#!/usr/bin/env python3
import pynetbox
import argparse
from dns import rdatatype
from dns import rdataclass
from dns.rdtypes.ANY.SOA import SOA
from dns.rdtypes.ANY.NS import NS
from dns.rdtypes.ANY.CNAME import CNAME
from dns.rdtypes.IN.A import A
from dns.zone import Zone
from pathlib import Path
from pprint import pprint


def build_auth_dns_zones(nb: pynetbox.api, nox_dir: Path):
    zones_dir = nox_dir / "data" / "zones"
    zones_dir.mkdir(parents=True,exist_ok=True)
    print(f"Fetching IPAM data to build authorative zonefiles in {zones_dir}")
    print(f"Building zone eh22.intern")
    zonefile_path = zones_dir / "eh22.intern.zone"

    # build zone management stuff (SOA record, NS record)
    zone = Zone(origin="eh22.intern")
    zone.get_rdataset("@", rdtype=rdatatype.SOA, create=True)\
        .add(SOA(rdclass=rdataclass.IN, rdtype=rdatatype.SOA, mname="auth-dns.noc.eh22.intern.", rname="noc.eh22.easterhegg.eu.", serial=1, refresh=7200, retry=3600, expire=3600000, minimum=60))
    zone.get_rdataset("@", rdtype=rdatatype.NS, create=True)\
        .add(NS(rdclass=rdataclass.IN, rdtype=rdatatype.NS, target="10.20.25.3"))

    # iterate over all ip addresses with dns names ending in noc.eh22.intern
    for i_addr in nb.ipam.ip_addresses.filter("eh22.intern"):
        raw_addr = i_addr.address.rsplit("/", maxsplit=1)[0]
        relative_name = i_addr.dns_name.removesuffix(".eh22.intern")

        # add A/AAAA record for the name itself
        if i_addr.family.value == 4:
            zone.get_rdataset(relative_name, rdtype=rdatatype.A, create=True)\
                .add(A(rdclass=rdataclass.IN, rdtype=rdatatype.A, address=raw_addr))
        else:
            raise RuntimeError(f"Got unknown IP family {i_addr.family} ({i_addr.family.value})")

        # add CNAME records for all registered alternative names
        if i_addr.custom_fields["altnames"]:
            for i_altname in i_addr.custom_fields["altnames"].split(","):
                i_altname = i_altname.strip().removesuffix(".eh22.intern")
                zone.get_rdataset(i_altname, rdtype=rdatatype.CNAME, create=True)\
                    .add(CNAME(rdclass=rdataclass.IN, rdtype=rdatatype.CNAME, target=relative_name + ".eh22.intern."))

    with open(zonefile_path, mode="w") as f:
        zone.to_file(f, want_comments=True, want_origin=True)


def main():
    argp = argparse.ArgumentParser(prog="fetch-netbox-data", description="Fetch current IPAM data from netbox")
    argp.add_argument("--base-url", default="https://netbox.eh22.easterhegg.eu", help="URL of the netbox installation")
    argp.add_argument("--token", required=True, help="Netbox API Token")
    argp.add_argument("--nox-dir", required=True, type=Path, help="Path to the nox repository")
    args = argp.parse_args()

    nb = pynetbox.api(args.base_url, token=args.token)
    build_auth_dns_zones(nb, args.nox_dir)



if __name__ == "__main__":
    main()