from machine import Pin, time_pulse_us
import time

# Pins
trig = Pin(26, Pin.OUT)
echo = Pin(18, Pin.IN)

led_red = Pin(3, Pin.OUT)
led_yellow = Pin(5, Pin.OUT)
led_green = Pin(4, Pin.OUT)  # Changed from GPIO6 to GPIO4
buzzer = Pin(27, Pin.OUT)

def get_distance():
    trig.value(0)
    time.sleep_us(2)
    trig.value(1)
    time.sleep_us(10)
    trig.value(0)

    try:
        duration = time_pulse_us(echo, 1, 30000)  # Timeout 30ms
        distance = (duration / 2) / 29.1
    except OSError:
        distance = None
    return distance

# Thresholds (in cm)
LOW_LEVEL = 20    # <=20 cm water level = HIGH water
MEDIUM_LEVEL = 40 # 21-40 cm = MEDIUM water
HIGH_LEVEL = 60   # >40 cm = LOW water

def indicate_level(distance):
    # Turn off all outputs first
    led_red.value(0)
    led_yellow.value(0)
    led_green.value(0)
    buzzer.value(0)

    if distance is None:
        print("Error reading distance")
        return

    print("Distance: {:.2f} cm".format(distance))

    if distance > HIGH_LEVEL:
        print("Water Level: LOW")
        led_red.value(1)
        buzzer.value(1)
    elif LOW_LEVEL < distance <= HIGH_LEVEL:
        print("Water Level: MEDIUM")
        led_yellow.value(1)
        buzzer.value(0)
    elif distance <= LOW_LEVEL:
        print("Water Level: HIGH")
        led_green.value(1)
        buzzer.value(0)
    else:
        print("Water Level: Unknown")

while True:
    dist = get_distance()
    indicate_level(dist)
    time.sleep(2)