import { Dict, Scope, TranslateOptions } from "../typing";
import { I18n } from "../I18n";
import { isSet } from "./isSet";

/**
 * Generate a list of translation options for default fallback.
 * `defaultValue` is also deleted from options as it is returned as part of
 * the translationOptions array.
 *
 * @private
 *
 * @param {I18n} i18n The I18n instance.
 *
 * @param {string|array} scope The translation scope.
 *
 * @param {object} options The translation options.
 *
 * @returns {array} Translation options
 */
export function createTranslationOptions(
  i18n: I18n,
  scope: Scope,
  options: Dict,
): TranslateOptions[] {
  let translationOptions: Dict[] = [{ scope }];

  // Defaults should be an array of hashes containing either
  // fallback scopes or messages
  if (isSet(options.defaults)) {
    translationOptions = translationOptions.concat(options.defaults);
  }

  // Maintain support for defaultValue. Since it is always a message
  // insert it in to the translation options as such.
  if (isSet(options.defaultValue)) {
    const message =
      typeof options.defaultValue === "function"
        ? options.defaultValue(i18n, scope, options)
        : options.defaultValue;

    translationOptions.push({ message });
    delete options.defaultValue;
  }

  return translationOptions as unknown as TranslateOptions[];
}