--[[
420-login script
by killerbyte12
for use on OpenComputers mod in minecraft
--]]

-- GLOBAL vars
ATTEMPTS = 3
LOGGED_IN = false

-- Ask for username
function userInput()
  -- ask for username, covert input to all uppercase.
  print("Username: ")
  local input = string.upper(io.read())

  -- compare input to user files. Does this user exist?
  local user_exists = userExists(input)
  if user_exists == nil then
    print("Username invalid.")
  -- if user exists, lets ask for their password
  else
    print("Username found.")
    passInput(input)
  end
end

-- checks if a user file exists, returns nil if it doesnt.
function userExists(user)
  local file = io.open(".dat/.usr/."..user..".txt", "r")
  if file ~= nil then
    file:close()
  end
  return file
end

-- Compare input to password on user file
function getPass(user, pass)
  local file_contents = {}
  local pass_valid = false
  local file = io.open(".dat/.usr/."..user..".txt", "r")
  for line in file:lines() do
    file_contents[#file_contents+1] = line
  end
  file:close()
  -- password is on 3rd line
  if file_contents[3] == pass then
    pass_valid = true
  end
  return pass_valid
end

-- Ask for password
function passInput(user)
  while ATTEMPTS > 0 do
    print("Password: ")
    local input = io.read()
    -- TODO md5 hash passwords

    local pass_valid = getPass(user, input)
    if pass_valid == true then
      print("Password accepted, logging in.")
      LOGGED_IN = true
      break
    else
      ATTEMPTS = ATTEMPTS - 1
      print("Password invalid. You have "..ATTEMPTS.." attempts left.")
    end
  end
  if ATTEMPTS <= 0 then
    print("You tried to many times, shutting down the system!")
    -- TODO, shutdown pc
  end
end

while LOGGED_IN == false do
  userInput()
end