SWITCH AUTOMATION

  # Libraries to add
  import paho.mqtt.client as mqtt
  import json
  import os
  import subprocess


  # Global variables:
  kw_out = 0
  flag = 1
  # Time flags for controlling updating
  counter = 0
  time_counter = 0

  # Function that counts up when solar is producing to change status
  def increase():
     global counter
     global flag
     if counter < 20:
      counter +=1
      print("Increased counter")
     else:
      counter = 0
      flag = 1
      start3()
      print("Started")

  # Function that counts up when solar is down to change status
  def decrease():
     global counter
     global flag
     if counter < 20:
      counter +=1
      print("Decreased counter")
     else:
      counter = 0
      flag = 0
      stop3()
      print("Stopped")

  # Start cluster and change status (in this case all the devices except master)
  def start3():
     os.system('expect /home/pi/control/start.exp 2')
     os.system('expect /home/pi/control/start.exp 3')
     os.system('expect /home/pi/control/start.exp 4')
     dictionary = {"status": 1,}
     with open("/var/www/cellar/status.json", "w") as outfile:
          json.dump(dictionary, outfile)

  # Stop cluster and change status (in this case all the devices except master)      
  def stop3():
     dictionary = {"status": 0,}
     with open("/var/www/cellar/status.json", "w") as outfile:
         json.dump(dictionary, outfile)
     os.system('expect /home/pi/control/stop.exp 2')
     os.system('expect /home/pi/control/stop.exp 3')
     os.system('expect /home/pi/control/stop.exp 4')

  # reads energy consumption from switch using expect to a json
  def read_energy():
      output = subprocess.check_output("expect /home/pi/control/energy.exp | cut -c 32-33", shell=True)
      watt = output.decode("utf-8")
      watt = watt[:-1]
      print(watt)
      dictionary = {
             "w": watt,
      }
      with open("/var/www/cellar/energy.json", "w") as outfile:
              json.dump(dictionary, outfile)

  # saves kw_out in json
  def update_kw():
      global kw_out
      global flag
      global time_counter
      print(kw_out)
      print(flag)
      if (time_counter == 15):
          read_energy()
          time_counter = 0
      else:
          time_counter += 1
      print(time_counter)
      if kw_out > 0 and flag == 0:
        increase()
      if kw_out == 0 and flag == 1:
        decrease()
      dictionary = {
         "kw_out": kw_out,
      }
      with open("/var/www/cellar/kwh.json", "w") as outfile:
          json.dump(dictionary, outfile)

  # the callback function, it will be triggered when receiving messages
  def on_message_minus(client, userdata, msg):
      global kw_out
      kw_out =float(msg.payload)
      update_kw()

  # Connect to MQTT
  def on_connect(client, userdata, flags, rc):
      # subscribe, which need to put into on_connect
      client.subscribe("") #Update to add  
      client.message_callback_add('', on_message_minus)

  # Reconnect
  def reconnect_mqtt():
      global client
      client.loop_stop()
      client.username_pw_set("user", "password")
      client.connect("server", port, 60)
      client.loop_forever()

  #Set upp MQTT connection
  client = mqtt.Client()
  client.on_connect = on_connect
  # create connection, the three parameters are broker address, broker port number, and keep-alive time respectively
  client.username_pw_set("user", "password")
  client.connect("server", port, 60)
  # set the network loop blocking, it will not actively end the program before calling disconnect() or the program crash
  client.loop_forever()