import machine
import time
from utime import sleep

#defining~
BUTTON_COUNT = 3
LED_COUNT = 9
INPUT_COUNT = 4

BUTTON_START_ID = 16
LED_GPIO_START = 7
last_button_time_stamp = 0
key_presses = []

# Extract the numeric pin id from the passed-in Pin instance 
def PinId(pin):
    return int(str(pin)[8:11].rstrip(","))

def interrupt_callback(pin):
    global last_button_time_stamp

    cur_button_ts = time.ticks_ms()
    button_press_delta = cur_button_ts - last_button_time_stamp
    if button_press_delta > 300:  # the debounce time
        last_button_time_stamp = cur_button_ts
        key_presses.append(pin)
        print(f'Button pressed: {PinId(pin) - BUTTON_START_ID}')

def main():
    global key_presses
    global last_button_time_stamp
    PASSCODE_LENGTH = 0

    s0 = machine.Pin(27, machine.Pin.OUT)
    s1 = machine.Pin(28, machine.Pin.OUT)
    mux_in = machine.Pin(26, machine.Pin.IN, machine.Pin.PULL_DOWN)

    buttons = []
    for btn_idx in range(BUTTON_COUNT):
        buttons.append(machine.Pin(BUTTON_START_ID + btn_idx, machine.Pin.IN, machine.Pin.PULL_DOWN))
        buttons[-1].irq(trigger=machine.Pin.IRQ_FALLING, handler=interrupt_callback)

    PASS_CODE = [buttons[0], buttons[2], buttons[1]]  # matches [0, 2, 1]
    PASSCODE_LENGTH = len(PASS_CODE)

    led_pins = [machine.Pin(LED_GPIO_START + i, machine.Pin.OUT) for i in range(LED_COUNT)]

    prev_binary_code = -1
    while True:
        binary_code = 0
        for selector_val in range(INPUT_COUNT):
            s0.value(selector_val % 2)
            s1.value(selector_val // 2)
            sleep(0.02)
            binary_code += (pow(2, selector_val) * mux_in.value())

        if prev_binary_code != binary_code:
            prev_binary_code = binary_code
            print(f'Selected output: {binary_code}')
        sleep(0.1)

        if len(key_presses) >= PASSCODE_LENGTH:
            if key_presses[:PASSCODE_LENGTH] == PASS_CODE:
                print('Correct passcode!')
                if binary_code < LED_COUNT:
                    print(f'Toggling LED {binary_code}')
                    led_pins[binary_code].toggle()
                else:
                    print(f'Invalid output: {binary_code}, valid range: 0-{LED_COUNT - 1}')
            else:
                print('Incorrect passcode!')
            print('')
            key_presses = key_presses[PASSCODE_LENGTH:]

if __name__ == "__main__":
    main()