## curltastic

A 1v1 async multiplayer 2D curling game for mobile browser.

- **Backend** — Rust, Axum, WebSocket, Rapier2D physics (server-authoritative, 120 Hz).
- **Frontend** — TypeScript, Vite, Canvas2D, portrait-first touch UI.

### Run locally

1. Install Rust via [rustup](https://rustup.rs/) (if not already installed).
2. Start the backend:
   ```bash
   cd backend
   cargo run --release
   # listens on 0.0.0.0:3000
   ```
3. Start the frontend dev server:
   ```bash
   cd frontend
   npm install
   npm run dev
   # opens on 0.0.0.0:5173 by default
   ```
4. Open one or more browser tabs to the same room URL, e.g.:
   ```
   http://localhost:5173/?room=DEMO1
   ```
   Use the team dropdown in the top-right to switch between Red and Yellow — this enables local pass-and-play on one device. Use the *Copy share link* button to invite an opponent on another device.

### Mobile devices

The frontend binds to `0.0.0.0` via `--host`. Find your machine's LAN IP and open `http://<ip>:5173/?room=CODE` on the phone. Both devices must be on the same Wi-Fi and able to reach the backend on port `3000`. The default view is zoomed in on the house; drag the sheet vertically to scroll up to the hog line.

### Controls

- Drag inside the house to place the broom (aim point).
- Use the team dropdown to choose which team's stone you are throwing.
- Use the left/right arrow buttons to select curl; the arrow points the direction the stone will curve.
- Tap **THROW**.
- The server runs the physics for every stone and streams their paths; the frontend interpolates the animation, so collisions animate smoothly for all stones.
- Drag anywhere outside the house (or when it's not your turn) to scroll up toward the hog line.

### Architecture

- WebSocket JSON protocol with tagged messages.
- Server simulates each throw at 120 Hz and sends a subset of `(x, y, t)` path points at 40 Hz.
- All game state, scoring, end management, and hammer rules live on the server.
- Disconnects are tolerated: the room and turn remain in memory.

### E2E tests

With the backend and frontend dev server running:

```bash
cd e2e
npm install -g ws   # or npm install ws locally in the project
node e2e_test.cjs   # room lifecycle, throw, trajectory, out-of-play removal
node e2e_score.cjs  # stones remain in play and alternate turns
node collision_trajectory_qa.cjs  # verifies every stone gets a trajectory during a collision
```

### Limitations / known simplifications

- No accounts, persistence, anti-cheat, replay log, or turn timer.
- Curl is fixed as a function of release speed (more curl at lower speed); sweeping is not implemented.
- Stones that pass the back line or leave the sheet are removed from play.