First engine-first step of PWA offline mode (Phase A): the client-side move
generator — the "robot brain" a local vs_ai game will run on-device — with no
runtime wiring yet (Phase B).
- dawg.ts: add the step-by-step cursor (root/final/next/arcs), a faithful port
of dafsa traverse.go over the reader's existing bitstream.
- generate.ts: the Appel-Jacobson generator (leftPart/extendRight + cross-sets +
counts-rack + board transpose + moveKey ranking), reusing the cursor and
validate.ts evaluate/connected. A cross-set LetterSet is a Uint8Array, so the
33-letter Russian alphabet (index 32) is exact under JS bit ops.
- validate.ts: export connected for the generator's connectivity filter.
- backend/cmd/movegen: dev tool building small sample dictionaries and emitting
golden move-generation fixtures from the real Go solver (EN + RU).
- tests: dawg.cursor.test.ts (enumeration bijection vs indexOf) and
generate.parity.test.ts (7/7 vs the Go solver: empty board, mid-game, blank,
single-word rule, Russian index-32 cross-set). The committed EN sample also
unblocks the existing skipped dawg.parity.test.ts once wired with DICT_* in CI.
Pure additive library code; no runtime behavior change.
Score and validate a tentative move on-device instead of a per-arrangement network
round trip. The dawg reader and the validate/score/direction slice of the
scrabble-solver engine are ported to TypeScript (ui/src/lib/dict), pinned
byte-for-byte to the Go engine by a `conformance` CI job (full-dictionary reader
parity plus a battery of plays across every variant and both cross-word rules,
including the inferred orientation). The server stays authoritative — submit_play
re-validates — so the local result is an advisory accelerator only.
- backend: Registry.DictBytes + an authed GET /api/v1/user/dict/{variant}/{version}
(immutable) streaming the pinned per-game dawg; caddy routes /dict to the gateway.
- gateway: a session-gated /dict edge route proxying it; fetchDict on the transport.
- client: the dictionary loads on game open (low priority so it never starves the
game on a slow link; aborted at a 5s cap or when leaving the game), is cached in
IndexedDB (best-effort, self-healing on a rejected blob) and reused across
sessions; a warm-up overlay covers a cold load, then the network preview is the
fallback; a bad-connection breaker stops warming after repeated misses; the move
preview cancels its in-flight request when the tiles change.
- parity generators backend/cmd/{dictgen,validategen} + gated Vitest suites, run in
CI against the release dictionaries. A hidden debug readout lists the cached
dictionaries + breaker state, and its reset clears the cache.
- docs: ARCHITECTURE §5, TESTING, UI_DESIGN, FUNCTIONAL (+ru).
Ilia Denisov