#!/usr/bin/env python3
"""Пассивная mDNS-проба модуля кондиционера: A-запрос <DSN>.local
на 224.0.0.251:5353 и :10276 (нестандартный порт Ayla из APK)."""
import socket, struct, sys, time

DSN = "AC000W00REDACTED"
HOST = DSN + ".local"

def qname(name):
    out = b""
    for lbl in name.split("."):
        out += bytes([len(lbl)]) + lbl.encode()
    return out + b"\x00"

def query_packet(txid):
    # standard query, RD=1, one question: A, class IN
    header = struct.pack(">HHHHHH", txid, 0x0100, 1, 0, 0, 0)
    return header + qname(HOST) + struct.pack(">HH", 1, 1)

def parse_name(buf, off):
    parts = []
    while True:
        l = buf[off]
        if l == 0:
            off += 1
            break
        if l & 0xC0 == 0xC0:
            ptr = struct.unpack(">H", buf[off:off+2])[0] & 0x3FFF
            parts.append(parse_name(buf, ptr)[0])
            off += 2
            break
        parts.append(buf[off+1:off+1+l].decode("latin1"))
        off += 1 + l
    return ".".join(parts), off

def parse_answers(buf):
    try:
        qd = struct.unpack(">H", buf[4:6])[0]
        an = struct.unpack(">H", buf[6:8])[0]
        off = 12
        for _ in range(qd):
            _, off = parse_name(buf, off)
            off += 4
        found = []
        for _ in range(an):
            name, off = parse_name(buf, off)
            rtype, rclass, ttl, rdlen = struct.unpack(">HHIH", buf[off:off+10])
            off += 10
            rdata = buf[off:off+rdlen]
            if rtype == 1 and rdlen == 4:
                ip = ".".join(str(b) for b in rdata)
                found.append((name, ip, rclass, ttl))
            off += rdlen
        return found
    except Exception as e:
        return [("parse-error", str(e), 0, 0)]

def probe(port, txid, wait=4.0):
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    s.bind(("", 0))
    pkt = query_packet(txid)
    for _ in range(3):
        s.sendto(pkt, ("224.0.0.251", port))
        time.sleep(0.5)
    s.settimeout(wait)
    try:
        while True:
            data, addr = s.recvfrom(4096)
            print(f"  [:{port}] from {addr}: {len(data)} bytes")
            for rec in parse_answers(data):
                print(f"    {rec}")
    except socket.timeout:
        pass
    finally:
        s.close()

if __name__ == "__main__":
    print("mDNS A?", HOST)
    print("-- querying :5353")
    probe(5353, 0x1234)
    print("-- querying :10276")
    probe(10276, 0x1235)