#!/usr/bin/python3

# Copyright (C) 2013-2021 Daniel Baumann <daniel@debian.org>
#
# SPDX-License-Identifier: GPL-3.0+
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# 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 <https://www.gnu.org/licenses/>.

from ipaddress import IPv6Address
from json import dumps
from os import getenv
from sys import exit

from pygments import highlight
from pygments.lexers import JsonLexer
from pygments.formatters import TerminalFormatter

def v0_ipv6_address():
    address = getenv('REMOTE_ADDR')
    cgi = getenv('GATEWAY_INTERFACE')

    try:
        ip = str(IPv6Address(address))
        message = 'valid IPv6 address'
        status = True
    except ValueError:
        ip = None
        message = 'invalid IPv6 address'
        status = False

    json = \
    {
      'data': {
        'ipv6_address': ip,
      },
      'meta': {
        'status': status,
        'message': message,
      },
    }

    if cgi:
        print('Content-Type: application/json\n')
        print(dumps(json))
    else:
        print(highlight(dumps(json, indent=4), JsonLexer(), TerminalFormatter()))

    exit(0)

if __name__ == '__main__':
    v0_ipv6_address()