# proto-sudoku

> Classic 9x9 sudoku in the browser, by Richard Hess. Single player. No
> accounts, no signup step and no key. Puzzles come from a Rust API compiled
> to WebAssembly on Cloudflare Workers.

The page at / is a web component ([proto-sudoku-wc](https://www.npmjs.com/package/proto-sudoku-wc)
on npm) and renders nothing useful without JavaScript. Use this file or the
API instead of scraping it.

## Pages

- [Play](https://sudoku.eswat2.app/): the game
- [About](https://sudoku.eswat2.app/about): how to play, with screenshots
- [Architecture](https://sudoku.eswat2.app/architecture): how it's built, layer by layer

## How it works

- One Cloudflare Worker. Static files are served by Workers Static Assets;
  the API is Rust compiled to WebAssembly (workers-rs and the sudoku crate).
- No server-side state. The browser checks the board itself: Check clears
  wrong entries and keeps right ones. The puzzle and checked entries are saved
  in localStorage.

## API

- [GET /api/puzzle](https://sudoku.eswat2.app/api/puzzle): a new puzzle with a
  unique solution on every call. CORS is open to any origin.

```
{
  "metrics": { "counts": { "blanks": 52, "clues": 29 } },
  "puzzle": "51..6...28.2......6..3.8.9.4..9..8.........5.1564............192...9...8...54....",
  "ref": "NTE5NzY0MzgyODMy...",
  "tag": "cloudflare"
}
```

- puzzle: 81 characters, row by row from the top left. Digits are clues,
  dots are blanks.
- ref: the solution as 81 digits, base64-encoded.
- metrics.counts: the number of blanks and clues.
- tag: the platform that served the response.

## Source

- [eswat2/proto-sudoku-cf](https://github.com/eswat2/proto-sudoku-cf): the
  Worker and this site, AGPL-3.0-or-later (it links the AGPL sudoku crate)

## Optional

- [eswat2.app](https://eswat2.app): small apps by Richard Hess