// see https://howtodoinjava.com/java/regex/java-regex-validate-international-phone-numbers/
sclass InternationalPhoneValidator {
  S rawInput;
  S filtered;
  CountryDialCode dialCode;
  S countryPart, localPart;
  bool valid;
  
  *() {}
  *(S *rawInput) {}
  
  // needs rawInput
  run {
    filtered = dropSpecialChars(rawInput);
    splitLocal();
  }
  
  S dropSpecialChars(S s) {
    ret replaceAll(s, "[\\s\\(\\)\\-]", "");
  }
  
  void splitLocal {
    S countryPart = longestPrefixInTreeSet(filtered, countryDialCodes_rawNumbersTreeMultiMap());
    if (countryPart == null) ret;
    CountryDialCode dialCode = countryDialCodes_rawNumbersTreeMultiMap().get(countryPart);
    localPart = dropPrefix(countryPart, filtered);
    valid = l(filtered) >= 7 && l(filtered) <= 15;
  }
}