import * as fs from 'fs/promises';
import { exec } from 'child_process';
import { join } from 'path';
import { CachedZone, DNSRecord } from 'src/types/dns.interfaces';
import { writeZoneFile } from './writer';

// TODO: in-depth validation for record types

const forbiddenCharacters = ['\n', '\r'];
const forbiddenOutsideStr = ['$', ';'];

export function validateRecord(record: DNSRecord): boolean {
  for (const char of forbiddenCharacters) {
    if (record.name.includes(char) || record.value.includes(char)) {
      return false;
    }
  }

  for (const char of forbiddenOutsideStr) {
    if (record.name.includes(char)) {
      return false;
    }
  }

  return true;
}

export async function validateZonefile(
  domain: string,
  file: string,
): Promise<string> {
  return new Promise((resolve, reject) => {
    exec(`named-checkzone ${domain} ${file}`, (error, stdout) => {
      if (error) {
        const errorFull = stdout.split('\n')[0].split(':');
        reject(
          new Error(
            `Validation error: ${errorFull[0]}: ${errorFull
              .slice(2)
              .join(':')}`,
          ),
        );
        return;
      }
      resolve(stdout);
    });
  });
}

export async function validateAndSave(
  name: string,
  zone: CachedZone,
): Promise<void> {
  const tempfile = join(process.cwd(), `.${name}-${Date.now()}.zone`);
  await writeZoneFile(zone.zone, tempfile);
  try {
    await validateZonefile(name, tempfile);
  } catch (e) {
    await fs.unlink(tempfile);
    throw e;
  }
  // TODO: cross-device move
  await fs.rename(tempfile, zone.file);
}