# Copyright (C) 2025 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/>.

# T7116: Remove unsupported "internet" community following FRR removal
# From
    # set policy route-map <name> rule <ord> set community [add | replace] internet
    # set policy community-list <name> rule <ord> regex internet
# To
    # set policy route-map <name> rule <ord> set community [add | replace] 0:0
    # set policy community-list <name> rule <ord> regex _0:0_

# NOTE: In FRR expanded community-lists, without the '_' delimiters, a regex of 
# "0:0" will match "65000:0" as well as "0:0". This doesn't line up with what
# we want when replacing "internet". 

from vyos.configtree import ConfigTree

rm_base = ['policy', 'route-map']
cl_base = ['policy', 'community-list']

def migrate(config: ConfigTree) -> None:
    if config.exists(rm_base):
        for policy_name in config.list_nodes(rm_base):
            for rule_ord in config.list_nodes(rm_base + [policy_name, 'rule'], path_must_exist=False):
                tmp_path = rm_base + [policy_name, 'rule', rule_ord, 'set', 'community']
                if config.exists(tmp_path + ['add']) and config.return_value(tmp_path + ['add']) == 'internet':
                    config.set(tmp_path + ['add'], '0:0')
                if config.exists(tmp_path + ['replace']) and config.return_value(tmp_path + ['replace']) == 'internet':
                    config.set(tmp_path + ['replace'], '0:0')

    if config.exists(cl_base):
        for policy_name in config.list_nodes(cl_base):
            for rule_ord in config.list_nodes(cl_base + [policy_name, 'rule'], path_must_exist=False):
                tmp_path = cl_base + [policy_name, 'rule', rule_ord, 'regex']
                if config.exists(tmp_path) and config.return_value(tmp_path) == 'internet':
                    config.set(tmp_path, '_0:0_')