package geo

// LanguageForIP returns an ISO 639-1 language code derived from
// sourceIP. The function looks up the country via LookupCountry and then
// consults the static country->language table. Returns "" when the
// country lookup fails or no language mapping exists for the country.
//
// Auth uses LanguageForIP as a fallback after the client-supplied locale
// (request body or Accept-Language header). The empty string signals
// "fall through to the platform default 'en'".
func (s *Service) LanguageForIP(sourceIP string) string {
	country := s.LookupCountry(sourceIP)
	return languageForCountry(country)
}