from machine import Pin
from time import sleep

red = Pin(2, Pin.OUT)
blue = Pin(4, Pin.OUT)
green = Pin(5, Pin.OUT)
yellow = Pin(18, Pin.OUT)

entry = Pin(26, Pin.IN, Pin.PULL_UP)
exit_button = Pin(27, Pin.IN, Pin.PULL_UP)

cars = 0
capacity = 15

green.on()
red.off()
yellow.off()
blue.off()

while True:

    if entry.value() == 0:
        if cars < capacity:
            cars += 1

            yellow.on()
            sleep(0.3)
            yellow.off()

            if cars == 15:
                green.off()
                red.on()
            else:
                green.on()
                red.off()

            print("Entry accepted")
            print("Cars:", cars)

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

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

            blue.on()
            sleep(0.3)
            blue.off()

            if cars == 15:
                green.off()
                red.on()
            else:
                green.on()
                red.off()

            print("Exit accepted")
            print("Cars:", cars)

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

    sleep(0.05)