Add secure login handling for playerbots (#1953)

Introduces PlayerbotsSecureLoginServerScript to handle secure login
scenarios for playerbots. Ensures that if a playerbot is already online
when a login is attempted, it is properly logged out before allowing the
new session. Registers the new script in the Playerbots initialization.

src/Playerbots.cpp

@@ -502,6 +502,8 @@ public:
     void OnBattlegroundEnd(Battleground* bg, TeamId /*winnerTeam*/) override { bgStrategies.erase(bg->GetInstanceID()); }
 };
 
+void AddPlayerbotsSecureLoginScripts();
+
 void AddPlayerbotsScripts()
 {
     new PlayerbotsDatabaseScript();
@@ -511,6 +513,7 @@ void AddPlayerbotsScripts()
     new PlayerbotsWorldScript();
     new PlayerbotsScript();
     new PlayerBotsBGScript();
+    AddPlayerbotsSecureLoginScripts();
 
     AddSC_playerbots_commandscript();
 }

src/PlayerbotsSecureLogin.cpp

@@ -0,0 +1,82 @@
+#include "ScriptMgr.h"
+#include "Opcodes.h"
+#include "Player.h"
+#include "ObjectAccessor.h"
+
+#include "Playerbots.h"
+
+namespace
+{
+    static Player* FindOnlineAltbotByGuid(ObjectGuid guid)
+    {
+        if (!guid)
+            return nullptr;
+
+        Player* p = ObjectAccessor::FindPlayer(guid);
+        if (!p)
+            return nullptr;
+
+        PlayerbotAI* ai = GET_PLAYERBOT_AI(p);
+        if (!ai || ai->IsRealPlayer())
+            return nullptr;
+
+        return p;
+    }
+
+    static void ForceLogoutViaPlayerbotHolder(Player* target)
+    {
+        if (!target)
+            return;
+
+        PlayerbotAI* ai = GET_PLAYERBOT_AI(target);
+        if (!ai)
+            return;
+
+        if (Player* master = ai->GetMaster())
+        {
+            if (PlayerbotMgr* mgr = GET_PLAYERBOT_MGR(master))
+            {
+                mgr->LogoutPlayerBot(target->GetGUID());
+                return;
+            }
+        }
+
+        if (sRandomPlayerbotMgr)
+        {
+            sRandomPlayerbotMgr->LogoutPlayerBot(target->GetGUID());
+            return;
+        }
+    }
+}
+
+class PlayerbotsSecureLoginServerScript : public ServerScript
+{
+public:
+    PlayerbotsSecureLoginServerScript()
+        : ServerScript("PlayerbotsSecureLoginServerScript", { SERVERHOOK_CAN_PACKET_RECEIVE }) {}
+
+    bool CanPacketReceive(WorldSession* /*session*/, WorldPacket& packet) override
+    {
+        if (packet.GetOpcode() != CMSG_PLAYER_LOGIN)
+            return true;
+
+        auto const oldPos = packet.rpos();
+        ObjectGuid loginGuid;
+        packet >> loginGuid;
+        packet.rpos(oldPos);
+
+        if (!loginGuid)
+            return true;
+
+        Player* existingAltbot = FindOnlineAltbotByGuid(loginGuid);
+        if (existingAltbot)
+            ForceLogoutViaPlayerbotHolder(existingAltbot);
+
+        return true;
+    }
+};
+
+void AddPlayerbotsSecureLoginScripts()
+{
+    new PlayerbotsSecureLoginServerScript();
+}