#!/usr/bin/env python
# SPDX-License-Identifier: ISC
#
# test_bgp_lu2.py
#
# Part of FRR/NetDEF Topology Tests
#
# Copyright (c) 2020 by Volta Networks
# Copyright (c) 2021 by Nvidia, Inc.
#

"""
test_bgp_lu2.py: Test BGP LU label allocation
"""

import os
import sys
import json
from functools import partial
import pytest

# Save the Current Working Directory to find configuration files.
CWD = os.path.dirname(os.path.realpath(__file__))
sys.path.append(os.path.join(CWD, "../"))

# pylint: disable=C0413
# Import topogen and topotest helpers
from lib import topotest
from lib.topogen import Topogen, TopoRouter, get_topogen
from lib.topolog import logger

# Required to instantiate the topology builder class.

pytestmark = [pytest.mark.bgpd]

#
# Basic scenario for BGP-LU. Nodes are directly connected.
# Node 3 is advertising routes to 2, which advertises them
# as BGP-LU to 1; this way we get routes with actual labels, as
# opposed to implicit-null routes in the 2-node case.
#
# R2 is an LER, with MPLS towards R1, and IP towards R3. R1 is an LSR, with
# MPLS on both sides.
#
#
#    AS4     BGP-LU      AS1       BGP-LU       AS2         iBGP        AS2
#  +-----+             +-----+                +-----+                 +-----+
#  |     |.4         .1|     |.1            .2|     |.2             .3|     |
#  |  4  +-------------+  1  +----------------+  2  +-----------------+  3  |
#  |     | 10.0.4.0/24 |     |   10.0.0.0/24  |     |   10.0.1.0/24   |     |
#  +-----+             +-----+                +-----+                 +-----+
#
#


def build_topo(tgen):
    "Build function"

    # This function's only purpose is to define allocation and relationship
    # between routers, switches and hosts.
    #
    #
    # Create routers
    tgen.add_router("R1")
    tgen.add_router("R2")
    tgen.add_router("R3")
    tgen.add_router("R4")

    # R1-R2
    switch = tgen.add_switch("s1")
    switch.add_link(tgen.gears["R1"])
    switch.add_link(tgen.gears["R2"])

    # R2-R3
    switch = tgen.add_switch("s2")
    switch.add_link(tgen.gears["R2"])
    switch.add_link(tgen.gears["R3"])

    # R1-R4
    switch = tgen.add_switch("s3")
    switch.add_link(tgen.gears["R1"])
    switch.add_link(tgen.gears["R4"])


def setup_module(mod):
    "Sets up the pytest environment"
    # This function initiates the topology build with Topogen...
    tgen = Topogen(build_topo, mod.__name__)

    # Skip if no mpls support
    if not tgen.hasmpls:
        logger.info("MPLS is not available, skipping test")
        pytest.skip("MPLS is not available, skipping")
        return

    # ... and here it calls Mininet initialization functions.
    tgen.start_topology()

    # This is a sample of configuration loading.
    router_list = tgen.routers()

    # Enable mpls input for routers, so we can ping
    sval = "net.mpls.conf.{}.input"
    topotest.sysctl_assure(router_list["R2"], sval.format("R2-eth0"), 1)
    topotest.sysctl_assure(router_list["R1"], sval.format("R1-eth0"), 1)
    topotest.sysctl_assure(router_list["R1"], sval.format("R1-eth1"), 1)
    topotest.sysctl_assure(router_list["R4"], sval.format("R4-eth0"), 1)

    # For all registered routers, load the zebra configuration file
    for rname, router in router_list.items():
        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))
        )

        # Have static config for R3 too
        if router == router_list["R3"]:
            router.load_config(
                TopoRouter.RD_STATIC, os.path.join(CWD, "{}/staticd.conf".format(rname))
            )

    # After loading the configurations, this function loads configured daemons.
    tgen.start_router()


def teardown_module(mod):
    "Teardown the pytest environment"
    tgen = get_topogen()

    # This function tears down the whole topology.
    tgen.stop_topology()


def check_labelpool(router):
    json_file = "{}/{}/labelpool.summ.json".format(CWD, router.name)
    expected = json.loads(open(json_file).read())

    test_func = partial(
        topotest.router_json_cmp, router, "show bgp labelpool summary json", expected
    )
    _, result = topotest.run_and_expect(test_func, None, count=20, wait=1)
    assertmsg = '"{}" JSON output mismatches - Did not converge'.format(router.name)
    assert result is None, assertmsg


def test_converge_bgplu():
    "Wait for protocol convergence"

    tgen = get_topogen()
    # Don't run this test if we have any failure.
    if tgen.routers_have_failure():
        pytest.skip(tgen.errors)

    # TODO -- enable for debugging
    # tgen.mininet_cli()

    r1 = tgen.gears["R1"]
    r2 = tgen.gears["R2"]

    check_labelpool(r1)
    check_labelpool(r2)


def test_ping():
    "Simple ping tests"

    tgen = get_topogen()

    # Don't run this test if we have any failure.
    if tgen.routers_have_failure():
        pytest.skip(tgen.errors)

    #
    logger.info("Ping from R2 to R3")
    router = tgen.gears["R2"]
    output = router.run("ping -c 4 -w 4 {}".format("10.0.1.3"))
    assert " 0% packet loss" in output, "Ping R2->R3 FAILED"
    logger.info("Ping from R2 to R3 ... success")

    #
    logger.info("Ping from R4 to R2")
    router = tgen.gears["R4"]
    output = router.run("ping -c 4 -w 4 {}".format("10.0.0.2"))
    assert " 0% packet loss" in output, "Ping R4->R2 FAILED"
    logger.info("Ping from R4 to R2 ... success")

    #
    logger.info("Ping from R4 to R3")
    router = tgen.gears["R4"]
    output = router.run("ping -c 4 -w 4 {}".format("10.0.1.3"))
    assert " 0% packet loss" in output, "Ping R4->R3 FAILED"
    logger.info("Ping from R4 to R3 ... success")


def test_memory_leak():
    "Run the memory leak test and report results."
    tgen = get_topogen()
    if not tgen.is_memleak_enabled():
        pytest.skip("Memory leak test/report is disabled")

    tgen.report_memory_leaks()


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