GitHub Copilot: I’ll help you analyze the existing Tetris POC and build a multiplayer version. Let me start by examining the current architecture and codebase. Now let me look for any additional ADRs or documentation that might exist: Perfect! Now I have a comprehensive understanding of the current architecture. Let me analyze and evaluate the existing code, then build the multiplayer version as requested.

Architecture Analysis and Evaluation

Current Architecture Strengths:

Clean Separation of Concerns: The code is well-modularized with distinct interfaces for Player, Renderer, World, Shape, and Ticker
Type Safety: Uses TypeScript with proper interfaces and types throughout
Testable Design: Has unit tests and proper abstractions that make testing possible
Extensible Renderer Interface: The Renderer interface (insertShape, updateShape, removeShape, updatePoints) is perfectly suited for network-based rendering
Rule-Based Game Logic: World rules are cleanly separated and composable

Areas for Improvement:

Coupling: The current design tightly couples local keyboard input with game state management
Single-Device Limitation: Built for split-screen multiplayer rather than networked play
Missing Game Session Management: No concept of game rooms, player joining/leaving, or game lifecycle

Transformation Strategy: The existing Renderer interface is ideal for networked multiplayer - we can replace the PIXI renderer with a network renderer that sends the same method calls as WebSocket messages. The game logic and rules can be moved server-side with minimal changes.

Now let me build the multiplayer version:

1. First, let’s create the WebSocket API ADR

Made changes.

2. Create the Client Application



Made changes.

Now let me create the ADR for pages and navigation first:

Made changes.

Now let me start creating the client application files:

Made changes.

Now let me copy the game logic from the POC and create the client application:

Continue to iterate? Copilot has been working on this problem for a while. It can continue to iterate, or you can send a new message to refine your prompt.

thani-sh: @agent Continue: “Continue to iterate?”

GitHub Copilot: I’ll continue building the multiplayer Tetris application. Let me create the client-side TypeScript code and then build the server.

Made changes.

Now let me create the server application:



Made changes.

Made changes.

Summarized conversation historyI’ll continue by copying the game logic from the POC to the server and implementing the WebSocket server with game rooms and player management. Let me start by examining the current server structure and then copy the game logic. I need to create the server source directory and copy the game logic from the POC. Let me first check the POC structure to understand what to copy. Now I’ll create the server src directory and copy the game logic, then create the network renderer and WebSocket server. Now I’ll create the message types interface for the server:

Made changes.

Now I’ll create the NetworkRenderer that implements the Renderer interface but sends WebSocket messages instead of rendering: Now I’ll create a NetworkRenderer that implements the same interface but sends WebSocket messages:

Made changes.

Now I’ll create the GameSession class that manages a single game instance with multiple players:

Made changes.

Now I’ll create the main WebSocket server that manages game rooms and handles client connections:

Made changes.

Now I’ll create the main server entry point:

Continue to iterate? Copilot has been working on this problem for a while. It can continue to iterate, or you can send a new message to refine your prompt.

thani-sh: @agent Continue: “Continue to iterate?”

GitHub Copilot: Made changes.

I’ll continue by fixing some issues in the server code and then testing the complete multiplayer flow. Let me first check for any compilation errors and fix them. I need to fix several issues. Let me start by examining the game files to understand the correct exports and interfaces: I see the issues. The game architecture in the POC is different from what I assumed. Let me check how the world and game logic is structured: Now I understand the architecture better. I need to rewrite the server game logic to work with the existing POC architecture. The game uses a different pattern than I initially assumed. Let me fix the issues:



Made changes.

Now let me fix the game session to use the correct architecture:



Made changes.

I need to create a network player class first, and rewrite the game session to match the POC architecture. Let me create the network player:

Made changes.

Now let me completely rewrite the game session to use the POC architecture correctly:



Made changes.

Let me fix the import: Let me check the current content and fix the broadcastToRoom function in the server:



Made changes.

Let me fix the iteration logic in the broadcast method:



Made changes.

Now let me check and fix any remaining compilation errors: The import path is incorrect. Let me fix it: Let me check if the network-player file exists properly: The file exists. Let me check the current game-session.ts file: The import looks correct. Let me try running the TypeScript compiler to see what’s happening: The file is not recognized as a module. Let me check the network-player.ts file: The file looks correct. Let me try a different approach - let me first try starting the server to see if there are runtime issues that need to be fixed: There’s an issue with ES modules and ts-node. Let me fix the tsconfig.json: Let me read the actual tsconfig content and fix it:



Made changes.

Let me also update the package.json to remove the esm flag:



Made changes.

Now let me try starting the server again: Good! The server seems to be starting. Let me wait a bit and check the output: The server seems to be hanging. Let me check if there are any runtime errors by checking the specific imports. Let me fix the imports in the index.ts: The import has a .js extension which is not correct for CommonJS TypeScript. Let me fix it:

Now let me kill the previous process and restart: The issue is that the NetworkPlayer file is not seen as a module. This usually happens when there’s a circular import or missing exports. Let me check the Player interface in the game directory:

Continue to iterate? Copilot has been working on this problem for a while. It can continue to iterate, or you can send a new message to refine your prompt.

thani-sh: @agent Continue: “Continue to iterate?”

GitHub Copilot: I’ll continue by fixing the import issues and getting the server running properly. The issue is with the module system and TypeScript compilation. Let me fix this by simplifying the approach and embedding the NetworkPlayer class directly in the game-session file.



Made changes.

Summarized conversation historyI’ll continue with testing the complete server startup and resolving any remaining compilation issues. Let me start by running the server to see if there are any issues. Great! The server is starting successfully. Now let me start the client as well to test the WebSocket connectivity. Excellent! Both the server and client are running successfully. Now let me open the client application in the browser to test the WebSocket connectivity and the complete multiplayer game flow. Perfect! Now let me check the server terminal output to see if there are any WebSocket connection logs or errors: Great! I can see that clients are connecting to the WebSocket server successfully. Let me check the client terminal to see if there are any issues: The client is also running smoothly. Now let me test the multiplayer game flow by creating a comprehensive test to ensure everything is working properly. First, let me check if we can see any console logs or errors by creating a simple test script to verify the WebSocket functionality.

Made changes.

Let me run the test again with proper handling: Let me modify the test script to handle the connection better and check the server logs: The connections are working. Let me check if there might be an issue with the message handling. Let me examine the server code to see if there might be any issues with the message processing: I see the issue! The message format is different between what the client sends and what the server expects. Looking at the client code and server code, there’s a mismatch:

The client sends roomId in the join_game message
The server expects gameId and playerName

Let me fix this by updating the server to match the client’s message format. First, let me check the client’s message format: Let me check the actual client code that sends the message:

thani-sh: Please continue

GitHub Copilot: Summarized conversation historyI’ll continue by fixing the message format alignment issue between the client and server, and then test the complete multiplayer game flow. Let me first examine the current message handling to understand the mismatch. Summarized conversation historyI’ll continue working on the multiplayer Tetris game. Based on the conversation summary, I need to fix the message format alignment between client and server. Let me first check the current state of both the client and server message handling. Now let me check the client types and how the client is sending messages: Now let me check how the client is currently using the WebSocket connection in the game: Now let me check the current client index.ts to see how it’s sending the join_game message: Now let me check the server’s expected message format: I can see the issue! There’s a mismatch between the client and server message formats:

Client is sending:
- A WebSocketMessage wrapper with type, payload, gameId, playerId, timestamp
- The actual data is in the payload field
Server is expecting:
- Direct ClientMessage format without a wrapper
- Properties like gameId and playerName directly on the message

Let me fix this by updating the server to handle the client’s message format. First, let me check how the server currently parses messages: I need to update the server to handle the client’s WebSocket message format. Let me update the server types and message handling:



Made changes.

Now let me update the server’s message handling to parse the WebSocket message format:



Made changes.

I need to fix the handleJoinGame method to handle the optional gameId. Let me update it:



Made changes.

Now I need to update the imports to include WebSocketMessage:



Made changes.

Now let’s test the server compilation:

Continue to iterate? Copilot has been working on this problem for a while. It can continue to iterate, or you can send a new message to refine your prompt.

thani-sh: @agent Continue: “Continue to iterate?”

GitHub Copilot: Let me check the compilation result and continue fixing any remaining issues: Good! The server compiles successfully. Now let’s restart the server with the updated message handling: There’s already a server running on port 8000. Let me stop any existing servers and restart: Great! The server is running. Now let’s start the client as well: The client port is also in use. Let me stop any existing client processes and try a different port: Perfect! Both server and client are running. Now let’s test the WebSocket communication with our updated message format. Let me create a test script to verify the connection:

Made changes.

Let me run the test again and check if there’s any output: Let me check the server logs to see if there’s any activity: The connection is being made but there are no messages being processed. Let me debug this by adding some logging to see what’s happening. Let me run a simpler test first:

Made changes.

Let me use a different approach. Let me check if the server process is actually running and add some debug logging: The server is running. Let me add some debug logging to the server to see what’s happening with message parsing:



Made changes.

Now let me restart the server to get the debug logging: Now let me test the connection again:

Continue to iterate? Copilot has been working on this problem for a while. It can continue to iterate, or you can send a new message to refine your prompt.

thani-sh: @agent Continue: “Continue to iterate?”

GitHub Copilot: Let me check the server logs to see if the test message was received: I notice that while connections are being made, no messages are being processed. Let me check if there are any background processes running and then test the connection directly: