/** 뱅! (docs/games/bang.md). Pure and deterministic; state is JSON. */
import { type GameDefinition, type GameResult, type PlayerId } from '@bg/engine';
import { CARDS, CHARACTER_IDS, CHARACTER_LIFE, cardById, kindOf, rolesFor } from './cards';
import { distance, rangeOf } from './distance';
import {
  AWAY_AFTER,
  P,
  autoSave,
  discardDown,
  doDraw,
  eliminate,
  log,
  endPlay,
  kitKeep,
  leave,
  limboCards,
  living,
  pickCharacter,
  playCard,
  randomDiscard,
  reactionOf,
  respond,
  responder,
  settle,
  sidHeal,
  storePick,
  takeHit,
  tryBarrel,
  type Ctx,
} from './effects';
import { bangLike, missedLike, playOptions, promptFor, sidHealContext, unlimitedBang, validateAction, waiting } from './rules';
import {
  bangActionSchema,
  bangOptionsSchema,
  type BangAction,
  type BangOptions,
  type BangState,
  type BangView,
  type LogEntry,
  type PlayerState,
  type Reaction,
} from './types';

export * from './cards';
export * from './types';
export { distance, rangeOf, seatDistance, hasEquip, weaponOf } from './distance';
export { checkPlay, playOptions, promptFor, waiting } from './rules';

const LOG_VIEW = 30;

/** Copy for `apply`: containers are copied; log entries and options are never mutated and are shared. */
function cloneState(s: BangState): BangState {
  return {
    ...s,
    players: s.players.map((p) => ({ ...p, hand: [...p.hand], inPlay: [...p.inPlay], characterOffer: p.characterOffer ? [...p.characterOffer] : null })),
    deck: [...s.deck],
    discard: [...s.discard],
    turn: { ...s.turn },
    reactions: s.reactions.map((r) => {
      if (r.kind === 'store') return { ...r, order: [...r.order], revealed: [...r.revealed] };
      if (r.kind === 'kitKeep') return { ...r, options: [...r.options] };
      return { ...r };
    }),
    deathOrder: [...s.deathOrder],
    log: [...s.log],
  };
}

/** Every card is in exactly one place (test invariant). */
export function allCards(s: BangState): string[] {
  return [...s.deck, ...s.discard, ...s.players.flatMap((p) => [...p.hand, ...p.inPlay]), ...limboCards(s)];
}

function deadlineOf(s: BangState): number | null {
  if (s.winner) return null;
  if (s.reactions.length) return Math.min(...s.reactions.map((r) => r.deadline));
  return s.turn.deadline;
}

/** Responders whose own deadline is the earliest (a later reaction must not be cut short). */
function timed(s: BangState): PlayerId[] {
  if (s.winner) return [];
  if (!s.reactions.length) return [s.turn.player];
  const d = deadlineOf(s)!;
  return [...new Set(s.reactions.filter((r) => r.deadline === d).map(responder))];
}

/** §8.5 automatic choice for a player who did not answer in time. */
function onTimeoutApply(s: BangState, ctx: Ctx, actor: PlayerId): void {
  const p = P(s, actor);
  const r = reactionOf(s, actor);
  if (r) {
    switch (r.kind) {
      case 'choose2':
        pickCharacter(s, ctx, actor, p.characterOffer![0]!);
        return;
      case 'kitKeep':
        kitKeep(s, ctx, actor, r.options.slice(0, 2));
        return;
      case 'store':
        storePick(s, ctx, r, r.revealed[0]!);
        return;
      case 'bang': {
        if (!s.options.autoDefend) return takeHit(s, ctx, actor);
        while (r.needed > 0 && tryBarrel(s, ctx, r));
        if (r.needed <= 0) {
          s.reactions.splice(s.reactions.indexOf(r), 1);
          return;
        }
        const cards = p.hand.filter((id) => missedLike(p, id));
        // Calamity Janet keeps 뱅! when a 빗나감! does the job.
        cards.sort((a, b) => Number(kindOf(a) !== 'missed') - Number(kindOf(b) !== 'missed'));
        if (cards.length >= r.needed) return respond(s, ctx, actor, cards.slice(0, r.needed));
        return takeHit(s, ctx, actor);
      }
      case 'indians':
      case 'duel': {
        const card = s.options.autoDefend ? p.hand.find((id) => bangLike(p, id)) : undefined;
        if (card) return respond(s, ctx, actor, [card]);
        return takeHit(s, ctx, actor);
      }
      case 'dying':
        return autoSave(s, ctx, actor);
    }
  }
  switch (s.turn.phase) {
    case 'draw':
      return doDraw(s, ctx, {});
    case 'play':
      endPlay(s, ctx, actor);
      if ((s.turn.phase as string) === 'discard') randomDiscard(s, ctx, actor);
      return;
    case 'discard':
      return randomDiscard(s, ctx, actor);
    default:
      throw new Error(`bang: timeout in ${s.turn.phase}`);
  }
}

function roleVisible(s: BangState, p: PlayerState, viewer: PlayerId | null): boolean {
  return p.role === 'sheriff' || !p.alive || p.id === viewer || !!s.winner;
}

function stripPrivate(e: LogEntry, viewer: PlayerId | null, over: boolean): LogEntry {
  if (e.t !== 'take' || !e.vis || over || (viewer && e.vis.includes(viewer))) return e;
  const { card: _card, ...rest } = e;
  return rest;
}

type Def = GameDefinition<BangState, BangAction, BangView, BangOptions>;

export const bang: Def = {
  id: 'bang',
  nameKo: '뱅!',
  minPlayers: 4,
  maxPlayers: 7,
  stateVersion: 1,
  defaultOptions: bangOptionsSchema.parse({}),
  optionsSchema: bangOptionsSchema as unknown as Def['optionsSchema'],
  actionSchema: bangActionSchema as unknown as Def['actionSchema'],

  setup({ players, options, rng, now }) {
    if (players.length < 4 || players.length > 7) throw new Error(`bang: ${players.length} players not allowed`);
    // §4: seats, roles, characters, then the deck.
    const seats = rng.shuffle(players);
    const roles = rng.shuffle(rolesFor(players.length, options.deputyCount7));
    const chars = rng.shuffle(CHARACTER_IDS);
    const draft = options.characterDraft === 'choose2';
    const ps: PlayerState[] = seats.map((id, i) => {
      const offer = draft ? [chars[2 * i]!, chars[2 * i + 1]!] : null;
      const character = draft ? offer![0]! : chars[i]!;
      const maxLife = CHARACTER_LIFE[character] + (roles[i] === 'sheriff' ? 1 : 0);
      return { id, seat: i, role: roles[i]!, character, characterOffer: offer, maxLife, life: maxLife, alive: true, hand: [], inPlay: [], timeoutsInRow: 0, away: false };
    });
    const s: BangState = {
      options,
      players: ps,
      deck: rng.shuffle(CARDS.map((c) => c.id)),
      discard: [],
      turn: { player: ps.find((p) => p.role === 'sheriff')!.id, phase: 'draft', bangsPlayed: 0, deadline: now, pausedAt: null, dynamiteChecked: false, jailChecked: false },
      reactions: draft ? ps.map((p) => ({ kind: 'choose2' as const, player: p.id, deadline: now + 30_000 })) : [],
      lastCheck: null,
      winner: null,
      deathOrder: [],
      round: 0,
      seq: 0,
      log: [],
      final: null,
    };
    settle(s, { rng, now, events: [] });
    return s;
  },

  validate: validateAction,

  apply(prev, actor, a, { rng, now }) {
    const s = cloneState(prev);
    const ctx: Ctx = { rng, now, events: [] };
    s.seq += 1;
    const p = P(s, actor);
    if (a.type !== 'timeout' && a.type !== 'leave') {
      p.timeoutsInRow = 0;
      p.away = false;
    }
    switch (a.type) {
      case 'timeout':
        p.timeoutsInRow += 1;
        if (p.timeoutsInRow >= AWAY_AFTER) p.away = true;
        log(s, ctx, { t: 'timeout', p: actor });
        onTimeoutApply(s, ctx, actor);
        break;
      case 'leave':
        leave(s, ctx, actor);
        break;
      case 'pickCharacter':
        pickCharacter(s, ctx, actor, a.character);
        break;
      case 'draw':
        doDraw(s, ctx, a);
        break;
      case 'kitKeep':
        kitKeep(s, ctx, actor, a.keep);
        break;
      case 'play':
        playCard(s, ctx, actor, a);
        break;
      case 'respond':
        respond(s, ctx, actor, a.cardIds);
        break;
      case 'useBarrel': {
        const r = reactionOf(s, actor) as Extract<Reaction, { kind: 'bang' }>;
        tryBarrel(s, ctx, r);
        if (r.needed <= 0) s.reactions.splice(s.reactions.indexOf(r), 1);
        break;
      }
      case 'takeHit':
        takeHit(s, ctx, actor);
        break;
      case 'giveUp': {
        const r = reactionOf(s, actor) as Extract<Reaction, { kind: 'dying' }>;
        s.reactions.splice(s.reactions.indexOf(r), 1);
        eliminate(s, ctx, actor, r.killer);
        break;
      }
      case 'storePick':
        storePick(s, ctx, reactionOf(s, actor) as Extract<Reaction, { kind: 'store' }>, a.cardId);
        break;
      case 'sidHeal':
        sidHeal(s, ctx, actor, a.cardIds);
        break;
      case 'endPlay':
        endPlay(s, ctx, actor);
        break;
      case 'discard':
        discardDown(s, ctx, actor, a.cardIds);
        break;
    }
    settle(s, ctx);
    return { state: s, events: ctx.events };
  },

  view(s, viewer) {
    const me = viewer && s.players.some((p) => p.id === viewer) ? viewer : null;
    const meP = me ? P(s, me) : null;
    const over = !!s.winner;
    const reactingOf = new Map(s.reactions.map((r) => [responder(r), r.kind]));
    const players = s.players.map((p) => {
      const hiddenChar = !!p.characterOffer && p.id !== me && !over;
      const dist = meP && meP.alive && p.alive && p.id !== me && !p.characterOffer && !meP.characterOffer ? distance(s, me!, p.id) : null;
      return {
        id: p.id,
        seat: p.seat,
        character: hiddenChar || p.characterOffer ? null : p.character,
        role: roleVisible(s, p, me) ? p.role : null,
        maxLife: p.maxLife,
        life: p.life,
        alive: p.alive,
        handCount: p.hand.length,
        inPlay: p.inPlay.map(cardById),
        isTurn: !over && s.turn.player === p.id && s.turn.phase !== 'draft',
        reacting: reactingOf.get(p.id) ?? null,
        away: p.away,
        distance: dist,
        inRange: dist !== null && dist <= rangeOf(meP!),
      };
    });
    return {
      options: s.options,
      me,
      players,
      current: s.turn.player,
      phase: s.turn.phase,
      round: s.round,
      bangsPlayed: s.turn.bangsPlayed,
      deckCount: s.deck.length,
      discardCount: s.discard.length,
      discardTop: s.discard.slice(-4).map(cardById),
      reactions: s.reactions.map((r) => ({
        kind: r.kind,
        who: responder(r),
        ...('source' in r && r.source ? { source: r.source } : {}),
        ...(r.kind === 'bang' ? { via: r.via, needed: r.needed } : {}),
        ...(r.kind === 'store' ? { revealed: r.revealed.map(cardById) } : {}),
        deadline: r.deadline,
      })),
      lastCheck: s.lastCheck,
      my: meP
        ? {
            role: meP.role,
            character: meP.characterOffer ? null : meP.character,
            hand: meP.hand.map(cardById),
            range: rangeOf(meP),
            unlimitedBang: unlimitedBang(meP),
            plays: playOptions(s, me!),
            canEndPlay: !over && s.turn.player === me && s.turn.phase === 'play' && s.reactions.length === 0 && meP.alive,
            canSidHeal: sidHealContext(s, me!) && meP.life < meP.maxLife && meP.hand.length >= 2,
            prompt: promptFor(s, me!),
          }
        : null,
      turnDeadline: s.turn.deadline,
      deadlineTotalMs: s.options.turnSeconds * 1000,
      reactionTotalMs: s.options.reactionSeconds * 1000,
      log: s.log.slice(-LOG_VIEW).map((e) => stripPrivate(e, me, over)),
      winner: s.winner,
      result: s.final,
    };
  },

  activePlayers: waiting,

  deadline: deadlineOf,

  timeoutPlayers: timed,

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

  onLeave(s, player) {
    const p = s.players.find((x) => x.id === player);
    if (!p || !p.alive || s.winner) return null;
    return { type: 'leave' };
  },

  result(s): GameResult | null {
    const f = s.final;
    if (!f) return null;
    const winners = f.ranking.filter((id) => f.players.find((p) => p.id === id)!.won);
    const losers = f.ranking.filter((id) => !winners.includes(id));
    return {
      ranking: [winners, ...losers.map((id) => [id])],
      scores: Object.fromEntries(f.players.map((p) => [p.id, p.won ? 1 : 0])),
      summary: f.summary,
      reason: 'normal',
    };
  },

  legalActions(s, player) {
    const p = s.players.find((x) => x.id === player);
    if (!p || !p.alive || s.winner) return [];
    const out: BangAction[] = [];
    const r = reactionOf(s, player);
    const sidPairs = (): BangAction[] => (p.hand.length >= 2 ? [{ type: 'sidHeal', cardIds: [p.hand[0]!, p.hand[1]!] }] : []);
    if (r) {
      switch (r.kind) {
        case 'choose2':
          for (const c of p.characterOffer ?? []) out.push({ type: 'pickCharacter', character: c });
          break;
        case 'kitKeep': {
          const o = r.options;
          for (let i = 0; i < o.length; i++) for (let j = i + 1; j < o.length; j++) out.push({ type: 'kitKeep', keep: [o[i]!, o[j]!] });
          break;
        }
        case 'store':
          for (const id of r.revealed) out.push({ type: 'storePick', cardId: id });
          break;
        case 'bang': {
          const cards = p.hand.filter((id) => missedLike(p, id));
          if (cards.length >= r.needed) out.push({ type: 'respond', cardIds: cards.slice(0, r.needed) });
          out.push({ type: 'takeHit' }, { type: 'useBarrel' }, ...sidPairs());
          break;
        }
        case 'indians':
        case 'duel': {
          const card = p.hand.find((id) => bangLike(p, id));
          if (card) out.push({ type: 'respond', cardIds: [card] });
          out.push({ type: 'takeHit' }, ...sidPairs());
          break;
        }
        case 'dying': {
          const beers = p.hand.filter((id) => kindOf(id) === 'beer');
          const need = 1 - p.life;
          if (beers.length >= need) out.push({ type: 'respond', cardIds: beers.slice(0, need) });
          out.push({ type: 'giveUp' }, ...sidPairs());
          break;
        }
      }
      return out.filter((a) => validateAction(s, player, a).ok);
    }
    if (s.reactions.length || s.turn.player !== player) return [];
    switch (s.turn.phase) {
      case 'draw':
        out.push({ type: 'draw' }, { type: 'draw', pedroDiscard: true });
        for (const q of living(s)) out.push({ type: 'draw', jesseFrom: q.id });
        break;
      case 'play':
        for (const o of playOptions(s, player)) {
          if (!o.ok) continue;
          const base = { type: 'play' as const, cardId: o.cardId, ...(o.as ? { as: o.as } : {}) };
          if (!o.targets) out.push(base);
          else
            for (const t of o.targets) {
              if (!t.ok) continue;
              if (t.cards) for (const tc of t.cards) out.push({ ...base, target: t.id, targetCard: tc });
              else out.push({ ...base, target: t.id });
            }
        }
        out.push({ type: 'endPlay' }, ...sidPairs());
        break;
      case 'discard': {
        const n = p.hand.length - p.life;
        if (n > 0) out.push({ type: 'discard', cardIds: p.hand.slice(0, n) }, { type: 'discard', cardIds: p.hand.slice(-n) });
        out.push(...sidPairs());
        break;
      }
    }
    return out.filter((a) => validateAction(s, player, a).ok);
  },

  /** Own hand, own Kit Carlson / choose2 offers, and the deck — ids exactly as they would appear in a view. */
  secretsOf(s, player) {
    const p = s.players.find((x) => x.id === player);
    if (!p) return [];
    const kit = s.reactions.flatMap((r) => (r.kind === 'kitKeep' && r.player === player ? r.options : []));
    return [...p.hand, ...kit, ...s.deck, ...(p.characterOffer ?? [])];
  },
};

export const _internal = { cloneState, timed, deadlineOf };