import { deepMerge } from '../../../shared/deepMerge';
import type { LanguageDetectorOptions } from '../instance';

export const DEFAULT_I18NEXT_DETECTION_OPTIONS = {
  caches: ['cookie', 'localStorage'],
  order: [
    'querystring',
    'cookie',
    'localStorage',
    'header',
    'navigator',
    'htmlTag',
    'path',
    'subdomain',
  ],
  cookieMinutes: 60 * 24 * 365,
  lookupQuerystring: 'lng',
  lookupCookie: 'i18next',
  lookupLocalStorage: 'i18nextLng',
  lookupHeader: 'accept-language',
};

export function mergeDetectionOptions(
  cliOptions?: LanguageDetectorOptions,
  userOptions?: LanguageDetectorOptions,
  defaultOptions: LanguageDetectorOptions = DEFAULT_I18NEXT_DETECTION_OPTIONS,
): LanguageDetectorOptions {
  return deepMerge(
    deepMerge(defaultOptions, cliOptions ?? {}),
    userOptions ?? {},
  );
}