class IdCardHelper {
  static bool isNumeric(String str) {
    if (str.isEmpty) {
      return false;
    }
    return double.tryParse(str) != null;
  }

  static bool validateIDCard(String idCard) {
    // 校验身份证号码长度
    if (idCard.length != 18) {
      return false;
    }

    // 校验前17位是否为数字
    String idCard17 = idCard.substring(0, 17);
    if (!isNumeric(idCard17)) {
      return false;
    }

    // 校验最后一位校验码
    String checkCode = getCheckCode(idCard17);
    if (idCard[17].toUpperCase() != checkCode) {
      print("checkCode: $checkCode");
      return false;
    }

    return true;
  }

  static String getCheckCode(String idCard17) {
    List<int> coefficients = [
      7,
      9,
      10,
      5,
      8,
      4,
      2,
      1,
      6,
      3,
      7,
      9,
      10,
      5,
      8,
      4,
      2
    ];
    List<String> checkCodes = [
      '1',
      '0',
      'X',
      '9',
      '8',
      '7',
      '6',
      '5',
      '4',
      '3',
      '2'
    ];

    int sum = 0;
    for (int i = 0; i < idCard17.length; i++) {
      int digit = int.parse(idCard17[i]);
      sum += digit * coefficients[i];
    }

    int remainder = sum % 11;
    return checkCodes[remainder];
  }
}