from machine import Pin
import time

keys = [
    ['1','2','3','A'],
    ['4','5','6','B'],
    ['7','8','9','C'],
    ['*','0','#','D']
]

row_pins = [32, 33, 25, 26]
col_pins = [27, 14, 12, 13]

rows = [Pin(pin, Pin.OUT) for pin in row_pins]
cols = [Pin(pin, Pin.IN, Pin.PULL_DOWN) for pin in col_pins]
AUTHORIZED_CARDS = ["1234", "5555", "9876"]

entered_id = ""

adding_user = False   # Mode flag
new_user = ""

ADMIN_PIN = "9999"    # Secret code to enter Add-User mode

print("Place RFID / Enter Code")

def get_key():
    for r in range(4):
        rows[r].value(1)
        for c in range(4):
            if cols[c].value():
                rows[r].value(0)
                return keys[r][c]
        rows[r].value(0)
    return None


while True:
    key = get_key()

    if key:
        print("Key Pressed:", key)
        if not adding_user:
            if key == '#':
                if entered_id in AUTHORIZED_CARDS:
                    print("✅ Access Granted")
                elif entered_id == ADMIN_PIN:
                    print("🔐 ADMIN MODE — Enter New Card Number then press #")
                    adding_user = True
                else:
                    print("❌ Access Denied")

                entered_id = ""

            elif key == '*':
                entered_id = ""
                print("Cleared")

            else:
                entered_id += key
                print("Current:", entered_id)

        else:
            if key == '#':
                if new_user != "":
                    AUTHORIZED_CARDS.append(new_user)
                    print("👤 New User Added:", new_user)
                    print("Current Users:", AUTHORIZED_CARDS)
                new_user = ""
                adding_user = False

            elif key == '*':
                new_user = ""
                print("Cancelled — Back to Normal Mode")

            else:
                new_user += key
                print("New ID:", new_user)

        time.sleep(0.3)