from cryptography import x509
from cryptography.x509.oid import NameOID
from cryptography.hazmat.primitives import hashes, serialization
from cryptography.hazmat.primitives.asymmetric import rsa
from cryptography.hazmat.backends import default_backend
import datetime


class GenerateCert:
    def __init__(self, cert_file='cqa-test-cert.pem', key_file='cqa-test-key.pem'):
        self.cert_file = cert_file
        self.key_file = key_file

    def create_self_signed_cert(self):
        try:
            # Generate RSA key
            key = rsa.generate_private_key(
                public_exponent=65537,
                key_size=2048,
                backend=default_backend()
            )
            # Generate test cert for cqa-test-app
            subject = x509.Name([
                x509.NameAttribute(NameOID.COMMON_NAME, u"localhost"),
            ])
            cert = x509.CertificateBuilder().subject_name(
                subject
            ).issuer_name(
                subject
            ).public_key(
                key.public_key()
            ).serial_number(
                x509.random_serial_number()
            ).not_valid_before(
                datetime.datetime.utcnow()
            ).not_valid_after(
                datetime.datetime.utcnow() + datetime.timedelta(days=36500)
            ).sign(key, hashes.SHA256(), default_backend())

            # Make cert and key files for cqa-test-app
            with open(self.cert_file, "wb") as f:
                f.write(cert.public_bytes(serialization.Encoding.PEM))
            with open(self.key_file, "wb") as f:
                f.write(key.private_bytes(
                    encoding=serialization.Encoding.PEM,
                    format=serialization.PrivateFormat.TraditionalOpenSSL,
                    encryption_algorithm=serialization.NoEncryption()
                ))
        except Exception as e:
            raise RuntimeError(f"Failed to generate test cert for cqa-test-app: {e}")
        return self.cert_file, self.key_file