/*
 * MIT License
 *
 * Copyright (c) 2018 Choko (choko@curioswitch.org)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

import { LocaleMessages, Messages } from '../containers/LanguageProvider';

function formatTranslationMessages(
  messages: Messages,
  defaultMessages: Messages,
) {
  return Object.keys(messages).reduce((formattedMessages, key) => {
    let message = messages[key];
    if (!message) {
      message = defaultMessages[key];
    }
    return {
      ...formattedMessages,
      [key]: message,
    };
  }, {});
}

export default function init(
  defaultLocale: string,
  translations: LocaleMessages,
): LocaleMessages {
  const defaultMessages = formatTranslationMessages(
    translations[defaultLocale],
    {},
  );
  const formattedMessages = Object.keys(translations)
    .filter((locale) => locale !== defaultLocale)
    .reduce(
      (localeMessages, locale) => ({
        ...localeMessages,
        [locale]: formatTranslationMessages(
          translations[locale],
          defaultMessages,
        ),
      }),
      {},
    );
  return {
    ...formattedMessages,
    [defaultLocale]: defaultMessages,
  };
}