from .. import Provider as CompanyProvider


class Provider(CompanyProvider):
    formats = (
        "{{last_name}} {{company_suffix}}",
        "{{last_name}} {{last_name}} {{company_suffix}}",
        "{{last_name}} {{last_name}} {{company_suffix}}",
        "{{last_name}}",
    )

    company_suffixes = (
        "As Oy",
        "Tmi",
        "Oy",
        "Oyj",
        "Ky",
        "Osk",
        "ry",
    )

    def company_business_id(self) -> str:
        """
        Returns Finnish company Business Identity Code (y-tunnus).
        Format is 8 digits - e.g. FI99999999,[8] last digit is a check
        digit utilizing MOD 11-2. The first digit is zero for some old
        organizations. This function provides current codes starting with
        non-zero.
        """

        def calculate_checksum(number: str) -> str:
            """Calculate the checksum using mod 11,2 method"""
            factors = [7, 9, 10, 5, 8, 4, 2]
            sum_ = 0
            for x, y in zip(number, factors):
                sum_ = sum_ + int(x) * y
            if sum_ % 11 == 1:
                raise ValueError("Checksum 1 is invalid")
            if sum_ % 11 == 0:
                return "0"
            else:
                return str(11 - sum_ % 11)

        while True:
            first_digit = str(self.random_digit_not_null())
            body = first_digit + self.bothify("######")
            try:
                cs = calculate_checksum(body)
            except ValueError:
                continue
            return body + "-" + str(cs)

    def company_vat(self) -> str:
        """
        Returns Finnish VAT identification number (Arvonlisaveronumero).
        This can be calculated from company business identity code by
        adding prefix "FI" and removing dash before checksum.
        """

        def convert_to_vat(business_id: str) -> str:
            """
            Convert business id to VATIN
            """
            return "FI" + business_id.replace("-", "")

        return convert_to_vat(self.company_business_id())