();
+}

src/server/game/Battlegrounds/BattlegroundUtils.h

@@ -0,0 +1,8 @@
+#ifndef BATTLEGROUNDUTILS_H
+#define BATTLEGROUNDUTILS_H
+
+#include "Battleground.h"
+
+uint32 GetMinPlayersPerTeam(Battleground* bg, PvPDifficultyEntry const* bracketEntry);
+
+#endif  // BATTLEGROUNDUTILS_H

src/server/game/World/IWorld.h

@@ -309,6 +309,7 @@ enum WorldIntConfigs
     CONFIG_DEATH_SICKNESS_LEVEL,
     CONFIG_INSTANT_LOGOUT,
     CONFIG_DISABLE_BREATHING,
+    CONFIG_BATTLEGROUND_OVERRIDE_LOWLEVELS_MINPLAYERS,
     CONFIG_BATTLEGROUND_QUEUE_ANNOUNCER_SPAM_DELAY,
     CONFIG_BATTLEGROUND_QUEUE_ANNOUNCER_TIMER,
     CONFIG_BATTLEGROUND_PREMATURE_FINISH_TIMER,

src/server/game/World/World.cpp

@@ -1112,6 +1112,7 @@ void World::LoadConfigSettings(bool reload)
     _float_configs[CONFIG_LISTEN_RANGE_TEXTEMOTE] = sConfigMgr->GetOption<float>("ListenRange.TextEmote", 25.0f);
     _float_configs[CONFIG_LISTEN_RANGE_YELL]      = sConfigMgr->GetOption<float>("ListenRange.Yell", 300.0f);
 
+    _int_configs[CONFIG_BATTLEGROUND_OVERRIDE_LOWLEVELS_MINPLAYERS]        = sConfigMgr->GetOption<uint32>("Battleground.Override.LowLevels.MinPlayers", 0);
     _bool_configs[CONFIG_BATTLEGROUND_DISABLE_QUEST_SHARE_IN_BG]           = sConfigMgr->GetOption<bool>("Battleground.DisableQuestShareInBG", false);
     _bool_configs[CONFIG_BATTLEGROUND_DISABLE_READY_CHECK_IN_BG]           = sConfigMgr->GetOption<bool>("Battleground.DisableReadyCheckInBG", false);
     _bool_configs[CONFIG_BATTLEGROUND_CAST_DESERTER]                       = sConfigMgr->GetOption<bool>("Battleground.CastDeserter", true);