from django.conf import settings
from django.core.management import BaseCommand

from desecapi.exceptions import PDNSException
from desecapi.pdns import (
    _pdns_delete,
    _pdns_get,
    _pdns_post,
    NSLORD,
    NSMASTER,
    pdns_id,
    construct_catalog_rrset,
)


class Command(BaseCommand):
    # https://tools.ietf.org/html/draft-muks-dnsop-dns-catalog-zones-04
    help = "Generate a catalog zone on nsmaster, based on zones known on nslord."

    def add_arguments(self, parser):
        pass

    def handle(self, *args, **options):
        catalog_zone_id = pdns_id(settings.CATALOG_ZONE)

        # Fetch zones from NSLORD
        response = _pdns_get(NSLORD, "/zones").json()
        zones = {zone["name"] for zone in response}

        # Retrieve catalog zone serial (later reused for recreating the catalog zone, for allow for smooth rollover)
        try:
            response = _pdns_get(NSMASTER, f"/zones/{catalog_zone_id}")
            serial = response.json()["serial"]
        except PDNSException as e:
            if e.response.status_code == 404:
                serial = None
            else:
                raise e

        # Purge catalog zone if exists
        try:
            _pdns_delete(NSMASTER, f"/zones/{catalog_zone_id}")
        except PDNSException as e:
            if e.response.status_code != 404:
                raise e

        # Create new catalog zone
        rrsets = [
            construct_catalog_rrset(
                subname="", qtype="NS", rdata="invalid."
            ),  # as per the specification
            construct_catalog_rrset(
                subname="version", qtype="TXT", rdata='"2"'
            ),  # as per the specification
            *(construct_catalog_rrset(zone=zone) for zone in zones),
        ]

        data = {
            "name": settings.CATALOG_ZONE + ".",
            "kind": "MASTER",
            "dnssec": False,  # as per the specification
            "nameservers": [],
            "rrsets": rrsets,
        }

        if serial is not None:
            data["serial"] = (
                serial + 1
            )  # actually, pdns does increase this as well, but let's not rely on this

        _pdns_post(NSMASTER, "/zones?rrsets=false", data)
        print(f"Aligned catalog zone ({len(zones)} member zones).")