twentefp-eventloop-graphics-0.1.0.3: src/EventLoop/Input/SystemMessage.hs

{-|
Module      : EventLoop.Input.SystemMessage
Description : Library of all the possible input 'SystemMessage' events in the example implementation.
Copyright   : (c) Sebastiaan la Fleur, 2014
License     : BSD3
Maintainer  : sebastiaan.la.fleur@gmail.com
Stability   : experimental
Portability : All

This module expresses how the incoming 'SystemMessage's are modelled in the example implementation. 
-}
module EventLoop.Input.SystemMessage(
    SystemMessageIn(..)
) where

import EventLoop.Json
import EventLoop.Config

{-|
 The different possible 'SystemMessageIn's.
-}
data SystemMessageIn = Setup      -- ^ A request for the 'Setup'. This should be generated when the connection to a client is made. The answer should be a 'EventLoop.Output.CanvasSetup' message.
                     | Background -- ^ A request for the 'Background'. This should be generated when the connection to a client is made. The answer could be the background of the graphical application.
                     | Time       -- ^ When a timer has been spawn, each \'tick\' a 'Time' is generated by the client to let the server know it is time.
                     
{-|
 Instance to express how to parse a 'SystemMessageIn' from a JSON formatted 'String'.
-}
instance FromJSON SystemMessageIn where
    fromJsonMessage (JSONObject ms) | message == setupS      = Setup
                                    | message == backgroundS = Background
                                    | message == timeS       = Time
                                      where
                                          JSONString message = retrieveError messageS ms