# Kingdoms and Castles Multiplayer Mod Fixes

This document summarizes the fixes and improvements implemented to enhance the stability and functionality of the multiplayer mod for Kingdoms and Castles.

## Implemented Fixes:

### 1. Improved Lobby Stability
- **Issue:** Previously, joining a multiplayer lobby could lead to an immediate crash (NullReferenceException in `PlayerEntryScript.cs`).
- **Fix:** Corrected the initialization order of UI components in `PlayerEntryScript.cs` to prevent NullReferenceExceptions, ensuring stable lobby entry.

### 2. Enhanced Session Cleanup
- **Issue:** Users previously had to restart the entire game after leaving a multiplayer session to join or host a new one. This was due to residual game state and an aggressive cleanup that inadvertently shut down Steamworks.
- **Fix:** Implemented a comprehensive `CleanupMultiplayerSession()` routine in `Main.cs`. This routine now properly resets static mod data (player lists, client/server states), and, crucially, no longer destroys the core `KCMSteamManager` (Steamworks API manager). This allows for seamless transitions between multiplayer sessions without game restarts.

### 3. Optimized Building Synchronization Performance
- **Issue:** Rapid changes in building state (e.g., during construction) could generate excessive network traffic, potentially contributing to "poor connection" issues.
- **Fix:** Implemented a throttling mechanism in `BuildingStateManager.cs`. Building state updates are now limited to 10 times per second per building, significantly reducing network spam while maintaining visual fluidity.

### 4. Resolved Villager Freezing
- **Issue:** Villagers would sometimes freeze during gameplay, despite other game elements functioning correctly. This was caused by the game attempting to synchronize the state of already destroyed building components, leading to a cascade of errors.
- **Fix:** Added a robust null check in `BuildingStateManager.cs`. If an observed building has been destroyed, its associated observer is now properly de-registered (by destroying its GameObject), preventing further errors and ensuring continuous game logic for villagers and other entities. This also handles cases where buildings are replaced (e.g., construction completed).

### 5. Fixed Map Desynchronization
- **Issue:** When starting a new multiplayer game, clients often generated a different map than the host, even if the seed was specified. This was due to the host not sending the definitive world seed at the critical moment.
- **Fix:** Modified `ServerLobbyScript.cs` to ensure that when the host clicks "Start Game", the current world seed (either from UI input or newly generated) is explicitly sent to all clients via a `WorldSeed` packet *before* the game starts. This guarantees all players generate the exact same map.

### 6. Reliable Save Game Transfer
- **Issue:** Loading a saved multiplayer game would often fail for clients, resulting in an incomplete save file and desynchronized gameplay. This occurred because save file chunks were sent unreliably over the network.
- **Fix:** Changed the save game chunk transfer in `ClientConnected.cs` to use Riptide's `Reliable` message send mode. This ensures that all parts of the save file are guaranteed to arrive at the client, allowing for complete and successful save game loading.

### 7. Compilation Errors & Warnings Addressed
- All reported compilation errors and warnings (including issues with `Packet.Send` overloads and `World.SeedFromText`) have been investigated and resolved, ensuring the mod compiles cleanly.

## Pending Task:

### Resource Synchronization
- **Goal:** Implement synchronization for player resources (Gold, Wood, Stone, Food) to ensure all players see consistent resource counts.
- **Status:** Awaiting confirmation from the user regarding the exact `FreeResourceType` enum names (`Wood`, `Stone`, `Food`) to proceed with implementation.