import time
import struct
from pymodbus.client import ModbusTcpClient

MODBUS_IP = "10.0.0.40"
SLAVE_ID = 1
POLL = 2.0  # Sekunden

def u16_to_i16(u16):
    return struct.unpack(">h", struct.pack(">H", u16 & 0xFFFF))[0]

def read_i16(client, addr, scale):
    rr = client.read_input_registers(address=addr, count=1, slave=SLAVE_ID)
    if rr.isError():
        return None
    raw = rr.registers[0]
    if raw == 65535:
        return None
    return round(u16_to_i16(raw) / scale, 1)

def fmt(v):
    return f"{v:5.1f}" if v is not None else "  ---"

client = ModbusTcpClient(MODBUS_IP, port=502)

try:
    if not client.connect():
        raise RuntimeError("Modbus connect failed")

    print("Logging temperatures (Ctrl+C to stop)\n")

    while True:
        # Eintrittsluft = Mittelwert aus 3x0324 & 3x0323 (scale 100)
        t_e1 = read_i16(client, 324, 100)
        t_e2 = read_i16(client, 323, 100)
        t_ein = None
        if t_e1 is not None and t_e2 is not None:
            t_ein = round((t_e1 + t_e2) / 2, 1)

        # Zuluft -> 3x0614 (/10)
        t_zuluft = read_i16(client, 614, 10)

        # Abluft -> Mittelwert aus 3x0581 & 3x0582 (/10)
        t_a1 = read_i16(client, 581, 10)
        t_a2 = read_i16(client, 582, 10)
        t_abluft = None
        if t_a1 is not None and t_a2 is not None:
            t_abluft = round((t_a1 + t_a2) / 2, 1)

        # Fortluft -> 3x0301 (/100)
        t_fortluft = read_i16(client, 301, 100)

        ts = time.strftime("%H:%M:%S")

        print(
            f"{ts} | "
            f"Eintritt: {fmt(t_ein)} °C | "
            f"Zuluft: {fmt(t_zuluft)} °C | "
            f"Abluft: {fmt(t_abluft)} °C | "
            f"Fortluft: {fmt(t_fortluft)} °C"
        )

        time.sleep(POLL)

except KeyboardInterrupt:
    print("\nStopped by user.")

finally:
    client.close()