--Code to SHA-256 it
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function clearScreen()
  term.clear()
  term.setCursorPos(1,1)
end

function loggedOn(username, password, balance, modem)
  while true do
  clearScreen()
  showTitle(username, balance)
  print("1 - Pay another user")
  print("2 - Deposit")
  print("3 - Withdraw")
  print("4 - View spending log")
  print("5 - Log Out")
  print("")
  write("Action> ")
  action = read()
  if action == "1" then
    payScreen(username, password, balance, modem)
  elseif action == "2" then

  elseif action == "3" then

  elseif action == "4" then

  elseif action == "5" then
    return
  end
end
end

function showTitle(username, balance)
  print("               The Bank Of Sanctuary")
  print("---------------------------------------------------")
  print("Acount: "..username.."                Balance: $"..balance)
  print("---------------------------------------------------")
end

function viewLog(username, password, balance, modem)
  clearScreen()
  showTitle(username, balance)
  return;
end

function userExists(username)

  local modem = peripheral.wrap("back")
  modem.transmit(1,1,"balance`"..username.."`password1234")

  modem.open(1)
  local _, side, freq, rfreq, message = os.pullEvent("modem_message")
  if message == "404" then
    return false
  end
  return true
end

function payScreen(username, password, balance, modem)
  clearScreen()
  showTitle(username, balance)
  write("Username to pay: ")
  payee = read()
  write("Amount to pay: $")
  amount = read()
  if amount > balance then
    clearScreen();
    difference = amount - balance;
    print("You do not have enough money to pay, you need $"..difference.." more!")
    os.sleep(4)
  elseif userExists(payee) == false then
    --Thats not a user!
    clearScreen()
    print(payee.." is not a valid user!")
    os.sleep(4)
  else
    --Update graphical balance
    balance = balance - amount
    modem.transmit(1,1,"pay`"..username.."`"..password.."`"..payee.."`"..amount)
  end
  return;
end

while true do
  clearScreen()
  print("Welcome to The Bank!")
  print("Press 1 for a new user")
  print("Press 2 for an existing user")
  print("")
  write("Key> ")

  key = read()
  local modem = peripheral.wrap("back")
  if key == "1" then
    --user wants to create a new account
    clearScreen()
    print("Register")
    write("Username: ")
    username = read()
    clearScreen()
    print("Register")
    write("Password: ")
    pssw = read("*")
    --Hash password
    password = sha256(pssw)
    pssw = ""
    print("Waiting for server...")
    modem.transmit(1,1,"register`"..username.."`"..password)
    modem.open(1)
    local _, side, freq, rfreq, message = os.pullEvent("modem_message")
    if messsage == "409" then
      print("This user is already registered!")
    else
      print("User "..username.." registered!")
    end
    os.sleep(4)
  elseif key == "2" then
    --user just wants to login
    clearScreen()
    print("Login")
    write("Username: ")
    username = read()
    clearScreen()
    print("Login")
    write("Password: ")
    pssw = read("*")
    password = sha256(pssw)
    clearScreen()
    modem.transmit(1,1,"balance`"..username.."`"..password)

    modem.open(1)
    local _, side, freq, rfreq, message = os.pullEvent("modem_message")
    if message == "403" then
      print("Incorrect password!")
    else if message == "404" then
      print("There is no user called "..username.."!")
    else
      loggedOn(username,password,message, modem)
      clearScreen()
      print("Logged out!")
    end
    os.sleep(2)
  end
  end
end