# -*- coding: utf-8 -*-
from __future__ import unicode_literals

import os
from django.db import models
from django.core.validators import RegexValidator
import requests

from coin.configuration.models import Configuration

FDN_ELIGIBILITY_URL = 'https://vador.fdn.fr/souscription/eligibilite.cgi'


def convert_bandwidth(value):
    """Convert bandwidth expression to Int
    """
    units = {'k': 1000, 'M': 1000000}
    if value[-1] not in units:
        raise ValueError('Incorrect bandwidth value: {}'.format(value))
    return int(value[:-1]) * units[value[-1]]


class FDNWhiteLabelError(Exception):
    pass


class FDNWhiteLabel(Configuration):
    class Meta:
        verbose_name = 'marque blanche FDN'
        # If Django's default pluralisation is not satisfactory
        # verbose_name_plural = 'very many DSL lines'

    # URL namespace associated to this configuration type, to build URLs
    # in various view.  Should also be defined in urls.py.  Here, we don't
    # define any view, so there's no need for an URL namespace.
    url_namespace = "fdn"
    phone_number = models.CharField(max_length=20,
                                    verbose_name='phone number',
                                    help_text='Phone number associated to the '
                                              'DSL line')
    address = models.TextField(
        verbose_name='adresse postale', blank=True, null=True)
    postal_code = models.CharField(max_length=5, blank=True, null=True,
                                   validators=[
                                       RegexValidator(regex=r'^\d{5}$',
                                                      message='Code postal '
                                                              'non valide.')
                                       ],
                                   verbose_name='code postal')
    city = models.CharField(max_length=200, blank=True, null=True,
                            verbose_name='commune')
    ppp_login = models.CharField(max_length=200, blank=True, null=True,
                                 verbose_name='identifiant PPP')
    ppp_password = models.CharField(max_length=200, blank=True, null=True,
                                    verbose_name='mot de passe PPP')
    fdn_option = models.CharField(max_length=10, verbose_name='Option chez'
                                  '  FDN', blank=True, null=True)
    _fdn_bundled_line = True

    def is_compatible_option(self, option):
        if self._fdn_bundled_line:
            return 'opt1' in option['code_offre']
        else:
            return 'opt1' not in option['code_offre']

    def check_eligibility(self):
        """sends a request to FDN in order to get DSL eligibility status for
        that number and postal code, and returns the best option, as a tuple of
        offer code, and bandwidth, or raises an exception if no offer is
        available.
        TODO: add caching
        """
        if not self.phone_number or not self.postal_code:
            raise AttributeError('Phone number and postal code must be '
                                 'defined')
        cert_file = os.path.join(os.getcwd(), 'fdnwhitelabel',
                                 'cacert.crt')
        request_params = {'tel': self.phone_number,
                          'cp': self.postal_code,
                          'etape': 'eligibilite',
                          'tarif': 'blanche'}
        eligibility = requests\
            .get(FDN_ELIGIBILITY_URL, params=request_params,
                 verify=cert_file).json()
        if 'erreur' in eligibility and eligibility['erreur']:
            raise FDNWhiteLabelError(eligibility['message'])
        offers = [o for o in eligibility['offres']
                  if self.is_compatible_option(o)]
        best_offer = sorted(offers,
                            key=lambda o: convert_bandwidth(o['debit']))[-1]
        return (best_offer['code_offre'], best_offer['debit'])

    def __unicode__(self):
        return self.phone_number

    def subnet_event(self):
        # Do something with self.ip_subnet.all() here.
        pass


class FDNUnbundledWhiteLabel(FDNWhiteLabel):
    _fdn_bundled_line = True