feat(Core): implement world availability option (#8755)

src/server/game/Handlers/CharacterHandler.cpp

@@ -665,17 +665,23 @@ void WorldSession::HandleCharDeleteOpcode(WorldPacket& recvData)
 
 void WorldSession::HandlePlayerLoginOpcode(WorldPacket& recvData)
 {
-    if (PlayerLoading() || GetPlayer() != nullptr)
-    {
-        LOG_ERROR("network", "Player tries to login again, AccountId = %d", GetAccountId());
-        KickPlayer("WorldSession::HandlePlayerLoginOpcode Another client logging in");
-        return;
-    }
-
     m_playerLoading = true;
     ObjectGuid playerGuid;
     recvData >> playerGuid;
 
+    if (PlayerLoading() || GetPlayer() != nullptr || !playerGuid.IsPlayer())
+    {
+        // limit player interaction with the world
+        if (!sWorld->getBoolConfig(CONFIG_REALM_LOGIN_ENABLED))
+        {
+            WorldPacket data(SMSG_CHARACTER_LOGIN_FAILED, 1);
+            // see LoginFailureReason enum for more reasons
+            data << uint8(LoginFailureReason::NoWorld);
+            SendPacket(&data);
+            return;
+        }
+    }
+
     if (!playerGuid.IsPlayer() || !IsLegitCharacterForAccount(playerGuid))
     {
         LOG_ERROR("network", "Account (%u) can't login with that character (%s).", GetAccountId(), playerGuid.ToString().c_str());

src/server/game/World/IWorld.h

@@ -170,6 +170,7 @@ enum WorldBoolConfigs
     CONFIG_REGEN_HP_CANNOT_REACH_TARGET_IN_RAID,
     CONFIG_SET_BOP_ITEM_TRADEABLE,
     CONFIG_ALLOW_LOGGING_IP_ADDRESSES_IN_DATABASE,
+    CONFIG_REALM_LOGIN_ENABLED,
     BOOL_CONFIG_VALUE_COUNT
 };
 

src/server/game/World/World.cpp

@@ -1436,6 +1436,9 @@ void World::LoadConfigSettings(bool reload)
         LOG_ERROR("server.loading", "LFG.KickPreventionTimer can't be higher than 15 minutes.");
     }
 
+    // Realm Availability
+    m_bool_configs[CONFIG_REALM_LOGIN_ENABLED] = sConfigMgr->GetOption<bool>("World.RealmAvailability", false);
+
     // call ScriptMgr if we're reloading the configuration
     sScriptMgr->OnAfterConfigLoad(reload);
 }