scrabble-game/docs/FUNCTIONAL.md

# Scrabble Game — Functional spec

Per-domain user stories: what each user-visible operation does. This is the
starting point for any change request that touches behaviour. The English
version is authoritative; [`FUNCTIONAL_ru.md`](FUNCTIONAL_ru.md) is a mirror for
the project owner — mirror every point edit in the same patch (translate only
the changed paragraphs). Sections deepen as stages land; *(Stage N)* marks where
the detail is authored.

## Domains

### Client app *(Stage 7 / 8)*
The web/app client (Svelte + Vite) realizes these stories. The **playable slice**
(Stage 7) covers signing in (guest or email), the "my games" lobby, starting an
auto-match, playing the board (place tiles by drag or tap, pass, exchange, resign),
the top-1 hint, the unlimited word-check with complaint, per-game chat and nudge,
real-time in-app updates, switching interface language (en/ru) and theme, and a
read-only profile. Managing friends and blocks, creating friend games (invitations),
editing the profile, the statistics screen and the history/GCG viewer arrive in
Stage 8.

### Identity & sessions *(Stage 1 / 6)*
A player arrives from a platform (Telegram first), via email login, or as an
ephemeral guest. The gateway validates the credential once and mints a thin
session token; the backend resolves it to an internal `user_id`. Guests are
session-only with restricted features (auto-match only; no friends, stats or
history). While the app is open the client keeps a live stream and receives
in-app updates in real time — the opponent's move, your turn, chat, nudges and a
found match; out-of-app push (your turn, nudge) is delivered by the platform
later (Stage 9).

### Accounts, linking & merge *(Stage 1 / 10)*
First platform contact auto-provisions a durable account. From the profile a
player links additional platform identities or an email via a confirm flow;
linking an identity that already has history merges it into the current
account (stats summed, games/friends transferred).

### Lobby & matchmaking *(Stage 4)*
Bottom tab menu: **my games**, **profile**. Auto-match (always 2 players) joins a
per-variant pool and is paired with the next waiting human; after 10 s with no
human the robot substitutes (the robot arrives in Stage 5). Friend games (2–4) are
formed by inviting players from the friend list or by internal ID (deep-link
invites arrive with the platform integration): the inviter chooses the settings
and the game starts once every invitee has accepted — any decline cancels it, and
an unanswered invitation expires after seven days.

### Playing a game *(Stage 3)*
Place tiles, pass, exchange, or resign. A play is validated against the game's
dictionary at submit time and scored; an unlimited preview reports what a
tentative move would score and whether it is legal. The dictionary check tool is
unlimited and offers a complaint on any result. Hints are governed per game —
whether they are allowed and how many each player starts with — and draw on a
personal hint wallet once the per-game allowance is spent. The game ends when the
bag empties and a player clears their rack, after 6 consecutive scoreless turns,
by resignation, or by the per-game move timeout (5 minutes to 24 hours, default
24 hours): a missed turn auto-resigns, except while the player is inside their
daily away window. In a two-player game a resignation or timeout gives the win to
the other player and the leaver keeps their score. In a game with three or four
players the leaver's seat is dropped and the others play on, the game ending when a
single active player remains; the disposition of the leaver's tiles (returned to
the bag or removed from play) is chosen when the game is created, and the leaver's
rack is never shown to the others.

### Robot opponent *(Stage 5)*
When auto-match finds no human within ten seconds, a robot opponent takes the empty
seat so the game starts without waiting. It is meant to feel like a person: it
decides once per game whether to play to win (about 40% of the time, so the human
wins most games), aims for a close score rather than crushing or throwing the game,
and plays at a human pace — short thinking times for most moves, the occasional long
one, and a night-time pause that tracks the player's own day. It answers a nudge
within a few minutes and nudges back when the player has been away a long time. It
carries a human-like name and neither chats nor accepts friend requests.

### Social: friends, block, chat, nudge *(Stage 4)*
Send a friend request and have it accepted (decline or cancel withdraws it,
unfriending removes the friendship). Block globally — switch off incoming chat
and/or friend requests — and block individual players (a per-user block hides that
person's chat and stops requests and game invitations both ways; it also ends any
existing friendship). Per-game chat is for quick reactions: messages are short
(up to 60 characters) and may not contain links, email addresses or phone numbers,
even disguised. Nudge the player whose turn is awaited at most once per hour (the
nudge is part of the game chat); the out-of-app push is delivered via the platform.

### Profile & settings *(Stage 4)*
Edit language (en/ru), display name, timezone, the daily away window and the block
toggles, and bind an email by confirm-code: the backend emails a short code that,
once entered, attaches the email to the account (an email already confirmed by
another account cannot be taken — that is a merge, a later stage). Linked platform
accounts and merge arrive in Stage 11.

### History & statistics *(Stage 3)*
Finished games are archived in a dictionary-independent form and exportable to
GCG. Statistics (durable accounts only): wins, losses, draws, max points in a
game, and max points for a single move (the best play, which already includes
every word it formed plus the all-tiles bonus).

### Administration *(Stage 10)*
Admin (Basic Auth at the gateway) reviews word complaints, manages dictionary
versions, and inspects users/games.