/**
 * 바퀴벌레 포커 (docs/games/cockroach-poker.md).
 *
 * Secret-id design: card ids ('rat-3', ...) encode the kind, so an id only ever appears in a view when the
 * viewer may know that card (own hand, face-up fronts, the passed card for players in `seen`, everything
 * after the game ends). Other hands are sent as counts; the passed card as `{ known: false }`.
 */
import { z } from 'zod';
import { fail, ok, type GameDefinition, type GameEvent, type GameResult, type PlayerId, type Rng, type Validation } from '@bg/engine';

export const KINDS = ['cockroach', 'bat', 'fly', 'toad', 'rat', 'scorpion', 'spider', 'stinkbug'] as const;
export type Kind = (typeof KINDS)[number];
export const KIND_KO: Record<Kind, string> = {
  cockroach: '바퀴벌레',
  bat: '박쥐',
  fly: '파리',
  toad: '두꺼비',
  rat: '쥐',
  scorpion: '전갈',
  spider: '거미',
  stinkbug: '노린재',
};
export const PER_KIND = 8;
export const REMOVED_2P = 10;

export const PHRASES = ['really', 'doubt', 'hmm', 'trust'] as const;
export type Phrase = (typeof PHRASES)[number];
export const PHRASE_KO: Record<Phrase, string> = {
  really: '정말이야!',
  doubt: '의심스러운데?',
  hmm: '음… 고민되네',
  trust: '믿어 볼게',
};
/** Quick-chat phrases per player per round (keeps the log small). */
export const SAY_PER_ROUND = 3;

const AWAY_AFTER = 3;
const AWAY_MS = 5000;
const SAID_KEEP = 6;

// ---------------------------------------------------------------- options

export const cockroachOptionsSchema = z.object({
  loseCount: z
    .union([z.literal('auto'), z.literal(3), z.literal(4), z.literal(5)])
    .default('auto')
    .meta({ title: '같은 벌레가 몇 장 모이면 패배', labels: { auto: '자동(2명 5장, 3~6명 4장)', 3: '3장(짧은 게임)', 4: '4장', 5: '5장' } }),
  turnSeconds: z
    .union([z.literal(15), z.literal(30), z.literal(60)])
    .default(30)
    .meta({ title: '건네기·판정 제한 시간', labels: { 15: '15초', 30: '30초', 60: '60초' } }),
  claimHistory: z.boolean().default(true).meta({ title: '이번 라운드 주장 기록 보이기' }),
  quickChat: z.boolean().default(true).meta({ title: '빠른 말 버튼("정말이야!", "의심스러운데?")' }),
  eightKindsRule: z.boolean().default(false).meta({ title: '앞마당에 8종을 모두 모아도 패배(하우스 룰)' }),
  twoPlayerPass: z.boolean().default(false).meta({ title: '2명일 때도 몰래 보고 되돌려 주기 허용(하우스 룰)' }),
});
export type CockroachOptions = z.infer<typeof cockroachOptionsSchema>;

// ---------------------------------------------------------------- actions

const kindSchema = z.enum(KINDS);
export const cockroachActionSchema = z.discriminatedUnion('type', [
  z.object({ type: z.literal('offer'), cardId: z.string().max(32), to: z.string().max(64), claim: kindSchema }),
  z.object({ type: z.literal('call'), call: z.enum(['true', 'false']) }),
  z.object({ type: z.literal('peek') }),
  z.object({ type: z.literal('pass'), to: z.string().max(64), claim: kindSchema }),
  z.object({ type: z.literal('say'), phrase: z.enum(PHRASES) }),
]);
export type CockroachClientAction = z.infer<typeof cockroachActionSchema>;
/** Client actions plus system-only actions (timer / leaving), which are not in the schema. */
export type CockroachAction = CockroachClientAction | { type: 'timeout' } | { type: 'leave' };
type TurnAction = Extract<CockroachClientAction, { type: 'offer' | 'call' | 'peek' | 'pass' }>;

// ---------------------------------------------------------------- state

export type LossReason = 'four' | 'emptyHand' | 'eight' | 'left';

export interface ClaimEntry {
  from: PlayerId;
  to: PlayerId;
  claim: Kind;
  auto: boolean;
}

export interface CockroachRound {
  no: number;
  starter: PlayerId;
  /** Card being passed (null while the starter is choosing). */
  card: string | null;
  /** Current receiver who must decide (null while the starter is choosing). */
  holder: PlayerId | null;
  lastPasser: PlayerId | null;
  claim: Kind | null;
  /** Players who know the passed card: the starter plus every holder who peeked. */
  seen: PlayerId[];
  /** The holder has looked at the card and must pass it on. */
  peeked: boolean;
  claims: ClaimEntry[];
}

export interface LastReveal {
  card: string;
  kind: Kind;
  claim: Kind;
  call: 'true' | 'false';
  caller: PlayerId;
  passer: PlayerId;
  correct: boolean;
  takenBy: PlayerId;
  auto: boolean;
  round: number;
}

export interface CockroachFinal {
  loser: PlayerId;
  reason: LossReason;
  losingKind: Kind | null;
  /** Detailed placings (§6): winners by fewest same-kind cards, then fewest front cards; loser last. */
  placings: PlayerId[][];
  fronts: Record<PlayerId, Record<Kind, number>>;
  summary: string;
}

export interface Said {
  seq: number;
  player: PlayerId;
  phrase: Phrase;
}

export interface CockroachState {
  options: CockroachOptions;
  loseCount: number;
  order: PlayerId[];
  hands: Record<PlayerId, string[]>;
  fronts: Record<PlayerId, string[]>;
  /** 2-player game: 10 cards removed unseen (secret until the end). */
  removed: string[];
  round: CockroachRound;
  lastReveal: LastReveal | null;
  timeoutsInRow: Record<PlayerId, number>;
  away: Record<PlayerId, boolean>;
  said: Said[];
  sayCount: Record<PlayerId, number>;
  turnStartedAt: number;
  seq: number;
  final: CockroachFinal | null;
}

// ---------------------------------------------------------------- view

export type DangerLevel = 'ok' | 'warn' | 'danger';

export interface FrontView {
  counts: Record<Kind, number>;
  /** Kinds with at least one card, most first (ties in KINDS order). */
  kinds: Kind[];
  level: Record<Kind, DangerLevel>;
  total: number;
  /** Distinct kinds (for the 8-kinds house rule). */
  distinct: number;
}

export interface CockroachView {
  options: CockroachOptions;
  loseCount: number;
  me: PlayerId | null;
  order: PlayerId[];
  phase: 'offer' | 'respond' | 'finished';
  handCounts: Record<PlayerId, number>;
  fronts: Record<PlayerId, FrontView>;
  /** Viewer's hand ids grouped by kind (null for spectators). */
  myHand: { kind: Kind; ids: string[] }[] | null;
  round: {
    no: number;
    starter: PlayerId;
    holder: PlayerId | null;
    lastPasser: PlayerId | null;
    claim: Kind | null;
    seen: PlayerId[];
    peeked: boolean;
    /** Empty when claimHistory is off. */
    claims: ClaimEntry[];
    passes: number;
  };
  /** The passed card: id/kind only for players who have seen it. */
  card: { known: true; id: string; kind: Kind } | { known: false } | null;
  /** What the viewer can do right now (null for spectators / when it is not the viewer's move). */
  my: {
    canOffer: boolean;
    offerTargets: PlayerId[];
    canCall: boolean;
    canPeek: boolean;
    peekBlocked: string | null;
    canPass: boolean;
    passTargets: PlayerId[];
    canSay: boolean;
  } | null;
  lastReveal: LastReveal | null;
  away: Record<PlayerId, boolean>;
  said: Said[];
  removedCount: number;
  turnStartedAt: number;
  turnMs: number;
  seq: number;
  final: CockroachFinal | null;
  /** After the game: every hand and the removed cards. */
  revealed: { hands: Record<PlayerId, string[]>; removed: string[] } | null;
}

// ---------------------------------------------------------------- cards

export const kindOf = (id: string): Kind => {
  const k = id.slice(0, id.lastIndexOf('-')) as Kind;
  if (!KINDS.includes(k)) throw new Error(`cockroach-poker: bad card id ${id}`);
  return k;
};
export const allCardIds = (): string[] => KINDS.flatMap((k) => Array.from({ length: PER_KIND }, (_, i) => `${k}-${i}`));
const isKind = (k: unknown): k is Kind => typeof k === 'string' && (KINDS as readonly string[]).includes(k);

export function loseCountFor(o: CockroachOptions, players: number): number {
  return o.loseCount === 'auto' ? (players === 2 ? 5 : 4) : o.loseCount;
}

/** Hand sizes dealt one at a time from the first player (§4 table). */
export function handSizes(players: number): number[] {
  const total = players === 2 ? KINDS.length * PER_KIND - REMOVED_2P : KINDS.length * PER_KIND;
  return Array.from({ length: players }, (_, i) => Math.floor(total / players) + (i < total % players ? 1 : 0));
}

export function countKinds(ids: readonly string[]): Record<Kind, number> {
  const out = Object.fromEntries(KINDS.map((k) => [k, 0])) as Record<Kind, number>;
  for (const id of ids) out[kindOf(id)] += 1;
  return out;
}

// ---------------------------------------------------------------- helpers

const finished = (s: CockroachState) => s.final !== null;

/** Seats clockwise starting after `p`. */
function after(s: CockroachState, p: PlayerId): PlayerId[] {
  const i = s.order.indexOf(p);
  return s.order.map((_, k) => s.order[(i + 1 + k) % s.order.length]!).filter((x) => x !== p);
}

function waiting(s: CockroachState): PlayerId[] {
  if (finished(s)) return [];
  return [s.round.holder ?? s.round.starter];
}

function passTargets(s: CockroachState, holder: PlayerId): PlayerId[] {
  const r = s.round;
  if (s.order.length === 2) return s.options.twoPlayerPass && r.claims.length === 1 ? after(s, holder) : [];
  return after(s, holder).filter((p) => !r.seen.includes(p));
}

/** Korean reason why the current holder may not peek, or null when peeking is allowed. */
function peekBlock(s: CockroachState): string | null {
  const r = s.round;
  if (r.peeked) return '이미 카드를 봤어요.';
  if (s.order.length === 2) {
    if (!s.options.twoPlayerPass) return '2명이 할 때는 몰래 보고 넘기기를 할 수 없어요. 진짜인지 거짓인지 골라 주세요.';
    if (r.claims.length > 1) return '되돌려 받은 카드는 다시 넘길 수 없어요. 진짜인지 거짓인지 골라 주세요.';
    return null;
  }
  return passTargets(s, r.holder!).length === 0 ? '모두 이 카드를 이미 봐서 넘길 사람이 없어요. 진짜인지 거짓인지 골라 주세요.' : null;
}

function turnMs(s: CockroachState): number {
  const p = waiting(s)[0];
  return p && s.away[p] ? AWAY_MS : s.options.turnSeconds * 1000;
}

function newRound(s: CockroachState, starter: PlayerId): void {
  s.round = { no: s.round.no + 1, starter, card: null, holder: null, lastPasser: null, claim: null, seen: [], peeked: false, claims: [] };
  s.sayCount = Object.fromEntries(s.order.map((p) => [p, 0]));
}

function placings(s: CockroachState, loser: PlayerId): PlayerId[][] {
  const key = (p: PlayerId) => {
    const c = countKinds(s.fronts[p]!);
    return [Math.max(...Object.values(c)), s.fronts[p]!.length] as const;
  };
  const winners = s.order.filter((p) => p !== loser).sort((a, b) => {
    const [ma, ta] = key(a);
    const [mb, tb] = key(b);
    return ma - mb || ta - tb;
  });
  const groups: PlayerId[][] = [];
  for (const p of winners) {
    const last = groups[groups.length - 1];
    if (last && key(last[0]!)[0] === key(p)[0] && key(last[0]!)[1] === key(p)[1]) last.push(p);
    else groups.push([p]);
  }
  groups.push([loser]);
  return groups;
}

function finish(s: CockroachState, loser: PlayerId, reason: LossReason, losingKind: Kind | null, events: GameEvent[]): void {
  let summary: string;
  switch (reason) {
    case 'four':
      summary = `앞마당에 ${KIND_KO[losingKind!]} ${s.loseCount}장이 모였어요! 그 사람이 지고, 나머지 모두 이겼어요`;
      break;
    case 'eight':
      summary = '앞마당에 벌레 8종이 모두 모였어요! 그 사람이 지고, 나머지 모두 이겼어요';
      break;
    case 'emptyHand':
      summary = '카드를 건넬 차례인데 손에 카드가 없어서 졌어요. 나머지 모두 이겼어요';
      break;
    case 'left':
      summary = '한 사람이 게임을 나가서 끝났어요. 나머지 모두 이겼어요';
      break;
  }
  s.final = {
    loser,
    reason,
    losingKind,
    placings: placings(s, loser),
    fronts: Object.fromEntries(s.order.map((p) => [p, countKinds(s.fronts[p]!)])),
    summary,
  };
  events.push({ type: 'gameEnded', loser, reason, ...(losingKind ? { kind: losingKind } : {}) });
}

/** The concrete move a timeout stands for (§8.5). Uses the RNG for the starter / unpeeked holder. */
export function autoAction(s: CockroachState, player: PlayerId, rng: Rng): TurnAction {
  const r = s.round;
  if (r.holder === null) {
    const hand = s.hands[player]!;
    return { type: 'offer', cardId: hand[rng.int(hand.length)]!, to: after(s, player)[0]!, claim: KINDS[rng.int(KINDS.length)]! };
  }
  if (!r.peeked) return { type: 'call', call: rng.int(2) === 0 ? 'true' : 'false' };
  return { type: 'pass', to: passTargets(s, player)[0]!, claim: kindOf(r.card!) };
}

function validateTurn(s: CockroachState, actor: PlayerId, a: TurnAction): Validation {
  const r = s.round;
  switch (a.type) {
    case 'offer': {
      if (r.holder !== null) return fail('지금은 카드를 건넬 때가 아니에요.');
      if (r.starter !== actor) return fail('지금은 내 차례가 아니에요.');
      if (!s.hands[actor]!.includes(a.cardId)) return fail('내 손에 없는 카드예요.');
      if (a.to === actor) return fail('나에게는 건넬 수 없어요.');
      if (!s.order.includes(a.to)) return fail('이 게임의 플레이어가 아니에요.');
      return isKind(a.claim) ? ok : fail('벌레 종류를 골라 주세요.');
    }
    case 'call':
      if (r.holder !== actor) return fail('지금은 내가 판정할 차례가 아니에요.');
      if (r.peeked) return fail('카드를 이미 봤으니 다른 사람에게 넘겨야 해요.');
      return a.call === 'true' || a.call === 'false' ? ok : fail('진짜인지 거짓인지 골라 주세요.');
    case 'peek': {
      if (r.holder !== actor) return fail('지금은 내가 카드를 받을 차례가 아니에요.');
      const why = peekBlock(s);
      return why ? fail(why) : ok;
    }
    case 'pass': {
      if (r.holder !== actor) return fail('지금은 내가 카드를 넘길 차례가 아니에요.');
      if (!r.peeked) return fail('먼저 카드를 몰래 봐야 넘길 수 있어요.');
      if (a.to === actor) return fail('나에게는 넘길 수 없어요.');
      if (!s.order.includes(a.to)) return fail('이 게임의 플레이어가 아니에요.');
      if (!passTargets(s, actor).includes(a.to)) return fail('이 카드를 이미 본 사람에게는 넘길 수 없어요.');
      return isKind(a.claim) ? ok : fail('벌레 종류를 골라 주세요.');
    }
  }
}

function applyTurn(s: CockroachState, actor: PlayerId, a: TurnAction, events: GameEvent[], auto: boolean): void {
  const r = s.round;
  switch (a.type) {
    case 'offer': {
      const hand = s.hands[actor]!;
      hand.splice(hand.indexOf(a.cardId), 1);
      r.card = a.cardId;
      r.holder = a.to;
      r.lastPasser = actor;
      r.claim = a.claim;
      r.seen = [actor];
      r.peeked = false;
      r.claims.push({ from: actor, to: a.to, claim: a.claim, auto });
      events.push({ type: 'offer', from: actor, to: a.to, claim: a.claim, auto });
      break;
    }
    case 'peek':
      if (!r.seen.includes(actor)) r.seen.push(actor);
      r.peeked = true;
      events.push({ type: 'peek', player: actor });
      break;
    case 'pass':
      r.lastPasser = actor;
      r.holder = a.to;
      r.claim = a.claim;
      r.peeked = false;
      r.claims.push({ from: actor, to: a.to, claim: a.claim, auto });
      events.push({ type: 'pass', from: actor, to: a.to, claim: a.claim, auto });
      break;
    case 'call': {
      const card = r.card!;
      const kind = kindOf(card);
      const truth = kind === r.claim;
      const correct = (a.call === 'true') === truth;
      const takenBy = correct ? r.lastPasser! : actor;
      s.fronts[takenBy]!.push(card);
      r.card = null;
      r.holder = null;
      s.lastReveal = { card, kind, claim: r.claim!, call: a.call, caller: actor, passer: r.lastPasser!, correct, takenBy, auto, round: r.no };
      events.push({ type: 'reveal', card, kind, claim: r.claim, call: a.call, caller: actor, correct, takenBy, auto });
      const counts = countKinds(s.fronts[takenBy]!);
      if (counts[kind] >= s.loseCount) finish(s, takenBy, 'four', kind, events);
      else if (s.options.eightKindsRule && KINDS.every((k) => counts[k] > 0)) finish(s, takenBy, 'eight', null, events);
      else {
        newRound(s, takenBy);
        if (s.hands[takenBy]!.length === 0) finish(s, takenBy, 'emptyHand', null, events);
        else events.push({ type: 'round', starter: takenBy });
      }
      break;
    }
  }
}

// ---------------------------------------------------------------- definition

export const cockroachPoker: GameDefinition<CockroachState, CockroachAction, CockroachView, CockroachOptions> = {
  id: 'cockroach-poker',
  nameKo: '바퀴벌레 포커',
  minPlayers: 2,
  maxPlayers: 6,
  stateVersion: 1,
  defaultOptions: cockroachOptionsSchema.parse({}),
  optionsSchema: cockroachOptionsSchema as unknown as z.ZodType<CockroachOptions>,
  actionSchema: cockroachActionSchema as unknown as z.ZodType<CockroachAction>,

  setup({ players, options, rng, now }) {
    if (players.length < 2 || players.length > 6) throw new Error(`cockroach-poker: ${players.length} players not allowed`);
    const deck = rng.shuffle(allCardIds());
    const removed = players.length === 2 ? deck.splice(0, REMOVED_2P) : [];
    const first = players[rng.int(players.length)]!;
    const per = <T>(f: (p: PlayerId) => T) => Object.fromEntries(players.map((p) => [p, f(p)])) as Record<PlayerId, T>;
    const hands = per<string[]>(() => []);
    // Deal one at a time clockwise from the first player, so the first player gets the most (§4).
    const fi = players.indexOf(first);
    deck.forEach((id, i) => hands[players[(fi + i) % players.length]!]!.push(id));
    return {
      options,
      loseCount: loseCountFor(options, players.length),
      order: [...players],
      hands,
      fronts: per(() => []),
      removed,
      round: { no: 1, starter: first, card: null, holder: null, lastPasser: null, claim: null, seen: [], peeked: false, claims: [] },
      lastReveal: null,
      timeoutsInRow: per(() => 0),
      away: per(() => false),
      said: [],
      sayCount: per(() => 0),
      turnStartedAt: now,
      seq: 0,
      final: null,
    };
  },

  validate(s, actor, a) {
    if (!s.order.includes(actor)) return fail('이 게임의 플레이어가 아니에요.');
    if (finished(s)) return fail('게임이 이미 끝났어요.');
    switch (a.type) {
      case 'leave':
        return ok;
      case 'timeout':
        return waiting(s).includes(actor) ? ok : fail('시간 초과 대상이 아니에요.');
      case 'say':
        if (!s.options.quickChat) return fail('이 방은 빠른 말을 쓰지 않아요.');
        if (!PHRASES.includes(a.phrase)) return fail('보낼 말을 골라 주세요.');
        return (s.sayCount[actor] ?? 0) >= SAY_PER_ROUND ? fail(`빠른 말은 한 라운드에 ${SAY_PER_ROUND}번까지 할 수 있어요.`) : ok;
      default:
        return validateTurn(s, actor, a);
    }
  },

  apply(prev, actor, a, { rng, now }) {
    const s = structuredClone(prev);
    const events: GameEvent[] = [];
    s.seq += 1;
    switch (a.type) {
      case 'leave':
        events.push({ type: 'left', player: actor });
        finish(s, actor, 'left', null, events);
        break;
      case 'say':
        s.sayCount[actor] = (s.sayCount[actor] ?? 0) + 1;
        s.said = [...s.said, { seq: s.seq, player: actor, phrase: a.phrase }].slice(-SAID_KEEP);
        events.push({ type: 'say', player: actor, phrase: a.phrase });
        // Chatting does not restart the turn clock.
        return { state: s, events };
      case 'timeout': {
        const concrete = autoAction(s, actor, rng);
        const v = validateTurn(s, actor, concrete);
        if (!v.ok) throw new Error(`cockroach-poker: auto action rejected: ${v.reason}`);
        s.timeoutsInRow[actor] = (s.timeoutsInRow[actor] ?? 0) + 1;
        events.push({ type: 'timeout', player: actor });
        if (s.timeoutsInRow[actor]! >= AWAY_AFTER && !s.away[actor]) {
          s.away[actor] = true;
          events.push({ type: 'away', player: actor });
        }
        applyTurn(s, actor, concrete, events, true);
        break;
      }
      default:
        s.timeoutsInRow[actor] = 0;
        s.away[actor] = false;
        applyTurn(s, actor, a, events, false);
    }
    s.turnStartedAt = now;
    return { state: s, events };
  },

  view(s, viewer) {
    const me = viewer && s.order.includes(viewer) ? viewer : null;
    const over = finished(s);
    const r = s.round;
    const fronts: Record<PlayerId, FrontView> = {};
    for (const p of s.order) {
      const counts = countKinds(s.fronts[p]!);
      const kinds = KINDS.filter((k) => counts[k] > 0).sort((a, b) => counts[b] - counts[a] || KINDS.indexOf(a) - KINDS.indexOf(b));
      const level = Object.fromEntries(
        KINDS.map((k) => [k, counts[k] >= s.loseCount - 1 ? 'danger' : counts[k] >= Math.max(2, s.loseCount - 2) ? 'warn' : 'ok']),
      ) as Record<Kind, DangerLevel>;
      fronts[p] = { counts, kinds, level, total: s.fronts[p]!.length, distinct: kinds.length };
    }
    let myHand: CockroachView['myHand'] = null;
    if (me) {
      const ids = s.hands[me]!;
      myHand = KINDS.map((kind) => ({ kind, ids: ids.filter((id) => kindOf(id) === kind).sort() })).filter((g) => g.ids.length > 0);
    }
    let card: CockroachView['card'] = null;
    if (r.card && !over) card = me && r.seen.includes(me) ? { known: true, id: r.card, kind: kindOf(r.card) } : { known: false };
    let my: CockroachView['my'] = null;
    if (me && !over) {
      const offering = r.holder === null && r.starter === me;
      const holding = r.holder === me;
      const why = holding ? peekBlock(s) : null;
      my = {
        canOffer: offering,
        offerTargets: offering ? after(s, me) : [],
        canCall: holding && !r.peeked,
        canPeek: holding && why === null,
        peekBlocked: holding && !r.peeked ? why : null,
        canPass: holding && r.peeked,
        passTargets: holding && r.peeked ? passTargets(s, me) : [],
        canSay: s.options.quickChat && (s.sayCount[me] ?? 0) < SAY_PER_ROUND,
      };
    }
    return {
      options: s.options,
      loseCount: s.loseCount,
      me,
      order: s.order,
      phase: over ? 'finished' : r.holder === null ? 'offer' : 'respond',
      handCounts: Object.fromEntries(s.order.map((p) => [p, s.hands[p]!.length])),
      fronts,
      myHand,
      round: {
        no: r.no,
        starter: r.starter,
        holder: r.holder,
        lastPasser: r.lastPasser,
        claim: r.claim,
        seen: [...r.seen],
        peeked: r.peeked,
        claims: s.options.claimHistory ? r.claims.map((c) => ({ ...c })) : [],
        passes: Math.max(0, r.claims.length - 1),
      },
      card,
      my,
      lastReveal: s.lastReveal,
      away: s.away,
      said: s.said,
      removedCount: s.removed.length,
      turnStartedAt: s.turnStartedAt,
      turnMs: turnMs(s),
      seq: s.seq,
      final: s.final,
      revealed: over ? { hands: s.hands, removed: s.removed } : null,
    };
  },

  activePlayers: waiting,

  deadline(s) {
    return finished(s) ? null : s.turnStartedAt + turnMs(s);
  },

  timeoutPlayers: waiting,

  onTimeout() {
    return { type: 'timeout' };
  },

  /** Leaving forfeits: the leaver becomes the one loser and everyone else wins. */
  onLeave(s, player) {
    if (!s.order.includes(player) || finished(s)) return null;
    return { type: 'leave' };
  },

  result(s): GameResult | null {
    const f = s.final;
    if (!f) return null;
    // Everyone but the loser wins together (§6); the detailed placings stay in the view.
    return {
      ranking: [s.order.filter((p) => p !== f.loser), [f.loser]],
      scores: Object.fromEntries(s.order.map((p) => [p, p === f.loser ? 0 : 1])),
      summary: f.summary,
      reason: f.reason === 'left' ? 'resign' : 'normal',
    };
  },

  /** Game moves only (quick chat is left out); same-kind cards are interchangeable, so one id per kind. */
  legalActions(s, p) {
    if (!s.order.includes(p) || finished(s)) return [];
    const r = s.round;
    const out: CockroachAction[] = [];
    if (r.holder === null) {
      if (r.starter !== p) return [];
      const seenKinds = new Set<Kind>();
      for (const id of s.hands[p]!) {
        const k = kindOf(id);
        if (seenKinds.has(k)) continue;
        seenKinds.add(k);
        for (const to of after(s, p)) for (const claim of KINDS) out.push({ type: 'offer', cardId: id, to, claim });
      }
      return out;
    }
    if (r.holder !== p) return [];
    if (r.peeked) {
      for (const to of passTargets(s, p)) for (const claim of KINDS) out.push({ type: 'pass', to, claim });
      return out;
    }
    out.push({ type: 'call', call: 'true' }, { type: 'call', call: 'false' });
    if (peekBlock(s) === null) out.push({ type: 'peek' });
    return out;
  },

  /** `player`'s hand, the passed card while only they have seen it, and the removed cards (secret to all). */
  secretsOf(s, player) {
    if (finished(s)) return [];
    const out = [...(s.hands[player] ?? []), ...s.removed];
    const r = s.round;
    if (r.card && r.seen.length === 1 && r.seen[0] === player) out.push(r.card);
    return out;
  },
};