import { codeToText, regionData } from 'element-china-area-data';

export { regionData as CHINA_REGION_OPTIONS };

export type OpenCityRef = {
  id: string;
  name: string;
  code: string;
  partnerId?: string | null;
  partner?: { id: string };
};

export type ParsedChinaRegion = {
  province: string;
  city: string;
  district: string;
  provinceCode: string;
  cityCode: string;
  districtCode: string;
};

/** 区县 adcode → 地级市 adcode（如 410105 → 410100） */
export function districtCodeToCityCode(districtCode: string): string {
  if (districtCode.length < 6) return districtCode;
  return `${districtCode.slice(0, 4)}00`;
}

export function parseRegionCodes(codes?: string[]): ParsedChinaRegion | null {
  if (!codes || codes.length < 3) return null;
  const [provinceCode, cityCode, districtCode] = codes;
  const province = codeToText[provinceCode];
  const city = codeToText[cityCode];
  const district = codeToText[districtCode];
  if (!province || !city || !district) return null;
  return { province, city, district, provinceCode, cityCode, districtCode };
}

export function formatRegionLabel(region: ParsedChinaRegion): string {
  return `${region.province} / ${region.city} / ${region.district}`;
}

export function matchOpenCityId(
  cities: OpenCityRef[],
  districtCode: string,
  partnerId?: string,
): string | undefined {
  const cityCode = districtCodeToCityCode(districtCode);
  const scoped = partnerId
    ? cities.filter((c) => {
        const pid = c.partnerId ?? c.partner?.id;
        return !pid || String(pid) === partnerId;
      })
    : cities;
  return (
    scoped.find((c) => c.code === cityCode)?.id
    ?? scoped.find((c) => c.code === districtCode)?.id
    ?? scoped.find((c) => districtCode.startsWith(c.code.slice(0, 4)))?.id
  );
}

export function resolveRegionBinding(
  codes: string[],
  cities: OpenCityRef[],
  partnerId?: string,
) {
  const region = parseRegionCodes(codes);
  if (!region) return null;
  const cityId = matchOpenCityId(cities, region.districtCode, partnerId);
  const matchedCity = cityId ? cities.find((c) => c.id === cityId) : undefined;
  return {
    region,
    cityId,
    matchedCity,
    cityCode: districtCodeToCityCode(region.districtCode),
  };
}