#!/usr/bin/env python
# -*- coding: utf-8 -*-

# Modular system for querying game servers.
#
# Author:  Roman Vasiyarov <rvasiyarov@gmail.com>
# License: GPLv3
# $Id$

#
# Minecraft module
#


import sys
import struct
from datetime import datetime


SOCK_TCP = True

NAMES = [
	"paragraph",
	"protocol",
	"version",
	"motd",
	"clients",
	"clientsmax",

	# should be last
	"ping"
]

MC_MAGIC_QUERY     = 0xfe
MC_MAGIC_RESPONSE  = 0xff
MC_MAGIC_SEPARATOR = b"\x00\xa7".decode("utf-16be")
# 0x00 for pre-1.4 and looked like motd$clients$clientsmax
# still works on 1.6.4
MC_QUERY_VERSION   = 0x01


def process(pkt, verbose=False):
	n   = 3   # "header" size
	seq = [None] * len(NAMES)
	out = ""

	try:
		seq = struct.unpack(">BH", pkt[:n])
	except:
		pass

	try:
		if seq[0] != MC_MAGIC_RESPONSE:
			raise

		# get byte-length of message
		ln  = seq[1] * 2
		msg = pkt[n:n + ln].decode("utf-16be")
		par, msg = msg.split(MC_MAGIC_SEPARATOR)
		seq = msg.split(b"\x00")
	except:
		seq = []

	return seq + [None] * max(0, len(NAMES) - 1 - len(seq))


def query(sock, servers, verbose = False):
	if not sock or not len(servers):
		return

	info = {}
	pkt  = struct.pack("<BB", MC_MAGIC_QUERY, MC_QUERY_VERSION)

	# send queries
	for sv in servers:
		if verbose:
			sys.stderr.write("sending query to %s...\n" % repr(sv))
		info[sv] = [None, datetime.utcnow()]
		sock.connect(sv)
		sock.send(pkt, 0)

	return info


if __name__ == "__main__":
	with open("/dev/stdin", "rb") as f:
		out = process(f.read())

	clients = "UNKNOWN" if not out[4] else out[4]
	print(clients)