#!/usr/bin/env python3
#
# Copyright (C) 2022 VyOS maintainers and contributors
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import os
import json
import jmespath

from pathlib import Path
from sys import exit

from vyos.config import Config
from vyos.utils.process import call
from vyos import ConfigError
from vyos import airbag
airbag.enable()


base = ['system', 'update-check']
service_name = 'vyos-system-update'
service_conf = Path(f'/run/{service_name}.conf')
motd_file = Path('/run/motd.d/10-vyos-update')


def get_config(config=None):
    if config:
        conf = config
    else:
        conf = Config()

    if not conf.exists(base):
        return None

    config = conf.get_config_dict(base, key_mangling=('-', '_'),
                                  get_first_key=True, no_tag_node_value_mangle=True)

    return config


def verify(config):
    # bail out early - looks like removal from running config
    if config is None:
        return

    if 'url' not in config:
        raise ConfigError('URL is required!')


def generate(config):
    # bail out early - looks like removal from running config
    if config is None:
        # Remove old config and return
        service_conf.unlink(missing_ok=True)
        # MOTD used in /run/motd.d/10-update
        motd_file.unlink(missing_ok=True)
        return None

    # Write configuration file
    conf_json = json.dumps(config, indent=4)
    service_conf.write_text(conf_json)

    return None


def apply(config):
    if config:
        if 'auto_check' in config:
            call(f'systemctl restart {service_name}.service')
    else:
        call(f'systemctl stop {service_name}.service')


if __name__ == '__main__':
    try:
        c = get_config()
        verify(c)
        generate(c)
        apply(c)
    except ConfigError as e:
        print(e)
        exit(1)