from time import sleep
from machine import Pin

class Key:
  def __init__(self, name):
    self.name = name
    self.active = False

row_pins = []
col_pins = []

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


for pin_num in range(15,11,-1):
  row_pins.append(Pin(pin_num, Pin.OUT))

for pin_num in range(11,7,-1):
  col_pins.append(Pin(pin_num, Pin.IN, Pin.PULL_DOWN))

def scan_keys():
  # turn on each row
  for row, row_pin in enumerate(row_pins):
    row_pin.on()

    # check each column to see if the key is pressed
    # and set that key to "active" in the keys matrix
    for col, col_pin in enumerate(col_pins):
      keys[row][col].active = bool(col_pin.value())

    # turn off the row
    row_pin.off()

entered_password = '' # track user's input
correct_password = '2023'
## main loop
while True:
  scan_keys()

  for row in keys:
    for key in row:
      if key.active:

        if key.name is '#':   # user pressed 'enter'
          print()
          if entered_password == correct_password:
            print("Welcome in!")
          else:
            print("Wrong Password")
          entered_password = ''

        else:
          print(key.name, end='')
          entered_password += key.name

        # debounce button press  
        sleep(0.25)