from django.db import models
from django.contrib.auth.models import User
from django.core.exceptions import ValidationError
from django.core.validators import RegexValidator
from django.conf import settings
from django.db.models.signals import post_save
from main import dnstools

import re


class BlacklistedDomain(models.Model):
    domain = models.CharField(
        max_length=256,
        unique=True,
        help_text='Blacklisted domain. Evaluated as regex (search).')

    last_update = models.DateTimeField(auto_now=True)
    created = models.DateTimeField(auto_now_add=True)
    created_by = models.ForeignKey(User, blank=True, null=True)

    def __unicode__(self):
        return u"%s" % (self.domain, )


def domain_blacklist_validator(value):
    for bd in BlacklistedDomain.objects.all():
        print bd.domain
        if re.search(bd.domain, value):
            raise ValidationError(u'This domain is not allowed')


class Domain(models.Model):
    domain = models.CharField(max_length=256, unique=True)

    last_update = models.DateTimeField(auto_now=True)
    created = models.DateTimeField(auto_now_add=True)
    created_by = models.ForeignKey(User, blank=True, null=True)

    def __unicode__(self):
        return u"%s" % (self.domain, )


class Host(models.Model):
    """TODO: hash update_secret on save (if not already hashed)"""
    subdomain = models.CharField(max_length=256, validators=[
        RegexValidator(
            regex=r'^(([a-z0-9][a-z0-9\-]*[a-z0-9])|[a-z0-9])$',
            message='Invalid subdomain: only "a-z", "0-9" and "-" is allowed'
        ),
        domain_blacklist_validator])
    domain = models.ForeignKey(Domain)
    update_secret = models.CharField(max_length=256)  # gets hashed on save
    comment = models.CharField(
        max_length=256, default='', blank=True, null=True)

    last_update = models.DateTimeField(auto_now=True)
    created = models.DateTimeField(auto_now_add=True)
    created_by = models.ForeignKey(
        settings.AUTH_USER_MODEL, related_name='hosts')

    def __unicode__(self):
        return u"%s.%s - %s" % (
            self.subdomain, self.domain.domain, self.comment)

    class Meta:
        unique_together = (('subdomain', 'domain'),)

    def get_fqdn(self):
        return self.subdomain.self.domain.domain


def post_delete_host(sender, **kwargs):
    obj = kwargs['instance']
    dnstools.delete(obj.get_fqdn())

post_save.connect(post_delete_host, sender=Host)