#!/usr/bin/env python3

from pathlib import Path
import sys

class DnsRootNoParentError(Exception):
    pass

def get_dns_parent(domain):
    s = domain.split('.', 1)
    if len(s) < 2:
        raise DnsRootNoParentError()
    return domain.split('.', 1)[1]

def find_dns_zone(map_dir, domain):
    dns_file = Path(map_dir) / domain
    if dns_file.exists():
        return domain
    else:
        return find_dns_zone(map_dir, get_dns_parent(domain))

def main():
    dns_map_dir = Path(sys.argv[0]).parent / "dns"
    if len(sys.argv) >= 1:
        domains = sys.argv[1:]
    else:
        domains = []
        for domain in sys.stdin:
            domains.append(domain.strip())
    for domain in domains:
        domain = domain.strip('.')
        try:
            print(find_dns_zone(dns_map_dir, domain))
        except DnsRootNoParentError:
            print(f'No dns zone found for "{domain}"', file=sys.stderr)
            sys.exit(1)

if __name__ == "__main__":
    main()