from django.dispatch import receiver
from django.db.models.signals import post_save

from .models import IPPrefix, IPResource

from ipaddress import ip_address, ip_network


@receiver(post_save, sender=IPPrefix, dispatch_uid='ip_prefix')
def ip_prefix(sender, instance, created, **kwargs):
    network = ip_network(instance.prefix)
    for ip in IPResource.objects.all():
        address = ip_address(ip.ip)
        if address in network:
            ip.prefixes.add(instance)
        else:
            ip.prefixes.remove(instance)


@receiver(post_save, sender=IPResource, dispatch_uid='ip_resource')
def ip_resource(sender, instance, created, **kwargs):
    address = ip_address(instance.ip)
    for prefix in IPPrefix.objects.all():
        network = ip_network(prefix.prefix)
        if address in network:
            instance.prefixes.add(prefix)
        else:
            instance.prefixes.remove(prefix)