const fs = require('fs'),
      path = require('path'),
      dir2read = process.argv[2] || '.',
      config = JSON.parse(fs.readFileSync('_config_.json', 'utf8')),
      escRegExp = /[\^$.*+?()[]{}|]/g,
      hasEscRegExp = RegExp(escRegExp.source);

const getFiles = (dir) => fs.readdirSync(dir)
  .reduce((files, file) =>
    fs.statSync(path.join(dir, file)).isDirectory() ?
      files.concat(getFiles(path.join(dir, file))) :
      files.concat(path.join(dir, file)),
    []);

const getFilterdFile = (filePath) => {
  return filePath.endsWith('.chunk.js') || filePath.endsWith('.bundle.js');
}

const escapeString = (string) => {
  return hasEscRegExp.test(string) ? string.replace(escRegExp, '\$&') : string;
}

const cacheRegExp = (string) => {
  string = string.replace(/^(w)/, '\b$1');
  string = string.replace(/(w)$/, '$1\b');
  return new RegExp(string, 'gm');
}

const replaceInFile = (string, find, replace) => {
  for (let key in find) {
    string = string.replace(cacheRegExp(escapeString(find[key])), replace[key]);
  }
  return string;
}

try {
  const files = getFiles(dir2read);
  const filteredFiles = files.filter(file => getFilterdFile(file));
  for (const filePath of filteredFiles) {
    try {
      let data = fs.readFileSync(filePath).toString();
      let newData = replaceInFile(data, config.originalConfig, config.replacementConfig);
      if (newData !== data) {
        fs.writeFileSync(filePath, newData);
        console.log(`Matches found`);
      } else {
        console.log(`No matches found`);
      }
    } catch (e) {
      console.log(e);
    }
  }
  console.log(`Replacement complete`);
} catch (e) {
  console.log(e);
}