#!/usr/bin/env python3

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

parser = argparse.ArgumentParser("spreadspace ansible CA-generator")
parser.add_argument("-n", "--variable-name", dest='varname', help="ansible variable name to be used", type=str, required=True)
parser.add_argument("-CN", "--common-name", dest='CN', help="Common Name field of the CA's subject", type=str, required=True)
parser.add_argument("-O", "--organization-name", dest='O', help="Organization Name field of the CA's subject", type=str)
parser.add_argument("-OU", "--organizational-unit", dest='OU', help="Organizational Unit field of the CA's subject", type=str)
parser.add_argument("-C", "--country-name", dest='C', help="Country Name field of the CA's subject", type=str)
parser.add_argument("-ST", "--state-or-provice", dest='ST', help="State-or-Province field of the CA's subject", type=str)
parser.add_argument("-L", "--locality", dest='L', help="Locality Name field of the CA's subject", type=str)
args = parser.parse_args()

subject_fields = []
if args.CN:
    subject_fields.append(x509.NameAttribute(NameOID.COMMON_NAME, args.CN))
if args.O:
    subject_fields.append(x509.NameAttribute(NameOID.ORGANIZATION_NAME, args.O))
if args.OU:
    subject_fields.append(x509.NameAttribute(NameOID.ORGANIZATIONAL_UNIT_NAME, args.OU))
if args.C:
    subject_fields.append(x509.NameAttribute(NameOID.COUNTRY_NAME, args.C))
if args.ST:
    subject_fields.append(x509.NameAttribute(NameOID.STATE_OR_PROVINCE_NAME, args.ST))
if args.L:
    subject_fields.append(x509.NameAttribute(NameOID.LOCALITY_NAME, args.L))

subject = issuer = x509.Name(subject_fields)
private_key = rsa.generate_private_key(
    public_exponent=65537,
    key_size=4096,
)
public_key = private_key.public_key()

builder = x509.CertificateBuilder()
builder = builder.subject_name(subject)
builder = builder.issuer_name(issuer)
builder = builder.not_valid_before(datetime.datetime.today() - datetime.timedelta(days=1))
builder = builder.not_valid_after(datetime.datetime.today() + datetime.timedelta(weeks=2080))  # about 20years
builder = builder.serial_number(x509.random_serial_number())
builder = builder.public_key(public_key)
builder = builder.add_extension(x509.BasicConstraints(ca=True, path_length=1), critical=True)
certificate = builder.sign(private_key=private_key, algorithm=hashes.SHA256())


private_key_pem = private_key.private_bytes(encoding=serialization.Encoding.PEM,
                                            format=serialization.PrivateFormat.TraditionalOpenSSL, encryption_algorithm=serialization.NoEncryption())
certificate_pem = certificate.public_bytes(serialization.Encoding.PEM)


print("## Add this to vault file")
print("")
print("vault_%s_key: |" % (args.varname))
for line in private_key_pem.splitlines():
    print("  {}".format(line.decode('utf-8')))

print("")
print("")
print("")
print("")
print("## Add this to vars file")
print("")
print("%s_key: \"{{ vault_%s_key }}\"" % (args.varname, args.varname))
print("%s_cert: |" % (args.varname))
for line in certificate_pem.splitlines():
    print("  {}".format(line.decode('utf-8')))