# Copyright 2021-2024 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.
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# along with this library.  If not, see <http://www.gnu.org/licenses/>.

# - T2450: drop interface-route and interface-route6 from "protocols static"

from vyos.configtree import ConfigTree

def migrate_interface_route(config, base, path, route_route6):
    """ Generic migration function which can be called on every instance of
    interface-route, beeing it ipv4, ipv6 or nested under the "static table" nodes.

    What we do?
      - Drop 'interface-route' or 'interface-route6' and migrate the route unter the
        'route' or 'route6' tag node.
    """
    if config.exists(base + path):
        for route in config.list_nodes(base + path):
            interface = config.list_nodes(base + path + [route, 'next-hop-interface'])

            tmp = base + path + [route, 'next-hop-interface']
            for interface in config.list_nodes(tmp):
                new_base = base + [route_route6, route, 'interface']
                config.set(new_base)
                config.set_tag(base + [route_route6])
                config.set_tag(new_base)
                config.copy(tmp + [interface], new_base + [interface])

        config.delete(base + path)

def migrate_route(config, base, path, route_route6):
    """ Generic migration function which can be called on every instance of
    route, beeing it ipv4, ipv6 or even nested under the static table nodes.

    What we do?
      - for consistency reasons rename next-hop-interface to interface
      - for consistency reasons rename next-hop-vrf to vrf
    """
    if config.exists(base + path):
        for route in config.list_nodes(base + path):
            next_hop = base + path + [route, 'next-hop']
            if config.exists(next_hop):
                for gateway in config.list_nodes(next_hop):
                    # IPv4 routes calls it next-hop-interface, rename this to
                    # interface instead so it's consitent with IPv6
                    interface_path = next_hop + [gateway, 'next-hop-interface']
                    if config.exists(interface_path):
                        config.rename(interface_path, 'interface')

                    # When VRFs got introduced, I (c-po) named it next-hop-vrf,
                    # we can also call it vrf which is simply shorter.
                    vrf_path = next_hop + [gateway, 'next-hop-vrf']
                    if config.exists(vrf_path):
                        config.rename(vrf_path, 'vrf')

            next_hop = base + path + [route, 'interface']
            if config.exists(next_hop):
                for interface in config.list_nodes(next_hop):
                    # IPv4 routes calls it next-hop-interface, rename this to
                    # interface instead so it's consitent with IPv6
                    interface_path = next_hop + [interface, 'next-hop-interface']
                    if config.exists(interface_path):
                        config.rename(interface_path, 'interface')

                    # When VRFs got introduced, I (c-po) named it next-hop-vrf,
                    # we can also call it vrf which is simply shorter.
                    vrf_path = next_hop + [interface, 'next-hop-vrf']
                    if config.exists(vrf_path):
                        config.rename(vrf_path, 'vrf')


base = ['protocols', 'static']

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

    # Migrate interface-route into route
    migrate_interface_route(config, base, ['interface-route'], 'route')

    # Migrate interface-route6 into route6
    migrate_interface_route(config, base, ['interface-route6'], 'route6')

    # Cleanup nodes inside route
    migrate_route(config, base, ['route'], 'route')

    # Cleanup nodes inside route6
    migrate_route(config, base, ['route6'], 'route6')

    #
    # PBR table cleanup
    table_path = base + ['table']
    if config.exists(table_path):
        for table in config.list_nodes(table_path):
            # Migrate interface-route into route
            migrate_interface_route(config, table_path + [table], ['interface-route'], 'route')

            # Migrate interface-route6 into route6
            migrate_interface_route(config, table_path + [table], ['interface-route6'], 'route6')

            # Cleanup nodes inside route
            migrate_route(config, table_path + [table], ['route'], 'route')

            # Cleanup nodes inside route6
            migrate_route(config, table_path + [table], ['route6'], 'route6')