# Copyright 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/>.

# T6747:
#   - Migrate static BFD configuration to match FRR possibillities
#   - Consolidate static multicast routing configuration under a new node

from vyos.configtree import ConfigTree

static_base = ['protocols', 'static']

def migrate(config: ConfigTree) -> None:
    # Check for static route/route6 configuration
    for route_route6 in ['route', 'route6']:
        route_route6_base = static_base + [route_route6]
        if not config.exists(route_route6_base):
            continue

        for prefix in config.list_nodes(route_route6_base):
            next_hop_base = route_route6_base + [prefix, 'next-hop']
            if not config.exists(next_hop_base):
                continue

            for next_hop in config.list_nodes(next_hop_base):
                multi_hop_base = next_hop_base + [next_hop, 'bfd', 'multi-hop']

                if not config.exists(multi_hop_base):
                    continue

                mh_source_base = multi_hop_base + ['source']
                source = None
                profile = None
                for src_ip in config.list_nodes(mh_source_base):
                    source = src_ip
                    if config.exists(mh_source_base + [source, 'profile']):
                        profile = config.return_value(mh_source_base + [source, 'profile'])
                    # FRR only supports one source, we will use the first one
                    break

                config.delete(multi_hop_base)
                config.set(multi_hop_base + ['source-address'], value=source)
                config.set(next_hop_base + [next_hop, 'bfd', 'profile'], value=profile)