# DiscoveryServer

Lightweight Node.js + WebSocket server for ZAMNY co-op matchmaking.

**Responsibilities**:

- Player registry + nicknames (max 16 chars)
- List available players
- Room creation / joining (2-player co-op)
- Relay for initial handshake

**No game logic** (AD-03). All simulation runs client-side.

## Quick Start

```bash
npm install
npm run dev      # tsx watch, ws://localhost:3001
npm test         # node:test via tsx
npm run build
npm start
```

## WebSocket Protocol

All messages are JSON objects with `type`.

### Client → Server

- `{ "type": "set_nickname", "nickname": "Player1" }`
- `{ "type": "list_players" }`
- `{ "type": "join_room", "target": "p123" }` (TODO)

### Server → Client

- `{ "type": "welcome", "id": "p1" }`
- `{ "type": "nickname_ok", "nickname": "Player1" }`
- `{ "type": "player_list", "players": [{ "id": "p2", "nickname": "ZomSlayer" }] }`
- `{ "type": "error", "message": "..." }`

## Notes

- Pure functions (`validateNickname`, `createRoomId`) are unit-tested.
- Server only starts when run directly (not during tests).
- Port 3001 (hardcoded for now).
- See root [ARCHITECTURE.md](../ARCHITECTURE.md) for full design.