# Copyright 2020-2024 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/>.

# - rename 'dhcpv6-options prefix-delegation' from single node to a new tag node
#   'dhcpv6-options pd 0'
# - delete 'sla-len' from CLI - value is calculated on demand

from vyos.configtree import ConfigTree

def migrate(config: ConfigTree) -> None:
    for type in config.list_nodes(['interfaces']):
        for interface in config.list_nodes(['interfaces', type]):
            # cache current config tree
            base_path = ['interfaces', type, interface, 'dhcpv6-options']
            old_base = base_path + ['prefix-delegation']
            new_base = base_path + ['pd']
            if config.exists(old_base):
                config.set(new_base)
                config.set_tag(new_base)
                config.copy(old_base, new_base + ['0'])
                config.delete(old_base)

                for pd in config.list_nodes(new_base):
                    for tmp in config.list_nodes(new_base + [pd, 'interface']):
                        sla_config = new_base + [pd, 'interface', tmp, 'sla-len']
                        if config.exists(sla_config):
                            config.delete(sla_config)