tavolo/server/README.md

# tavolo

The backend for a multiplayer card-game platform, built on the
[kaya](../kaya) framework. The first game implemented is **scopone
scientifico**, the four-player, fixed-partnership variant of the classic
Italian card game.

Players authenticate with the configured **OIDC** provider. Live game state
is kept in **Redis** (with real-time play over WebSocket), and completed
matches — every participant and the final score — are persisted to
**Postgres** for history and leaderboard statistics.

## Quick start (Docker Compose)

```sh
# From the repository root (docker-compose.yml lives there):
docker compose up --build
```

The stack starts Postgres, Redis, a mock OIDC provider
(navikt/mock-oauth2-server) with four ready-made players
(`alice`, `bob`, `carol`, `dave`), a one-shot database migration service,
and the app itself on `http://127.0.0.1:8080`. The same container also
serves the Sycamore/WASM frontend (built from `../web/` by the Docker
image), so the UI is available at that address.

Because the browser and the app both talk to the OIDC issuer at
`http://mockoauth:8180/tavolo`, add a host entry once:

```sh
echo "127.0.0.1 mockoauth" | sudo tee -a /etc/hosts
```

Then log in: `GET http://localhost:8080/auth/login`, type any username
(e.g. `alice`) in the interactive login, and you are redirected back with a
session cookie. That cookie authenticates both the REST API and the
WebSocket endpoint.

OpenAPI documentation is served at `/api/docs` (`/api/openapi.json`).

## Configuration

All configuration comes from environment variables (see `.env.example`):

| Variable | Default | Description |
|---|---|---|
| `DATABASE_URL` | `postgres://tavolo:tavolo@localhost:5432/tavolo` | Postgres DSN for match statistics |
| `REDIS_URL` | unset | Redis DSN for sessions + live games. Unset falls back to in-memory stores |
| `OIDC_ISSUER` | `http://localhost:8180/tavolo` | OIDC issuer URL |
| `OIDC_CLIENT_ID` | `tavolo` | OIDC client id |
| `OIDC_CLIENT_SECRET` | unset | OIDC client secret |
| `OIDC_REDIRECT_URI` | `http://localhost:8080/auth/callback` | Login callback URL |
| `GAME_TTL_SECONDS` | `86400` | Sliding TTL of a live game in Redis |
| `HAND_ACK_TIMEOUT_SECONDS` | `30` | Seconds the between-hands scoring summary waits for acknowledgements |
| `TURN_TIMEOUT_SECONDS` | `30` | Seconds a player has to play before the server plays a random legal card for them |
| `APP_HOST` / `APP_PORT` | `0.0.0.0` / `8080` | Bind address |

## Data model

### Redis (live games)

- `tavolo:game:<uuid>` — the whole match as JSON: players (seat 0/2 = team A,
  1/3 = team B), hands, table, captured piles, scope, current turn, dealer,
  scores, phase (`lobby` → `playing` → `finished`). Sliding TTL
  (`GAME_TTL_SECONDS`).
- `tavolo:code:<JOINCODE>` — the 6-character join code → game id index.
- `tavolo:game:<uuid>:lock` — a short-lived lock serializing every mutation.
- `tavolo:game:<uuid>:events` — a pub/sub channel carrying "state changed"
  signals; every open WebSocket reloads the state and pushes the
  personalized view to its player.

### Postgres (statistics, via Tortoise ORM + aerich migrations)

- `match` — one row per finished match: both teams' final scores, winner,
  target score, hands played, start/finish timestamps.
- `match_player` — one row per participant: the OIDC `sub`, display name,
  seat, team and whether they won. Unique per `(match, user_sub)`.

When a match ends, the result is written transactionally to Postgres
(once, guarded by a flag on the Redis state); the finished state stays in
Redis until its TTL expires so clients can still fetch the final board.

## REST API

All endpoints except `/api/health`, `/api/docs` and `/api/openapi.json`
require authentication.

| Method | Path | Description |
|---|---|---|
| `POST` | `/api/games` | Create a lobby game. Optional body `{"target_score": 11}`. Returns `{id, join_code}` |
| `POST` | `/api/games/join` | Join with `{"code": "ABC123"}`. The fourth player triggers the deal |
| `GET` | `/api/games/{id}` | Personalized snapshot (only your own hand is visible) |
| `GET` | `/api/me/matches` | Cursor-paginated match history with final scores (`?limit=&cursor=`) |
| `GET` | `/api/leaderboard` | Aggregated wins / matches / team points per player |

## WebSocket protocol

Connect to `/ws/games/{game_id}` with your session cookie. Only seated
players are accepted; unauthenticated, unknown-game and non-player
connections are closed with codes `4401`, `4404` and `4403` respectively.

Server → client messages are JSON objects with a `type`:

- `{"type": "state", "game": {...}}` — personalized game view. Your own
  hand is included; other players expose only their card counts.
  `your_turn: true` is present when it is your move.
- `{"type": "game_over", "scores": {"A": 11, "B": 7}, "winner": "A"}`
- `{"type": "error", "code": "illegal_move", "message": "..."}`

Client → server messages:

```json
{"action": "play", "card": "07D", "capture": ["02D", "05C"]}
{"action": "play", "card": "07D"}
{"action": "ack"}
{"action": "state"}
```

- `card` is the card you play, rendered as `RRSUIT` (`01A`..`10D`; suits
  `D` denari, `C` coppe, `S` spade, `B` bastoni — e.g. `07D` is the
  settebello).
- `capture` lists the table cards to take. When a capture is legal it is
  mandatory to provide one; when no capture exists it must be omitted.
- `ack` acknowledges the hand-end scoring summary (see below). The next
  hand is dealt once all four players have acknowledged, or automatically
  after `HAND_ACK_TIMEOUT_SECONDS`.
- `state` asks for a fresh snapshot.

After every accepted move the new state is broadcast to all four players.

### Turn timeout

The state carries a `turn_deadline` while a hand is being played. If the
player on turn does not move before it, the server plays a random legal
card for them (picking one of the legal captures at random when a capture
is required), so a disconnected or idle player cannot stall the match. The
timeout is `TURN_TIMEOUT_SECONDS` (default 30); the auto-played move is
broadcast like any other.

### Hand-end summary

When a hand finishes but the match continues, the game enters the
`hand_end` phase instead of dealing immediately: the state carries
`last_hand` (a full scoring breakdown with an `award` map naming the team
that won each category), the `acknowledged` seats and a
`hand_end_deadline`. The frontend renders this as a screen every player
must dismiss. A play attempted in this phase is rejected with an
`illegal_move` error.

## Rules implemented

- 40-card Italian deck, ten cards per player, empty table at hand start.
- A card captures a **single card of equal rank** (mandatory when present)
  or a **combination of table cards whose ranks sum to its own**.
- Emptying the table scores a *scopa* (+1), except on the last play of a
  hand. Remaining table cards go to the last player who captured.
- Hand points: `carte` (most captured cards), `denara` (most diamonds),
  `settebello` (7♦), `primiera` (best 7/6/5/4 per suit, all four suits
  required), plus one point per scopa. Ties award nothing.
- The match ends when a team reaches the target score (default 11,
  configurable per game) with a clear lead; a tie at or above the target is
  broken by another hand.

## Development

```sh
python3 -m venv .venv
.venv/bin/pip install -r requirements.txt
.venv/bin/pip install -e '.[dev]'
.venv/bin/python -m unittest discover -s tests -t .
.venv/bin/mypy src
```

Tests run fully in-process: in-memory sqlite for Postgres, in-memory stores
for Redis, a fake OIDC user patched onto the mixins, and `httpx` /
`httpx-ws` ASGI transports for HTTP and WebSocket coverage.

### Migrations

The Postgres schema is owned by aerich migrations in `migrations/`. The
`db-migrate` compose service runs `aerich upgrade` before the app starts.
To add a migration after changing `src/tavolo/models.py`:

```sh
DATABASE_URL=postgres://tavolo:tavolo@localhost:5432/tavolo .venv/bin/aerich migrate
DATABASE_URL=postgres://tavolo:tavolo@localhost:5432/tavolo .venv/bin/aerich upgrade
```

(`aerich init-db` produces sqlite-flavored DDL when pointed at sqlite;
adjust `UUID`/`TIMESTAMPTZ`/`BOOL`/`JSONB` for Postgres like the existing
baseline.)

## Layout

Everything lives under `server/`:

```
src/tavolo/
├── app.py              # composition root: session/OIDC/Tortoise/OpenAPI mixins
├── config.py           # env -> frozen Settings
├── auth.py             # auth helpers (HTTP + WebSocket)
├── http.py             # JSON request/response helpers
├── pagination.py       # keyset (cursor) pagination
├── openapi.py          # shared OpenAPI parameter fragments
├── tortoise_mixin.py   # TortoiseORM lifecycle (HTTP + WebSocket)
├── aerich_config.py    # aerich CLI configuration
├── models.py           # Match, MatchPlayer (Postgres)
├── stats.py            # finished match -> Postgres persistence
├── store.py            # Redis / in-memory live-game store
├── ws.py               # WebSocket live-play endpoint
├── game/
│   ├── state.py        # GameState / PlayerState / Card, JSON (de)serialization
│   ├── engine.py       # pure scopone scientifico rules
│   └── errors.py       # typed rule violations
└── routes/
    ├── health.py       # GET /api/health
    ├── games.py        # lobby: create / join / snapshot
    └── stats.py        # match history + leaderboard
```