#!/usr/bin/python3

"""
You can redistribute it and/or modify it under the terms of the GNU General
Public License as published by the Free Software Foundation, either version 2
of the License.
Copyright Andrea Briganti a.k.a 'Kbyte'
"""
import io
import subprocess
import argparse

import nagiosplugin


class SystemdStatus(nagiosplugin.Resource):
    name = 'SYSTEMD'

    def probe(self):
        # Execute systemctl --failed --no-legend and get output
        try:
            p = subprocess.Popen(['systemctl', '--failed', '--no-legend'],
                                 stderr=subprocess.PIPE,
                                 stdin=subprocess.PIPE,
                                 stdout=subprocess.PIPE,
                                 universal_newlines=True)

            stdout, err = p.communicate()
        except OSError as e:
            raise nagiosplugin.CheckError(e)

        if err:
            raise nagiosplugin.CheckError(err)

        if stdout:
            lines = list(filter(lambda x: "service" in x, stdout.split("\n")))
            result = ""
            for line in lines:
                result += "{}".format(line.split(' ')[1])

            return [nagiosplugin.Metric('systemd', (False, result), context='systemd')]

        return [nagiosplugin.Metric('systemd', (True, None), context='systemd')]


class ServiceStatus(nagiosplugin.Resource):
    name = 'SYSTEMD'

    def __init__(self, *args, **kwargs):
        self.service = kwargs.pop('service')
        super(nagiosplugin.Resource, self).__init__(*args, **kwargs)

    def probe(self):
        # Execute systemctl is-active and get output
        try:
            p = subprocess.Popen(['systemctl', 'is-active', self.service],
                                 stderr=subprocess.PIPE,
                                 stdin=subprocess.PIPE,
                                 stdout=subprocess.PIPE)
            pres, err = p.communicate()
        except OSError as e:
            raise nagiosplugin.CheckError(e)

        if err:
            raise nagiosplugin.CheckError(err)
        if pres:
            result = ""
            for line in io.StringIO(pres.decode('utf-8')):
                result = "%s %s" % (result, line.split(' ')[0])
            result = result.strip()
            if result == "active":
                return [nagiosplugin.Metric('systemd', (True, None), context='systemd')]
            else:
                return [nagiosplugin.Metric('systemd', (False, self.service), context='systemd')]

        return [nagiosplugin.Metric('systemd', (False, "No Service given"), context='systemd')]


class SystemdContext(nagiosplugin.Context):
    def __init__(self):
        super(SystemdContext, self).__init__('systemd')

    def evaluate(self, metric, resource):
        value, output = metric.value
        if value:
            return self.result_cls(nagiosplugin.Ok, metric=metric)
        else:
            return self.result_cls(nagiosplugin.Critical, metric=metric, hint='failed units: %s' % output)


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("-s", "--service", type=str, dest="service", help="Name of the Service that is beeing tested")

    args = parser.parse_args()

    if args.service is None:
        check = nagiosplugin.Check(
            SystemdStatus(),
            SystemdContext())
    else:
        check = nagiosplugin.Check(
            ServiceStatus(service=args.service),
            SystemdContext())
    check.main()


if __name__ == '__main__':
    main()