#!/usr/bin/env python
# SPDX-License-Identifier: ISC

#
# Copyright (c) 2023 by
# Donatas Abraitis <donatas@opensourcerouting.org>
#

"""
Check if IPv6 Link-Local BGP peering works fine.
"""

import os
import sys
import json
import pytest
import functools

CWD = os.path.dirname(os.path.realpath(__file__))
sys.path.append(os.path.join(CWD, "../"))

# pylint: disable=C0413
from lib import topotest
from lib.topogen import Topogen, TopoRouter, get_topogen

pytestmark = [pytest.mark.bgpd]


def build_topo(tgen):
    for routern in range(1, 4):
        tgen.add_router("r{}".format(routern))

    switch = tgen.add_switch("s1")
    switch.add_link(tgen.gears["r1"])
    switch.add_link(tgen.gears["r2"])

    switch = tgen.add_switch("s2")
    switch.add_link(tgen.gears["r1"])
    switch.add_link(tgen.gears["r3"])


def setup_module(mod):
    tgen = Topogen(build_topo, mod.__name__)
    tgen.start_topology()

    router_list = tgen.routers()

    for _, (rname, router) in enumerate(router_list.items(), 1):
        router.load_config(
            TopoRouter.RD_ZEBRA, os.path.join(CWD, "{}/zebra.conf".format(rname))
        )
        router.load_config(
            TopoRouter.RD_BGP, os.path.join(CWD, "{}/bgpd.conf".format(rname))
        )

    tgen.start_router()


def teardown_module(mod):
    tgen = get_topogen()
    tgen.stop_topology()


def test_bgp_ipv6_link_local_peering():
    tgen = get_topogen()

    if tgen.routers_have_failure():
        pytest.skip(tgen.errors)

    r1 = tgen.gears["r1"]
    r3 = tgen.gears["r3"]

    def _bgp_converge():
        output = json.loads(r1.vtysh_cmd("show bgp summary json"))
        expected = {
            "ipv4Unicast": {
                "peers": {
                    "fe80:1::2": {
                        "state": "Established",
                    }
                }
            }
        }
        return topotest.json_cmp(output, expected)

    test_func = functools.partial(_bgp_converge)
    _, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
    assert result is None, "Failed to see BGP convergence on R2"

    def _bgp_router_id_missing():
        output = json.loads(r3.vtysh_cmd("show bgp summary failed json"))
        expected = {
            "ipv4Unicast": {
                "routerId": "0.0.0.0",
                "as": 65003,
                "peers": {
                    "fe80:1::1": {
                        "connectionsEstablished": 0,
                        "connectionsDropped": 0,
                        "peerUptime": "never",
                        "lastResetDueTo": "Router ID is missing",
                    }
                },
            }
        }
        return topotest.json_cmp(output, expected)

    test_func = functools.partial(_bgp_router_id_missing)
    _, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
    assert result is None, "r3 should stay down due to missing router ID"


if __name__ == "__main__":
    args = ["-s"] + sys.argv[1:]
    sys.exit(pytest.main(args))