#!/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/>.

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

if __name__ == '__main__':
    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 = ['interfaces', 'tunnel']

    if not config.exists(base):
        # Nothing to do
        exit(0)

    #
    # Migrate "interface tunnel <tunX> encapsulation gre-bridge" to gretap
    for interface in config.list_nodes(base):
        path = base + [interface, 'encapsulation']
        if config.exists(path):
            tmp = config.return_value(path)
            if tmp == 'gre-bridge':
                config.set(path, value='gretap')

    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)