from machine import Pin
from machine import ADC
from utime import sleep_us, sleep
from machine import time_pulse_us

led1 = Pin(15, Pin.OUT)
led2 = Pin(2, Pin.OUT)
trig = Pin(21, Pin.OUT)
echo = Pin(19, Pin.IN)
gas_sensor = ADC(Pin(4))
gas_sensor.atten(ADC.ATTN_11DB)
ldr = ADC(Pin(0))
ldr.atten(ADC.ATTN_11DB)

DANGER_DIST = 15
VEHICLE_DIST = 30
GAS_LIMIT = 2000
LIGHT_THRESHOLD = 1500

red_light = led1
tunnel_light = led2

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

    duration = time_pulse_us(echo, 1, 30000)
    if duration < 0:
        return None
    return (duration * 0.0343) / 2

# STATE FUNC
def distance_state(d):
    if d is None:
        return "NO SIGNAL"
    elif d < DANGER_DIST:
        return "TOO CLOSE"
    elif d < VEHICLE_DIST:
        return "VEHICLE"
    else:
        return "CLEAR"

def gas_state(g):
    if g > GAS_LIMIT:
        return "DANGER"
    else:
        return "SAFE"

def light_state(l):
    if l < LIGHT_THRESHOLD:
        return "DARK"
    else:
        return "LIGHT"

# MAIN LOOP
while True:
    distance = get_distance()
    gas_value = gas_sensor.read()
    light_value = ldr.read()

    dist_status = distance_state(distance)
    gas_status = gas_state(gas_value)
    light_status = light_state(light_value)
    system_status = "ENERGY SAVE"

    # TOO CLOSE OBJECT (RED LED)
    if dist_status == "TOO CLOSE":
        red_light.value(1)
        tunnel_light.value(0)
        system_status = "OBJECT DANGER"

    # VEHICLE DETECTED (LIGHT ON)
    elif dist_status == "VEHICLE":
        tunnel_light.value(1)
        red_light.value(0)
        system_status = "VEHICLE PRESENT"

    # DARK AREA (LIGHT ON)
    elif light_status == "DARK":
        tunnel_light.value(1)
        red_light.value(0)
        system_status = "DARK AREA"

    # SAFE (EVERYTHING OFF)
    else:
        system_status = "ENERGY SAVE"
        tunnel_light.value(0)
        red_light.value(0)

    print("Distance:", dist_status,
          "| Gas:", gas_status,
          "| Light:", light_status,
          "| System:", system_status)

    sleep(1)