// //////////////////////////////////////////////////////////////////////////////
//
// Locale verification script
//
// usage:
//
//     node app/scripts/verify-locale-strings.js [<locale>] [--fix] [--quiet]
//
// This script will validate that locales have no unused messages. It will check
// the English locale against string literals found under `ui/`, and it will check
// other locales by comparing them to the English locale. It will also validate
// that non-English locales have all descriptions present in the English locale.
//
// A report will be printed to the console detailing any unused messages.
//
// The if the optional '--fix' argument is given, locales will be automatically
// updated to remove any unused messages.
//
// The optional '--quiet' argument reduces the verbosity of the output, printing
// just a single summary of results for each locale verified
//
// //////////////////////////////////////////////////////////////////////////////

const fs = require('fs');
const path = require('path');
const { promisify } = require('util');
const log = require('loglevel');
const matchAll = require('string.prototype.matchall').getPolyfill();
const localeIndex = require('../app/_locales/index.json');
const {
  compareLocalesForMissingDescriptions,
  compareLocalesForMissingItems,
  getLocale,
  getLocalePath,
} = require('./lib/locales');

const readdir = promisify(fs.readdir);
const readFile = promisify(fs.readFile);
const writeFile = promisify(fs.writeFile);

log.setDefaultLevel('info');

let fix = false;
let specifiedLocale;
for (const arg of process.argv.slice(2)) {
  if (arg === '--fix') {
    fix = true;
  } else if (arg === '--quiet') {
    log.setLevel('error');
  } else {
    specifiedLocale = arg;
  }
}

main().catch((error) => {
  log.error(error);
  process.exit(1);
});

async function main() {
  if (specifiedLocale) {
    log.info(`Verifying selected locale "${specifiedLocale}":\n`);
    const localeEntry = localeIndex.find(
      (localeMeta) => localeMeta.code === specifiedLocale,
    );
    if (!localeEntry) {
      throw new Error(`No localize entry found for ${specifiedLocale}`);
    }

    const failed =
      specifiedLocale === 'en'
        ? await verifyEnglishLocale()
        : await verifyLocale(specifiedLocale);
    if (failed) {
      process.exit(1);
    } else {
      console.log('No invalid entries!');
    }
  } else {
    log.info('Verifying all locales:\n');
    let failed = await verifyEnglishLocale(fix);
    const localeCodes = localeIndex
      .filter((localeMeta) => localeMeta.code !== 'en')
      .map((localeMeta) => localeMeta.code);

    for (const code of localeCodes) {
      const localeFailed = await verifyLocale(code, fix);
      failed = failed || localeFailed;
    }

    if (failed) {
      process.exit(1);
    } else {
      console.log('No invalid entries!');
    }
  }
}

async function writeLocale(code, locale) {
  try {
    const localeFilePath = getLocalePath(code);
    return writeFile(
      localeFilePath,
      `${JSON.stringify(locale, null, 2)}\n`,
      'utf8',
    );
  } catch (e) {
    if (e.code === 'ENOENT') {
      log.error('Locale file not found');
    } else {
      log.error(`Error writing your locale ("${code}") file: `, e);
    }
    process.exit(1);
  }
}

async function verifyLocale(code) {
  const englishLocale = await getLocale('en');
  const targetLocale = await getLocale(code);

  const extraItems = compareLocalesForMissingItems({
    base: targetLocale,
    subject: englishLocale,
  });

  if (extraItems.length) {
    console.log(`**${code}**: ${extraItems.length} unused messages`);
    log.info('Extra items that should not be localized:');
    extraItems.forEach(function (key) {
      log.info(`  - [ ] ${key}`);
    });
  }

  const missingDescriptions = compareLocalesForMissingDescriptions({
    englishLocale,
    targetLocale,
  });

  if (missingDescriptions.length) {
    console.log(
      `**${code}**: ${missingDescriptions.length} missing descriptions`,
    );
    log.info('Messages with missing descriptions:');
    missingDescriptions.forEach(function (key) {
      log.info(`  - [ ] ${key}`);
    });
  }

  if (extraItems.length > 0 || missingDescriptions.length > 0) {
    if (fix) {
      const newLocale = { ...targetLocale };
      for (const item of extraItems) {
        delete newLocale[item];
      }
      for (const message of Object.keys(englishLocale)) {
        if (englishLocale[message].description && targetLocale[message]) {
          targetLocale[message].description =
            englishLocale[message].description;
        }
      }
      await writeLocale(code, newLocale);
    }
    return true;
  }

  return false;
}

async function verifyEnglishLocale() {
  const englishLocale = await getLocale('en');
  const uiJSFiles = await findJavascriptFiles(
    path.resolve(__dirname, '..', 'ui'),
  );
  const sharedJSFiles = await findJavascriptFiles(
    path.resolve(__dirname, '..', 'shared'),
  );

  const javascriptFiles = sharedJSFiles.concat(uiJSFiles);

  // match "t(`...`)" because constructing message keys from template strings
  // prevents this script from finding the messages, and then inappropriately
  // deletes them
  const templateStringRegex = /\bt\(`.*`\)/gu;
  const templateUsage = [];

  // match the keys from the locale file
  const keyRegex = /'(\w+)'|"(\w+)"/gu;
  const usedMessages = new Set();
  for await (const fileContents of getFileContents(javascriptFiles)) {
    for (const match of matchAll.call(fileContents, keyRegex)) {
      usedMessages.add(match[1] || match[2]);
    }

    const templateMatches = fileContents.match(templateStringRegex);
    if (templateMatches) {
      // concat doesn't work here for some reason
      templateMatches.forEach((match) => templateUsage.push(match));
    }
  }

  // never consider these messages as unused
  const messageExceptions = ['appName', 'appDescription'];

  const englishMessages = Object.keys(englishLocale);
  const unusedMessages = englishMessages.filter(
    (message) =>
      !messageExceptions.includes(message) && !usedMessages.has(message),
  );

  if (unusedMessages.length) {
    console.log(`**en**: ${unusedMessages.length} unused messages`);
    log.info(`Messages not present in UI:`);
    unusedMessages.forEach(function (key) {
      log.info(`  - [ ] ${key}`);
    });
  }

  if (templateUsage.length) {
    log.info(`Forbidden use of template strings in 't' function:`);
    templateUsage.forEach(function (occurrence) {
      log.info(` - ${occurrence}`);
    });
  }

  if (!unusedMessages.length && !templateUsage.length) {
    return false; // failed === false
  }

  if (unusedMessages.length > 0 && fix) {
    const newLocale = { ...englishLocale };
    for (const key of unusedMessages) {
      delete newLocale[key];
    }
    await writeLocale('en', newLocale);
  }

  return true; // failed === true
}

async function findJavascriptFiles(rootDir) {
  const javascriptFiles = [];
  const contents = await readdir(rootDir, { withFileTypes: true });
  for (const file of contents) {
    if (file.isDirectory()) {
      javascriptFiles.push(
        ...(await findJavascriptFiles(path.join(rootDir, file.name))),
      );
    } else if (file.isFile() && file.name.endsWith('.js')) {
      javascriptFiles.push(path.join(rootDir, file.name));
    }
  }
  return javascriptFiles;
}

async function* getFileContents(filenames) {
  for (const filename of filenames) {
    yield readFile(filename, 'utf8');
  }
}