From fed03f970cd6ba83653e6a72865a424414b3454c Mon Sep 17 00:00:00 2001
From: Kelsi <kelsihates2fa@gmail.com>
Date: Wed, 11 Mar 2026 04:22:18 -0700
Subject: [PATCH] fix: correct SMSG_BATTLEFIELD_STATUS Classic 1.12 packet
 layout

Classic uses queueSlot(4)+bgTypeId(4)+unk(2)+instanceId(4)+isReg(1)+statusId(4);
TBC/WotLK prefixes arenaType(1)+unk(1) before bgTypeId. Reading TBC format on
Classic caused bgTypeId to be read from wrong offset, corrupting BG queue state.
---
 src/game/game_handler.cpp | 38 +++++++++++++++++++++++++++++---------
 1 file changed, 29 insertions(+), 9 deletions(-)

diff --git a/src/game/game_handler.cpp b/src/game/game_handler.cpp
index 06e4c057..18b5a54f 100644
--- a/src/game/game_handler.cpp
+++ b/src/game/game_handler.cpp
@@ -12242,20 +12242,40 @@ void GameHandler::handleMoveKnockBack(network::Packet& packet) {
 // ============================================================
 
 void GameHandler::handleBattlefieldStatus(network::Packet& packet) {
+    // SMSG_BATTLEFIELD_STATUS wire format differs by expansion:
+    //
+    // Classic 1.12 (vmangos/cmangos):
+    //   queueSlot(4) bgTypeId(4) unk(2) instanceId(4) isRegistered(1) statusId(4) [status fields...]
+    //   STATUS_NONE sends only: queueSlot(4) bgTypeId(4)
+    //
+    // TBC 2.4.3 / WotLK 3.3.5a:
+    //   queueSlot(4) arenaType(1) unk(1) bgTypeId(4) unk2(2) instanceId(4) isRated(1) statusId(4) [status fields...]
+    //   STATUS_NONE sends only: queueSlot(4) arenaType(1)
+
     if (packet.getSize() - packet.getReadPos() < 4) return;
     uint32_t queueSlot = packet.readUInt32();
 
-    // Minimal packet = just queueSlot + arenaType(1) when status is NONE
-    if (packet.getSize() - packet.getReadPos() < 1) {
-        LOG_INFO("Battlefield status: queue slot ", queueSlot, " cleared");
-        return;
+    const bool classicFormat = isClassicLikeExpansion();
+
+    uint8_t arenaType = 0;
+    if (!classicFormat) {
+        // TBC/WotLK: arenaType(1) + unk(1) before bgTypeId
+        // STATUS_NONE sends only queueSlot + arenaType
+        if (packet.getSize() - packet.getReadPos() < 1) {
+            LOG_INFO("Battlefield status: queue slot ", queueSlot, " cleared");
+            return;
+        }
+        arenaType = packet.readUInt8();
+        if (packet.getSize() - packet.getReadPos() < 1) return;
+        packet.readUInt8();  // unk
+    } else {
+        // Classic STATUS_NONE sends only queueSlot + bgTypeId (4 bytes)
+        if (packet.getSize() - packet.getReadPos() < 4) {
+            LOG_INFO("Battlefield status: queue slot ", queueSlot, " cleared");
+            return;
+        }
     }
 
-    uint8_t arenaType = packet.readUInt8();
-    if (packet.getSize() - packet.getReadPos() < 1) return;
-
-    // Unknown byte
-    packet.readUInt8();
     if (packet.getSize() - packet.getReadPos() < 4) return;
     uint32_t bgTypeId = packet.readUInt32();