#!/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/>.

# T3417: migrate BGP tagNode to node as we can only have one BGP process

from sys import argv
from sys import exit

from vyos.configtree import ConfigTree

if len(argv) < 2:
    print("Must specify file name!")
    exit(1)

file_name = argv[1]

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

base = ['protocols', 'bgp']
config = ConfigTree(config_file)

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

# Only one BGP process is supported, thus this operation is savea
asn = config.list_nodes(base)
bgp_base = base + asn

# We need a temporary copy of the config
tmp_base = ['protocols', 'bgp2']
config.copy(bgp_base, tmp_base)

# Now it's save to delete the old configuration
config.delete(base)

# Rename temporary copy to new final config and set new "local-as" option
config.rename(tmp_base, 'bgp')
config.set(base + ['local-as'], value=asn[0])

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