#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright © 2015  Codethink Limited
#
# 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; version 2 of the License.
#
# 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, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
# =*= License: GPL-2 =*=


import os
import sys
import socket

import writeexts

def validate(var, line):
    xs = line.split()
    if len(xs) == 0:
        raise writeexts.ExtensionError(
            "`%s: %s': line is empty" % (var, line))

    ip = xs[0]
    hostnames = xs[1:]

    if len(hostnames) == 0:
        raise writeexts.ExtensionError(
            "`%s: %s': missing hostname" % (var, line))

    family = socket.AF_INET6 if ':' in ip else socket.AF_INET

    try:
        socket.inet_pton(family, ip)
    except socket.error:
        raise writeexts.ExtensionError("`%s: %s' invalid ip" % (var, ip))

envvars = {k: v for (k, v) in os.environ.iteritems() if k.startswith('HOSTS_')}

conf_file = os.path.join(sys.argv[1], 'etc/hosts')
writeexts.write_from_dict(conf_file, envvars, validate)