# Modules
from machine import Pin
from time import sleep


# Declaring LED Pins
led_pins = [19, 18, 5, 17]
leds = [Pin(i, Pin.OUT, value = 0) for i in led_pins]


# Declaring registers sequence and an index variable
register = [0, 0, 0, 0]
dat_seq = [1, 0, 1, 1, 0, 1, 0, 1, 0, 1]
dat_ind = 0


# A function that shifts the register's bits to the right
def shift_right(reg, new_bit):
    for i in range(len(reg) - 1, 0, -1):
        reg[i] = reg[i - 1]
    reg[0] = new_bit


# A function that visualizes the register into LEDs
def write_register_to_leds():
    for i, led in enumerate(leds):
        led.value(register[i])


# Main loop
while True:
    # Assigning a new value for new_bit
    new_bit = dat_seq[dat_ind]

    # Shifting the register by the new bit
    shift_right(register, new_bit)

    # Displaying the register with the new bit
    print(f"Register: {register}, New Bit: {new_bit}")

    # Visualising the register with LEDs
    write_register_to_leds()

    # Increasing index by one
    dat_ind += 1

    # If statement that makes sure that no IndexError will happen
    if dat_ind >= len(dat_seq):
        dat_ind = 0

    sleep(1) # 1 second delay