import ecdsa
from hashlib import sha256, sha512


class Signer:
    def sign_rfc6979(self, private_key: bytes, message: bytes) -> bytes:
        if len(private_key) == 0 or private_key is None:
            raise ValueError(f"Incorrect private_key: {private_key}")

        sk = ecdsa.SigningKey.from_string(private_key, curve=ecdsa.NIST256p, hashfunc=sha256)

        signature = sk.sign_deterministic(message)

        return signature

    def sign(self, private_key: bytes, message: bytes) -> bytes:
        if len(private_key) == 0 or private_key is None:
            raise ValueError(f"Incorrect private key: {private_key}")

        sk = ecdsa.SigningKey.from_string(private_key, curve=ecdsa.NIST256p, hashfunc=sha512)

        signature = sk.sign(message)

        return signature