from subprocess import check_output, CalledProcessError
import agent_util
import logging
import os
from os import listdir
from os.path import isfile, join
import datetime

"""
Config file example:
    [cert]
    certpath = /path/to/the/certs
"""
class CertPlugin(agent_util.Plugin):
    textkey = "cert"
    label = "Cert Expiration Date"

    @classmethod
    def get_metadata(cls, config):
        try:
            certpath = config.get('certpath')
            if not os.path.exists(certpath):
                status = agent_util.UNSUPPORTED
                msg = "Missing cert directory in configuration"
                options = []
            else:
                status = agent_util.SUPPORTED
                msg = []
                options = CertPlugin.get_certs(certpath, config)
    
        except Exception:
            status = agent_util.UNSUPPORTED
            msg = "Exception gathering cert directory"
            options = []

        metadata = { 
            "days_to_expire": {
                "label": "Certificate Expiration Status",
                "options": options,
                "status": status,
                "error_message": msg,
                "unit": "days"
                    },
                }

        return metadata

    def check(self, textkey, data, config):
        self.log.debug("Checking cert expiration {} - {}".format(textkey, data))
        day = CertPlugin._get_cert_data(config, data)
        return day

    @staticmethod
    def _get_cert_data(config, name):

        certpath = config.get('certpath')
        certs = CertPlugin.get_certs(certpath, config)
        for each in certs:
            if each != name:
                continue
            cert = certpath + "/" + each
            openssl = "openssl x509 -in " + cert + " -noout -enddate"
            try:
                ret, output = agent_util.execute_command(openssl)
                if ret != 0:
                    logging.error(output)
                    raise ValueError('Error Reading cert file')
            except ValueError:
                return False
            datestr = output.split('=')[-1]
            datespl = datestr.split('\n',1)[0]
            dateformat = datetime.datetime.strptime(datespl, '%b %d %H:%M:%S %Y %Z')
            diff = dateformat - datetime.datetime.utcnow()
            day = diff.days
            return day

    @staticmethod
    def get_certs(certpath, config):
    # Collect all the .crt files in a list

        if not os.path.isdir(certpath):
            logging.error("certpath specified on config file:" + certpath + " does not exist")
        else:
            certfiles = [f for f in listdir(certpath) if isfile(join(certpath, f)) and f.endswith('.crt')]
            logging.info("Certificates found under"+ str(certpath) + ":" + str(certfiles))
            return certfiles