#! /usr/bin/python3
import time
import sys
from paho.mqtt import client as mqtt_client
import os
import serial

MAXIMUM_COMMUNICATION_FAILURE=100

# MQTT Settings
mqtt_server=os.environ['MQTT_SERVER']
mqtt_topic=os.environ['MQTT_TOPIC']
# SERIAL Port
serial_device=os.environ['SERIAL_DEVICE']

# The callback for when a PUBLISH message is received from the server.
def on_message(client, userdata, msg):
    print(msg.topic+" "+str(msg.payload))


# Start mqtt
client_id = f'python-fan-ctrl'
client = mqtt_client.Client(mqtt_client.CallbackAPIVersion.VERSION2)
client.on_message = on_message

if (not (mqtt_server)):
    print("MQTT_SERVER is not set")

if (not (mqtt_topic)):
    print("MQTT_TOPIC is not set")

# Start MQTT Client
client.connect(mqtt_server, 1883)
client.loop_start()

# Start Serial communication
ser = serial.Serial(serial_device, 115200, timeout=1)  # open serial port
client.publish(mqtt_topic + "device", ser.name) # check which port was really used

SerialCommunicationFailureCounter=0

# Endless Loop
while True:
    try:
        try:
            if (not (ser.is_open)):
                ser.open()
                continue
        except (serial.SerialException):
            client.publish(mqtt_topic + "exception", "serial reopen") # check which port was really used
            time.sleep(1.0)

        try:
            line = ser.readline()   # read a '\n' terminated line
        except (serial.SerialException):
            SerialCommunicationFailureCounter = SerialCommunicationFailureCounter + 1
            client.publish(mqtt_topic + "serialcom/failure", str(SerialCommunicationFailureCounter))
            line=None
            if (SerialCommunicationFailureCounter > MAXIMUM_COMMUNICATION_FAILURE):
                raise serial.SerialException("device reports readiness / device disconnected " + str(MAXIMUM_COMMUNICATION_FAILURE) + " times")

        if (line):
            client.publish(mqtt_topic + "exception", "") # clear exception
            # convert byte array to string
            l = line.decode("utf-8")
            try:
                # Parse the controller information
                # e.g. : 22.00;0%;0RPM
                temperatur, percent, rpm = l.split(";")
            except (ValueError):
                # activate debug code
                temperatur = None
                percent = None
                rpm = None

            if ((temperatur) and (percent) and (rpm)):
                parseError=False
                temperatur = temperatur.strip()
                client.publish(mqtt_topic + "temperatur", str(temperatur))
                if (percent.endswith('/100')):
                    client.publish(mqtt_topic + "target", str(percent[:-4]))
                else:
                    client.publish(mqtt_topic + "debug", "target%% invalid:" + str(percent))
                    parseError=True
                
                # remove new line for last element
                rpm = rpm.replace('\r','').replace('\n','')
                if (rpm.endswith('RPM')):
                    client.publish(mqtt_topic + "rpm", str(rpm[:-3]))
                else:
                    client.publish(mqtt_topic + "debug", "RPM invalid:" + str(rpm))
                    parseError=True

                # cleanup debugging
                if (parseError == False):
                    client.publish(mqtt_topic + "debug", None)
            else:
                client.publish(mqtt_topic + "debug", line) # line was invalid and could not be parsed
        else:
            time.sleep(0.2)

    except (KeyboardInterrupt, SystemExit):
        cleanAndExit()

client.loop_stop()