Finnish VAT number spec has been changed since 1.1.2023

[makimat]

CountryValidator/CountryValidator/CountriesValidators/FinlandValidator.cs

Lines 30 to 69 in 169bf00

	public override ValidationResult ValidateIndividualTaxCode(string id)
	{
	if (!Regex.IsMatch(id, "^[0-9]{6}[-+A][0-9]{3}[0-9ABCDEFHJKLMNPRSTUVWXY]$"))
	{
	return ValidationResult.Invalid("Invalid code");
	}
	var day = int.Parse(id.Substring(0, 2));
	var month = int.Parse(id.Substring(2, 2));
	var year = int.Parse(id.Substring(4, 2));
	var centuries = new Dictionary<char, int>(){
	{ '+', 1800 },
	{ '-', 1900},
	{ 'A', 2000}
	};
	year = centuries[id[6]] + year;
	try
	{
	DateTime date = new DateTime(year, month, day);
	if (date > DateTime.Now)
	{
	return ValidationResult.InvalidDate();
	}
	}
	catch
	{
	return ValidationResult.InvalidDate();
	}
	var individual = int.Parse(id.Substring(7, 3));
	if (individual < 2)
	{
	return ValidationResult.Invalid("Invalid");
	}
	var n = id.Substring(0, 6) + id.Substring(7, 3);
	long intn = long.Parse(n);
	return "0123456789ABCDEFHJKLMNPRSTUVWXY"[(int)intn % 31] == id[10] ? ValidationResult.Success() : ValidationResult.InvalidChecksum();
	}

There are new separator characters being introduced in addition to -, + and A.

More information and test data available here: https://dvv.fi/en/reform-of-personal-identity-code