from machine import Pin
import time

 
redA = Pin(23, Pin.OUT); yellowA = Pin(22, Pin.OUT); greenA = Pin(16, Pin.OUT)
redB = Pin(21, Pin.OUT); yellowB = Pin(5, Pin.OUT);  greenB = Pin(4, Pin.OUT)
redC = Pin(27, Pin.OUT); yellowC = Pin(26, Pin.OUT); greenC = Pin(2, Pin.OUT)
redD = Pin(32, Pin.OUT); yellowD = Pin(33, Pin.OUT); greenD = Pin(13, Pin.OUT)


emergency = False
pedestrian = False
night = False
density = 2    

while True:

    # Emergency Vehicle Mode
    if emergency:
        for _ in range(5):
            redA.on(); redB.on(); redC.on(); redD.on()
            time.sleep(0.5)
            redA.off(); redB.off(); redC.off(); redD.off()
            time.sleep(0.5)

    # Pedestrian Crossing Mode 
    elif pedestrian:
        redA.on(); redB.on(); redC.on(); redD.on()
        time.sleep(5)
        redA.off(); redB.off(); redC.off(); redD.off()

    # Night Mode 
    elif night:
        for _ in range(5):
            yellowA.on(); yellowB.on(); yellowC.on(); yellowD.on()
            time.sleep(1)
            yellowA.off(); yellowB.off(); yellowC.off(); yellowD.off()
            time.sleep(1)

    # Normal Traffic Cycle 
    else:
        
        if density == 1:
            green_time = 2
        elif density == 2:
            green_time = 4
        else:
            green_time = 6

        # Side A Green
        redA.off(); redB.on(); redC.on(); redD.on()
        greenA.on()
        time.sleep(green_time)
        greenA.off(); yellowA.on()
        time.sleep(2)
        yellowA.off(); redA.on()

        # Side B Green
        redB.off(); redA.on(); redC.on(); redD.on()
        greenB.on()
        time.sleep(green_time)
        greenB.off(); yellowB.on()
        time.sleep(2)
        yellowB.off(); redB.on()

        # Side C Green
        redC.off(); redA.on(); redB.on(); redD.on()
        greenC.on()
        time.sleep(green_time)
        greenC.off(); yellowC.on()
        time.sleep(2)
        yellowC.off(); redC.on()

        # Side D Green
        redD.off(); redA.on(); redB.on(); redC.on()
        greenD.on()
        time.sleep(green_time)
        greenD.off(); yellowD.on()
        time.sleep(2)
        yellowD.off(); redD.on()