function split (s, splitter)
result = {};
for match in (s..splitter):gmatch("(.-)"..splitter) do
table.insert(result, match);
end
return result;
end

function verify(username, password)
  if fs.exists("/data/"..username) == false then
    return "404"
    print("Invalid user "..username.." just tried to login!")
  else
    --the user exists
    local file = fs.open("/data/"..username,"r")
    print(password)
    if password == file.readLine() then
      --correct password
      modem.transmit(1,1,"Logging into "..username)
      print("User "..username.." just logged in!")
    else
      --incorrect password
      return "403"
    end
  end
end

local modem = peripheral.wrap("top")
textutils.slowPrint("Starting Server...")

while true do
  modem.open(1)

  local _, side, freq, rfreq, message = os.pullEvent("modem_message")
  print(message)
  msg = split(message, "`")
  for key, value in pairs(msg) do
    if key == 0 then
      action = value
    else if key == 1 then
      var1 = value
    else if key == 2 then
      var2 = value
    end
  end
  print(action..var1..var2)
  if fs.exists("/data") == false then
    fs.makeDir("/data")
  end
--Do the requested action
  if action == "balance" then
    user = verify(var1, var2)
      if user == "0" then
          --Correct user just a fake balance for now because we do not actually store it
          modem.transmit(1,1,"1200")
      else if user == "403" then
        print("Failed login attempt for user "..username)
        modem.transmit(1,1,"403")
      else if user == "404" then
        print("Non existant "..username.." just tried to login")
        modem.transmit(1,1,"404")
      end
    end
  else if action == "register" then
    --Checking if the user exists
    if verify(var1,"") != "404" then
      --user already exists
      modem.transmit(1,1,"409")
    else
      --its a new user!
      local file = fs.open("/data/"..username,"a")
      file.writeLine(password)
      file.close()
    end
  end
end
end