"""
MicroPython MQTT LED light control Example for Wokwi.com

To control the led:

1. Open MQTTX application, New connection
2. Name: test, Server Address: broker.emqx.io
3. Click "Connect"
4. Add subscription, set the topic to "wokwi-message"
5. Under "JSON" option, set the Topic to "wokwi-light"
6. Turn on the light: In the Message field type (json format): {"setValue": true}
7. click "Publish"
8. Turn off the light: In the Message field type (json format): {"setValue": false}
9. click "Publish"

Copyright (C) 2022, Uri Shaked

Reference:
https://wokwi.com/arduino/projects/315787266233467457

umqtt.simple参考：
https://mpython.readthedocs.io/en/master/library/mPython/umqtt.simple.html
https://pypi.org/project/micropython-umqtt.simple/
"""

import network
from machine import Pin
from time import sleep
import ujson
from umqtt.simple import MQTTClient

# MQTT Server Parameters
MQTT_CLIENT_ID = "micropython-mqtt-esp32-demo"
MQTT_BROKER    = "broker.emqx.io"
MQTT_USER      = ""
MQTT_PASSWORD  = ""
MQTT_SUB_TOPIC     = "wokwi-light"
MQTT_PUB_TOPIC     = "wokwi-message"

# 延时次数计数变量，每次延时0.2秒，10次延时是2秒钟
counter=0

# LED灯连接在ESP32的D13引脚
led = Pin(13, Pin.OUT)

# mqtt回调函数，当收到订阅主体的MQTT消息时执行
def mqtt_message(topic, msg):
  print("Incoming message:", msg)
  try:
    msg = ujson.loads(msg)
    print(msg)
    if(msg['method']=='setValue' and msg['params']): led.on()
    elif(msg['method']=='setValue' and not msg['params']): led.off()
  except Exception as e:
    print("Error:", e)

# 连接WiFi
print("Connecting to WiFi...", end="")
wifi = network.WLAN(network.STA_IF)
wifi.active(True)
wifi.connect("Wokwi-GUEST", "")
while not wifi.isconnected():
  sleep(0.5)
  print(".", end="")
print("Wifi Connection Done")

# 连接 MQTT服务器
print("Connecting to MQTT...")
client = MQTTClient(MQTT_CLIENT_ID, MQTT_BROKER, user=MQTT_USER, password=MQTT_PASSWORD)
client.set_callback(mqtt_message)
client.connect()
client.subscribe(MQTT_SUB_TOPIC)
print("MQTT Connected!")

# 如下循环执行两个周期性事务
# 1. 调用mqtt的check_msg()方法检查是否有来自MQTT服务器的消息
# 2. 每2秒钟，上报一个数据
while True:
  if (counter<10): counter=counter+1  
  elif (counter>=10):
    counter=0
    client.publish(MQTT_PUB_TOPIC,"hello from esp32")
  sleep(0.2)
  client.check_msg()