# need pip install dnspython
import dns.name, dns.query, dns.resolver
import socket

def wait_for_dns(new_domain: str) -> typing.List[str]:
    """
    Waits until a dns record becomes awailable, resolves it and returns the corresponding ip addresses.
    NOTE: Amazon route53 will report status as INSYNC even though the changes have not propogated to
    the authorative nameserver.
    :param new_domain: The domain to query for
    :return: A list of corresponding ip addresses
    """
    authority_nameservers = \
        dns.query.udp(dns.message.make_query(new_domain, dns.rdatatype.NS), PUBLIC_NAMESERVER).authority
    if len(authority_nameservers) == 0:
        raise ValueError("Could not find authorative nameserver, aborting")

    # authority_ns.to_string() will return something like this:
    # 'aws.g.is. 899 IN SOA ns-1834.awsdns-37.co.uk. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400'
    authority_ns = authority_nameservers[0].to_text().split()[4].rstrip('.')

    domain_resolver = dns.resolver.Resolver(configure=False)
    print("Using %s as authorative nameserver" % (authority_ns,))
    domain_resolver.nameservers = [socket.gethostbyname(authority_ns)]
    while True:
        try:
            result = domain_resolver.query(new_domain, 'A')
            print()
            break
        except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
            sys.stdout.write('.')
            sys.stdout.flush()
        time.sleep(1)
    return [r.to_text() for r in result]