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

# WIFI Connection
SSID = "Wokwi-GUEST"
PASSWORD = ""

# MQTT Broker Details
BROKER_ADDRESS = "broker.hivemq.com"
TOPIC = "your_topic"

# HC-SR04 Pins
TRIGGER_PIN = 12
ECHO_PIN = 14

# Constants
MAX_DISTANCE_CM = 400  # Maximum distance in cm for the sensor
NUM_MEASUREMENTS = 5  # Number of measurements to take for averaging
TIMEOUT_US = 1000000  # Timeout in microseconds for sensor response

# Connect to WIFI
def connect_wifi():
    wifi = network.WLAN(network.STA_IF)
    wifi.active(True)
    if not wifi.isconnected():
        print("Connecting to WiFi...")
        wifi.connect(SSID, PASSWORD)
        while not wifi.isconnected():
            pass
    print("Connected to WiFi:", SSID)

# Get distance from HC-SR04
def get_distance():
    trigger = Pin(TRIGGER_PIN, Pin.OUT)
    echo = Pin(ECHO_PIN, Pin.IN)
    
    distances = []
    for _ in range(NUM_MEASUREMENTS):
        trigger.value(0)
        time.sleep_us(5)
        trigger.value(1)
        time.sleep_us(10)
        trigger.value(0)
        
        pulse_start = pulse_end = time.ticks_us()
        timeout = time.ticks_us() + TIMEOUT_US
        
        while echo.value() == 0 and time.ticks_us() < timeout:
            pulse_start = time.ticks_us()
        while echo.value() == 1 and time.ticks_us() < timeout:
            pulse_end = time.ticks_us()
        
        if pulse_end > pulse_start:
            pulse_duration = pulse_end - pulse_start
            distance = (pulse_duration * 0.0343) / 2
            if 0 < distance < MAX_DISTANCE_CM:
                distances.append(distance)
    
    if distances:
        return sum(distances) / len(distances)
    else:
        return None

# MQTT Client
def send_to_mqtt(data):
    client = MQTTClient("esp32", BROKER_ADDRESS)
    client.connect()
    client.publish(TOPIC, str(data))
    client.disconnect()

# Main function
def main():
    connect_wifi()
    while True:
        try:
            distance = get_distance()
            if distance is not None:
                print("Distance:", distance, "cm")
                send_to_mqtt(distance)
            else:
                print("Distance measurement failed")
        except Exception as e:
            print("Error:", e)
        time.sleep(1)

if __name__ == "__main__":
    main()