const { promises: fsPromises } = require('fs');
const fse = require('fs-extra');
const { resolve: pathResolve } = require('path');
const Piscina = require('piscina');
const { processHosts, processFilterRules, preprocessFullDomainSetBeforeUsedAsWorkerData } = require('./lib/parse-filter');
const cpuCount = require('os').cpus().length;
const { isCI } = require('ci-info');
const threads = isCI ? cpuCount : cpuCount / 2;

const { HOSTS, ADGUARD_FILTERS, PREDEFINED_WHITELIST } = require('./lib/reject-data-source');
const { withBanner } = require('./lib/with-banner');

const filterRuleWhitelistDomainSets = new Set(PREDEFINED_WHITELIST);

(async () => {
  console.time('Total Time - build-reject-domain-set');

  /** @type Set<string> */
  const domainSets = new Set();

  console.log('Downloading hosts file...');
  console.time('* Download and process Hosts');

  // Parse from remote hosts & domain lists
  (await Promise.all(
    HOSTS.map(entry => processHosts(entry[0], entry[1]))
  )).forEach(hosts => {
    hosts.forEach(host => {
      if (host) {
        domainSets.add(host);
      }
    });
  });

  console.timeEnd('* Download and process Hosts');

  let previousSize = domainSets.size;
  console.log(`Import ${previousSize} rules from hosts files!`);

  // Parse from AdGuard Filters
  console.time('* Download and process AdBlock Filter Rules');
  await Promise.all(ADGUARD_FILTERS.map(input => {
    const promise = Array.isArray(input) && input.length === 2
      ? processFilterRules(input[0], input[1])
      : processFilterRules(input);

    return promise.then((i) => {
      if (i) {
        const { white, black, foundDebugDomain } = i;
        if (foundDebugDomain) {
          process.exit(1);
        };
        white.forEach(i => filterRuleWhitelistDomainSets.add(i));
        black.forEach(i => domainSets.add(i));
      } else {
        process.exit(1);
      }
    });
  }));

  console.timeEnd('* Download and process AdBlock Filter Rules');

  previousSize = domainSets.size - previousSize;
  console.log(`Import ${previousSize} rules from adguard filters!`);

  await fsPromises.readFile(pathResolve(__dirname, '../Source/domainset/reject_sukka.conf'), { encoding: 'utf-8' }).then(data => {
    data.split('\n').forEach(line => {
      const trimmed = line.trim();
      if (
        line.startsWith('#')
        || line.startsWith(' ')
        || line.startsWith('\r')
        || line.startsWith('\n')
        || trimmed === ''
      ) {
        return;
      }

      domainSets.add(trimmed);
    });
  });

  // Copy reject_sukka.conf for backward compatibility
  await fse.copy(pathResolve(__dirname, '../Source/domainset/reject_sukka.conf'), pathResolve(__dirname, '../List/domainset/reject_sukka.conf'))

  previousSize = domainSets.size - previousSize;
  console.log(`Import ${previousSize} rules from reject_sukka.conf!`);

  // Read DOMAIN Keyword
  const domainKeywordsSet = new Set();
  const domainSuffixSet = new Set();

  await fsPromises.readFile(pathResolve(__dirname, '../List/non_ip/reject.conf'), { encoding: 'utf-8' }).then(data => {
    data.split('\n').forEach(line => {
      if (line.startsWith('DOMAIN-KEYWORD')) {
        const [, ...keywords] = line.split(',');
        domainKeywordsSet.add(keywords.join(',').trim());
      } else if (line.startsWith('DOMAIN-SUFFIX')) {
        const [, ...keywords] = line.split(',');
        domainSuffixSet.add(keywords.join(',').trim());
      }
    });
  });

  // Read Special Phishing Suffix list
  await fsPromises.readFile(pathResolve(__dirname, '../List/domainset/reject_phishing.conf'), { encoding: 'utf-8' }).then(data => {
    data.split('\n').forEach(line => {
      const trimmed = line.trim();
      if (
        line.startsWith('#')
        || line.startsWith(' ')
        || line.startsWith('\r')
        || line.startsWith('\n')
        || trimmed === ''
      ) {
        return;
      }

      domainSuffixSet.add(trimmed);
    });
  });

  console.log(`Import ${domainKeywordsSet.size} black keywords and ${domainSuffixSet.size} black suffixes!`);

  previousSize = domainSets.size;
  // Dedupe domainSets
  console.log(`Start deduping from black keywords/suffixes! (${previousSize})`);
  console.time(`* Dedupe from black keywords/suffixes`);

  for (const domain of domainSets) {
    let isTobeRemoved = false;

    for (const suffix of domainSuffixSet) {
      if (domain.endsWith(suffix)) {
        isTobeRemoved = true;
        break;
      }
    }

    if (!isTobeRemoved) {
      for (const keyword of domainKeywordsSet) {
        if (domain.includes(keyword)) {
          isTobeRemoved = true;
          break;
        }
      }
    }

    if (!isTobeRemoved) {
      if (isInWhiteList(domain)) {
        isTobeRemoved = true;
      }
    }

    if (isTobeRemoved) {
      domainSets.delete(domain);
    }
  }

  console.timeEnd(`* Dedupe from black keywords/suffixes`);
  console.log(`Deduped ${previousSize} - ${domainSets.size} = ${previousSize - domainSets.size} from black keywords and suffixes!`);

  previousSize = domainSets.size;
  // Dedupe domainSets
  console.log(`Start deduping! (${previousSize})`);

  const START_TIME = Date.now();

  const piscina = new Piscina({
    filename: pathResolve(__dirname, 'worker/build-reject-domainset-worker.js'),
    workerData: preprocessFullDomainSetBeforeUsedAsWorkerData([...domainSets]),
    idleTimeout: 50,
    minThreads: threads,
    maxThreads: threads
  });

  console.log(`Launching ${threads} threads...`)

  const tasksArray = Array.from(domainSets)
    .reduce((result, element, index) => {
      const chunk = index % threads;
      result[chunk] ??= [];

      result[chunk].push(element);
      return result;
    }, []);

  (
    await Promise.all(
      Array.from(domainSets)
        .reduce((result, element, index) => {
          const chunk = index % threads;
          result[chunk] ??= [];
          result[chunk].push(element);
          return result;
        }, [])
        .map(chunk => piscina.run({ chunk }, { name: 'dedupe' }))
    )
  ).forEach((result, taskIndex) => {
    const chunk = tasksArray[taskIndex];
    for (let i = 0, len = result.length; i < len; i++) {
      if (result[i]) {
        domainSets.delete(chunk[i]);
      }
    }
  });

  console.log(`* Dedupe from covered subdomain - ${(Date.now() - START_TIME) / 1000}s`);
  console.log(`Deduped ${previousSize - domainSets.size} rules!`);

  console.time('* Write reject.conf');
  await Promise.all([
    fsPromises.writeFile(
      pathResolve(__dirname, '../List/domainset/reject.conf'),
      withBanner(
        'Reject Domain Set for Surge',
        [
          '(AdBlock, Tracking Protection, Privacy Protection, Anti-Phishing, Anti-Mining)',
          'Build from:',
          ...HOSTS.map(host => `- ${host[0]}`),
          ...ADGUARD_FILTERS.map(filter => `- ${Array.isArray(filter) ? filter[0] : filter}`),
        ],
        new Date(),
        [...domainSets].sort()
      ),
      { encoding: 'utf-8' }
    ),
    piscina.destroy()
  ]);
  console.timeEnd('* Write reject.conf');

  console.timeEnd('Total Time - build-reject-domain-set');
  if (piscina.queueSize === 0) {
    process.exit(0);
  }
})();

function isInWhiteList (domain) {
  for (const white of filterRuleWhitelistDomainSets) {
    if (domain === white || domain.endsWith(white)) {
      return true;
    }
  }

  return false;
}