import { randomUUID } from 'node:crypto';
import type { GameState, GameView, GameEventEnvelope, ClientMessage, Card } from '../src/engine/types';

/** Some upstream skills pass another player's hand IDs in a selection prompt. Their IDs contain
 * the card's name and suit! Use opaque choices for that blind selection, in snapshots AND events.
 * Public equipment remains face-up; a played/revealed card is still shown by its normal event. */
export class BlindChoices {
  private ids = new Map<number, Map<string, string>>();
  private token(viewer: number, id: string): string {
    let map = this.ids.get(viewer);
    if (!map) this.ids.set(viewer, map = new Map());
    if (!map.has(id)) map.set(id, `hidden-${randomUUID()}`);
    return map.get(id)!;
  }
  private prompt(state: GameState, viewer: number, prompt: unknown): unknown {
    if (!prompt || typeof prompt !== 'object') return prompt;
    const p = prompt as { type?: string; cardIds?: string[] };
    if (p.type !== 'distribute' || !p.cardIds) return prompt;
    const hidden = new Set(state.players.flatMap((x, i) => i !== viewer ? x.hand : []));
    return { ...p, cardIds: p.cardIds.map((id) => hidden.has(id) ? this.token(viewer, id) : id) };
  }
  view(state: GameState, viewer: number, view: GameView): GameView {
    if (!view.pending) return view;
    const atom = view.pending.atom as unknown as { prompt?: unknown };
    const prompt = this.prompt(state, viewer, view.pending.prompt);
    if (prompt === view.pending.prompt) return view;
    const cardMap = { ...view.cardMap };
    for (const token of this.ids.get(viewer)?.values() ?? []) cardMap[token] = blindCard(token);
    return { ...view, cardMap, pending: { ...view.pending, prompt, atom: { ...atom, prompt } } } as GameView;
  }
  events(state: GameState, viewer: number, events: GameEventEnvelope[]): GameEventEnvelope[] {
    return events.map((e) => {
      if (e.view?.type !== '请求回应' || !e.view.prompt) return e;
      return { ...e, view: { ...e.view, prompt: this.prompt(state, viewer, e.view.prompt) } } as GameEventEnvelope;
    });
  }
  message(state: GameState, viewer: number, message: ClientMessage): ClientMessage | null {
    const back = new Map([...this.ids.get(viewer)?.entries() ?? []].map(([a, b]) => [b, a]));
    const hidden = new Set(state.players.flatMap((p, i) => i !== viewer ? p.hand : []));
    const atom = state.pendingSlots.get(viewer)?.atom as unknown as { prompt?: { type?: string; cardIds?: string[] } } | undefined;
    // Some skills (攻心) legitimately reveal another hand. Reject raw IDs only in the
    // particular blind distribute prompt, never in an authorized reveal/selection window.
    const protectedIds = new Set(atom?.prompt?.type === 'distribute' ? (atom.prompt.cardIds ?? []).filter((id) => hidden.has(id)) : []);
    let invalid = false;
    const visit = (value: unknown): unknown => {
      if (typeof value === 'string') {
        if (back.has(value)) return back.get(value);
        if (protectedIds.has(value)) invalid = true;
        return value;
      }
      if (Array.isArray(value)) return value.map(visit);
      if (value && typeof value === 'object') return Object.fromEntries(Object.entries(value).map(([k, v]) => [k, visit(v)]));
      return value;
    };
    const out = visit(message) as ClientMessage;
    return invalid ? null : out;
  }
}

export function blindCard(id: string): Card {
  return { id, name: '暗牌', type: '基本牌', subtype: '暗牌', suit: '', rank: '', color: '无色', description: '对方的手牌；只能盲选，牌面不可见。' } as Card;
}