//@ts-check
const path = require('path');
const fs = require('fs');
const { defaultLanguage } = require('./constants');

/**
 * @param {string} file
 * @param {string[]} extensions
 *
 * @returns {boolean}
 */
function hasValidExtension(file, extensions) {
  return extensions.includes(path.extname(file).toLowerCase());
}

/**
 * @param {string} dir
 * @param {string[]} extensions
 *
 * @returns {Promise<string[]>}
 */
async function getFiles(dir, extensions) {
  const files = await fs.promises.readdir(dir);
  const allFiles = await Promise.all(
    files.map(async file => {
      const filePath = path.join(dir, file);
      const stats = await fs.promises.stat(filePath);

      if (stats.isDirectory()) {
        return getFiles(filePath, extensions);
      } else if (stats.isFile() && hasValidExtension(file, extensions)) {
        return filePath;
      }
      return null;
    })
  );

  const validFiles = /** @type {string[]} */ (allFiles.flat().filter(file => file !== null));

  return validFiles;
}

/**
 * @param {string | string[]} value
 *
 * @returns {string}
 */
function formatDefaultValue(value) {
  if (Array.isArray(value)) {
    return value.join(', ');
  }
  return value;
}

const scriptDir = getScriptDir();
/** @param {string} file
 *
 * @returns {string}
 */
function resolveFile(file) {
  if (path.isAbsolute(file)) {
    return file;
  }

  return path.resolve(scriptDir, '..', '..', file);
}

/** @param {string[]} dirs
 *
 * @returns {string[]}
 */
function resolveDirs(dirs) {
  return dirs.map(resolveFile);
}

/**
 * @param {string[]} extensions
 *
 * @returns {string[]}
 */
function resolveExtensions(extensions) {
  return extensions.map(ext => (ext.startsWith('.') ? ext : `.${ext}`));
}

function getScriptDir() {
  if (require.main?.filename) {
    return path.dirname(require.main.filename);
  }

  if ('pkg' in process && process.pkg) {
    return path.dirname(process.execPath);
  }

  return __dirname;
}

/**
 * @param {string} file
 */
function ensureFileDirExists(file) {
  const dir = path.dirname(file);

  if (!fs.existsSync(dir)) {
    fs.mkdirSync(dir, { recursive: true });
  }
}

/**
 * @param {Record<string, string>} existingTranslations - Previously extracted translations
 * @param {Record<string, string>} newTranslations - Newly extracted translations
 * @returns {{ added: string[], removed: string[], updated: string[] }} Translation changes
 */
const getTranslationChanges = (existingTranslations, newTranslations) => {
  const existingKeys = new Set(Object.keys(existingTranslations || {}));
  const newKeys = new Set(Object.keys(newTranslations));

  const added = [...newKeys].filter(key => !existingKeys.has(key));
  const removed = [...existingKeys].filter(key => !newKeys.has(key));
  const updated = [...newKeys].filter(
    key => existingKeys.has(key) && existingTranslations[key] !== newTranslations[key]
  );

  return { added, removed, updated };
};

function getDefaultTranslations() {
  return getLanguageTranslations(defaultLanguage);
}

/**
 * @param {string} language
 *
 * @returns {Record<string, string>}
 */
function getLanguageTranslations(language) {
  const file = resolveFile(`translations/${language}.json`);
  const content = fs.readFileSync(file, 'utf-8');

  return JSON.parse(content);
}

/**
 * @param {string} language
 * @param {Record<string, string>} translations
 */
function setLanguageTranslations(language, translations) {
  const file = resolveFile(`translations/${language}.json`);
  fs.writeFileSync(file, JSON.stringify(translations, null, 2));
}

/**
 * @param {string} language
 * @param {Record<string, string>} newTranslations
 */
function updateLanguageTranslations(language, newTranslations) {
  const translations = getLanguageTranslations(language);
  const updatedTranslations = { ...translations, ...newTranslations };

  setLanguageTranslations(language, updatedTranslations);
}

function getAllLanguages() {
  const dir = resolveFile('translations');

  const files = fs.readdirSync(dir);
  const languages = files.filter(file => file.endsWith('.json')).map(file => file.replace('.json', ''));

  return languages;
}

function getAllNonDefaultLanguages() {
  return getAllLanguages().filter(language => language !== defaultLanguage);
}

module.exports = {
  hasValidExtension,
  getFiles,
  formatDefaultValue,
  resolveFile,
  resolveDirs,
  resolveExtensions,
  ensureFileDirExists,
  getTranslationChanges,
  getDefaultTranslations,
  getLanguageTranslations,
  setLanguageTranslations,
  updateLanguageTranslations,
  getAllLanguages,
  getAllNonDefaultLanguages,
};