# Copyright 2023-2024 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/>.

# T3316:
# - Adjust hostname to have valid FQDN characters only (underscores aren't allowed anymore)
# - Adjust duid (old identifier) to comply with duid format
# - Rename "service dhcpv6-server shared-network-name ... static-mapping <hostname> identifier ..."
#       to "service dhcpv6-server shared-network-name ... static-mapping <hostname> duid ..."
# - Rename "service dhcpv6-server shared-network-name ... static-mapping <hostname> mac-address ..."
#       to "service dhcpv6-server shared-network-name ... static-mapping <hostname> mac ..."

import re
from vyos.configtree import ConfigTree

base = ['service', 'dhcpv6-server', 'shared-network-name']

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

    for network in config.list_nodes(base):
        # Run this for every specified 'subnet'
        if config.exists(base + [network, 'subnet']):
            for subnet in config.list_nodes(base + [network, 'subnet']):
                base_subnet = base + [network, 'subnet', subnet]
                if config.exists(base_subnet + ['static-mapping']):
                    for hostname in config.list_nodes(base_subnet + ['static-mapping']):
                        base_mapping = base_subnet + ['static-mapping', hostname]
                        if config.exists(base_mapping + ['identifier']):

                            # Adjust duid to comply with duid format (a:3:b:04:... => 0a:03:0b:04:...)
                            duid = config.return_value(base_mapping + ['identifier'])
                            new_duid = ':'.join(x.rjust(2,'0') for x in duid.split(':'))
                            if new_duid != duid:
                                config.set(base_mapping + ['identifier'], new_duid)

                            # Rename the 'identifier' node to 'duid'
                            config.rename(base_mapping + ['identifier'], 'duid')

                        # Rename the 'mac-address' node to 'mac'
                        if config.exists(base_mapping + ['mac-address']):
                            config.rename(base_mapping + ['mac-address'], 'mac')

                        # Adjust hostname to have valid FQDN characters only
                        new_hostname = re.sub(r'[^a-zA-Z0-9-.]', '-', hostname)
                        if new_hostname != hostname:
                            config.rename(base_mapping, new_hostname)