import { readFile, writeFile } from 'node:fs/promises';
import { resolve } from 'node:path';

const input = resolve(process.argv[2] || 'ok_data_level3.csv');
const output = resolve(process.argv[3] || 'src/data/china-regions.mjs');

function parseCsvLine(line) {
  const values = [];
  let value = '';
  let quoted = false;
  for (let index = 0; index < line.length; index += 1) {
    const char = line[index];
    if (char === '"') {
      if (quoted && line[index + 1] === '"') { value += '"'; index += 1; }
      else quoted = !quoted;
    } else if (char === ',' && !quoted) {
      values.push(value);
      value = '';
    } else value += char;
  }
  values.push(value);
  return values;
}

const source = await readFile(input, 'utf8');
const rows = source.replace(/^\uFEFF/, '').trim().split(/\r?\n/).slice(1).map(line => {
  const [id, pid, deep, , , , extId, extName] = parseCsvLine(line);
  return { id, pid, deep: Number(deep), code: extId.slice(0, 6), name: extName };
});

const provinces = rows.filter(item => item.deep === 0 && item.code !== '0').map(province => ({
  code: province.code,
  name: province.name,
  cities: rows.filter(city => city.deep === 1 && city.pid === province.id).map(city => ({
    code: city.code,
    name: city.name,
    districts: rows.filter(district => district.deep === 2 && district.pid === city.id).map(district => ({
      code: district.code,
      name: district.name
    }))
  }))
}));

const hotan = provinces.find(item => item.code === '650000')?.cities.find(item => item.code === '653200');
for (const district of [
  { code: '653228', name: '和康县' },
  { code: '653229', name: '和安县' }
]) {
  if (hotan && !hotan.districts.some(item => item.code === district.code)) hotan.districts.push(district);
}
hotan?.districts.sort((a, b) => a.code.localeCompare(b.code));

const banner = `// Generated from AreaCity-JsSpider-StatsGov release 2025.251231.260403.\n// Source snapshot: 国家地名信息库 2025-12-31; generated 2026-07-20.\n// Manual official additions: 和康县 653228, 和安县 653229.\n`;
await writeFile(output, `${banner}export const chinaRegionsVersion = '2025-12-31';\nexport const chinaRegions = ${JSON.stringify(provinces)};\n`, 'utf8');
console.log(`Generated ${provinces.length} provinces at ${output}`);