import tldts from 'tldts-experimental';
import { looseTldtsOpt } from '../constants/loose-tldts-opt';
import picocolors from 'picocolors';

import DNS2 from 'dns2';
import asyncRetry from 'async-retry';
import * as whoiser from 'whoiser';

import { createRetrieKeywordFilter as createKeywordFilter } from 'foxts/retrie';

import process from 'node:process';

const mutex = new Map<string, Promise<unknown>>();
export function keyedAsyncMutexWithQueue<T>(key: string, fn: () => Promise<T>) {
  if (mutex.has(key)) {
    return mutex.get(key) as Promise<T>;
  }
  const promise = fn();
  mutex.set(key, promise);
  return promise;
}

class DnsError extends Error {
  name = 'DnsError';
  constructor(readonly message: string, public readonly server: string) {
    super(message);
  }
}

interface DnsResponse extends DNS2.$DnsResponse {
  dns: string
}

const dohServers: Array<[string, DNS2.DnsResolver]> = ([
  '8.8.8.8',
  '8.8.4.4',
  '1.0.0.1',
  '1.1.1.1',
  '162.159.36.1',
  '162.159.46.1',
  '101.101.101.101', // TWNIC
  '185.222.222.222', // DNS.SB
  '45.11.45.11', // DNS.SB
  'dns10.quad9.net', // Quad9 unfiltered
  'doh.sandbox.opendns.com', // OpenDNS sandbox (unfiltered)
  'unfiltered.adguard-dns.com',
  // '0ms.dev', // Proxy Cloudflare
  // '76.76.2.0', // ControlD unfiltered, path not /dns-query
  // '76.76.10.0', // ControlD unfiltered, path not /dns-query
  // 'dns.bebasid.com', // BebasID, path not /dns-query but /unfiltered
  // '193.110.81.0', // dns0.eu
  // '185.253.5.0', // dns0.eu
  // 'zero.dns0.eu',
  'dns.nextdns.io',
  'anycast.dns.nextdns.io',
  'wikimedia-dns.org',
  // 'ordns.he.net',
  // 'dns.mullvad.net',
  'basic.rethinkdns.com'
  // 'ada.openbld.net',
  // 'dns.rabbitdns.org'
] as const).map(dns => [
  dns,
  DNS2.DOHClient({
    dns,
    http: false
    // get: (url: string) => undici.request(url).then(r => r.body)
  })
] as const);

const domesticDohServers: Array<[string, DNS2.DnsResolver]> = ([
  '223.5.5.5',
  '223.6.6.6',
  '120.53.53.53',
  '1.12.12.12'
] as const).map(dns => [
  dns,
  DNS2.DOHClient({
    dns,
    http: false
    // get: (url: string) => undici.request(url).then(r => r.body)
  })
] as const);

function createResolve(server: Array<[string, DNS2.DnsResolver]>): DNS2.DnsResolver<DnsResponse> {
  return async (...args) => {
    try {
      return await asyncRetry(async () => {
        const [dohServer, dohClient] = server[Math.floor(Math.random() * server.length)];

        try {
          return {
            ...await dohClient(...args),
            dns: dohServer
          } satisfies DnsResponse;
        } catch (e) {
          // console.error(e);
          throw new DnsError((e as Error).message, dohServer);
        }
      }, { retries: 5 });
    } catch (e) {
      console.log('[doh error]', ...args, e);
      throw e;
    }
  };
}

const resolve = createResolve(dohServers);
const domesticResolve = createResolve(domesticDohServers);

async function getWhois(domain: string) {
  return asyncRetry(() => whoiser.domain(domain), { retries: 5 });
}

const domainAliveMap = new Map<string, boolean>();
function onDomainAlive(domain: string): [string, boolean] {
  domainAliveMap.set(domain, true);
  return [domain, true];
}
function onDomainDead(domain: string): [string, boolean] {
  domainAliveMap.set(domain, false);
  return [domain, false];
}

export async function isDomainAlive(domain: string, isSuffix: boolean): Promise<[string, boolean]> {
  if (domainAliveMap.has(domain)) {
    return [domain, domainAliveMap.get(domain)!];
  }

  const apexDomain = tldts.getDomain(domain, looseTldtsOpt);
  if (!apexDomain) {
    console.log(picocolors.gray('[domain invalid]'), picocolors.gray('no apex domain'), { domain });
    return onDomainAlive(domain);
  }

  const apexDomainAlive = await keyedAsyncMutexWithQueue(apexDomain, () => isApexDomainAlive(apexDomain));
  if (isSuffix) {
    return apexDomainAlive;
  }
  if (!apexDomainAlive[1]) {
    return apexDomainAlive;
  }

  const $domain = domain[0] === '.' ? domain.slice(1) : domain;

  const aDns: string[] = [];
  const aaaaDns: string[] = [];

  // test 2 times before make sure record is empty
  for (let i = 0; i < 2; i++) {
    // eslint-disable-next-line no-await-in-loop -- sequential
    const aRecords = (await resolve($domain, 'A'));
    if (aRecords.answers.length > 0) {
      return onDomainAlive(domain);
    }

    aDns.push(aRecords.dns);
  }
  for (let i = 0; i < 2; i++) {
    // eslint-disable-next-line no-await-in-loop -- sequential
    const aaaaRecords = (await resolve($domain, 'AAAA'));
    if (aaaaRecords.answers.length > 0) {
      return onDomainAlive(domain);
    }

    aaaaDns.push(aaaaRecords.dns);
  }

  // only then, let's test once with domesticDohServers
  const aRecords = (await domesticResolve($domain, 'A'));
  if (aRecords.answers.length > 0) {
    return onDomainAlive(domain);
  }
  aDns.push(aRecords.dns);

  const aaaaRecords = (await domesticResolve($domain, 'AAAA'));
  if (aaaaRecords.answers.length > 0) {
    return onDomainAlive(domain);
  }
  aaaaDns.push(aaaaRecords.dns);

  console.log(picocolors.red('[domain dead]'), 'no A/AAAA records', { domain, a: aDns, aaaa: aaaaDns });
  return onDomainDead($domain);
}

const apexDomainNsResolvePromiseMap = new Map<string, Promise<DnsResponse>>();

async function isApexDomainAlive(apexDomain: string): Promise<[string, boolean]> {
  if (domainAliveMap.has(apexDomain)) {
    return [apexDomain, domainAliveMap.get(apexDomain)!];
  }

  let resp: DnsResponse;
  if (apexDomainNsResolvePromiseMap.has(apexDomain)) {
    resp = await apexDomainNsResolvePromiseMap.get(apexDomain)!;
  } else {
    const promise = resolve(apexDomain, 'NS');
    apexDomainNsResolvePromiseMap.set(apexDomain, promise);
    resp = await promise;
  }

  if (resp.answers.length > 0) {
    return onDomainAlive(apexDomain);
  }

  console.log(picocolors.gray('[domain check]'), picocolors.gray('no NS records'), { domain: apexDomain });

  let whois;

  try {
    whois = await getWhois(apexDomain);
  } catch (e) {
    console.log(picocolors.red('[domain dead]'), 'whois error', { domain: apexDomain }, e);
    return onDomainDead(apexDomain);
  }

  if (process.env.DEBUG) {
    console.log(JSON.stringify(whois, null, 2));
  }

  if (whoisExists(whois)) {
    console.log(picocolors.gray('[domain alive]'), picocolors.gray('whois found'), { domain: apexDomain });
    return onDomainAlive(apexDomain);
  }

  console.log(picocolors.red('[domain dead]'), 'whois not found', { domain: apexDomain });
  return onDomainDead(apexDomain);
}

// TODO: this is a workaround for https://github.com/LayeredStudio/whoiser/issues/117
const whoisNotFoundKeywordTest = createKeywordFilter([
  'no match for',
  'does not exist',
  'not found',
  'no entries',
  'no data found',
  'is available for registration',
  'currently available for application',
  'no matching record',
  'no information available about domain name'
]);

// whois server can redirect, so whoiser might/will get info from multiple whois servers
// some servers (like TLD whois servers) might have cached/outdated results
// we can only make sure a domain is alive once all response from all whois servers demonstrate so
export function whoisExists(whois: whoiser.WhoisSearchResult) {
  let empty = true;

  for (const key in whois) {
    if (Object.hasOwn(whois, key)) {
      empty = false;

      if (key === 'error') {
        // if (
        //   (typeof whois.error === 'string' && whois.error)
        //   || (Array.isArray(whois.error) && whois.error.length > 0)
        // ) {
        //   console.error(whois);
        //   return true;
        // }
        continue;
      }

      if (key === 'text') {
        if (Array.isArray(whois.text) && whois.text.some(value => whoisNotFoundKeywordTest(value.toLowerCase()))) {
          return false;
        }
        continue;
      }
      if (key === 'Name Server') {
        // if (Array.isArray(whois[key]) && whois[key].length === 0) {
        //   return false;
        // }
        continue;
      }

      if (typeof whois[key] === 'object' && !Array.isArray(whois[key]) && !whoisExists(whois[key])) {
        return false;
      }
    }
  }

  return !empty;
}