import { isForbiddenPropertyName } from 'botframework-webchat-core';

import LocalizedStrings from '../types/LocalizedStrings';

type LocalizedStringsMap = { [language: string]: LocalizedStrings };

export default function mergeLocalizedStrings(...args: LocalizedStringsMap[]): LocalizedStringsMap {
  const merged = {};
  const languages = args.reduce((keys, arg) => [...keys, ...Object.keys(arg)], []);

  for (const language of new Set(languages)) {
    if (!isForbiddenPropertyName(language)) {
      // Mitigation through denylisting.
      // eslint-disable-next-line security/detect-object-injection
      merged[language] = args.reduce((merged, arg) => ({ ...merged, ...arg[language] }), {});
    }
  }

  return merged;
}