#!/usr/bin/env python

import socket

class nec_control:
    def __init__(self, address, id, port=7142):
        self.__id = (id + int("40", 16)).to_bytes(1, "big")
        self.__socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.__socket.connect((address, port))

    def __genmsg(self, msgbody, msglength):
        # Header
        message = b""
        message += b"\x01\x30" # SOH (Start Of Header)
        message += self.__id # Destination (Monitor ID)
        message += b"\x30" # Source (for controller - always 0x30h (ASCII '0'))
        message += b"\x41" # Message type
        message += msglength # Message length in hex (example: 0x3Ah must be encoded as ASCII characters '3' and 'A')

        # Message
        message += b"\x02" # STX (Start of Message)
        message += msgbody
        message += b"\x03" # ETX (End of message)

        # Check code
        xor = message[1]
        for i in range (2, len(message)):
            xor = xor ^ message[i]
        message += bytes([xor])

        # Delimiter
        message += b"\x0d" # CR (carriage return)

        return(message)

    def powerOn(self):
        msgbody = b"\x43\x32\x30\x33\x44\x36\x30\x30\x30\x31"
        msglength = b"0C"
        message = self.__genmsg(msgbody, msglength)
        self.__socket.send(message)

    def powerOff(self):
        msgbody = b"\x43\x32\x30\x33\x44\x36\x30\x30\x30\x34"
        msglength = b"0C"
        message = self.__genmsg(msgbody, msglength)
        self.__socket.send(message)