#!/usr/bin/env python3
"""Host probe v8 — live household wattage (stdlib only).

Three socket APIs (all verified in disassembly; detail/load pending live
confirmation on this unit, EMS already answered live):
* DEVICE_DETAIL_INFO (1301, no args) -> totalPower  [home-page poll]
* LOAD_STATUS        (1411, no args) -> SW1ExpPower [per-switch watts]
* EMS                (1707, no args) -> grid/load V+A [watts via math]

Run on the SoftAP-joined host:
    python3 host_probe8.py --sn A03X2516013210060005 --ports 9000
"""

import argparse
import json
import socket
import time
import zlib

DETAIL, LOAD, EMS = 0x515, 0x583, 0x6AB
SNNO = [0]


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, 16)
    return a + bytes((b[i] + i + len(a) + n) & 0xFF
                     for i in range(len(b)))


def decrypt_wire(wire):
    first = wire.find(b",")
    second = wire.find(b",", first + 1)
    if first < 0 or second < 0:
        return ""
    a, b = wire[:second + 1], wire[second + 1:]
    try:
        probe = json.loads(a[:-1].decode() + "}")
    except Exception:
        return ""
    if not isinstance(probe, dict):
        return ""
    n = int(secret_key(str(probe.get("equipNo", ""))), 16)
    try:
        return (a + bytes((t - i - len(a) - n) & 0xFF
                          for i, t in enumerate(b))).decode()
    except Exception:
        return ""


def recv_all(sock, idle=8.0):
    out = bytearray()
    sock.settimeout(idle)
    while True:
        try:
            chunk = sock.recv(65536)
        except (socket.timeout, TimeoutError):
            break
        if not chunk:
            break
        out.extend(chunk)
    return bytes(out)


def run(label, host, port, tx, timeout):
    rx, err, reply = b"", None, None
    try:
        with socket.create_connection((host, port),
                                      timeout=timeout) as sock:
            sock.sendall(tx)
            rx = recv_all(sock)
            if rx:
                dec = decrypt_wire(rx)
                reply = json.loads(dec) if dec else {"_raw": rx.hex()}
    except (ConnectionError, socket.error, TimeoutError) as exc:
        err = "%s: %s" % (type(exc).__name__, exc)
    print("--- %s -> %s:%d" % (label, host, port))
    print("  rx (%d B)" % len(rx))
    if reply is not None:
        print("  reply: " + json.dumps(reply, default=str)[:2000])
    if err:
        print("  error: %s" % err)
    return reply


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 16)" % (args.sn, key))
    for port in [int(p) for p in args.ports.split(",") if p.strip()]:
        for label, cmd in (("detail/1301", DETAIL), ("load/1411", LOAD),
                           ("ems/1707", EMS)):
            tx = encrypt(build_envelope(args.sn, cmd), key)
            run(label, args.host, port, tx, args.timeout)


if __name__ == "__main__":
    main()