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

from .models import Service, IPPrefix, IPResource, Switch, Port

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)


@receiver(post_delete, sender=Service, dispatch_uid='delete_service_contribution')
def delete_service_contribution(sender, instance, **kwargs):
    instance.contribution.delete()


@receiver(post_save, sender=Switch, dispatch_uid='create_switch_ports')
def create_switch_ports(sender, instance, created, **kwargs):
    if created:
        ports = [ Port(switch=instance, port=i) for i in range(instance.first_port, instance.last_port + 1) ]
        Port.objects.bulk_create(ports)