#!/usr/bin/env python3

# Copyright (C) 2023 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/>.

# T5791:
# - migrate "service dns dynamic address web web-options ..."
#        to "service dns dynamic name <service> address web ..." (per service)
# - migrate "service dns dynamic address <address> rfc2136 <service> ..."
#        to "service dns dynamic name <service> address <interface> protocol 'nsupdate'"
# - migrate "service dns dynamic address <interface> service <service> ..."
#        to "service dns dynamic name <service> address <interface> ..."
# - normalize the all service names to conform with name constraints

import sys
import re
from unicodedata import normalize
from vyos.configtree import ConfigTree

def normalize_name(name):
    """Normalize service names to conform with name constraints.

    This is necessary as part of migration because there were no constraints in
    the old name format.
    """
    # Normalize unicode characters to ASCII (NFKD)
    # Replace all separators with hypens, strip leading and trailing hyphens
    name = normalize('NFKD', name).encode('ascii', 'ignore').decode()
    name = re.sub(r'(\s|_|\W)+', '-', name).strip('-')

    return name


if len(sys.argv) < 2:
    print("Must specify file name!")
    sys.exit(1)

file_name = sys.argv[1]

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

config = ConfigTree(config_file)

base_path = ['service', 'dns', 'dynamic']
address_path = base_path + ['address']
name_path = base_path + ['name']

if not config.exists(address_path):
    # Nothing to do
    sys.exit(0)

# config.copy does not recursively create a path, so initialize the name path as tagged node
if not config.exists(name_path):
    config.set(name_path)
    config.set_tag(name_path)

for address in config.list_nodes(address_path):

    address_path_tag = address_path + [address]

    # Move web-option as a configuration in each service instead of top level web-option
    if config.exists(address_path_tag + ['web-options']) and address == 'web':
        for svc_type in ['service', 'rfc2136']:
            if config.exists(address_path_tag + [svc_type]):
                for svc_cfg in config.list_nodes(address_path_tag + [svc_type]):
                    config.copy(address_path_tag + ['web-options'],
                                address_path_tag + [svc_type, svc_cfg, 'web-options'])
        config.delete(address_path_tag + ['web-options'])

    for svc_type in ['service', 'rfc2136']:
        if config.exists(address_path_tag + [svc_type]):
            # Set protocol to 'nsupdate' for RFC2136 configuration
            if svc_type == 'rfc2136':
                for rfc_cfg in config.list_nodes(address_path_tag + ['rfc2136']):
                    config.set(address_path_tag + ['rfc2136', rfc_cfg, 'protocol'], 'nsupdate')

            # Add address as config value in each service before moving the service path
            # And then copy the services from 'address <interface> service <service>'
            #                              to 'name (service|rfc2136)-<service>-<address>'
            # Note: The new service is named (service|rfc2136)-<service>-<address>
            #       to avoid name conflict with old entries
            for svc_cfg in config.list_nodes(address_path_tag + [svc_type]):
                config.set(address_path_tag + [svc_type, svc_cfg, 'address'], address)
                config.copy(address_path_tag + [svc_type, svc_cfg],
                            name_path + ['-'.join([svc_type, svc_cfg, address])])

# Finally cleanup the old address path
config.delete(address_path)

# Normalize the all service names to conform with name constraints
index = 1
for name in config.list_nodes(name_path):
    new_name = normalize_name(name)
    if new_name != name:
        # Append index if there is still a name conflicts after normalization
        # For example, "foo-?(" and "foo-!)" both normalize to "foo-"
        if config.exists(name_path + [new_name]):
            new_name = f'{new_name}-{index}'
            index += 1
        config.rename(name_path + [name], new_name)

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))
    sys.exit(1)