#!/usr/bin/env python3
#
# Copyright (C) 2017 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 sys
import os
import fnmatch
import jinja2

from vyos.config import Config
from vyos import ConfigError

config_file = r'/etc/default/udp-broadcast-relay'

config_tmpl = """
### Autogenerated by bcast_relay.py ###

# UDP broadcast relay configuration for instance {{ id }}
{%- if description %}
# Comment: {{ description }}
{% endif -%}
DAEMON_ARGS="{% if address %}-s {{ address }} {% endif %}{{ id }} {{ port }} {{ interfaces | join(' ') }}"
"""

default_config_data = {
    'disabled': False,
    'instances': []
}

def get_config():
    relay = default_config_data
    conf = Config()
    if not conf.exists('service broadcast-relay'):
        return None
    else:
        conf.set_level('service broadcast-relay')

    # Service can be disabled by user
    if conf.exists('disable'):
        relay['disabled'] = True
        return relay

    # Parse configuration of each individual instance
    if conf.exists('id'):
        for id in conf.list_nodes('id'):
            conf.set_level('service broadcast-relay id {0}'.format(id))
            config = {
                'id': id,
                'disabled': False,
                'address': '',
                'description': '',
                'interfaces': [],
                'port': ''
            }

            # Check if individual broadcast relay service is disabled
            if conf.exists('disable'):
                config['disabled'] = True

            # Source IP of forwarded packets, if empty original senders address is used
            if conf.exists('address'):
                config['address'] = conf.return_value('address')

            # A description for each individual broadcast relay service
            if conf.exists('description'):
                config['description'] = conf.return_value('description')

            # UDP port to listen on for broadcast frames
            if conf.exists('port'):
                config['port'] = conf.return_value('port')

            # Network interfaces to listen on for broadcast frames to be relayed
            if conf.exists('interface'):
                config['interfaces'] = conf.return_values('interface')

            relay['instances'].append(config)

    return relay

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

    if relay['disabled']:
        return None

    for r in relay['instances']:
        # we don't have to check this instance when it's disabled
        if r['disabled']:
            continue

        # we certainly require a UDP port to listen to
        if not r['port']:
            raise ConfigError('UDP broadcast relay "{0}" requires a port number'.format(r['id']))

        # Relaying data without two interface is kinda senseless ...
        if len(r['interfaces']) < 2:
            raise ConfigError('UDP broadcast relay "id {0}" requires at least 2 interfaces'.format(r['id']))

    return None


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

    config_dir = os.path.dirname(config_file)
    config_filename = os.path.basename(config_file)
    active_configs = []

    for config in fnmatch.filter(os.listdir(config_dir), config_filename + '*'):
        # determine prefix length to identify service instance
        prefix_len = len(config_filename)
        active_configs.append(config[prefix_len:])

    # sort our list
    active_configs.sort()

    # delete old configuration files
    for id in active_configs[:]:
        if os.path.exists(config_file + id):
            os.unlink(config_file + id)

    # If the service is disabled, we can bail out here
    if relay['disabled']:
        print('Warning: UDP broadcast relay service will be deactivated because it is disabled')
        return None

    for r in relay['instances']:
        # Skip writing instance config when it's disabled
        if r['disabled']:
            continue

        # configuration filename contains instance id
        file = config_file + str(r['id'])
        tmpl = jinja2.Template(config_tmpl)
        config_text = tmpl.render(r)
        with open(file, 'w') as f:
            f.write(config_text)

    return None

def apply(relay):
    # first stop all running services
    os.system('sudo systemctl stop udp-broadcast-relay@{1..99}')

    if (relay is None) or relay['disabled']:
        return None

    # start only required service instances
    for r in relay['instances']:
        # Don't start individual instance when it's disabled
        if r['disabled']:
            continue
        os.system('sudo systemctl start udp-broadcast-relay@{0}'.format(r['id']))

    return None

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

@@ -998,17 +998,16 @@
 %25 endif 
--
 %25%7D%0ADAEMO
@@ -1108,16 +1108,17 @@
  ') %7D%7D%22%0A
+%0A
 %22%22%22%0A%0Adef

fix missing newline between comment and options.