import { task } from './trace';
import { fetchRemoteTextByLine } from './lib/fetch-text-by-line';
import { HostnameSmolTrie } from './lib/trie';
import { SHARED_DESCRIPTION } from './constants/description';
import { createMemoizedPromise } from './lib/memo-promise';
import { extractDomainsFromFelixDnsmasq } from './lib/parse-dnsmasq';
import { RulesetOutput } from './lib/create-file';
import { appendArrayInPlace } from './lib/append-array-in-place';

const PROBE_DOMAINS = ['.microsoft.com', '.windows.net', '.windows.com', '.windowsupdate.com', '.windowssearch.com', '.office.net'];

const DOMAINS = [
  'res.cdn.office.net',
  'res-1.cdn.office.net',
  'statics.teams.cdn.office.net'
];
const DOMAIN_SUFFIXES = ['download.prss.microsoft.com'];

const BLACKLIST = [
  'www.microsoft.com',
  'windowsupdate.com'
];

export const getMicrosoftCdnRulesetPromise = createMemoizedPromise<[domains: string[], domainSuffixes: string[]]>(async () => {
  // First trie is to find the microsoft domains that matches probe domains
  const trie = new HostnameSmolTrie();

  for await (const line of await fetchRemoteTextByLine('https://raw.githubusercontent.com/felixonmars/dnsmasq-china-list/master/accelerated-domains.china.conf')) {
    const domain = extractDomainsFromFelixDnsmasq(line);
    if (domain) {
      trie.add(domain);
    }
  }

  // remove blacklist domain from trie, to prevent them from being included in the later dump
  BLACKLIST.forEach(black => trie.whitelist(black));

  const domains: string[] = DOMAINS;
  const domainSuffixes = appendArrayInPlace(PROBE_DOMAINS.flatMap(domain => trie.find(domain)), DOMAIN_SUFFIXES);

  return [domains, domainSuffixes] as const;
});

export const buildMicrosoftCdn = task(require.main === module, __filename)(async (span) => {
  const description = [
    ...SHARED_DESCRIPTION,
    '',
    'This file contains Microsoft\'s domains using their China mainland CDN servers.',
    '',
    'Data from:',
    ' - https://github.com/felixonmars/dnsmasq-china-list'
  ];

  const [domains, domainSuffixes] = await span.traceChildPromise('get microsoft cdn domains', getMicrosoftCdnRulesetPromise());

  return new RulesetOutput(span, 'microsoft_cdn', 'non_ip')
    .withTitle('Sukka\'s Ruleset - Microsoft CDN')
    .withDescription(description)
    .bulkAddDomain(domains)
    .bulkAddDomainSuffix(domainSuffixes)
    .write();
});