import time
import board
import digitalio

# 1. SETUP SHARED BCD PINS (GP2, GP3, GP4, GP5)
# A=GP2, B=GP3, C=GP4, D=GP5
bcd_pins = []
for p_num in [board.GP2, board.GP3, board.GP4, board.GP5]:
    pin = digitalio.DigitalInOut(p_num)
    pin.direction = digitalio.Direction.OUTPUT
    bcd_pins.append(pin)

# 2. SETUP LATCH PINS (GP1=Tens, GP0=Ones)
latch_tens = digitalio.DigitalInOut(board.GP1)
latch_tens.direction = digitalio.Direction.OUTPUT
latch_tens.value = True

latch_ones = digitalio.DigitalInOut(board.GP0)
latch_ones.direction = digitalio.Direction.OUTPUT
latch_ones.value = True

# 3. SETUP BUTTONS (GP15=Start, GP16=Reset)
sw1 = digitalio.DigitalInOut(board.GP15)
sw1.direction = digitalio.Direction.INPUT
sw1.pull = digitalio.Pull.UP

sw2 = digitalio.DigitalInOut(board.GP16)
sw2.direction = digitalio.Direction.INPUT
sw2.pull = digitalio.Pull.UP

# FUNCTION TO SEND DATA
def write_digit(target_latch, value):
    # Prepare BCD data on shared bus
    for i in range(4):
        bcd_pins[i].value = (value >> i) & 1
    
    # Pulse the specific latch (Low then High)
    target_latch.value = False  # Enable
    time.sleep(0.01)            # Wait for hardware
    target_latch.value = True   # Hold/Latch

def update_display(current_time):
    tens = current_time // 10
    ones = current_time % 10
    write_digit(latch_tens, tens)
    write_digit(latch_ones, ones)

# MAIN VARIABLES
count = 0
running = False
y = 60

# Initial Display 00
update_display(count)

while True:
    # START BUTTON
    if not sw1.value:
        if not running:
            running = True
            print(">>> START")
        time.sleep(0.2)

    # RESET BUTTON
    if not sw2.value:
        running = False
        count = 0
        update_display(count)
        print(">>> RESET")
        time.sleep(0.2)

    # COUNTING LOGIC
    if running:
        time.sleep(1.0)
        count += 1
        if count > y:
            count = 0
        
        update_display(count)
        print("Time: {:02d}".format(count))