"""
┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ An example code to demonstrate how to use mqtt           ┃
┃ Raspberry Pi Pico.                                       ┃
┃                                                          ┃
┃ Copyright (c) 2023 Vinh Bui                              ┃
┃ License: MIT                                             ┃
┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
"""

import network
import time
from machine import Pin
import dht
import ujson
from umqttsimple import MQTTClient

# WiFi Network Parameters
# SSID: Wokwi-GUEST
# Security: Open
print("Connecting to WiFi", end="")
wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect("Wokwi-GUEST", "")
while not wlan.isconnected():
  print(".", end="")
  time.sleep(0.1)
print(wlan.ifconfig())
print("WiFi Connected!")

# MQTT Server Parameters
MQTT_CLIENT_ID = "picow-01"
MQTT_BROKER    = "5d2b1e680bc4427bbacc7535a47a72eb.s1.eu.hivemq.cloud"
MQTT_USER      = "user1"
MQTT_PASSWORD  = "1234567890"
MQTT_TOPIC     = "wokwi-weather"
print("Connecting to MQTT server... ", end="")
client = MQTTClient(client_id=MQTT_CLIENT_ID, 
server=MQTT_BROKER, user=MQTT_USER, 
password=MQTT_PASSWORD, 
keepalive=7200,
ssl=True,
ssl_params={'server_hostname':'5d2b1e680bc4427bbacc7535a47a72eb.s1.eu.hivemq.cloud'})

# LED pin
led = Pin(0, Pin.OUT)

# The callback function
def sub_callback(topic, msg):
  print("Received: {}:{}".format(topic.decode(), msg.decode()))
  led.high() #turn the led ON

client.set_callback(sub_callback)
client.connect()
client.subscribe(topic = MQTT_TOPIC)
print("MQTT Connected!")

# Read data from the DHT22 sensor and publish to the MQTT brocker
prev_weather = ""
sensor = dht.DHT22(Pin(28))
while True:
  print("Measuring weather conditions... ", end="")
  sensor.measure() 
  message = ujson.dumps({
    "temp": sensor.temperature(),
    "humidity": sensor.humidity(),
  })
  if message != prev_weather:
    print("Updated!")
    print("Reporting to MQTT topic {}: {}".format(MQTT_TOPIC, message))
    client.publish(MQTT_TOPIC, message)
    prev_weather = message
  else:
    print(".")
  client.ping()
  client.check_msg()
  time.sleep(1)
  led.low()