from machine import Pin
from time import sleep

increment = Pin(18, Pin.IN, Pin.PULL_UP)
decrement = Pin(19, Pin.IN, Pin.PULL_UP)

green = Pin(25, Pin.OUT)
red = Pin(26, Pin.OUT)
yellow = Pin(27, Pin.OUT)
blue = Pin(14, Pin.OUT)

MAX_CARS = 15
cars = 0

def update_state():
    if cars < MAX_CARS:
        green.value(1)
        red.value(0)
    else:
        green.value(0)
        red.value(1)

green.value(1)
red.value(0)
yellow.value(0)
blue.value(0)

update_state()

while True:

    if increment.value() == 0:
        if cars < MAX_CARS:
            cars += 1

            print("Car entered")
            print("Cars inside:", cars)

            yellow.value(1)
            sleep(0.7)
            yellow.value(0)

            update_state()

        while increment.value() == 0:
            sleep(0.05)

    if decrement.value() == 0:
        if cars > 0:
            cars -= 1

            print("Car exited")
            print("Cars inside:", cars)

            blue.value(1)
            sleep(0.7)
            blue.value(0)

            update_state()

        while decrement.value() == 0:
            sleep(0.05)

    sleep(0.05)