#!/usr/bin/env python3
#
# Copyright (C) 2024 VyOS maintainers and contributors
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# T5643: move from 'set nat [source|destination] rule X [inbound-interface|outbound interface] <iface>'
# to
# 'set nat [source|destination] rule X [inbound-interface|outbound interface] interface-name <iface>'

# T6100: Migration from 1.3.X to 1.4
# Change IP/netmask to Network/netmask in
#   'set nat [source|destination] rule X [source| destination| translation] address <IP/Netmask| !IP/Netmask>'

import ipaddress
from sys import argv,exit
from vyos.configtree import ConfigTree


def _func_T5643(conf, base_path):
    for iface in ['inbound-interface', 'outbound-interface']:
        if conf.exists(base_path + [iface]):
            tmp = conf.return_value(base_path + [iface])
            if tmp:
                conf.delete(base_path + [iface])
                conf.set(base_path + [iface, 'interface-name'], value=tmp)
    return


def _func_T6100(conf, base_path):
    for addr_type in ['source', 'destination', 'translation']:
        base_addr_type = base_path + [addr_type]
        if not conf.exists(base_addr_type) or not conf.exists(
                base_addr_type + ['address']):
            continue

        address = conf.return_value(base_addr_type + ['address'])

        if not address or '/' not in address:
            continue

        negative = ''
        network = address
        if '!' in address:
            negative = '!'
            network = str(address.split(negative)[1])

        network_ip = ipaddress.ip_network(network, strict=False)
        if str(network_ip) != network:
            network = f'{negative}{str(network_ip)}'
            conf.set(base_addr_type + ['address'], value=network)
    return


if __name__ == '__main__':
    if len(argv) < 2:
        print("Must specify file name!")
        exit(1)

    file_name = argv[1]

    with open(file_name, 'r') as f:
        config_file = f.read()

    config = ConfigTree(config_file)

    if not config.exists(['nat']):
        # Nothing to do
        exit(0)

    for direction in ['source', 'destination']:
        # If a node doesn't exist, we obviously have nothing to do.
        if not config.exists(['nat', direction]):
            continue

        # However, we also need to handle the case when a 'source' or 'destination' sub-node does exist,
        # but there are no rules under it.
        if not config.list_nodes(['nat', direction]):
            continue

        for rule in config.list_nodes(['nat', direction, 'rule']):
            base = ['nat', direction, 'rule', rule]
            _func_T5643(config,base)
            _func_T6100(config,base)

    try:
        with open(file_name, 'w') as f:
            f.write(config.to_string())
    except OSError as e:
        print("Failed to save the modified config: {}".format(e))
        exit(1)