#!/usr/bin/env python3
#
# Copyright (C) 2021 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/>.

# T3795: merge "system name-servers-dhcp" into "system name-server"

import os

from sys import argv
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()

base = ['system', 'name-servers-dhcp']
config = ConfigTree(config_file)
if not config.exists(base):
    # Nothing to do
    exit(0)

for interface in config.return_values(base):
    config.set(['system', 'name-server'], value=interface, replace=False)

config.delete(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)