#!/usr/bin/env python3
#
# Copyright (C) 2018-2020 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
import argparse
import jinja2
import sys
import time

from vyos.config import Config
from vyos.util import call

cache_file = r'/run/ddclient/ddclient.cache'

OUT_TMPL_SRC = """
{% for entry in hosts %}
ip address   : {{ entry.ip }}
host-name    : {{ entry.host }}
last update  : {{ entry.time }}
update-status: {{ entry.status }}

{% endfor %}
"""

def show_status():
    # A ddclient status file must not always exist
    if not os.path.exists(cache_file):
        sys.exit(0)

    data = {
        'hosts': []
    }

    with open(cache_file, 'r') as f:
        for line in f:
            if line.startswith('#'):
                continue

            outp = {
                'host': '',
                'ip': '',
                'time': ''
            }

            if 'host=' in line:
                host = line.split('host=')[1]
                if host:
                    outp['host'] = host.split(',')[0]

            if 'ip=' in line:
                ip = line.split('ip=')[1]
                if ip:
                    outp['ip'] = ip.split(',')[0]

            if 'atime=' in line:
                atime = line.split('atime=')[1]
                if atime:
                    tmp = atime.split(',')[0]
                    outp['time'] = time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime(int(tmp, base=10)))

            if 'status=' in line:
                status = line.split('status=')[1]
                if status:
                    outp['status'] = status.split(',')[0]

            data['hosts'].append(outp)

    tmpl = jinja2.Template(OUT_TMPL_SRC)
    print(tmpl.render(data))


def update_ddns():
    call('systemctl stop ddclient.service')
    if os.path.exists(cache_file):
        os.remove(cache_file)
    call('systemctl start ddclient.service')


if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    group = parser.add_mutually_exclusive_group()
    group.add_argument("--status", help="Show DDNS status", action="store_true")
    group.add_argument("--update", help="Update DDNS on a given interface", action="store_true")
    args = parser.parse_args()

    # Do nothing if service is not configured
    c = Config()
    if not c.exists_effective('service dns dynamic'):
        print("Dynamic DNS not configured")
        sys.exit(1)

    if args.status:
        show_status()
    elif args.update:
        update_ddns()