const fs = require('fs');
const path = require('path');
const crypto = require('crypto');

const jsonPath = path.join(__dirname, '..', 'iran_provinces_cities.json');
const list = JSON.parse(fs.readFileSync(jsonPath, 'utf8'));

let sql = '-- Migration: Populate all provinces and cities of Iran\n';
sql += '-- Preserves existing tree structure: Country (ایران) -> Provinces (استان ...) -> Cities\n\n';

// 1. Ensure Country exists
sql += 'INSERT INTO "City" ("id", "name", "parentId")\n';
sql += "VALUES ('city-iran', 'ایران', NULL)\n";
sql += 'ON CONFLICT ("id") DO NOTHING;\n\n';

function makeId(prefix, str) {
  return prefix + '-' + crypto.createHash('md5').update(str).digest('hex').substring(0, 16);
}

// 2. Insert Provinces
for (const item of list) {
  let pName = item.province.trim();
  if (!pName.startsWith('استان')) {
    pName = 'استان ' + pName;
  }
  const provId = makeId('prov', pName);
  const escapedName = pName.replace(/'/g, "''");

  sql += 'INSERT INTO "City" ("id", "name", "parentId")\n';
  sql += `SELECT '${provId}', '${escapedName}', 'city-iran'\n`;
  sql += `WHERE NOT EXISTS (SELECT 1 FROM "City" WHERE "name" = '${escapedName}');\n`;
}

sql += '\n-- 3. Insert Cities under their respective Province\n';

for (const item of list) {
  let pName = item.province.trim();
  if (!pName.startsWith('استان')) {
    pName = 'استان ' + pName;
  }
  const escapedProvName = pName.replace(/'/g, "''");

  for (const c of item.cities) {
    const cName = c.trim();
    if (!cName) continue;
    const cityId = makeId('city', pName + '-' + cName);
    const escapedCityName = cName.replace(/'/g, "''");

    sql += 'INSERT INTO "City" ("id", "name", "parentId")\n';
    sql += `SELECT '${cityId}', '${escapedCityName}', (\n`;
    sql += `  SELECT "id" FROM "City" WHERE "name" = '${escapedProvName}' LIMIT 1\n`;
    sql += ')\n';
    sql += 'WHERE NOT EXISTS (\n';
    sql += '  SELECT 1 FROM "City" c2\n';
    sql += '  JOIN "City" p2 ON c2."parentId" = p2."id"\n';
    sql += `  WHERE c2."name" = '${escapedCityName}' AND p2."name" = '${escapedProvName}'\n`;
    sql += ');\n';
  }
}

const targetDir = path.join(__dirname, '..', 'apps', 'api', 'prisma', 'migrations', '20261025120000_seed_iran_cities');
if (!fs.existsSync(targetDir)) {
  fs.mkdirSync(targetDir, { recursive: true });
}
const targetFile = path.join(targetDir, 'migration.sql');
fs.writeFileSync(targetFile, sql, 'utf8');
console.log('Migration generated at:', targetFile);
console.log('Total bytes:', fs.statSync(targetFile).size);