from django import forms
from django.db.models import Q

from whoisdb.models import InetNum
from whoisdb.forms import MntFormMixin
from whoisdb.validators import IP46CIDRValidator

from .models import Domain, Nameserver, ReverseZone

import re
import ipaddress


class DomainForm(MntFormMixin, forms.ModelForm):
	class Meta:
		model = Domain
		fields = ['name', 'nameservers', 'mnt_by', 'admin_c']

	def __init__(self, user, *args, **kwargs):
		self._user = user

		super(DomainForm, self).__init__(*args, **kwargs)

		mnts = self._user.maintainer_set.all()
		self.fields['nameservers'].queryset = Nameserver.objects.filter(Q(mnt_by__in=mnts))

		instance = getattr(self, "instance", None)
		self._create = not (instance and instance.pk)

		if not self._create:
			self.fields['name'].disabled = True
			self.fields['nameservers'].queryset |= self.instance.nameservers.all()

		self.fields['nameservers'].queryset.distinct()

	def clean_name(self):
		name = self.cleaned_data['name'].lower()
		if self._create:
			if not name.endswith("."):
				name += "."

			if not name.endswith("dn."):
				raise forms.ValidationError("Only .dn domains can be registered at this point")

			if name.count(".") > 2:
				raise forms.ValidationError("No subdomains can be registered")

			if not re.match("^[a-z0-9.-]+$", name):
				raise forms.ValidationError("Only a-z, 0-9 and - are allowed inside the domain name")

			try:
				Domain.objects.get(name=name)
				raise forms.ValidationError("Domain already exists")
			except Domain.DoesNotExist:
				pass

		return name


class NameserverForm(MntFormMixin, forms.ModelForm):
	class Meta:
		model = Nameserver
		fields = ['name', 'glueIPv4', 'glueIPv6', 'mnt_by', 'admin_c']

	def __init__(self, user, *args, **kwargs):
		self._user = user

		super(NameserverForm, self).__init__(*args, **kwargs)

		instance = getattr(self, "instance", None)
		self._create = not (instance and instance.pk)

	def clean_name(self):
		name = self.cleaned_data['name'].lower().strip()
		if not name.endswith("."):
			name += "."

		if name.count(".") <= 2:
			raise forms.ValidationError("Nameserver must be inside a domain (e.g. ns1.noot.dn.)")

		zone = ".".join(name.split(".")[-3:])

		mnts = self._user.maintainer_set.all()
		domains = Domain.objects.filter(mnt_by__in=mnts)
		found = False
		for domain in domains:
			if domain.name == zone:
				found = True
				break

		if not found:
			raise forms.ValidationError("This nameserver is not under a domain you control.")

		return name

	def clean(self):
		cleaned_data = super(NameserverForm, self).clean()

		return cleaned_data


class ReverseZoneForm(forms.ModelForm):
	prefix = forms.CharField(validators=[IP46CIDRValidator])

	class Meta:
		model = ReverseZone
		fields = ['parentNet', 'nameservers']

	def __init__(self, user, *args, **kwargs):
		self._user = user

		super(ReverseZoneForm, self).__init__(*args, **kwargs)

		instance = getattr(self, "instance", None)
		self._create = not (instance and instance.pk)

		mnts = self._user.maintainer_set.all()
		self.fields['parentNet'].queryset = InetNum.objects.filter(Q(mnt_by__in=mnts) | Q(mnt_lower__in=mnts)).distinct()

		self.fields['nameservers'].queryset = Nameserver.objects.filter(Q(mnt_by__in=mnts))

		if not self._create:
			self.fields['prefix'].disabled = True
			self.fields['nameservers'].queryset |= self.instance.nameservers.all()

		self.fields['nameservers'].queryset.distinct()



	def clean(self):
		cleaned_data = super(ReverseZoneForm, self).clean()

		if not self.errors:
			if self._create:
				net = ipaddress.ip_network(cleaned_data['prefix'])
				parentNet = cleaned_data['parentNet'].getNetwork()

				if net.network_address not in parentNet:
					raise forms.ValidationError("Given prefix %s is not inside of parent netblock %s" % (net, parentNet))

				# For now just check all the zones...
				#zones = ReverseZone.objects.filter(parentNet=cleaned_data['parentNet'])
				zones = ReverseZone.objects.all()
				for zone in zones:
					if net.network_address in zone.parentNet.getNetwork():
						raise forms.ValidationError("Given prefix already has a reverse zone object associated to it: %s" % zone)

				self.instance.address = str(net.network_address)
				self.instance.netmask = net.prefixlen


		return cleaned_data