import RPi.GPIO as GPIO
import time

# Define GPIO Pins
TRIGGER_PIN = 23
ECHO_PIN = 24
LED_PIN = 18

# Setup GPIO
GPIO.setmode(GPIO.BCM)
GPIO.setup(TRIGGER_PIN, GPIO.OUT)
GPIO.setup(ECHO_PIN, GPIO.IN)
GPIO.setup(LED_PIN, GPIO.OUT)

def measure_distance():
    """ Measure distance using HC-SR04 """
    GPIO.output(TRIGGER_PIN, False)
    time.sleep(0.1)
    
    # Send trigger pulse
    GPIO.output(TRIGGER_PIN, True)
    time.sleep(0.00001)
    GPIO.output(TRIGGER_PIN, False)

    # Wait for response
    start_time = time.time()
    while GPIO.input(ECHO_PIN) == 0:
        start_time = time.time()
    while GPIO.input(ECHO_PIN) == 1:
        end_time = time.time()

    # Calculate distance
    elapsed_time = end_time - start_time
    distance = (elapsed_time * 34300) / 2  # Convert to cm
    return distance

try:
    while True:
        distance = measure_distance()
        print(f"Distance: {distance:.2f} cm")

        if distance < 10:  # Threshold
            print("⚠️ Flood Detected! Alert!")
            GPIO.output(LED_PIN, GPIO.HIGH)
        else:
            GPIO.output(LED_PIN, GPIO.LOW)

        time.sleep(1)

except KeyboardInterrupt:
    print("Measurement stopped by user")
    GPIO.cleanup()