from time import sleep
sleep(0.1) # Wait for USB to become ready
from arrays import OutArray
from machine import Pin

# pins for values A & V
B_list = [2, 3, 4, 5]
A_list = [6, 7, 8, 9]
# create carry in input
btn = Pin(10, Pin.IN, Pin.PULL_UP)
cin = Pin(11, Pin.OUT, value=0)
cin.value(btn.value())
# create output arrays of GPIO pins
A = OutArray(A_list)
B = OutArray(B_list)
print("Welcome to 4 bit Adder/Subtractor")

while True:
    try:
        # get values of A & B
        x = input('Value of A: ')
        numA = int(x)   # convert to integer
        while numA > 15:    # check a valid value
            print("Error: A must be a value less than 16")
            x = input('Value of A: ')
            numA = int(x)
        x = input('Value of B: ')
        numB = int(x) # convert to integer
        while numB > 15:    # check a valid value
            print("Error: B must be a value less than 16")
            x = input('Value of B: ')
            numB = int(x)
        cin.value(btn.value())
        A.write(numA)
        B.write(numB)
        if btn.value():
            print(f"A - B: {numA} - {numB} = {numA - numB}")
        else:
            print(f"A + B: {numA} + {numB} = {numA + numB}")
        sleep(0.1)
    except KeyboardInterrupt:
        break
# clear all leds at end
A.write(0)
B.write(0)
cin.value(0)
print(f'\nfinished')