# -*- coding: utf-8 -*-

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

#
# Steam module (written for Wurm Unlimited)
#


import sys
import struct
from datetime import datetime


NAMES = [
	"name",
	"mapname",
	"gamedir",
	"game",
	"appid",
	"clients",
	"clientsmax",
	"bots",
	"servertype",
	"ostype",
	"private",
	"vac",

	# should be last
	"ping"
]

# for struct.unpack
FMT = {
	"name"      : "s",
	"mapname"   : "s",
	"gamedir"   : "s",
	"game"      : "s",
	"appid"     : "<h",
	"clients"   : "B",
	"clientsmax": "B",
	"bots"      : "B",
	"servertype": "c",
	"ostype"    : "c",
	"private"   : "B",
	"vac"       : "B",
}

STEAM_MAGIC = 0xffffffff
STEAM_QUERY = b"T" + b"Source Engine Query" + b"\x00"
STEAM_HEADER = b"I"
STEAM_PROTOCOL = 0x11
MAX_STRING = 256


def process(pkt, verbose=False):
	n   = 6 # "magic" + "header" + "protocol" size
	seq = []
	out = ""

	if verbose:
		sys.stderr.write("processing packet %d: %s...\n" % (len(pkt), repr(pkt)))

	try:
		seq = struct.unpack("<Ibb", pkt[:n])
		#out = pkt[n:].decode("utf-8")
	except:
		pass

	try:
		if seq[0] != STEAM_MAGIC and seq[1] != STEAM_HEADER and seq[2] != STEAM_PROTOCOL:
			raise
		if verbose:
			sys.stderr.write("seq: %s %s %s\n" % seq)

		# format:
		#   s:name s:map s:folder s:game
		#   s16:appid u8:players u8:maxplayers u8:bots
		#   u8:servertype:'d|l|p' environment:'l|w|m|o' u8:private:[01] vac:[01]...
		# see https://developer.valvesoftware.com/wiki/Server_queries#A2S_INFO

		# w/o special "ping" at the end
		pos = n
		lst = []
		for name in NAMES[0:-1]:
			if verbose:
				sys.stderr.write("pos: %04d, name: %s, fmt: '%s'\n" % (pos, name, FMT[name]))
			# string, null-terminated
			if FMT[name] == "s":
				v = b""
				while pkt[pos] != "\x00":
					v += pkt[pos]
					pos += 1
				pos += 1
				if verbose:
					sys.stderr.write("name: %s, fmt: '%s', pos: %d, v: '%s', len(v): %d\n" % (name, FMT[name], pos, repr(v), len(v)))
				lst += [v.decode("utf-8")]
				continue

			# other types
			v = 0
			sz = struct.calcsize(FMT[name])
			try:
				v, = struct.unpack(FMT[name], pkt[pos:pos+sz])
			except:
#				raise
				pass
			pos += sz
			lst += [v]
			if verbose:
				sys.stderr.write("name: %s, pos: %d, sz: %d, '%s'\n" % (name, pos, sz, repr(v)))
		if verbose:
			sys.stderr.write("lst: %s\n" % repr(lst))

		#lst = out.split(b"\x00")
		out = lst[::]

		return out
	except:
		return [None] * (len(NAMES) - 1)


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

	info = {}
	pkt  = struct.pack("<I", STEAM_MAGIC)
	pkt += STEAM_QUERY

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

	return info