import time
time.sleep(0.1) # Wait for USB to become ready

print("Hello, Pi Pico!")
import machine  # Import the machine module to interact with hardware components
import time     # Import the time module for time-related functions
from utime import sleep  # Import sleep from utime for delays

# Define the number of buttons and LEDs
BUTTON_COUNT = 3
LED_COUNT = 9

# Define the starting GPIO numbers for buttons and LEDs
BUTTON_START_ID = 16
LED_START_ID = 7

# Initialize variables to keep track of button presses and passcode status
last_button_time_stamp = 0
key_presses = []
passcode_entered = False

# Function to get the number from a pin object
def PinId(pin):
    # Convert the pin object to a string, extract the pin number, and convert it back to an integer
    return int(str(pin)[8:11].rstrip(","))

# Function to handle button press interrupts
def interrupt_callback(pin):
    global last_button_time_stamp  # Access the global variable for the last button timestamp
    global passcode_entered        # Access the global variable for passcode entry status
    cur_button_ts = time.ticks_ms()  # Get the current time in milliseconds
    button_press_delta = cur_button_ts - last_button_time_stamp  # Calculate the time since the last button press
    
    # If more than 200 ms have passed since the last press, it's not a bounce
    if button_press_delta > 200:
        last_button_time_stamp = cur_button_ts  # Update the last button timestamp
        key_presses.append(pin)  # Add the pressed button to the list of key presses
        print(f'Button {PinId(pin) - BUTTON_START_ID} pressed')  # Print which button was pressed
        if not passcode_entered:
            start_timer()  # Start the passcode timer if it's not already started

# Function to start the passcode timer
def start_timer():
    global passcode_entered
    global last_button_time_stamp
    last_button_time_stamp = time.ticks_ms()  # Reset the last button timestamp
    passcode_entered = True  # Set the passcode entry status to True

# The main function where the setup and loop logic will run
def main():
    global key_presses
    global last_button_time_stamp
    global passcode_entered

    # Initialize the multiplexer control pins
    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)

    # Set up the buttons and attach interrupt handlers
    buttons = []
    for btn_idx in range(BUTTON_COUNT):
        button_pin = machine.Pin(BUTTON_START_ID + btn_idx, machine.Pin.IN, machine.Pin.PULL_DOWN)
        button_pin.irq(trigger=machine.Pin.IRQ_FALLING, handler=interrupt_callback)
        buttons.append(button_pin)

    # Define the correct sequence of buttons for the passcode
    PASS_CODE = [buttons[0], buttons[2], buttons[1]]

    # Initialize the LED pins
    LED_pins = [machine.Pin(LED_START_ID + out_id, machine.Pin.OUT) for out_id in range(LED_COUNT)]

    last_dev = -1  # Variable to keep track of the last device (multiplexer output)

    # Main loop
    while True:
        binary_code = 0  # Variable to store the binary code from the multiplexer
        # Read the binary code from the multiplexer
        for selector_val in range(4):
            s0.value(selector_val % 2)
            s1.value(selector_val // 2)
            sleep(0.02)  # Wait a bit for the value to stabilize
            binary_code += (pow(2, selector_val) * mux_in.value())  # Calculate the binary code

        # If the binary code has changed, print it
        if last_dev != binary_code:
            last_dev = binary_code
            print(f'Multiplexer output is now: {last_dev}')
        sleep(0.1)  # Short delay before the next loop iteration

        # Check if the passcode has been entered
        if passcode_entered:
            # If 3 seconds have passed since the last button press, reset the passcode entry
            if time.ticks_diff(time.ticks_ms(), last_button_time_stamp) >= 3000:
                print("Time's up! Please enter the passcode again.")
                key_presses.clear()  # Clear the list of key presses
                passcode_entered = False  # Reset the passcode entry status
            # If the passcode length matches the number of key presses, check if it's correct
            elif len(key_presses) == len(PASS_CODE):
                if key_presses == PASS_CODE:
                    print('Passcode is correct!')
                    # If the binary code is within the range of LEDs, toggle the corresponding LED
                    if binary_code < LED_COUNT:
                        print(f'Toggling LED number: {binary_code}')
                        LED_pins[binary_code].toggle()
                    else:
                        print(f'Invalid output: {binary_code}. No action taken.')
                else:
                    print('Passcode is incorrect. Try again.')
                key_presses.clear()  # Clear the list of key presses
                passcode_entered = False  # Reset the passcode entry status

# Run the main function if this script is executed
if __name__ == "__main__":
    main()