#!/usr/bin/env python3
"""Host probe v5 — session behaviour on 9000 (stdlib only).

v4 (correct ids + opt payloads) is still met with silence, so this probe
tests *session* hypotheses instead of bytes:
* persistent connection: discovery → directed queries on ONE socket, with
  app-like sequential snno (the app reuses its SocketManager connection;
  the field captures show a discovery frame minutes before directed ones);
* close-vs-timeout distinction for every read (immediate close = active
  reject; 8 s idle + open conn = device thinking/forwarding upstream);
* high-snno opens (in case the device tracks sequence per sender).
"""

import argparse
import json
import socket
import time
import zlib

APOWER, QUERY_INFO, BMS = 0x51B, 0x44D, 0x6A9
SNNO = [100]


def secret_key(sn):
    return format(sum(sn.encode()) & 0xFF, "x")


def build_envelope(sn, cmd, args=None, snno=None, ts=None, equip=None):
    if snno is None:
        SNNO[0] = (SNNO[0] % 9999) + 1
        snno = SNNO[0]
    data = {"opt": 0}
    if args:
        data.update(args)
    compact = json.dumps(data, separators=(",", ":"))
    env = {"cmdType": cmd, "equipNo": equip if equip is not None else sn,
           "type": 0,
           "timeStamp": ts if ts is not None else int(time.time()),
           "snno": snno,
           "len": len(compact.encode()),
           "crc": format(zlib.crc32(compact.encode()), "X"),
           "dataArea": data}
    return json.dumps(env, separators=(",", ":"))


def encrypt(json_str, key):
    parts = json_str.split(",")
    a = (parts[0] + "," + parts[1] + ",").encode()
    b = ",".join(parts[2:]).encode()
    n = int(key, 32)
    return a + bytes((b[i] + i + len(a) + n) & 0xFF
                     for i in range(len(b)))


def recv_all_verbose(sock, idle=8.0):
    """Return (bytes, how) where how is closed|idle-timeout."""
    out = bytearray()
    sock.settimeout(idle)
    while True:
        try:
            chunk = sock.recv(65536)
        except (socket.timeout, TimeoutError):
            return bytes(out), "idle-timeout(%.1fs)" % idle
        if not chunk:
            return bytes(out), "closed-by-peer"
        out.extend(chunk)


def one_shot(label, host, port, tx, timeout, snno):
    try:
        with socket.create_connection((host, port),
                                      timeout=timeout) as sock:
            t0 = time.time()
            sock.sendall(tx)
            rx, how = recv_all_verbose(sock)
            dt = time.time() - t0
    except (ConnectionError, socket.error, TimeoutError) as exc:
        print("--- %s snno=%d -> %s:%d" % (label, snno, host, port))
        print("  tx (%d B): %s" % (len(tx), tx.hex()))
        print("  error: %s: %s" % (type(exc).__name__, exc))
        return b""
    print("--- %s snno=%d -> %s:%d (%.1fs, %s)" % (
        label, snno, host, port, dt, how))
    print("  tx (%d B): %s" % (len(tx), tx.hex()))
    print("  rx (%d B): %s" % (len(rx), rx.hex() or "(empty)"))
    return rx


def session(label, host, port, frames, timeout):
    print("=== %s -> %s:%d (one connection)" % (label, host, port))
    try:
        with socket.create_connection((host, port),
                                      timeout=timeout) as sock:
            for name, tx in frames:
                t0 = time.time()
                sock.sendall(tx)
                rx, how = recv_all_verbose(sock)
                dt = time.time() - t0
                print("--- %s tx=%dB rx=%dB (%.1fs, %s)" % (
                    name, len(tx), len(rx), dt, how))
                if rx:
                    print("  rx: %s" % rx.hex()[:3000])
                if how == "closed-by-peer" and not rx:
                    print("  (peer closed; stopping session)")
                    break
    except (ConnectionError, socket.error, TimeoutError) as exc:
        print("  error: %s: %s" % (type(exc).__name__, exc))


def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("--sn", required=True)
    ap.add_argument("--host", default="10.100.1.1")
    ap.add_argument("--ports", default="9000")
    ap.add_argument("--timeout", type=float, default=5.0)
    args = ap.parse_args()
    key = secret_key(args.sn)
    print("secret key for %s: %s (radix 32)" % (args.sn, key))

    def tx(cmd, data, equip=None, snno=None):
        return encrypt(build_envelope(
            args.sn, cmd, data, snno=snno,
            equip=args.sn if equip is None else equip or "00000000"), key)

    ports = [int(p) for p in args.ports.split(",") if p.strip()]
    for port in ports:
        # A. persistent session: discovery first, then directed (app order)
        session("discovery-then-directed", args.host, port, [
            ("disc/1101+empty",
             tx(QUERY_INFO, {"minProtocolVer": "V1.00.00"}, equip="")),
            ("info/1101+SN",
             tx(QUERY_INFO, {"minProtocolVer": "V1.00.00"})),
            ("apower/1307",
             tx(APOWER, {"update": 2})),
            ("bms/1705", tx(BMS, None)),
        ], args.timeout)
        # B. high-snno fresh opens
        one_shot("apower-high-snno", args.host, port,
                 tx(APOWER, {"update": 2}, snno=500), args.timeout, 500)
        one_shot("info-high-snno", args.host, port,
                 tx(QUERY_INFO, {"minProtocolVer": "V1.00.00"}, snno=501),
                 args.timeout, 501)


if __name__ == "__main__":
    main()