#!/usr/bin/python3
from sys import stderr, stdout
from dns.resolver import resolve, LifetimeTimeout
from dns.query import udp
from dns.message import make_query
from dns.exception import Timeout
from dns.rcode import NXDOMAIN
from requests import get
from random import sample
candidates = []
# for d in get("https://data.iana.org/TLD/tlds-alpha-by-domain.txt").content.split(b"\n"):
for d in [b"ac", b"af", b"ag", b"ai", b"am", b"bo", b"by", b"bz", b"cm", b"cn", b"co", b"cr", b"cx", b"cz", b"de", b"dk", b"fm", b"gd", b"gg", b"gl", b"gp", b"gs", b"gt", b"gy", b"hn", b"hr", b"ht", b"ie", b"im", b"io", b"is", b"je", b"kg", b"ki", b"kw", b"la", b"lb", b"lc", b"ly", b"md", b"mg", b"mk", b"mp", b"ms", b"mw", b"mx", b"mu", b"nf", b"np", b"nz", b"pe", b"ph", b"pk", b"pl", b"pn", b"pr", b"pw", b"ro", b"sh", b"st", b"tc", b"tl", b"tt", b"to", b"tv", b"ua", b"vc", b"vg", b"vn", b"vu", b"ws"]:
	if d.startswith(b"# ") or d == b"":
		continue
	if len(d) != 2:
		continue
	d = d.decode()
	# print(d, file=stderr)
	ips = []
	try:
		for ns in resolve(d, "NS"):
			for ip in resolve(ns.to_text()):
				ips.append(ip.to_text())
	except LifetimeTimeout:
		print(f"{d} timeout resolving tld ns")
		continue
	nx = []
	has = None
	for c in "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ":
		try:
			tries_left = 5
			while True:
				try:
					ip = sample(ips, 1)[0]
					r = udp(make_query(c + "." + d, "NS"), ip, 1, raise_on_truncation=False)
				except Timeout:
					print(f"{c}.{d} timeout with ip {ip}", file=stderr)
					ips.remove(ip)
					tries_left -= 1
					if tries_left < 0:
						raise Timeout
				else:
					break
		except Timeout:
			print(f"{c}.{d} timeouted, skipping TLD")
			break
		except ValueError:
			print(f"{d} is unreachable -- all ips timeouted")
			continue
		if r.rcode() == NXDOMAIN:
			nx.append(c)
		else:
			# TODO check if NS points to an unregistered domain
			# print(f"{c}.{d} resolves to {r.sections}")
			has = c
	else:
		if has is not None:
			print(f"{d} nxdomains are {nx}")
			for n in nx:
				candidates.append(n + "." + d)
		else:
			print(f"{d} doesn't have")
	stdout.flush()
print("*************** SCRIPT EXEC FINISHED, candidate list:")
for candidate in candidates:
	print(candidate)