-- Variables -----------------------------------------------
local password = "123"
local keypadtable = {{3,2,"1"}, {4,2,"2"}, {5,2,"3"}, {3,3,"4"}, {4,3,"5"}, {5,3,"6"}, {3,4,"7"}, {4,4,"8"}, {5,4,"9"}}
local dooropendelay = 4
local errordelay = 3
local monitorlocation = 'back'
local redstonesignalside = 'left'

------------------------------------------------------------

local monitor = peripheral.wrap(monitorlocation)
local maxx, maxy = monitor.getSize()

local function idleScreen ()
  monitor.clear()
  monitor.setCursorPos(2,2)
  monitor.write("Enter")
  monitor.setCursorPos(3,3)
  monitor.write("PIN")
end

local function loginOK ()
  monitor.clear()
  monitor.setCursorPos(1,3)
  monitor.write("Welcome")
end

local function loginFail ()
  monitor.clear()
  monitor.setCursorPos(2,3)
  monitor.write("Error")
end

local function printKeyPad ()
  monitor.clear()
  for i=1,#keypadtable do
        monitor.setCursorPos(keypadtable[i][1],keypadtable[i][2])
        monitor.write(keypadtable[i][3])
  end
end

local function getKeyFromPad (xclick, yclick)
  for i=1,#keypadtable do
        if ((keypadtable[i][1] == xclick) and (keypadtable[i][2] == yclick)) then
          return (keypadtable[i][3])
        end
  end
  return ('')
end

local function openDoor ()
  redstone.setOutput (redstonesignalside, true)
end

local function closeDoor ()
  redstone.setOutput (redstonesignalside, false)
end

-- MAIN ------------------------------------------------------------

while true do
  idleScreen()
  local pwentered = ''

  -- Get first keypress and show pinpad
  local event, monside, xpos, ypos = os.pullEvent()
  if event == 'monitor_touch' then
        print ('* Starting keypad entry')
        printKeyPad()
  end

  while (tonumber(string.len(pwentered)) < tonumber(string.len(password))) do
        local pressed = ''
        local event, monside, xpos, ypos = os.pullEvent()

        if event == 'monitor_touch' then
         local pressed = tostring(getKeyFromPad (xpos, ypos))
         if pressed ~= "" then
          pwentered = pwentered .. pressed
          print ("* Pressed: " .. pressed)
         end
        end
  end

  if (pwentered == password) then
        print ('* Login SUCCESS')
        loginOK ()
        openDoor ()
        sleep (dooropendelay)
        closeDoor ()
  else
        print ('* Login FAIL')
        loginFail ()
        sleep (errordelay)
  end
end