# 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/>.

# migrate disable-dhcp-nameservers (boolean) to name-servers-dhcp <interface>
# if disable-dhcp-nameservers is set, just remove it
# else retrieve all interface names that have configured dhcp(v6) address and
# add them to the new name-servers-dhcp node

from vyos.ifconfig import Interface
from vyos.configtree import ConfigTree

base = ['system']

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

    if config.exists(base + ['disable-dhcp-nameservers']):
        config.delete(base + ['disable-dhcp-nameservers'])
    else:
        dhcp_interfaces = []

        # go through all interfaces searching for 'address dhcp(v6)?'
        for sect in Interface.sections():
            sect_base = ['interfaces', sect]

            if not config.exists(sect_base):
                continue

            for intf in config.list_nodes(sect_base):
                intf_base = sect_base + [intf]

                # try without vlans
                if config.exists(intf_base + ['address']):
                    for addr in config.return_values(intf_base + ['address']):
                        if addr in ['dhcp', 'dhcpv6']:
                            dhcp_interfaces.append(intf)

                # try vif
                if config.exists(intf_base + ['vif']):
                    for vif in config.list_nodes(intf_base + ['vif']):
                        vif_base = intf_base + ['vif', vif]
                        if config.exists(vif_base + ['address']):
                            for addr in config.return_values(vif_base + ['address']):
                                if addr in ['dhcp', 'dhcpv6']:
                                    dhcp_interfaces.append(f'{intf}.{vif}')

                # try vif-s
                if config.exists(intf_base + ['vif-s']):
                    for vif_s in config.list_nodes(intf_base + ['vif-s']):
                        vif_s_base = intf_base + ['vif-s', vif_s]
                        if config.exists(vif_s_base + ['address']):
                            for addr in config.return_values(vif_s_base + ['address']):
                                if addr in ['dhcp', 'dhcpv6']:
                                    dhcp_interfaces.append(f'{intf}.{vif_s}')

                    # try vif-c
                    if config.exists(intf_base + ['vif-c']):
                        for vif_c in config.list_nodes(vif_s_base + ['vif-c']):
                            vif_c_base = vif_s_base + ['vif-c', vif_c]
                            if config.exists(vif_c_base + ['address']):
                                for addr in config.return_values(vif_c_base + ['address']):
                                    if addr in ['dhcp', 'dhcpv6']:
                                        dhcp_interfaces.append(f'{intf}.{vif_s}.{vif_c}')

        # set new config nodes
        for intf in dhcp_interfaces:
            config.set(base + ['name-servers-dhcp'], value=intf, replace=False)