from machine import Pin, I2C,Timer
import ssd1306
import dht
import network
import time
import ujson
from umqtt.simple import MQTTClient
# ESP32 Pin assignment 
i2c = I2C(0, scl=Pin(22), sda=Pin(21))

oled_width = 128
oled_height = 64
oled = ssd1306.SSD1306_I2C(oled_width, oled_height, i2c)

oled.text('zhanglisi',10,10)
oled.show()

d = dht.DHT22(Pin(15))
def getdht(t):
    d.measure()
    a=d.temperature()
    b=d.humidity()
    print('tmp:%f dc'%a)
    print('humidity:%f %%'%b)
    oled.fill(0)
    oled.text('zhanglisi',10,10)
    oled.text('tmp:%2.1f dc'%a,10,30)
    oled.text('humidity:%2.1f dc'%b,10,50)
    oled.show()
tim = Timer(-1)
tim.init(period=2000,mode=Timer.PERIODIC,callback=getdht)

# MQTT Server Parameters
MQTT_CLIENT_ID = "micropython-weather-demo"
MQTT_BROKER    = "broker.mqttdashboard.com"
MQTT_USER      = ""
MQTT_PASSWORD  = ""
MQTT_TOPIC     = "wokwi-weather"

sensor = dht.DHT22(Pin(15))

print("Connecting to WiFi", end="")
sta_if = network.WLAN(network.STA_IF)
sta_if.active(True)
sta_if.connect('Wokwi-GUEST', '')
while not sta_if.isconnected():
  print(".", end="")
  time.sleep(0.1)
print(" Connected!")

print("Connecting to MQTT server... ", end="")
client = MQTTClient(MQTT_CLIENT_ID, MQTT_BROKER, user=MQTT_USER, password=MQTT_PASSWORD)
client.connect()

print("Connected!")

prev_weather = ""
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("No change")
  time.sleep(1)