scrabble-game/ui/src/lib/lobbysort.ts

// Pure grouping + ordering of the lobby's game list. The lobby shows three
// sections — games awaiting the caller's move, games awaiting the opponent, and finished
// games — each ordered by last activity: your-turn oldest-first (the longest-neglected on
// top), the other two newest-first.

import type { GameView } from './model';

/** isMyTurn reports whether an active game's seat-to-move belongs to the caller. */
export function isMyTurn(game: GameView, myId: string): boolean {
  const me = game.seats.find((s) => s.accountId === myId);
  return game.status === 'active' && !!me && game.toMove === me.seat;
}

/** LobbyGroups holds the three ordered lobby sections. */
export interface LobbyGroups {
  yourTurn: GameView[];
  theirTurn: GameView[];
  finished: GameView[];
}

/**
 * groupGames partitions games for myId into the three lobby sections and orders each: the
 * your-turn games by ascending last activity (the longest-waiting first), the opponent-turn
 * and finished games by descending last activity (the most recent first).
 */
export function groupGames(games: GameView[], myId: string): LobbyGroups {
  const yourTurn: GameView[] = [];
  const theirTurn: GameView[] = [];
  const finished: GameView[] = [];
  for (const g of games) {
    if (g.status !== 'active') finished.push(g);
    else if (isMyTurn(g, myId)) yourTurn.push(g);
    else theirTurn.push(g);
  }
  yourTurn.sort((a, b) => a.lastActivityUnix - b.lastActivityUnix);
  theirTurn.sort((a, b) => b.lastActivityUnix - a.lastActivityUnix);
  finished.sort((a, b) => b.lastActivityUnix - a.lastActivityUnix);
  return { yourTurn, theirTurn, finished };
}