#!/usr/bin/env python3
#
# Copyright (C) 2020 VyOS maintainers and contributors
#
# 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 os

from ipaddress import IPv4Address
from sys import exit

from vyos import ConfigError
from vyos.config import Config
from vyos.util import call
from vyos.template import render

from vyos import airbag
airbag.enable()

config_file = r'/tmp/igmp.frr'

def get_config():
    conf = Config()
    igmp_conf = {
        'igmp_conf' : False,
        'old_ifaces'    : {},
        'ifaces'    : {}
    }
    if not (conf.exists('protocols igmp') or conf.exists_effective('protocols igmp')):
        return None

    if conf.exists('protocols igmp'):
        igmp_conf['igmp_conf'] = True

    conf.set_level('protocols igmp')

    # # Get interfaces
    for iface in conf.list_effective_nodes('interface'):
        igmp_conf['old_ifaces'].update({
            iface : {
                'version' : conf.return_effective_value('interface {0} version'.format(iface)),
                'query_interval' : conf.return_effective_value('interface {0} query-interval'.format(iface)),
                'query_max_resp_time' : conf.return_effective_value('interface {0} query-max-response-time'.format(iface)),
                'gr_join' : {}
            }
        })
        for gr_join in conf.list_effective_nodes('interface {0} join'.format(iface)):
            igmp_conf['old_ifaces'][iface]['gr_join'][gr_join] = conf.return_effective_values('interface {0} join {1} source'.format(iface, gr_join))

    for iface in conf.list_nodes('interface'):
        igmp_conf['ifaces'].update({
            iface : {
                'version' : conf.return_value('interface {0} version'.format(iface)),
                'query_interval' : conf.return_value('interface {0} query-interval'.format(iface)),
                'query_max_resp_time' : conf.return_value('interface {0} query-max-response-time'.format(iface)),
                'gr_join' : {}
            }
        })
        for gr_join in conf.list_nodes('interface {0} join'.format(iface)):
            igmp_conf['ifaces'][iface]['gr_join'][gr_join] = conf.return_values('interface {0} join {1} source'.format(iface, gr_join))

    return igmp_conf

def verify(igmp):
    if igmp is None:
        return None

    if igmp['igmp_conf']:
        # Check interfaces
        if not igmp['ifaces']:
            raise ConfigError(f"IGMP require defined interfaces!")
        # Check, is this multicast group
        for intfc in igmp['ifaces']:
            for gr_addr in igmp['ifaces'][intfc]['gr_join']:
                if IPv4Address(gr_addr) < IPv4Address('224.0.0.0'):
                    raise ConfigError(gr_addr + " not a multicast group")

def generate(igmp):
    if igmp is None:
        return None

    render(config_file, 'frr/igmp.frr.tmpl', igmp)
    return None

def apply(igmp):
    if igmp is None:
        return None

    if os.path.exists(config_file):
        call(f'vtysh -d pimd -f {config_file}')
        os.remove(config_file)

    return None

if __name__ == '__main__':
    try:
        c = get_config()
        verify(c)
        generate(c)
        apply(c)
    except ConfigError as e:
        print(e)
        exit(1)