#!/usr/bin/env python3
# -*- coding: utf-8 -*-

from pymodbus.client import ModbusTcpClient
import struct, sys

MODBUS_IP   = "192.168.1.112"
MODBUS_PORT = 502
UNIT_ID     = 1

METER_START = 40240  # Startadresse Model 203-Felder

def to_i16(u16):  # unsigned 16 → signed 16
    return struct.unpack(">h", struct.pack(">H", u16))[0]

def read_regs(client, addr, count):
    rr = client.read_holding_registers(address=addr, count=count, slave=UNIT_ID)
    if rr.isError():
        return None
    return rr.registers

def read_meter_power(client):
    base = METER_START
    p  = read_regs(client, base + 16, 1)   # M_AC_Power
    pa = read_regs(client, base + 17, 1)   # Phase A
    pb = read_regs(client, base + 18, 1)   # Phase B
    pc = read_regs(client, base + 19, 1)   # Phase C
    sf = read_regs(client, base + 20, 1)   # Scale Factor
    if not p or not sf:
        return None
    sff = to_i16(sf[0])
    return {
        "total": to_i16(p[0])  * (10 ** sff),
        "A":     to_i16(pa[0]) * (10 ** sff) if pa else None,
        "B":     to_i16(pb[0]) * (10 ** sff) if pb else None,
        "C":     to_i16(pc[0]) * (10 ** sff) if pc else None,
        "sf":    sff
    }

def fmt_w(v):
    if v is None: return "-"
    neg = v < 0
    v = abs(v)
    return f"{'-' if neg else ''}{v/1000:.2f} kW" if v >= 1000 else f"{'-' if neg else ''}{v:.0f} W"

def main():
    client = ModbusTcpClient(MODBUS_IP, port=MODBUS_PORT)
    if not client.connect():
        print("❌ Verbindung fehlgeschlagen."); sys.exit(1)
    try:
        m = read_meter_power(client)
        if m:
            print(f"Meter-Leistung: {fmt_w(m['total'])} "
                  f"(A {fmt_w(m['A'])}, B {fmt_w(m['B'])}, C {fmt_w(m['C'])})  [SF={m['sf']}]")
        else:
            print("Meter-Leistung konnte nicht gelesen werden.")
    finally:
        client.close()

if __name__ == "__main__":
    main()