#!/usr/bin/python3

import paho.mqtt.client as mqtt
from gpiozero import PWMOutputDevice

# MQTT configuration
broker = '127.0.0.1'
device_id = 'test_fan'
on_topic = 'homeassistant/' + device_id + '/on/set'
on_state_topic = 'homeassistant/' + device_id + '/on/state'
speed_topic = 'homeassistant/' + device_id + '/speed/set'
speed_state_topic = 'homeassistant/' + device_id + '/speed/state'

# gpio settings
gpio_pin = 18
pwm_freq = 5000
speeds = {'low':  0.05, 'medium': 0.4, 'high': 1}

class PwmFan:
  on_state = 'OFF'
  pwm = PWMOutputDevice(gpio_pin,frequency=pwm_freq)
  speed_state = 'high'

  def switch(self, onoff):
    if onoff == 'ON':
      if self.on_state == 'OFF':
        self.on_state = 'ON'
        self.set_speed(self.speed_state)
    elif onoff == 'OFF':
      if self.on_state == 'ON':
        self.on_state = 'OFF'
        self.pwm.off()

  def set_speed(self,speed):
    if speed in speeds:
      if self.on_state == 'ON':
        self.pwm.value=speeds[speed]
      self.speed_state = speed


fan = PwmFan()

def on_message(client, userdata, message):
  payload = str(message.payload.decode("utf-8"))
  topic = message.topic
  if topic == on_topic:
    print("ON/OF command received")
    if (payload == 'ON') or (payload == 'OFF'):
      print("turning " + payload)
      fan.switch(payload)
      client.publish(on_state_topic, payload)
      if payload == 'ON':
        client.publish(speed_state_topic, fan.speed_state)
  elif message.topic == speed_topic:
    if payload in speeds:
      print('Setting speed to ' + payload)
      fan.set_speed(payload)
      if fan.on_state == 'ON':
        client.publish(speed_state_topic, fan.speed_state)

# Send messages in a loop
client = mqtt.Client("myfan")
client.on_message = on_message
# If your homeassistant is protected by as password, uncomment this next line:
# client.username_pw_set('homeassistant','yourpasswordhere')
client.connect(broker)
client.subscribe(on_topic)
client.subscribe(speed_topic)
client.loop_forever()