Adds no such user response for private messaging.

src/Link/Client.hs

@@ -38,7 +38,7 @@ runClient Server {..} client@Client {..} = do
   pingThread <- forkIO $ ping clientAlive
   run clientAlive `finally` killThread pingThread
   where
-    pingDelay = 5
+    pingDelay       = 120
     pingDelayMicros = pingDelay * 1000 * 1000
 
     ping clientAlive = do
@@ -65,7 +65,7 @@ runClient Server {..} client@Client {..} = do
                   Left mcommand -> case mcommand of
                     Nothing      -> printf "Could not parse command\n"
                     Just command -> handleCommand command
-                  Right message -> handleMessage message
+                  Right message -> sendResponse message
                 run clientAlive
 
     readCommand = do
@@ -78,10 +78,10 @@ runClient Server {..} client@Client {..} = do
     handleCommand (PrivMsg user msg) =
       withMVar serverUsers $ \clientMap ->
         case Map.lookup user clientMap of
-          Nothing -> printf "No such user: %s\n" (userName user)
+          Nothing      -> sendResponse $ NoSuchUser (userName user)
           Just client' -> sendMessage (PrivMsg clientUser msg) client'
     handleCommand Pong = do
       now <- getCurrentTime
       void $ swapMVar clientPongTime now
 
-    handleMessage = printToHandle clientHandle . formatMessage
+    sendResponse = printToHandle clientHandle . formatMessage

src/Link/Protocol.hs

@@ -15,3 +15,4 @@ formatMessage (PrivMsg user msg) = printf "PRIVMSG %s %s" (userName user) msg
 formatMessage (NameInUse name)   = printf "NAMEINUSE %s" name
 formatMessage (Connected name)   = printf "CONNECTED %s" name
 formatMessage Ping               = "PING"
+formatMessage (NoSuchUser name)  = printf "NOSUCHUSER %s" name

src/Link/Types.hs

@@ -26,4 +26,5 @@ data Message = NameInUse UserName
              | Ping
              | Pong
              | PrivMsg User String
+             | NoSuchUser UserName
                deriving (Show, Eq)