/play #

This route renders a free-roam, random Takuzu board: not the daily, which is its own route (see /daily).

Every puzzle is generated client-side by takuzu-grid-factory compiled to wasm ($lib/game/generator.ts, pnpm run wasm:build), for a picked size ($lib/game/board.ts's BOARD_SIZES, shared with /daily) and difficulty ($lib/game/difficulty.ts), from a fresh crypto.getRandomValues seed drawn per attempt: no date or puzzle-number scheme, unlike /daily, which stays on the native CLI path (scripts/generate-daily.ts) and is untouched by any of this. It tracks the toggle count and the elapsed time in the browser. It checks for a win by comparing the filled grid to the known solution (held client-side the whole time: unlike /daily, there's no server round-trip to keep it hidden). It has no persistence yet.

Board rendering and rule validation are shared with /daily via $lib/game/board.ts and $lib/components/Board.svelte.

wasm and native threading. takuzu.rs's uniqueness search (the expensive part of digging a puzzle) parallelizes via rayon::join natively, which needs real OS threads, unavailable to wasm32-unknown-unknown without SharedArrayBuffer + Web Workers + COOP/COEP headers. Rather than take that on, rayon (and clap, CLI-only) are excluded from the wasm build entirely (Cargo.toml's [target.'cfg(...)'.dependencies]), and the one rayon::join call site falls back to a plain sequential join helper on wasm32 (takuzu.rs). Measured in-browser: 12x12 (the largest size /play offers) generates in ~250ms single-threaded, so this was never worth the complexity; confirm this still holds if /play ever offers larger sizes. main.rs (native CLI, used offline by scripts/generate-daily.ts) is unaffected and keeps the parallel path.

Difficulty tiers. The wasm generate_puzzle call always returns the hardest puzzle for its seed (dig is minimal by inclusion, no clue removable without breaking uniqueness). Easy and Medium are a client-side post-process on top of that ($lib/game/difficulty.ts's applyDifficulty): reveal extra cells from the solution, in a random order, up to a target clue fraction (~65% / ~50%; Hard reveals nothing extra). This needs no re-validation against the Rust search: revealing more cells can only narrow the solution set, never break its uniqueness.

Board theme. A global preference (not route-specific), picked from an icon button in Header.svelte (opens ThemePicker.svelte in a compact Modal). $lib/state/theme.svelte.ts holds the current Theme ("digits" | "sunmoon" | "colors"), always mirrored to localStorage, and, when logged in, to com.tomplanche.atkuzu.preferences (src/lib/server/atproto/preferences.ts, src/routes/preferences/+server.ts), same singleton-record pattern as the stats record. +layout.svelte hydrates from localStorage once on mount (client-only: no localStorage during SSR) and reconciles with the PDS if logged in, re-running on login. Board.svelte takes an explicit theme prop (kept prop-driven, not importing the store itself) and switches cell content: digits (unchanged), sun/moon SVGs, or two flat colors (--accent / --rust-green, chosen for the same clear separation as the /daily calendar's status colors) with no glyph at all. The color theme's fill has to win over a given cell's usual lighter background too, since the color is the value there.

TODO #

• Add live rule validation.
  • Highlight violations as the player plays, not only on completion.
    • Three identical symbols in a row or column turn red.
    • An unbalanced row or column (more than half 0s or 1s) turns red. Only the cells holding the overflowing value turn red, not the whole line.
    • A duplicate row or column turns red.
• Connect a real puzzle source instead of the single hardcoded sample.
  • Compile takuzu-grid-factory to wasm32-unknown-unknown and call it from the client.
  • Pick the puzzle size and the difficulty tiers to generate.
  • Draw a fresh random seed per attempt. No date or puzzle-number scheme here; that belongs to /daily.
• Add keyboard support (shared by /daily through Board.svelte).
  • Move focus between cells with the arrow keys.
  • Toggle the focused cell with the spacebar.
  • Submit the puzzle for validation with enter.
• Add theme support (shared by /daily through Board.svelte).
  • Let the player pick a symbol set: 0/1, sun/moon, or colors.
  • Store the choice as a user preference on the PDS.
  • Read the preference on load and render the board with it.