#!/usr/bin/env python3
"""Sanity-check byte-level probe for EG4 LifePower4 V2 over USB-RS485.

Sends the 'general status' frame and prints the raw reply. If you see bytes
starting with 0x7E coming back, the protocol is confirmed and eg4_lifepower.py
will decode them.

Usage:
  python3 probe.py                        # auto-detect likely USB-serial port
  python3 probe.py /dev/tty.usbserial-XXX # explicit port
  python3 probe.py COM5                   # Windows
"""
import sys
import time
import glob
import serial  # pip install pyserial

BAUD = 9600
CMDS = {
    "general":  bytes.fromhex("7E01010000FE0D"[:-2] + "0D"),  # 7E 01 01 00 FE 0D
    "hw_ver":   bytes.fromhex("7E01420000FC0D"[:-2] + "0D"),  # 7E 01 42 00 FC 0D
    "fw_ver":   bytes.fromhex("7E01330000FE0D"[:-2] + "0D"),  # 7E 01 33 00 FE 0D
}
# (the [:-2]+"0D" dance above is just to keep the literal aligned with the
# canonical 6-byte frames documented upstream; simpler form below)
CMDS = {
    "general": bytes([0x7E, 0x01, 0x01, 0x00, 0xFE, 0x0D]),
    "hw_ver":  bytes([0x7E, 0x01, 0x42, 0x00, 0xFC, 0x0D]),
    "fw_ver":  bytes([0x7E, 0x01, 0x33, 0x00, 0xFE, 0x0D]),
}


def autodetect() -> str | None:
    candidates = (
        glob.glob("/dev/tty.usbserial*")     # macOS FTDI/CH340
        + glob.glob("/dev/tty.usbmodem*")    # macOS CDC-ACM
        + glob.glob("/dev/ttyUSB*")          # Linux FTDI/CH340
        + glob.glob("/dev/ttyACM*")          # Linux CDC-ACM
    )
    return candidates[0] if candidates else None


def probe(port: str) -> None:
    print(f"opening {port} @ {BAUD} 8N1")
    with serial.Serial(port, BAUD, bytesize=8, parity="N", stopbits=1, timeout=1.5) as s:
        for name, cmd in CMDS.items():
            s.reset_input_buffer()
            s.write(cmd)
            time.sleep(0.2)
            reply = s.read(256)
            print(f"\n[{name}] sent {cmd.hex(' ')}")
            if reply:
                print(f"  got  ({len(reply)} bytes) {reply.hex(' ')}")
                if reply[0] == 0x7E and reply[-1] == 0x0D:
                    print("  -> frame looks valid (7E ... 0D)")
            else:
                print("  got  (nothing — timeout)")


if __name__ == "__main__":
    port = sys.argv[1] if len(sys.argv) > 1 else autodetect()
    if not port:
        sys.exit("no serial port found; pass one explicitly: python3 probe.py /dev/tty.usbserial-XXXX")
    probe(port)