/**
 * 형상 선택지 (spec §5.2 · plan C5). Only the default of each group can be chosen until the rules for the other
 * options are confirmed (Q6). The other options are shown but cannot be selected.
 */
export type MemberId = 'bearing' | 'coping' | 'column' | 'footing' | 'ground';

export interface ShapeOption {
  label: string;
  /** 굵은 글씨 in the spec: the default that the 1단계 model builds. */
  isDefault: boolean;
  /** The rule for this option is confirmed (승인 2026-10-26: 하상), so it can be chosen even if it is not the default. */
  confirmed?: boolean;
}

export interface ShapeGroup {
  title: string;
  options: ShapeOption[];
}

const d = (label: string): ShapeOption => ({ label, isDefault: true });
const x = (label: string): ShapeOption => ({ label, isDefault: false });
const ok = (label: string): ShapeOption => ({ label, isDefault: false, confirmed: true });

export const SHAPE_GROUPS: Record<MemberId, ShapeGroup[]> = {
  bearing: [{ title: '배치', options: [d('분리'), ok('일체')] }],
  coping: [
    { title: '교좌면', options: [d('직각'), x('모따기'), x('라운드')] },
    { title: '하면', options: [d('직선'), x('곡선 오목'), x('곡선 볼록')] },
  ],
  column: [
    { title: '단면', options: [d('원형'), x('트랙'), x('사각')] },
    { title: '중공', options: [d('중실'), x('중공')] },
  ],
  footing: [
    { title: '형상', options: [d('직사각'), x('경사')] },
    { title: '모따기', options: [d('없음'), x('있음')] },
    { title: '말뚝 종류', options: [d('강관'), x('PHC'), x('복합')] },
    { title: '경사말뚝', options: [d('없음'), x('있음')] },
  ],
  ground: [{ title: '위치', options: [d('육상'), ok('하상'), ok('해상')] }],
};

export const UNDEFINED_REASON = '규칙 미정 (Q6 확정 전 선택 불가)';

/** Options currently selectable: the defaults and the options whose rule is confirmed. */
export function isSelectable(option: ShapeOption): boolean {
  return option.isDefault || option.confirmed === true;
}

/** The default summary of a member, e.g. "교좌면 직각 · 하면 직선". */
export function defaultSummary(member: MemberId): string {
  return SHAPE_GROUPS[member].map((g) => g.options.find((o) => o.isDefault)!.label).join(' · ');
}

/** Chooses an option in a group. Refuses options whose rules are not confirmed. */
export function choose(member: MemberId, groupIndex: number, optionLabel: string): string {
  const group = SHAPE_GROUPS[member][groupIndex];
  const option = group?.options.find((o) => o.label === optionLabel);
  if (!option) throw new Error(`알 수 없는 선택지: ${optionLabel}`);
  if (!isSelectable(option)) throw new Error(`${optionLabel}: ${UNDEFINED_REASON}`);
  return option.label;
}