from machine import PWM, Pin
from time import sleep
from hcsr04 import HCSR04
from lcd_api import LcdApi
from i2c_lcd import I2cLcd
from machine import Pin, I2C
import ujson
import network
import time
from umqtt.simple import MQTTClient

# Constants
frequency = 5000
threshold_distance = 250  
MQTT_CLIENT_ID = "micropython-distance-sensor"
MQTT_BROKER = "broker.mqttdashboard.com"
MQTT_USER = ""  
MQTT_PASSWORD = ""
MQTT_TOPIC = "wokwi-distancee"


led = PWM(Pin(2), frequency)
led.duty(0)  


i2c = I2C(scl=Pin(22), sda=Pin(21), freq=400000)
lcd = I2cLcd(i2c, 0x27, 2, 16)  


sensor1 = HCSR04(trigger_pin=5, echo_pin=18, echo_timeout_us=100000)


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!")

while True:
    try:
        distance = sensor1.distance_cm()
        if distance < threshold_distance:
            duty_cycle = int((1 - (distance / threshold_distance)) * 1023)
            led.duty(duty_cycle)
            led_state = "ON"
        else:
            led.duty(0)
            led_state = "OFF"
        lcd.clear()  
        lcd.putstr("Distance:\n{} cm".format(distance))  # Display distance on the LCD

        print('Distance:', distance, 'cm')
        print('LED State:', led_state)


        message = ujson.dumps({
            "distance": distance,
            "led_state": led_state
        })

       
        print("Reporting to MQTT topic {}: {}".format(MQTT_TOPIC, message))
        client.publish(MQTT_TOPIC, message)

     
        sleep(0.5)

    except Exception as e:
        print("Error:", e)
        lcd.clear()
        lcd.putstr("Error reading\nsensor")
        sleep(1)