#!/usr/bin/env python3
#
# Copyright VyOS maintainers and contributors <maintainers@vyos.io>
#
# 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/>.

import json
import os
import unittest

from base_vyostest_shim import VyOSUnitTestSHIM

from vyos.configsession import ConfigSessionError
from vyos.utils.system import sysctl_read

base_path = ['nat64']
src_path = base_path + ['source']

jool_nat64_config = '/run/jool/instance-100.json'

class TestNAT64(VyOSUnitTestSHIM.TestCase):
    @classmethod
    def setUpClass(cls):
        super(TestNAT64, cls).setUpClass()

        # ensure we can also run this test on a live system - so lets clean
        # out the current configuration :)
        cls.cli_delete(cls, base_path)

    def tearDown(self):
        self.cli_delete(base_path)
        self.cli_commit()
        self.assertFalse(os.path.exists(jool_nat64_config))
        # always forward to base class
        super().tearDown()

    def test_snat64(self):
        rule = '100'
        translation_rule = '10'
        prefix_v6 = '64:ff9b::/96'
        pool = '192.0.2.10'
        pool_port = '1-65535'

        rule_path = src_path + ['rule', rule]
        self.cli_set(rule_path + ['source', 'prefix', prefix_v6])
        self.cli_set(rule_path + ['translation', 'pool', translation_rule,
                                  'address', pool])
        self.cli_set(rule_path + ['translation', 'pool', translation_rule,
                                  'port', pool_port])

        # pool_port overlaps with the Linux Kernel ephemeral port range
        with self.assertRaises(ConfigSessionError):
            self.cli_commit()

        # https://nicmx.github.io/Jool/en/usr-flags-pool4.html#port-range
        # Jool is incapable of ensuring pool4 does not intersect with other defined
        # port ranges; this validation is the operator’s responsibility.
        tmp = sysctl_read(['net', 'ipv4', 'ip_local_port_range'])
        _, ephemeral_port_max = map(int, tmp.split())
        pool_port = f'{ephemeral_port_max +1}-{ephemeral_port_max +1000}'
        self.cli_set(rule_path + ['translation', 'pool', translation_rule,
                                  'port', pool_port])
        self.cli_commit()

        # Load the JSON file
        with open(f'/run/jool/instance-{rule}.json', 'r') as json_file:
            config_data = json.load(json_file)

        # Assertions based on the content of the JSON file
        self.assertEqual(config_data['instance'], f'instance-{rule}')
        self.assertEqual(config_data['framework'], 'netfilter')
        self.assertEqual(config_data['global']['pool6'], prefix_v6)
        self.assertTrue(config_data['global']['manually-enabled'])

        # Check the pool4 entries
        pool4_entries = config_data.get('pool4', [])
        self.assertIsInstance(pool4_entries, list)
        self.assertGreater(len(pool4_entries), 0)

        for entry in pool4_entries:
            self.assertIn('protocol', entry)
            self.assertIn('prefix', entry)
            self.assertIn('port range', entry)

            protocol = entry['protocol']
            prefix = entry['prefix']
            port_range = entry['port range']

            if protocol == 'ICMP':
                self.assertEqual(prefix, pool)
                self.assertEqual(port_range, pool_port)
            elif protocol == 'UDP':
                self.assertEqual(prefix, pool)
                self.assertEqual(port_range, pool_port)
            elif protocol == 'TCP':
                self.assertEqual(prefix, pool)
                self.assertEqual(port_range, pool_port)
            else:
                self.fail(f'Unexpected protocol: {protocol}')


if __name__ == '__main__':
    unittest.main(verbosity=2, failfast=VyOSUnitTestSHIM.TestCase.debug_on())