#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# MIDTOOLS.PY -- Gestion de la conversion mid <-> IP
#
# Copyright (C) 2010 Olivier Iffrig
# Authors: Olivier Iffrig <iffrig@crans.org>
#
# 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 <http://www.gnu.org/licenses/>.

import config

import iptools

class Mid(object):
    """
    Permet de décortiquer un mid et d'obtenir les IP correspondantes
    """

    def __init__(self, mid=None):
        if mid is not None:
            self.parse(mid)
        else:
            self.mid = None
            self.reste = False
            self.type = None
            self.ipv4_dispo = False
            self.priv = False

    def parse(self, mid):
        self.mid = mid
        self.type = None
        for tp in config.mid.keys():
            if mid <= config.mid[tp][1] and mid >= config.mid[tp][0]:
                self.type = tp
        if self.type is None:
            raise ValueError("mid inconnu : %d" % mid)

        self.ipv4_dispo = False
        if (mid & (1 << 15)) == 0 and self.type != 'special':
            self.ipv4_dispo = True

        self.priv = True
        if (mid & (1 << 14)) == 0:
            self.priv = False

        self.reste = mid & 0x7ff
#        if self.type == 'ens': # Inutile pour l'instant
#            self.reste &= 0xff

    def from_ipv4(self, ip):
        """
        Met à jour l' instance pour correspondre à l'IPv4 donnée
        """
        self.ipv4_dispo = True
        self.priv = ip.startswith('10.')
        for tp in ['fil', 'wifi', 'adm', 'gratuit', 'ens']:
            if iptools.AddrInNet(ip, config.NETs[tp]):
                self.type = tp
                break
        if self.type is None:
            raise ValueError("Impossible de convertir l'adresse IP")

        self.mid = int(iptools.QuadToDec(ip))
        self.mid -= int(iptools.param(config.NETs[self.type][0],
            True)['network'])
        self.reste = self.mid & 0x7ff
        return self.mid
    #    if self.type == 'ens': # Inutile pour l'instant
    #        self.reste &= 0xff

    def to_ipv4(self):
        """
        Génère l'IPv4 associée à la machine
        """
        if not self.ipv4_dispo:
            raise ValueError("Pas d'adresse ipv4 disponible pour la machine")

        ip = iptools.param(config.NETs[self.type][0], True)['network']
        ip += self.reste
        return iptools.DecToQuad(ip)

    def to_ipv6_vlan(self):
        """
        Génère le préfix IPv6 associé à la machine
        """
        if self.priv:
            raise ValueError("Pas de prefix ipv6 disponible pour cette machine")

        ip = config.prefix['subnet'][0].split(":/")[0]
        ip += hex(self.mid)[2:]
        ip += "::/64"
        return ip