From b24703db308261c4b5eb7bc3dd85b63c26315352 Mon Sep 17 00:00:00 2001
From: Kelsi <kelsihates2fa@gmail.com>
Date: Fri, 20 Feb 2026 02:23:19 -0800
Subject: [PATCH] Drive level-up effects from server packets instead of local
 field prediction

Switch level-up callback triggering to SMSG_LEVELUP_INFO/SMSG_LEVELUP_INFO_ALT so animation and SFX are server-authoritative.

Parse the new level directly from the level-up packet, update cached player/character level state, and fire callback only when level increases.

Remove duplicate callback firing from UNIT_FIELD_LEVEL update-field handling to prevent double-triggered level-up effects when values sync after the packet.
---
 src/game/game_handler.cpp | 31 +++++++++++++++++++++++++------
 1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/src/game/game_handler.cpp b/src/game/game_handler.cpp
index 4b4f9a26..baeeee78 100644
--- a/src/game/game_handler.cpp
+++ b/src/game/game_handler.cpp
@@ -1777,10 +1777,33 @@ void GameHandler::handlePacket(network::Packet& packet) {
         case Opcode::SMSG_ENVIRONMENTALDAMAGELOG:
         case Opcode::SMSG_SET_PROFICIENCY:
         case Opcode::SMSG_ACTION_BUTTONS:
-        case Opcode::SMSG_LEVELUP_INFO:
-        case Opcode::SMSG_LEVELUP_INFO_ALT:
             break;
 
+        case Opcode::SMSG_LEVELUP_INFO:
+        case Opcode::SMSG_LEVELUP_INFO_ALT: {
+            // Server-authoritative level-up event.
+            // First field is always the new level in Classic/TBC/WotLK-era layouts.
+            if (packet.getSize() - packet.getReadPos() >= 4) {
+                uint32_t newLevel = packet.readUInt32();
+                if (newLevel > 0) {
+                    uint32_t oldLevel = serverPlayerLevel_;
+                    serverPlayerLevel_ = std::max(serverPlayerLevel_, newLevel);
+                    for (auto& ch : characters) {
+                        if (ch.guid == playerGuid) {
+                            ch.level = serverPlayerLevel_;
+                            break;
+                        }
+                    }
+                    if (newLevel > oldLevel && levelUpCallback_) {
+                        levelUpCallback_(newLevel);
+                    }
+                }
+            }
+            // Remaining payload (hp/mana/stat deltas) is optional for our client.
+            packet.setReadPos(packet.getSize());
+            break;
+        }
+
         case Opcode::SMSG_PLAY_SOUND:
             if (packet.getSize() - packet.getReadPos() >= 4) {
                 uint32_t soundId = packet.readUInt32();
@@ -5121,7 +5144,6 @@ void GameHandler::handleUpdateObject(network::Packet& packet) {
                                 LOG_INFO("Next level XP updated: ", val);
                             }
                             else if (key == ufPlayerLevel) {
-                                uint32_t oldLevel = serverPlayerLevel_;
                                 serverPlayerLevel_ = val;
                                 LOG_INFO("Level updated: ", val);
                                 for (auto& ch : characters) {
@@ -5130,9 +5152,6 @@ void GameHandler::handleUpdateObject(network::Packet& packet) {
                                         break;
                                     }
                                 }
-                                if (val > oldLevel && oldLevel > 0 && levelUpCallback_) {
-                                    levelUpCallback_(val);
-                                }
                             }
                             else if (key == ufCoinage) {
                                 playerMoneyCopper_ = val;