import type { ActState, ChapterState, GameState } from '../../types';

function resolveActIndex(chapterState: ChapterState | null | undefined) {
  if (!chapterState) return 0;
  if (chapterState.stage === 'climax' || chapterState.stage === 'aftermath') return 2;
  if (chapterState.stage === 'turning_point') return 1;
  return 0;
}

export function buildActPlan(params: {
  state: GameState;
}) {
  const primaryThreads = params.state.storyEngineMemory?.activeThreadIds ?? [];
  return [
    {
      id: 'act-1',
      title: '第一幕·起线',
      actIndex: 0,
      theme: '铺陈与引线',
      primaryThreadIds: primaryThreads.slice(0, 2),
      status: 'opening',
    },
    {
      id: 'act-2',
      title: '第二幕·扩张',
      actIndex: 1,
      theme: '冲突升级',
      primaryThreadIds: primaryThreads.slice(0, 3),
      status: 'midgame',
    },
    {
      id: 'act-3',
      title: '第三幕·收束',
      actIndex: 2,
      theme: '决战与余波',
      primaryThreadIds: primaryThreads.slice(0, 3),
      status: 'finale',
    },
  ] satisfies ActState[];
}

export function resolveCurrentActState(params: {
  state: GameState;
  chapterState?: ChapterState | null;
}) {
  const chapterState = params.chapterState ?? params.state.chapterState ?? null;
  const actIndex = resolveActIndex(chapterState);
  const actPlan = buildActPlan(params);
  const candidate = actPlan[actIndex] ?? actPlan[0];
  if (!candidate) return null;

  return {
    ...candidate,
    theme: chapterState?.theme ?? candidate.theme,
    primaryThreadIds: chapterState?.primaryThreadIds ?? candidate.primaryThreadIds,
    status:
      chapterState?.stage === 'opening'
        ? 'opening'
        : chapterState?.stage === 'expansion'
          ? 'midgame'
          : chapterState?.stage === 'turning_point'
            ? 'late_game'
            : chapterState?.stage === 'climax'
              ? 'finale'
              : chapterState?.stage === 'aftermath'
                ? 'resolved'
                : candidate.status,
  } satisfies ActState;
}