#!/usr/bin/python3
# -*- coding: utf8 -*-

#Get LM75 temperature value and send it to MQTT broker

import smbus
import paho.mqtt.publish as mqtt
import datetime

# MQTT settings
mqtt_server =   'localhost'
mqtt_port=      1883
mqtt_auth=      {'username':'cameteo',
                 'password':'CaMeteo'}
mqtt_client_id= 'papirus_temp2mqtt'
mqtt_qos=2

mqtt_topic="pi/papirus_zero_hat/temperature/"

#LM75B settings
LM75B_ADDRESS             = 0x48
LM75B_TEMP_REGISTER       = 0
LM75B_CONF_REGISTER       = 1
LM75B_THYST_REGISTER      = 2
LM75B_TOS_REGISTER        = 3
LM75B_CONF_NORMAL         = 0

class LM75B(object):
    def __init__(self, address=LM75B_ADDRESS, busnum=1):
        self._address = address
        self._bus = smbus.SMBus(busnum)
        self._bus.write_byte_data(self._address, LM75B_CONF_REGISTER, LM75B_CONF_NORMAL)

    def getTempC(self):
        """Return temperature in degrees Celsius"""
        raw = self._bus.read_word_data(self._address, LM75B_TEMP_REGISTER) & 0xFFFF
        raw = (((raw << 8) & 0xFF00) + (raw >> 8) +128 ) /256
        return raw
    
########
# Main #
########

#Get and print data
date = datetime.datetime.now().replace(microsecond=0).isoformat()
print(date)

sens = LM75B()
lm75_temp = sens.getTempC()
print("Temperature (Papirus HAT LM75b) : %s °C" % lm75_temp)


#Send data to MQTT broker
mqtt_data = [{'topic':mqtt_topic + "value",     'payload':lm75_temp,        'qos':mqtt_qos, 'retain':True},
             {'topic':mqtt_topic + "date",      'payload':date,             'qos':mqtt_qos, 'retain':True},
             {'topic':mqtt_topic + "unit",      'payload':"\u00B0C",           'qos':mqtt_qos, 'retain':True},
             {'topic':mqtt_topic + "desc",      'payload':"LM75b sensor",   'qos':mqtt_qos, 'retain':True}]

mqtt.multiple(mqtt_data,
              hostname=  mqtt_server    ,
              port=      mqtt_port      ,
              auth=      mqtt_auth      ,
              client_id= mqtt_client_id )