# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Project Overview

AzerothCore is an open-source MMORPG server emulator for World of Warcraft patch 3.3.5a (Wrath of the Lich King). It's a C++ project built with CMake, using MySQL for data storage. Licensed under GNU GPL v2.

## Build Commands

### Configure and build (out-of-source build required)

```bash
# Create build directory and configure
mkdir -p build && cd build
cmake .. -DCMAKE_INSTALL_PREFIX=$HOME/azeroth-server -DCMAKE_BUILD_TYPE=RelWithDebInfo \
  -DSCRIPTS=static -DMODULES=static

# Build (use appropriate core count)
make -j$(nproc)
make install
```

### Key CMake options

- `SCRIPTS`: none, static, dynamic, minimal-static, minimal-dynamic (default: static)
- `MODULES`: none, static, dynamic (default: static)
- `APPS_BUILD`: none, all, auth-only, world-only (default: all)
- `TOOLS_BUILD`: none, all, db-only, maps-only (default: none)
- `BUILD_TESTING`: Enable unit tests (default: OFF)
- `USE_COREPCH` / `USE_SCRIPTPCH`: Precompiled headers (default: ON)

### Unit tests

```bash
# Configure with testing enabled
cmake .. -DBUILD_TESTING=ON
make -j$(nproc)

# Run tests
./src/test/unit_tests
# or
ctest
```

Tests use Google Test and live in `src/test/`. The test binary links against the `game` library.

## Architecture

### Two server executables
- **authserver** (`src/server/apps/authserver/`): Handles authentication and realm selection (port 3724)
- **worldserver** (`src/server/apps/worldserver/`): Main game server handling all gameplay (port 8085)

### Source layout (`src/`)

- **`src/common/`** - Shared libraries: networking (Asio), cryptography, configuration, logging, threading, collision detection, utilities
- **`src/server/game/`** - Core game logic (~52 subsystems), the heart of the worldserver
- **`src/server/scripts/`** - Content scripts (bosses, spells, commands, instances)
- **`src/server/database/`** - Database abstraction layer and schema updater
- **`src/server/shared/`** - Code shared between auth and world servers (packets, network, realm definitions)
- **`src/test/`** - Unit tests (Google Test)

### Key game subsystems (`src/server/game/`)

- **Entities/** - Core game objects: `Player`, `Creature`, `Unit`, `Item`, `GameObject`
- **Spells/** - Spell mechanics, aura system, spell effects
- **Maps/** - Map management, grid system, instancing
- **Handlers/** - Client packet handlers (one file per system: `MovementHandler.cpp`, `SpellHandler.cpp`, etc.). These are methods on `WorldSession`
- **AI/** - Creature AI framework
- **Scripting/** - Script system with typed base classes (`ScriptObject` subclasses: `CreatureScript`, `SpellScript`, `InstanceMapScript`, `GameObjectScript`, `CommandScript`, etc.)
- **Server/** - `WorldSession` (per-player connection), `World` (global state), opcode definitions

### Scripting system

Scripts follow a registration pattern:
1. Define a class inheriting from `SpellScript`, `CreatureScript`, etc.
2. Implement an `AddSC_*()` function that calls `RegisterSpellScript(ClassName)` (or similar)
3. The `AddSC_*()` is declared and called from the regional `*_script_loader.cpp`
4. Script loaders per region: `spells_script_loader.cpp`, `eastern_kingdoms_script_loader.cpp`, `northrend_script_loader.cpp`, etc.
5. Spell script files are organized by class: `spell_dk.cpp`, `spell_mage.cpp`, `spell_generic.cpp`, etc.

### Three databases
- **acore_auth** - Accounts, realm list, bans (`data/sql/base/db_auth/`)
- **acore_characters** - Character data, inventories, progress (`data/sql/base/db_characters/`)
- **acore_world** - Game content: creatures, items, quests, spells, loot (`data/sql/base/db_world/`)

SQL updates go in `data/sql/updates/pending_*` with separate subdirectories per database until pull request is merged.
SQL updates go in `data/sql/updates/` with separate subdirectories per database after their pull request is merged.

### Module system

External modules are loaded from the `modules/` directory. Each module is a subdirectory with its own `CMakeLists.txt`. Disable specific modules with `-DDISABLED_AC_MODULES="mod1;mod2"`. Module skeleton: https://github.com/azerothcore/skeleton-module/

### Dependencies

Bundled in `deps/`: boost, MySQL client, OpenSSL, zlib, recastnavigation (pathfinding), g3dlite (geometry), fmt, argon2, jemalloc, and others.

## Commit Message Format

Uses Conventional Commits:
```
Type(Scope/Subscope): Short description (max 50 chars)
```

- **Types**: feat, fix, refactor, style, docs, test, chore
- **Scopes**: Core (C++ changes), DB (SQL changes)
- **Examples**: `fix(Core/Spells): Fix damage calculation for Fireball`, `fix(DB/SAI): Missing spell to NPC Hogger`

## Code Style

- 4-space indentation for C++ (no tabs)
- 2-space indentation for JSON, YAML, shell scripts
- UTF-8 encoding, LF line endings
- Max 80 character line length
- No braces around single-line statements
- Use {} to parse variables into output instead of %u etc.
- CI enforces code style checks and compiles with `-Werror`

## PR Requirements

- AI tool usage must be disclosed in PRs
- In-game testing expected
- Changes to generic code require regression testing of related systems