# -*- coding: utf8 -*-
"""
Manage X.509 certificate life cycle
===================================

This state is useful for managing X.509 certificates' life cycles.

Copyright (c) 2014-2020 Jan Dittberner <jan@dittberner.info>
"""

from cryptography import x509
from cryptography.hazmat.backends import default_backend
from datetime import datetime
import os


def _error(ret, err_msg):
    ret["result"] = False
    ret["comment"] = err_msg
    return ret


def valid_certificate(
    name, mindays=14, keyfile=None, checkchain=False, trustedcerts=None
):
    """
    Checks whether the given certificate file is valid.

    name
        The name of the certificate file to check
    mindays
        Mark the certificate as invalid if it is valid for less then this many
        days
    """
    ret = {"name": name, "changes": {}, "result": None, "comment": ""}
    if not os.path.isfile(name):
        return _error(ret, "certificate file {0} does not exist".format(name))
    with open(name, "rb") as pemfile:
        try:
            cert = x509.load_pem_x509_certificate(pemfile.read(), default_backend())
        except Exception as e:
            return _error(ret, "error loading certificate {0}: {1}".format(name, e))
    notafter = cert.not_valid_after
    delta = notafter - datetime.utcnow()
    if delta.days < mindays:
        return _error(
            ret,
            "certificate {0} is only valid for {1} more day(s)".format(
                name, delta.days
            ),
        )
    # TODO: check keyfile match
    # TODO: check trust chain
    ret["comment"] = "certificate {0} is ok and still valid for {1} days".format(
        name, delta.days
    )
    ret["result"] = True
    return ret