# Copyright 2022-2024 VyOS maintainers and contributors <maintainers@vyos.io>
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this library.  If not, see <http://www.gnu.org/licenses/>.

from vyos.configtree import ConfigTree

base = ['system', 'ipv6']

def migrate(config: ConfigTree) -> None:
    if not config.exists(base):
        # Nothing to do
        return

    # T4346: drop support to disbale IPv6 address family within the OS Kernel
    if config.exists(base + ['disable']):
        config.delete(base + ['disable'])
        # IPv6 address family disable was the only CLI option set - we can cleanup
        # the entire tree
        if len(config.list_nodes(base)) == 0:
            config.delete(base)