/**
 * 라스베가스 (docs/games/las-vegas.md). Hidden info: the bill pile (only its size is public) and, with
 * `hideMoney`, the amounts other players won (only the number of bills is public until the end).
 */
import type { ZodType } from 'zod';
import { fail, nextSeat, ok, type GameDefinition, type GameEvent, type GameResult, type PlayerId, type Rng } from '@bg/engine';
import {
  ALL_NOTES,
  AWAY_AFTER,
  AWAY_MS,
  CASINO_VALUES,
  HOUSE,
  OWN_DICE,
  autoPlaceValue,
  diceLeft,
  houseExtraFor,
  lasVegasActionSchema,
  lasVegasOptionsSchema,
  neutralPerFor,
  ownerOrder,
  placementPreview,
  refillCasinos,
  settleCasino,
  sum,
  type CasinoValue,
  type LasVegasAction,
  type LasVegasOptions,
  type LasVegasState,
  type Note,
  type Owner,
  type Payout,
} from './rules';

export * from './rules';

// ---------------------------------------------------------------- result & view types

export interface LasVegasRankRow {
  rank: number;
  player: PlayerId;
  total: number;
  notes: Note[];
  conceded: boolean;
}

export interface LasVegasResult {
  ranking: LasVegasRankRow[];
  winners: PlayerId[];
  /** Points won per round. */
  roundTotals: Record<PlayerId, number[]>;
  summary: string;
  reason: GameResult['reason'];
}

export interface LasVegasMoneyView {
  count: number;
  /** null when hidden from this viewer (`hideMoney`). */
  total: number | null;
  notes: Note[] | null;
}

export interface LasVegasPayoutView {
  casino: number;
  removedTies: Owner[];
  /** `note`/`key` are null for another player's bill while `hideMoney` hides amounts. */
  awards: { owner: Owner; note: Note | null; key: string | null }[];
  returned: Note[];
}

export interface LasVegasChoice {
  value: number;
  own: number;
  neutral: number;
  /** For the player to move, after placing these dice (§9 미리 보기). */
  standing: 'first' | 'award' | 'tie' | 'none';
  note: Note | null;
  countAfter: number;
}

export interface LasVegasView {
  options: LasVegasOptions;
  me: PlayerId | null;
  seats: PlayerId[];
  round: number;
  rounds: number;
  startPlayer: PlayerId;
  /** Player to act, null once finished. */
  current: PlayerId | null;
  phase: LasVegasState['phase'];
  pileCount: number;
  casinos: { value: CasinoValue; notes: Note[]; dice: Partial<Record<Owner, number>> }[];
  hand: Record<PlayerId, { own: number; neutral: number }>;
  neutralPer: number;
  houseExtra: number;
  houseRoll: LasVegasState['houseRoll'];
  lastRoll: LasVegasState['lastRoll'];
  /** Number groups of the current roll with previews (phase `place`). */
  choices: LasVegasChoice[];
  /** What a timeout would pick now (phase `place`). */
  autoValue: number | null;
  lastPlace: LasVegasState['lastPlace'];
  money: Record<PlayerId, LasVegasMoneyView>;
  roundResults: { round: number; payouts: LasVegasPayoutView[] }[];
  conceded: PlayerId[];
  away: PlayerId[];
  rollSeq: number;
  turnSeq: number;
  deadlineAt: number | null;
  result: LasVegasResult | null;
}

// ---------------------------------------------------------------- state machine

type S = LasVegasState;

const curId = (s: S): PlayerId => s.seats[s.current]!;
const isIn = (s: S, p: PlayerId) => !s.conceded.includes(p);
const activeIds = (s: S) => s.seats.filter((p) => isIn(s, p));
/** Stable React key / leak-check token of one received bill. */
export const awardKey = (round: number, casino: number, owner: Owner, note: Note): string => `lv-r${round}c${casino}-${owner}-${note}`;

function activeOf(s: S): PlayerId[] {
  return s.phase === 'finished' ? [] : [curId(s)];
}

function refreshDeadline(s: S, now: number): void {
  if (s.phase === 'finished') {
    s.deadlineAt = null;
    return;
  }
  const away = (s.timeouts[curId(s)] ?? 0) >= AWAY_AFTER;
  if (away) s.deadlineAt = now + AWAY_MS;
  else s.deadlineAt = s.options.turnSeconds === null ? null : now + s.options.turnSeconds * 1000;
}

function finish(s: S, ev: GameEvent[]): void {
  s.phase = 'finished';
  s.lastRoll = null;
  s.deadlineAt = null;
  ev.push({ type: 'gameOver' });
}

function startRound(s: S, rng: Rng, ev: GameEvent[]): void {
  for (const p of s.seats) s.hand[p] = isIn(s, p) ? { own: OWN_DICE, neutral: s.neutralPer } : { own: 0, neutral: 0 };
  refillCasinos(s);
  ev.push({ type: 'casinosRefilled', round: s.round, casinos: s.casinos.map((c) => [...c.notes]) });
  s.houseRoll = null;
  if (s.houseExtra > 0) {
    const values: number[] = [];
    for (let i = 0; i < s.houseExtra; i++) values.push(1 + rng.int(6));
    for (const v of values) {
      const c = s.casinos[v - 1]!;
      c.dice[HOUSE] = (c.dice[HOUSE] ?? 0) + 1;
    }
    const player = s.seats[s.startSeat]!;
    s.houseRoll = { round: s.round, player, values };
    ev.push({ type: 'houseDicePlaced', player, values: [...values] });
  }
  s.current = diceLeft(s, s.seats[s.startSeat]!) > 0 ? s.startSeat : nextSeat(s.startSeat, s.seats.length, (i) => diceLeft(s, s.seats[i]!) === 0);
  s.phase = 'roll';
  s.lastRoll = null;
  s.turnSeq++;
  ev.push({ type: 'roundStart', round: s.round, player: curId(s) });
}

function settleRound(s: S, ev: GameEvent[]): void {
  const payouts: Payout[] = [];
  const back: Note[] = [];
  const order = ownerOrder(s);
  for (const c of s.casinos) {
    const { removedTies, awards, returned } = settleCasino(c.notes, c.dice, order);
    if (removedTies.length) ev.push({ type: 'tiesRemoved', casino: c.value, owners: [...removedTies] });
    for (const a of awards) {
      if (a.owner !== HOUSE) s.money[a.owner]!.push(a.note);
      ev.push({ type: 'paid', casino: c.value, owner: a.owner, ...(a.owner === HOUSE || !s.options.hideMoney ? { note: a.note } : {}) });
    }
    back.push(...returned);
    payouts.push({ casino: c.value, removedTies, awards, returned });
    c.notes = [];
    c.dice = {};
  }
  s.pile.push(...back);
  if (back.length) ev.push({ type: 'notesReturned', notes: back });
  s.roundResults.push({ round: s.round, payouts });
  ev.push({ type: 'roundEnd', round: s.round });
}

/** Next seat with dice left (the same player again if only they have dice); settles the round when nobody has. */
function advance(s: S, rng: Rng, ev: GameEvent[]): void {
  s.lastRoll = null;
  const n = s.seats.length;
  const hasDice = (i: number) => diceLeft(s, s.seats[i]!) > 0;
  const next = nextSeat(s.current, n, (i) => !hasDice(i));
  if (hasDice(next)) {
    s.current = next;
    s.phase = 'roll';
    s.turnSeq++;
    ev.push({ type: 'turnChanged', player: curId(s) });
    return;
  }
  settleRound(s, ev);
  if (s.round >= s.options.rounds) {
    finish(s, ev);
    return;
  }
  s.round++;
  s.startSeat = nextSeat(s.startSeat, n, (i) => !isIn(s, s.seats[i]!));
  startRound(s, rng, ev);
}

function doRoll(s: S, rng: Rng, ev: GameEvent[]): void {
  const p = curId(s);
  const h = s.hand[p]!;
  const own: number[] = [];
  const neutral: number[] = [];
  for (let i = 0; i < h.own; i++) own.push(1 + rng.int(6));
  for (let i = 0; i < h.neutral; i++) neutral.push(1 + rng.int(6));
  s.lastRoll = { own, neutral };
  s.phase = 'place';
  s.rollSeq++;
  ev.push({ type: 'rolled', player: p, own: [...own], neutral: [...neutral] });
}

function doPlace(s: S, value: number, auto: boolean, rng: Rng, ev: GameEvent[]): void {
  const p = curId(s);
  const roll = s.lastRoll;
  if (!roll) throw new Error('las-vegas: place without a roll');
  const ownCount = roll.own.filter((d) => d === value).length;
  const neutralCount = roll.neutral.filter((d) => d === value).length;
  if (ownCount + neutralCount === 0) throw new Error('las-vegas: value not rolled');
  const c = s.casinos[value - 1]!;
  if (ownCount) c.dice[p] = (c.dice[p] ?? 0) + ownCount;
  if (neutralCount) c.dice[HOUSE] = (c.dice[HOUSE] ?? 0) + neutralCount;
  s.hand[p]!.own -= ownCount;
  s.hand[p]!.neutral -= neutralCount;
  s.lastPlace = { player: p, value, own: ownCount, neutral: neutralCount, auto };
  ev.push({ type: 'placed', player: p, value, ownCount, neutralCount, auto });
  advance(s, rng, ev);
}

function doConcede(s: S, p: PlayerId, rng: Rng, ev: GameEvent[]): void {
  const wasCurrent = curId(s) === p;
  s.conceded.push(p);
  s.hand[p] = { own: 0, neutral: 0 };
  for (const c of s.casinos) delete c.dice[p];
  ev.push({ type: 'conceded', player: p });
  if (activeIds(s).length <= 1) {
    finish(s, ev);
    return;
  }
  if (wasCurrent) advance(s, rng, ev);
}

// ---------------------------------------------------------------- result

function rankRows(s: S): LasVegasRankRow[] {
  const rows = s.seats.map((p) => ({ player: p, total: sum(s.money[p]!), notes: [...s.money[p]!].sort((a, b) => b - a), conceded: !isIn(s, p) }));
  rows.sort((a, b) => Number(a.conceded) - Number(b.conceded) || b.total - a.total || b.notes.length - a.notes.length);
  const out: LasVegasRankRow[] = [];
  rows.forEach((r, i) => {
    const prev = out[i - 1];
    const tied = prev && prev.conceded === r.conceded && prev.total === r.total && prev.notes.length === r.notes.length;
    out.push({ ...r, rank: tied ? prev.rank : i + 1 });
  });
  return out;
}

function buildResult(s: S): LasVegasResult {
  const ranking = rankRows(s);
  const winners = ranking.filter((r) => r.rank === 1).map((r) => r.player);
  const roundTotals: Record<PlayerId, number[]> = {};
  for (const p of s.seats)
    roundTotals[p] = s.roundResults.map((rr) => sum(rr.payouts.flatMap((po) => po.awards.filter((a) => a.owner === p).map((a) => a.note))));
  const top = ranking[0]!;
  const early = s.conceded.length > 0 && activeIds(s).length <= 1;
  let summary: string;
  if (winners.length > 1) summary = `공동 1위 ${winners.length}명, ${top.total}점 (지폐 ${top.notes.length}장)`;
  else {
    const second = ranking[1];
    summary = `1위 ${top.total}점 (지폐 ${top.notes.length}장)${second ? ` · 2위 ${second.total}점` : ''}`;
  }
  if (early) summary = `다른 사람이 모두 기권했어요. ${summary}`;
  return { ranking, winners, roundTotals, summary, reason: early ? 'resign' : 'normal' };
}

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

export const lasVegas: GameDefinition<LasVegasState, LasVegasAction, LasVegasView, LasVegasOptions> = {
  id: 'las-vegas',
  nameKo: '라스베가스',
  minPlayers: 2,
  maxPlayers: 5,
  stateVersion: 1,
  defaultOptions: lasVegasOptionsSchema.parse({}),
  optionsSchema: lasVegasOptionsSchema as unknown as ZodType<LasVegasOptions>,
  actionSchema: lasVegasActionSchema as unknown as ZodType<LasVegasAction>,

  playerCountError(options, count) {
    return neutralPerFor(options.neutralDice, count) === null ? '5명일 때는 중립(흰) 주사위를 켤 수 없어요. "자동"이나 "끄기"로 바꿔 주세요.' : null;
  },

  setup({ players, options, rng, now }) {
    if (players.length < 2 || players.length > 5) throw new Error('las-vegas: 2~5명이 할 수 있어요.');
    if (players.includes(HOUSE)) throw new Error('las-vegas: reserved player id');
    const neutralPer = neutralPerFor(options.neutralDice, players.length);
    if (neutralPer === null) throw new Error('las-vegas: 5명일 때는 중립 주사위를 켤 수 없어요.');
    const pile = rng.shuffle(ALL_NOTES);
    const startSeat = rng.int(players.length);
    const s: S = {
      options,
      seats: [...players],
      round: 1,
      startSeat,
      current: startSeat,
      phase: 'roll',
      pile,
      casinos: CASINO_VALUES.map((value) => ({ value, notes: [], dice: {} })),
      hand: {},
      lastRoll: null,
      money: Object.fromEntries(players.map((p) => [p, []])),
      roundResults: [],
      neutralPer,
      houseExtra: houseExtraFor(neutralPer, players.length),
      houseRoll: null,
      lastPlace: null,
      conceded: [],
      timeouts: Object.fromEntries(players.map((p) => [p, 0])),
      rollSeq: 0,
      turnSeq: 0,
      deadlineAt: null,
    };
    startRound(s, rng, []);
    refreshDeadline(s, now);
    return s;
  },

  validate(s, actor, a) {
    if (!s.money[actor]) return fail('이 게임의 플레이어가 아니에요.');
    if (s.phase === 'finished') return fail('게임이 이미 끝났어요.');
    if (!isIn(s, actor)) return fail('이미 기권했어요.');
    if (a.type === 'CONCEDE') return ok;
    if (a.type === 'TIMEOUT') return activeOf(s).includes(actor) ? ok : fail('지금은 시간 초과를 처리할 수 없어요.');
    if (curId(s) !== actor) return fail('지금은 내 차례가 아니에요.');
    switch (a.type) {
      case 'ROLL':
        if (s.phase !== 'roll' || diceLeft(s, actor) === 0) return fail('지금은 굴릴 차례가 아니에요.');
        return ok;
      case 'PLACE': {
        if (s.phase !== 'place' || !s.lastRoll) return fail('먼저 주사위를 굴려 주세요.');
        const v = a.value;
        if (!Number.isInteger(v) || !s.lastRoll.own.concat(s.lastRoll.neutral).includes(v)) return fail('그 숫자는 나오지 않았어요.');
        return ok;
      }
    }
    return fail('알 수 없는 행동이에요.');
  },

  apply(prev, actor, a, { rng, now }) {
    const s = structuredClone(prev);
    const ev: GameEvent[] = [];
    if (a.type === 'TIMEOUT') {
      s.timeouts[actor] = (s.timeouts[actor] ?? 0) + 1;
      ev.push({ type: 'timeout', player: actor });
      if (s.timeouts[actor] === AWAY_AFTER) ev.push({ type: 'away', player: actor });
      if (s.phase === 'roll') doRoll(s, rng, ev);
      else doPlace(s, autoPlaceValue(s, s.lastRoll!), true, rng, ev);
    } else {
      if (a.type !== 'CONCEDE') s.timeouts[actor] = 0;
      switch (a.type) {
        case 'ROLL':
          if (s.phase !== 'roll') throw new Error('las-vegas: not the roll phase');
          doRoll(s, rng, ev);
          break;
        case 'PLACE':
          if (s.phase !== 'place') throw new Error('las-vegas: not the place phase');
          doPlace(s, a.value, false, rng, ev);
          break;
        case 'CONCEDE':
          doConcede(s, actor, rng, ev);
          break;
      }
    }
    refreshDeadline(s, now);
    return { state: s, events: ev };
  },

  view(s, viewer) {
    const me = viewer !== null && s.money[viewer] ? viewer : null;
    const done = s.phase === 'finished';
    const visible = (p: Owner) => done || !s.options.hideMoney || p === me || p === HOUSE;
    const money: LasVegasView['money'] = {};
    for (const p of s.seats) {
      const notes = s.money[p]!;
      money[p] = visible(p)
        ? { count: notes.length, total: sum(notes), notes: [...notes].sort((a, b) => b - a) }
        : { count: notes.length, total: null, notes: null };
    }
    const roundResults = s.roundResults.map((rr) => ({
      round: rr.round,
      payouts: rr.payouts.map((po) => ({
        casino: po.casino,
        removedTies: [...po.removedTies],
        awards: po.awards.map((aw) =>
          visible(aw.owner)
            ? { owner: aw.owner, note: aw.note, key: awardKey(rr.round, po.casino, aw.owner, aw.note) }
            : { owner: aw.owner, note: null, key: null },
        ),
        returned: [...po.returned],
      })),
    }));
    const cur = done ? null : curId(s);
    const choices: LasVegasChoice[] = [];
    if (cur && s.phase === 'place' && s.lastRoll) {
      for (const v of CASINO_VALUES) {
        const own = s.lastRoll.own.filter((d) => d === v).length;
        const neutral = s.lastRoll.neutral.filter((d) => d === v).length;
        if (own + neutral === 0) continue;
        const pv = placementPreview(s, cur, v, own, neutral);
        choices.push({ value: v, own, neutral, standing: pv.standing, note: pv.note, countAfter: pv.count });
      }
    }
    return {
      options: s.options,
      me,
      seats: [...s.seats],
      round: s.round,
      rounds: s.options.rounds,
      startPlayer: s.seats[s.startSeat]!,
      current: cur,
      phase: s.phase,
      pileCount: s.pile.length,
      casinos: s.casinos.map((c) => ({ value: c.value, notes: [...c.notes], dice: { ...c.dice } })),
      hand: Object.fromEntries(s.seats.map((p) => [p, { ...s.hand[p]! }])),
      neutralPer: s.neutralPer,
      houseExtra: s.houseExtra,
      houseRoll: s.houseRoll,
      lastRoll: s.lastRoll,
      choices,
      autoValue: cur && s.phase === 'place' && s.lastRoll ? autoPlaceValue(s, s.lastRoll) : null,
      lastPlace: s.lastPlace,
      money,
      roundResults,
      conceded: [...s.conceded],
      away: s.seats.filter((p) => isIn(s, p) && (s.timeouts[p] ?? 0) >= AWAY_AFTER),
      rollSeq: s.rollSeq,
      turnSeq: s.turnSeq,
      deadlineAt: s.deadlineAt,
      result: done ? buildResult(s) : null,
    };
  },

  activePlayers: activeOf,

  deadline(s) {
    return s.phase === 'finished' ? null : s.deadlineAt;
  },

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

  onLeave(s, player) {
    if (s.phase === 'finished' || !s.money[player] || !isIn(s, player)) return null;
    return { type: 'CONCEDE' };
  },

  result(s): GameResult | null {
    if (s.phase !== 'finished') return null;
    const r = buildResult(s);
    const groups = new Map<number, PlayerId[]>();
    for (const row of r.ranking) groups.set(row.rank, [...(groups.get(row.rank) ?? []), row.player]);
    const scores: Record<PlayerId, number> = {};
    for (const row of r.ranking) scores[row.player] = row.total;
    return { ranking: [...groups.entries()].sort((a, b) => a[0] - b[0]).map(([, ps]) => ps), scores, summary: r.summary, reason: r.reason };
  },

  /** Test helper: ROLL, or one PLACE per rolled number (CONCEDE left out). */
  legalActions(s, player) {
    if (s.phase === 'finished' || curId(s) !== player || !isIn(s, player)) return [];
    if (s.phase === 'roll') return [{ type: 'ROLL' }];
    const vals = [...new Set([...s.lastRoll!.own, ...s.lastRoll!.neutral])].sort((a, b) => a - b);
    return vals.map((value) => ({ type: 'PLACE' as const, value }));
  },

  /** Test helper: keys of this player's bills that other viewers must not see (while amounts are hidden). */
  secretsOf(s, player) {
    if (s.phase === 'finished' || !s.options.hideMoney) return [];
    return s.roundResults.flatMap((rr) =>
      rr.payouts.flatMap((po) => po.awards.filter((a) => a.owner === player).map((a) => awardKey(rr.round, po.casino, player, a.note))),
    );
  },
};