timezone

timezone.ts

import { CityData, cityMapping } from 'city-timezones';
import { Country, getTimezone, getCountry as getCountryByCode } from 'countries-and-timezones';

/**
 * Retrieves the country associated with a given timezone.
 * @param timezone - The IANA timezone string (e.g., 'Europe/Paris').
 * @returns The country object or null if not found.
 */
function getCountryByTimezone(timezone: string): Country | null {
  const timezoneData = getTimezone(timezone);
  if (timezoneData && timezoneData.countries.length > 0) {
    const countryCode = timezoneData.countries[0]; // Assuming the first country is the primary one
    const country = getCountryByCode(countryCode);
    return country ? country : null;
  }
  return null;
}

/**
 * Retrieves cities associated with a given timezone.
 * @param {string} timezone - The IANA timezone string (e.g., 'Europe/Paris').
 * @returns {Array} An array of city objects associated with the timezone.
 */
function getCitiesByTimezone(timezone: string): CityData[] {
  return cityMapping.filter(city => city.timezone === timezone);
}

function getCountry(timezone: string): string | null {
  const country = getCountryByTimezone(timezone);
  return country ? country.name : null;
}

function getCity(timezone: string): string | null {
  const cities = getCitiesByTimezone(timezone);
  if (!cities || cities.length === 0) {
    return null;
  }

  const cityLikeTimezone = cities.find(city => timezone.toLowerCase().includes(city.city.toLowerCase()));
  if (cityLikeTimezone) {
    return cityLikeTimezone.city;
  }

  return cities[0].city;
}

export { getCountry, getCity };