#!/usr/bin/env python3
#
# Copyright (C) 2020 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/>.

# - remove primary/secondary identifier from nameserver

import os
import sys

from sys import argv, exit
from vyos.configtree import ConfigTree

if (len(argv) < 1):
    print("Must specify file name!")
    exit(1)

file_name = argv[1]

with open(file_name, 'r') as f:
    config_file = f.read()

config = ConfigTree(config_file)
base = ['vpn', 'l2tp', 'remote-access']
if not config.exists(base):
    # Nothing to do
    exit(0)
else:

    # Migrate IPv4 DNS servers
    dns_base = base + ['dns-servers']
    if config.exists(dns_base):
        for server in ['server-1', 'server-2']:
          if config.exists(dns_base + [server]):
            dns = config.return_value(dns_base + [server])
            config.set(base + ['name-server'], value=dns, replace=False)

        config.delete(dns_base)

    # Migrate IPv6 DNS servers
    dns_base = base + ['dnsv6-servers']
    if config.exists(dns_base):
        for server in config.return_values(dns_base):
            config.set(base + ['name-server'], value=server, replace=False)

        config.delete(dns_base)

    try:
        with open(file_name, 'w') as f:
            f.write(config.to_string())
    except OSError as e:
        print("Failed to save the modified config: {}".format(e))
        exit(1)