// @ts-check

const path = require('path');
const { PathScurry } = require('path-scurry');
const { readFileByLine } = require('./lib/fetch-remote-text-by-line');
const { processLine } = require('./lib/process-line');
const { compareAndWriteFile } = require('./lib/string-array-compare');
const { withBannerArray } = require('./lib/with-banner');
const { domainDeduper } = require('./lib/domain-deduper');
const { surgeRulesetToClashClassicalTextRuleset, surgeDomainsetToClashDomainset } = require('./lib/clash');

const MAGIC_COMMAND_SKIP = '# $ custom_build_script';
const MAGIC_COMMAND_TITLE = '# $ meta_title ';
const MAGIC_COMMAND_DESCRIPTION = '# $ meta_description ';

const sourceDir = path.resolve(__dirname, '../Source');
const outputSurgeDir = path.resolve(__dirname, '../List');
const outputClashDir = path.resolve(__dirname, '../Clash');

(async () => {
  /** @type {Promise<void>[]} */
  const promises = [];

  const pw = new PathScurry(sourceDir);
  for await (const entry of pw) {
    if (entry.isFile()) {
      if (path.extname(entry.name) === '.js') {
        continue;
      }

      const relativePath = entry.relative();
      if (relativePath.startsWith('domainset/')) {
        promises.push(transformDomainset(entry.fullpath(), relativePath));
        continue;
      }
      if (
        relativePath.startsWith('ip/')
        || relativePath.startsWith('non_ip/')
      ) {
        promises.push(transformRuleset(entry.fullpath(), relativePath));
        continue;
      }
    }
  }

  await Promise.all(promises);
})();

/**
 * @param {string} sourcePath
 */
const processFile = async (sourcePath) => {
  /** @type {Set<string>} */
  const lines = new Set();

  let title = '';
  /** @type {string[]} */
  const descriptions = [];

  for await (const line of readFileByLine(sourcePath)) {
    if (line === MAGIC_COMMAND_SKIP) {
      return;
    }

    if (line.startsWith(MAGIC_COMMAND_TITLE)) {
      title = line.slice(MAGIC_COMMAND_TITLE.length).trim();
      continue;
    }

    if (line.startsWith(MAGIC_COMMAND_DESCRIPTION)) {
      descriptions.push(line.slice(MAGIC_COMMAND_DESCRIPTION.length).trim());
      continue;
    }

    const l = processLine(line);
    if (l) {
      lines.add(l);
    }
  }

  return /** @type {const} */ ([title, descriptions, lines]);
};

/**
 * @param {string} sourcePath
 * @param {string} relativePath
 */
async function transformDomainset(sourcePath, relativePath) {
  const res = await processFile(sourcePath);
  if (!res) return;
  const [title, descriptions, lines] = res;

  const deduped = domainDeduper(Array.from(lines));
  const description = [
    'License: AGPL 3.0',
    'Homepage: https://ruleset.skk.moe',
    'GitHub: https://github.com/SukkaW/Surge',
    ...(
      descriptions.length
        ? ['', ...descriptions]
        : []
    )
  ];

  await Promise.all([
    // Surge DOMAIN-SET
    compareAndWriteFile(
      withBannerArray(
        title,
        description,
        new Date(),
        deduped
      ),
      path.resolve(outputSurgeDir, relativePath)
    ),
    // Clash domain text
    compareAndWriteFile(
      withBannerArray(
        title,
        description,
        new Date(),
        surgeDomainsetToClashDomainset(deduped)
      ),
      // change path extname to .txt
      path.resolve(outputClashDir, `${relativePath.slice(0, -path.extname(relativePath).length)}.txt`)
    )
  ]);
}

/**
 * Output Surge RULE-SET and Clash classical text format
 *
 * @param {string} sourcePath
 * @param {string} relativePath
 */
async function transformRuleset(sourcePath, relativePath) {
  const res = await processFile(sourcePath);
  if (!res) return;
  const [title, descriptions, set] = res;

  const description = [
    'License: AGPL 3.0',
    'Homepage: https://ruleset.skk.moe',
    'GitHub: https://github.com/SukkaW/Surge',
    ...(
      descriptions.length
        ? ['', ...descriptions]
        : []
    )
  ];

  const lines = Array.from(set);

  const clashSupported = surgeRulesetToClashClassicalTextRuleset(set);

  await Promise.all([
    // Surge RULE-SET
    compareAndWriteFile(
      withBannerArray(
        title,
        description,
        new Date(),
        lines
      ),
      path.resolve(outputSurgeDir, relativePath)
    ),
    // Clash domainset
    compareAndWriteFile(
      withBannerArray(
        title,
        description,
        new Date(),
        clashSupported
      ),
      // change path extname to .txt
      path.resolve(outputClashDir, `${relativePath.slice(0, -path.extname(relativePath).length)}.txt`)
    )
  ]);
}