/**
 * 生成全国县级行政区划快照：node scripts/gen-china-districts.js
 * 数据源：devDependency @province-city-china/data（GB/T 2260，省市区四级全量）
 * 输出：src/enumerate/chinaDistricts.json，仅保留县级约 3300 条（[code, 名称, 省+市]，160KB 左右）
 * 行政区划调整后重新执行本脚本即可刷新快照
 */
const fs = require("fs");
const path = require("path");

const all = require("@province-city-china/data");

/** 省级名称表：code 形如 XX0000 */
const provinceNameByCode = {};
/** 地级名称表：code 形如 XXYY00 */
const cityNameByCode = {};
all.forEach((item) => {
  const isProvince = item.city === 0 && item.area === 0 && item.town === 0;
  const isCity = item.city !== 0 && item.area === 0 && item.town === 0;
  if (isProvince) provinceNameByCode[item.province] = item.name;
  if (isCity) cityNameByCode[item.province + item.city] = item.name;
});

const districts = all
  .filter((item) => item.city !== 0 && item.area !== 0 && item.town === 0)
  .map((item) => {
    const province = provinceNameByCode[item.province] || "";
    const city = cityNameByCode[item.province + item.city] || "";
    // 直辖市等省市同名时不重复拼接
    const region = city && city !== province ? `${province}${city}` : province;
    return [item.code, item.name, region];
  });

const outFile = path.join(__dirname, "../src/enumerate/chinaDistricts.json");
fs.writeFileSync(outFile, `${JSON.stringify(districts)}\n`, "utf8");
console.log(`已生成 ${path.relative(process.cwd(), outFile)}：${districts.length} 条`);