#!/usr/bin/env python3
import os
from serial import Serial
from umodbus.client.serial import rtu
import umodbus

from pyheatpump.config import config

from pyheatpump.logger import logger_init
logger = logger_init()

serial_conn = None

def connect():
    global serial_conn

    if serial_conn is None:
        real_serial_port = os.path.realpath(
            config.get('heatpump', 'serial_port'))

        logger.info('Connecting to serial port *%s* (%s)',
            config.get('heatpump', 'serial_port'),
            real_serial_port)

        serial_conn = Serial(
            port=real_serial_port,
            baudrate=config.get('heatpump', 'baudrate'),
            bytesize=8,
            parity='N',
            stopbits=1,
            timeout=20)

    if serial_conn.open is False:
        logger.debug('Opening serial port *%s*', config.get('heatpump', 'serial_port')
        serial_conn.open()

    return serial_conn

def read_coils(start, end):
    global serial_con
    connect()
    res = []

    address = -1
    qty = -1

    logger.info('read_coils: [%s, %s]', start, end)
    try:
        for address in range(start, end + 1, 125):
            qty = 125 if (end - address) >= 125 else (end - address)
            if not qty:
                break

            req_adu = rtu.read_coils(
                slave_id=1,
                starting_address=address,
                quantity=qty)

            response = rtu.send_message(req_adu, serial_conn)
            res.extend(response)
    except umodbus.exceptions.IllegalDataAddressError as e:
        logger.error(e)
        logger.debug('address:%s qty:%s', address, qty)

    logger.debug('read_coils [%s, %s] result: %s', start, end, res)
    return res



def read_holding_registers(start, end):
    global serial_conn
    connect()
    res = []

    address = -1
    qty = -1

    logger.debug('read_holding_registers [%s, %s]',
        start, end
    )

    try:
        for address in range(start, end + 1, 125):
            qty = 125 if (end - address) >= 125 else (end - address)
            if not qty:
                break

            req_adu = rtu.read_holding_registers(
                slave_id=1,
                starting_address=address,
                quantity=qty)

            response = rtu.send_message(req_adu, serial_conn)
            res.extend(response)
    except umodbus.exceptions.IllegalDataAddressError as e:
        logger.error('read_holding_registers(%s, %s): address:%s, qty:%s\n%s',
            start, end, address, qty, e)

    logger.debug('read_holding_registers [%s, %s] result: %s', start, end, res)
    return res

def write_coil(var_value):
    global serial_conn
    connect()

    logger.debug('write_coil address: %s, value: %s',
        var_value.address, var_value.value
    )

    try:
        req_adu = rtu.write_single_coil(
            slave_id=1,
            address=var_value.address,
            value=var_value.value)
        response = rtu.send_message(req_adu, serial_conn)

        logger.debug('write_coil address: %s, response: %s',
                var_value.address, response)

        if response != var_value.value:
            return False
        return True
    except Exception as e:
        raise e


def write_holding_register(var_value):
    global serial_conn
    connect()

    logger.debug('write_holding_register address: %s, value: %s',
        var_value.address, var_value.value
    )

    try:
        req_adu = rtu.write_single_register(
            slave_id=1,
            address=var_value.address,
            value=var_value.value)
        response = rtu.send_message(req_adu, serial_conn)
        logger.debug('write_holding_register, addres: %s, response: %s',
                var_value.address, response)
        if response != var_value.value:
            return False
        return True
    except Exception as e:
        raise e