//REF: https://github.com/home-assistant/frontend/blob/dev/src/common/translations/localize.ts

import IntlMessageFormat from "intl-messageformat";
import { Resources } from "../types";

export type LocalizeFunc = (key: string, ...args: any[]) => string;

interface FormatType {
  [format: string]: any;
}
export interface FormatsType {
  number: FormatType;
  date: FormatType;
  time: FormatType;
}

// !!! Polyfills do not have to be handles since they get handled by the homeassistant frontend already !!!
// Ref -> https://discord.com/channels/330944238910963714/351047592588869643/898945966953078804

/**
 * Adapted from Polymer app-localize-behavior.
 *
 * Copyright (c) 2016 The Polymer Project Authors. All rights reserved.
 * This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
 * The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
 * The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
 * Code distributed by Google as part of the polymer project is also
 * subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */

export const computeLocalize = async (
  cache: any,
  language: string,
  resources: Resources,
  formats?: FormatsType
): Promise<LocalizeFunc> => {
  // Everytime any of the parameters change, invalidate the strings cache.
  cache._localizationCache = {};

  return (key, ...args) => {
    if (!key || !resources || !language || !resources[language]) {
      return "";
    }

    // Cache the key/value pairs for the same language, so that we don't
    // do extra work if we're just reusing strings across an application.
    const translatedValue = resources[language][key];

    if (!translatedValue) {
      return "";
    }

    const messageKey = key + translatedValue;
    let translatedMessage = cache._localizationCache[messageKey] as
      | IntlMessageFormat
      | undefined;

    if (!translatedMessage) {
      try {
        translatedMessage = new IntlMessageFormat(
          translatedValue,
          language,
          formats
        );
      } catch (err: any) {
        return "Translation error: " + err.message;
      }
      cache._localizationCache[messageKey] = translatedMessage;
    }

    let argObject = {};
    if (args.length === 1 && typeof args[0] === "object") {
      argObject = args[0];
    } else {
      for (let i = 0; i < args.length; i += 2) {
        argObject[args[i]] = args[i + 1];
      }
    }

    try {
      return translatedMessage.format<string>(argObject) as string;
    } catch (err: any) {
      return "Translation " + err;
    }
  };
};