bugfixes in server and cli-client

buildSrc/src/main/kotlin/Dependencies.kt

@@ -86,3 +86,17 @@ object JavaWebSocket {
     const val group = "org.java-websocket"
     const val id = "$group:Java-WebSocket:$version"
 }
+
+object SpringBoot {
+    const val version = "2.5.6"
+    const val group = "org.springframework.boot"
+    const val plugin = group
+    const val starterWebsocket = "$group:spring-boot-starter-websocket"
+    const val starterTomcat = "$group:spring-boot-starter-tomcat"
+    const val starterLog4j2 = "$group:spring-boot-starter-log4j2"
+}
+
+object SpringDependencyManagement {
+    const val version = "1.0.11.RELEASE"
+    const val plugin = "io.spring.dependency-management"
+}

wizard-client/wizard-client-cli/src/main/java/eu/jonahbauer/wizard/client/cli/Client.java

@@ -25,7 +25,14 @@ import java.util.concurrent.locks.ReentrantLock;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
+import static picocli.CommandLine.*;
+
+@Command
 public class Client extends TimeoutContext<ClientState, Client> implements Runnable {
+    @Option(names = "-v")
+    @Getter
+    private boolean verbose;
+
     private LineReader reader;
 
     @Getter
@@ -39,7 +46,7 @@ public class Client extends TimeoutContext<ClientState, Client> implements Runna
     private CommandSpec spec;
 
     public static void main(String[] args) {
-        new Client().run();
+        new CommandLine(new Client()).execute(args);
     }
 
     public Client() {
@@ -126,6 +133,9 @@ public class Client extends TimeoutContext<ClientState, Client> implements Runna
     }
 
     public void onMessage(ServerMessage message) {
+        if (verbose) {
+            println(message.toString());
+        }
         execute(s -> s.onMessage(this, message));
     }
 
@@ -239,7 +249,7 @@ public class Client extends TimeoutContext<ClientState, Client> implements Runna
         Exception exception = exceptionRef.get();
         if (exception == null) {
             Object result;
-            CommandLine.ParseResult parseResult = commandLine.getParseResult();
+            ParseResult parseResult = commandLine.getParseResult();
             if (parseResult.subcommand() != null) {
                 CommandLine sub = parseResult.subcommand().commandSpec().commandLine();
                 result = sub.getExecutionResult();

wizard-client/wizard-client-cli/src/main/java/eu/jonahbauer/wizard/client/cli/commands/GameCommand.java

@@ -1,15 +1,12 @@
 package eu.jonahbauer.wizard.client.cli.commands;
 
 import eu.jonahbauer.wizard.client.cli.Client;
-import eu.jonahbauer.wizard.client.cli.state.AwaitingAcknowledgement;
 import eu.jonahbauer.wizard.client.cli.state.Game;
-import eu.jonahbauer.wizard.client.cli.state.Menu;
 import eu.jonahbauer.wizard.common.messages.client.InteractionMessage;
 import eu.jonahbauer.wizard.common.messages.player.JuggleMessage;
 import eu.jonahbauer.wizard.common.messages.player.PickTrumpMessage;
 import eu.jonahbauer.wizard.common.messages.player.PlayCardMessage;
 import eu.jonahbauer.wizard.common.messages.player.PredictMessage;
-import eu.jonahbauer.wizard.common.messages.server.NackMessage;
 import eu.jonahbauer.wizard.common.model.Card;
 import org.jetbrains.annotations.NotNull;
 
@@ -21,60 +18,41 @@ import static picocli.CommandLine.*;
 @Command(name = "\b", subcommands = {HelpCommand.class, QuitCommand.class, ShowCommand.class})
 public class GameCommand {
     private final Client client;
-    private final Game game;
 
-    public GameCommand(Client client, Game game) {
+    public GameCommand(Client client) {
         this.client = client;
-        this.game = game;
     }
 
     @Command(name = "play")
-    public AwaitingAcknowledgement play(
+    public void play(
             @Parameters(index = "0", paramLabel = "<card>", completionCandidates = HandCompletion.class) Card card
     ) {
         this.client.send(new InteractionMessage(new PlayCardMessage(card)));
-        return awaitAcknowledgement();
+        this.client.waitForReady();
     }
 
     @Command(name = "predict")
-    public AwaitingAcknowledgement predict(
+    public void predict(
             @Parameters(index = "0", paramLabel = "<prediction>") int prediction
     ) {
         this.client.send(new InteractionMessage(new PredictMessage(prediction)));
-        return awaitAcknowledgement();
+        this.client.waitForReady();
     }
 
     @Command(name = "trump")
-    public AwaitingAcknowledgement trump(
+    public void trump(
             @Parameters(index = "0", paramLabel = "<suit>") Card.Suit suit
     ) {
         this.client.send(new InteractionMessage(new PickTrumpMessage(suit)));
-        return awaitAcknowledgement();
+        this.client.waitForReady();
     }
 
     @Command(name = "juggle")
-    public AwaitingAcknowledgement juggle(
+    public void juggle(
             @Parameters(index = "0", paramLabel = "<card>", completionCandidates = JuggleCompletion.class) Card card
     ) {
         this.client.send(new InteractionMessage(new JuggleMessage(card)));
-        return awaitAcknowledgement();
+        this.client.waitForReady();
-    }
-
-    private AwaitingAcknowledgement awaitAcknowledgement() {
-        return new AwaitingAcknowledgement(
-                () -> game,
-                message -> {
-                    if (message instanceof NackMessage nack) {
-                        int code = nack.getCode();
-                        if (code == NackMessage.ILLEGAL_ARGUMENT || code == NackMessage.ILLEGAL_STATE) {
-                            client.println("Error: " + nack.getMessage());
-                            return game;
-                        }
-                    }
-                    client.println("Fatal: Unexpected message " + message + ". Returning to menu.");
-                    return new Menu();
-                }
-        );
     }
 
     public static class HandCompletion implements Iterable<String> {

wizard-client/wizard-client-cli/src/main/java/eu/jonahbauer/wizard/client/cli/commands/SessionCommand.java

@@ -1,7 +1,6 @@
 package eu.jonahbauer.wizard.client.cli.commands;
 
 import eu.jonahbauer.wizard.client.cli.Client;
-import eu.jonahbauer.wizard.client.cli.state.AwaitingAcknowledgement;
 import eu.jonahbauer.wizard.client.cli.state.AwaitingJoinLobby;
 import eu.jonahbauer.wizard.client.cli.state.Session;
 import eu.jonahbauer.wizard.common.messages.client.LeaveSessionMessage;
@@ -20,13 +19,12 @@ public class SessionCommand {
     }
 
     @Command(name = "ready")
-    public AwaitingAcknowledgement ready(
+    public void ready(
             @Parameters(index = "0", paramLabel = "<ready>", defaultValue = "true") boolean ready
     ) {
+        session.setNextReady(ready);
         client.send(new ReadyMessage(ready));
-        return new AwaitingAcknowledgement(
+        client.waitForReady();
-                () -> new Session(session.getSelf(), session.getSession(), ready, session.getPlayers())
-        );
     }
 
     @Command(name = "leave", description = "Leaves the current session and returns to the lobby")

wizard-client/wizard-client-cli/src/main/java/eu/jonahbauer/wizard/client/cli/state/AwaitingAcknowledgement.java

@@ -1,43 +0,0 @@
-package eu.jonahbauer.wizard.client.cli.state;
-
-import eu.jonahbauer.wizard.client.cli.Client;
-import eu.jonahbauer.wizard.common.messages.server.AckMessage;
-import eu.jonahbauer.wizard.common.messages.server.Response;
-import eu.jonahbauer.wizard.common.messages.server.ServerMessage;
-
-import java.util.Optional;
-import java.util.function.Function;
-import java.util.function.Predicate;
-import java.util.function.Supplier;
-
-public final class AwaitingAcknowledgement extends Awaiting {
-    private final Supplier<ClientState> success;
-    private final Function<ServerMessage, ClientState> failure;
-
-    public AwaitingAcknowledgement(Supplier<ClientState> success, Function<ServerMessage, ClientState> failure) {
-        this.success = success;
-        this.failure = failure;
-    }
-
-    public AwaitingAcknowledgement(Supplier<ClientState> success) {
-        this.success = success;
-        this.failure = null;
-    }
-
-    @Override
-    public Optional<ClientState> onEnter(Client client) {
-        client.println("Waiting for acknowledgment...");
-        return super.onEnter(client);
-    }
-
-    @Override
-    public Optional<ClientState> onMessage(Client client, ServerMessage message) {
-        if (message instanceof AckMessage) {
-            return Optional.of(success.get());
-        } else if (failure != null) {
-            return Optional.of(failure.apply(message));
-        } else {
-            return super.onMessage(client, message);
-        }
-    }
-}

wizard-client/wizard-client-cli/src/main/java/eu/jonahbauer/wizard/client/cli/state/AwaitingJoinSession.java

@@ -1,9 +1,7 @@
 package eu.jonahbauer.wizard.client.cli.state;
 
 import eu.jonahbauer.wizard.client.cli.Client;
-import eu.jonahbauer.wizard.common.messages.server.NackMessage;
+import eu.jonahbauer.wizard.common.messages.server.*;
-import eu.jonahbauer.wizard.common.messages.server.ServerMessage;
-import eu.jonahbauer.wizard.common.messages.server.SessionJoinedMessage;
 
 import java.util.Optional;
 
@@ -28,6 +26,9 @@ public final class AwaitingJoinSession extends Awaiting {
                 default -> { return super.onMessage(client, message); }
             }
             return Optional.of(new AwaitingJoinLobby());
+        } else if (message instanceof SessionModifiedMessage || message instanceof SessionRemovedMessage) {
+            // drop
+            return Optional.empty();
         } else {
             return super.onMessage(client, message);
         }

wizard-client/wizard-client-cli/src/main/java/eu/jonahbauer/wizard/client/cli/state/BaseState.java

@@ -31,6 +31,9 @@ public abstract class BaseState implements ClientState {
     protected static Optional<ClientState> unexpectedMessage(Client client, ServerMessage message) {
         // return to menu on unexpected message
         client.println("Fatal: Unexpected message " + message + ". Returning to menu.");
+        if (client.isVerbose()) {
+            new Exception().printStackTrace();
+        }
         return Optional.of(new Menu());
     }
 }

wizard-client/wizard-client-cli/src/main/java/eu/jonahbauer/wizard/client/cli/state/Game.java

@@ -5,7 +5,9 @@ import eu.jonahbauer.wizard.client.cli.commands.GameCommand;
 import eu.jonahbauer.wizard.client.cli.util.Pair;
 import eu.jonahbauer.wizard.common.messages.data.PlayerData;
 import eu.jonahbauer.wizard.common.messages.observer.*;
+import eu.jonahbauer.wizard.common.messages.server.AckMessage;
 import eu.jonahbauer.wizard.common.messages.server.GameMessage;
+import eu.jonahbauer.wizard.common.messages.server.NackMessage;
 import eu.jonahbauer.wizard.common.messages.server.ServerMessage;
 import eu.jonahbauer.wizard.common.model.Card;
 import lombok.Getter;
@@ -149,6 +151,18 @@ public final class Game extends BaseState {
                 throw new AssertionError("Unknown observer message " + observerMessage.getClass().getSimpleName() + "");
             }
             return Optional.empty();
+        } else if (message instanceof NackMessage nack) {
+            int code = nack.getCode();
+            if (code == NackMessage.ILLEGAL_ARGUMENT || code == NackMessage.ILLEGAL_STATE) {
+                client.println("Error: " + nack.getMessage());
+                client.ready();
+                return Optional.empty();
+            } else {
+                return unexpectedMessage(client, message);
+            }
+        } else if (message instanceof AckMessage) {
+            client.ready();
+            return Optional.empty();
         } else {
             return unexpectedMessage(client, message);
         }

wizard-client/wizard-client-cli/src/main/java/eu/jonahbauer/wizard/client/cli/state/Menu.java

@@ -23,7 +23,9 @@ public final class Menu extends BaseState {
 
     @Override
     public Optional<ClientState> onMessage(Client client, ServerMessage message) {
-        throw new AssertionError("Received a ServerMessage while not connected.");
+        // it is possible that there are messages still queued after
+        // returning to the menu as a result of a previous message
+        return Optional.empty();
     }
 
     @Override

wizard-client/wizard-client-cli/src/main/java/eu/jonahbauer/wizard/client/cli/state/Session.java

@@ -5,6 +5,7 @@ import eu.jonahbauer.wizard.client.cli.commands.SessionCommand;
 import eu.jonahbauer.wizard.common.messages.data.PlayerData;
 import eu.jonahbauer.wizard.common.messages.server.*;
 import lombok.Getter;
+import lombok.Setter;
 import picocli.CommandLine.Model.CommandSpec;
 
 import java.util.HashMap;
@@ -19,9 +20,12 @@ public final class Session extends BaseState {
 
     private final UUID self;
     private final UUID session;
-    private final boolean ready;
     private final Map<UUID, PlayerData> players = new HashMap<>();
 
+    private boolean ready;
+    @Setter
+    private Boolean nextReady;
+
     public Session(SessionJoinedMessage joined) {
         this.self = joined.getPlayer();
         this.session = joined.getSession();
@@ -68,6 +72,16 @@ public final class Session extends BaseState {
                     session,
                     players.values().stream().collect(Collectors.toMap(PlayerData::getUuid, PlayerData::getName))
             ));
+        } else if (nextReady != null && message instanceof NackMessage nack) {
+            client.println("Error: " + nack.getMessage());
+            nextReady = null;
+            client.ready();
+            return Optional.empty();
+        } else if (nextReady != null && message instanceof AckMessage) {
+            ready = nextReady;
+            nextReady = null;
+            client.ready();
+            return Optional.empty();
         } else {
             return unexpectedMessage(client, message);
         }

wizard-server/build.gradle.kts

@@ -1,15 +1,16 @@
 plugins {
-    id("org.springframework.boot").version("2.5.6")
+    id(SpringBoot.plugin) version SpringBoot.version
-    //id("io.spring.dependency-management").version("1.0.7-RELEASE")
+    id(SpringDependencyManagement.plugin) version SpringDependencyManagement.version
     id("java")
-}
+    id("war")
-
-repositories {
-    mavenCentral()
 }
 
 dependencies {
     implementation(project(":wizard-core"))
     implementation(project(":wizard-common"))
-    implementation("org.springframework.boot:spring-boot-starter-websocket:2.5.6")
+    implementation(SpringBoot.starterWebsocket) {
+        exclude(group = SpringBoot.group, module = "spring-boot-starter-logging")
+    }
+    implementation(SpringBoot.starterLog4j2)
+    providedRuntime(SpringBoot.starterTomcat)
 }

wizard-server/src/main/java/eu/jonahbauer/wizard/server/Session.java

@@ -9,19 +9,23 @@ import eu.jonahbauer.wizard.common.model.Configuration;
 import eu.jonahbauer.wizard.core.machine.Game;
 import eu.jonahbauer.wizard.core.messages.Observer;
 import eu.jonahbauer.wizard.core.model.Configurations;
-import eu.jonahbauer.wizard.core.model.GameConfiguration;
 import eu.jonahbauer.wizard.server.machine.Player;
 import lombok.AccessLevel;
 import lombok.Data;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
+import lombok.extern.log4j.Log4j2;
 
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ThreadLocalRandom;
 
 @Getter
+@Log4j2
 @EqualsAndHashCode(of = "uuid")
 public class Session implements Observer {
     private static final int MIN_PLAYERS = 3;
@@ -46,7 +50,7 @@ public class Session implements Observer {
     }
 
     /**
-     * Associates the given player with this session, removes him from the lobby, notifies all other players in the
+     * Associates the given player with this session and notifies all other players in the
      * session with a {@link PlayerJoinedMessage}, the joining player with a {@link SessionJoinedMessage} and all
      * players in the lobby with a {@link SessionModifiedMessage}.
      *
@@ -55,18 +59,19 @@ public class Session implements Observer {
      * @return the players uuid
      */
     public synchronized UUID join(Player player, String name) {
-        if (players.size() == MAX_PLAYERS) {
+        if (game != null) {
+            throw new NackException(NackMessage.GAME_ALREADY_STARTED, "Game has already started.");
+        } else if (players.size() == MAX_PLAYERS) {
             throw new NackException(NackMessage.SESSION_FULL, "Session is full.");
         } else if (players.values().stream().anyMatch(p -> p.getName().equalsIgnoreCase(name))) {
             throw new NackException(NackMessage.NAME_TAKEN, "Name is already taken.");
         }
 
-        Lobby.getInstance().leave(player);
-
         SessionPlayer sessionPlayer;
         do {
-            sessionPlayer = new SessionPlayer(UUID.randomUUID(), name, player);
+            sessionPlayer = new SessionPlayer(UUID.randomUUID(), name);
         } while (players.putIfAbsent(sessionPlayer.getUuid(), sessionPlayer) != null);
+        sessionPlayer.setPlayer(player);
 
         notifyJoined(sessionPlayer.toData());
         Lobby.getInstance().notifyPlayers(new SessionModifiedMessage(toData()));
@@ -75,54 +80,120 @@ public class Session implements Observer {
     }
 
     public synchronized void leave(UUID player) {
-        if (players.remove(player) != null) {
+        if (game == null) {
-            if (players.size() == 0) {
+            if (players.remove(player) != null) {
-                Lobby.getInstance().removeSession(uuid);
+                if (players.size() == 0) {
-            } else {
+                    Lobby.getInstance().removeSession(uuid);
-                notifyPlayers(new PlayerLeftMessage(player));
+                } else {
-                Lobby.getInstance().notifyPlayers(new SessionModifiedMessage(toData()));
+                    notifyPlayers(new PlayerLeftMessage(player));
+                    Lobby.getInstance().notifyPlayers(new SessionModifiedMessage(toData()));
+                }
+            }
+        } else {
+            var sessionPlayer = players.get(player);
+            if (sessionPlayer != null) {
+                sessionPlayer.setPlayer(null);
+                if (players.values().stream().noneMatch(SessionPlayer::isConnected)) {
+                    Lobby.getInstance().removeSession(uuid);
+                }
             }
         }
     }
 
-    public synchronized void ready(UUID player, boolean ready) {
+    public synchronized void ready(UUID uuid, boolean ready) {
-        var sessionPlayer = players.get(player);
+        var player = players.get(uuid);
-        if (sessionPlayer == null) {
+        if (player == null) {
             throw new NackException(NackMessage.PLAYER_NOT_FOUND, "Who are you?");
+        } else if (game != null) {
+            throw new NackException(NackMessage.GAME_ALREADY_STARTED, "Game has already started.");
         }
 
-        if (sessionPlayer.isReady() != ready) {
+        player.send(new AckMessage());
-            sessionPlayer.setReady(ready);
+        if (player.isReady() != ready) {
-            sessionPlayer.getPlayer().send(new AckMessage());
+            player.setReady(ready);
-            notifyPlayers(new PlayerModifiedMessage(sessionPlayer.toData()));
+            notifyPlayers(new PlayerModifiedMessage(player.toData()));
         }
 
         if (players.size() >= MIN_PLAYERS && players.values().stream().allMatch(SessionPlayer::isReady)) {
-            game = new Game(Configurations.get(configuration), this);
+            startGame();
-            notifyPlayers(new StartingGameMessage());
-            game.start(players.keySet().stream().toList());
         }
     }
 
+    /**
+     * Forwards the message sent by the player to the game.
+     *
+     * @param uuid the player
+     * @param message the players message
+     */
+    public synchronized void handlePlayerMessage(UUID uuid, PlayerMessage message) {
+        var player = players.get(uuid);
+        if (player == null) {
+            throw new NackException(NackMessage.PLAYER_NOT_FOUND, "Who are you?");
+        } else if (game == null) {
+            throw new NackException(NackMessage.GAME_NOT_YET_STARTED, "Game hat not yet started.");
+        } else {
+            try {
+                game.execute(s -> {
+                    // start buffering while game is locked
+                    player.buffer();
+                    return s.onMessage(game, uuid, message);
+                });
+                player.send(new AckMessage());
+            } catch (IllegalStateException e) {
+                throw new NackException(NackMessage.ILLEGAL_STATE, e.getMessage());
+            } catch (IllegalArgumentException e) {
+                throw new NackException(NackMessage.ILLEGAL_ARGUMENT, e.getMessage());
+            }
+        }
+    }
+
+    private void startGame() {
+        notifyPlayers(new StartingGameMessage());
+        game = new Game(Configurations.get(configuration).withTimeout(timeout), this);
+        game.start(List.copyOf(players.keySet()));
+        CompletableFuture.runAsync(() -> {
+            while (true) {
+                try {
+                    game.await();
+                    break;
+                } catch (InterruptedException e) {
+                    // ignored
+                } catch (ExecutionException e) {
+                    log.warn("Game completed with exception.", e);
+                    break;
+                }
+            }
+            players.forEach((id, player) -> player.setReady(false));
+            synchronized (this) {
+                game = null;
+                for (SessionPlayer player : List.copyOf(players.values())) {
+                    if (!player.isConnected()) {
+                        leave(player.getUuid());
+                    }
+                }
+            }
+        });
+    }
+
     private void notifyJoined(PlayerData joined) {
         var message = new PlayerJoinedMessage(joined);
         for (SessionPlayer player : players.values()) {
             if (player.getUuid().equals(joined.getUuid())) {
-                player.getPlayer().send(new SessionJoinedMessage(
+                player.send(new SessionJoinedMessage(
                         getUuid(),
                         player.getUuid(),
                         players.values().stream().map(SessionPlayer::toData).toList(),
                         player.getSecret()
                 ));
             } else {
-                player.getPlayer().send(message);
+                player.send(message);
             }
         }
     }
 
     private void notifyPlayers(ServerMessage message) {
         for (SessionPlayer player : players.values()) {
-            player.getPlayer().send(message);
+            player.send(message);
         }
     }
 
@@ -130,16 +201,6 @@ public class Session implements Observer {
         return new SessionData(uuid, name, players.size(), configuration);
     }
 
-    /**
-     * Forwards the message sent by the player to the game.
-     *
-     * @param player the player
-     * @param message the players message
-     */
-    public void handlePlayerMessage(UUID player, PlayerMessage message) {
-        game.onMessage(player, message);
-    }
-
     @Override
     public void notify(ObserverMessage message) {
         notifyPlayers(new GameMessage(message));
@@ -147,7 +208,7 @@ public class Session implements Observer {
 
     @Override
     public void notify(UUID player, ObserverMessage message) {
-        players.get(player).getPlayer().send(new GameMessage(message));
+        players.get(player).send(new GameMessage(message));
     }
 
     @Data
@@ -155,8 +216,8 @@ public class Session implements Observer {
     private static class SessionPlayer {
         private final UUID uuid;
         private final String name;
-        private final Player player;
         private final String secret = generateSecret();
+        private Player player;
         private boolean ready;
 
         private static String generateSecret() {
@@ -169,5 +230,21 @@ public class Session implements Observer {
         public PlayerData toData() {
             return new PlayerData(uuid, name, ready);
         }
+
+        public void send(ServerMessage message) {
+            if (player != null) {
+                player.send(message);
+            }
+        }
+
+        public void buffer() {
+            if (player != null) {
+                player.buffer();
+            }
+        }
+
+        public boolean isConnected() {
+            return player != null;
+        }
     }
 }

wizard-server/src/main/java/eu/jonahbauer/wizard/server/machine/ClientState.java

@@ -3,18 +3,18 @@ package eu.jonahbauer.wizard.server.machine;
 import eu.jonahbauer.wizard.common.machine.State;
 import eu.jonahbauer.wizard.common.messages.client.ClientMessage;
 import eu.jonahbauer.wizard.common.messages.server.NackMessage;
+import eu.jonahbauer.wizard.server.NackException;
 import org.springframework.web.socket.CloseStatus;
 
 import java.util.Optional;
 
 public interface ClientState extends State<ClientState, Player> {
     default Optional<ClientState> onOpen(Player player) {
-        throw new IllegalStateException(); // TODO nachdenken
+        throw new IllegalStateException();
     }
 
     default Optional<ClientState> onMessage(Player player, ClientMessage message) {
-        player.send(new NackMessage(NackMessage.BAD_REQUEST, "Unexpected message."));
+        throw new NackException(NackMessage.UNEXPECTED_MESSAGE, "Don't know what to do with " + message + ".");
-        return Optional.empty();
     }
 
     Optional<ClientState> onClose(Player player, CloseStatus status);

wizard-server/src/main/java/eu/jonahbauer/wizard/server/machine/Player.java

@@ -2,17 +2,20 @@ package eu.jonahbauer.wizard.server.machine;
 
 import eu.jonahbauer.wizard.common.machine.Context;
 import eu.jonahbauer.wizard.common.messages.client.ClientMessage;
-import eu.jonahbauer.wizard.common.messages.server.NackMessage;
+import eu.jonahbauer.wizard.common.messages.server.Response;
 import eu.jonahbauer.wizard.common.messages.server.ServerMessage;
-import eu.jonahbauer.wizard.server.NackException;
 import eu.jonahbauer.wizard.server.machine.states.CreatedState;
 import lombok.SneakyThrows;
 import org.springframework.web.socket.CloseStatus;
 import org.springframework.web.socket.TextMessage;
 import org.springframework.web.socket.WebSocketSession;
 
+import java.util.ArrayList;
+
 public class Player extends Context<ClientState, Player> {
     private final WebSocketSession session;
+    private final ArrayList<ServerMessage> buffer = new ArrayList<>();
+    private Class<?> shouldBuffer = null;
 
     public Player(WebSocketSession session) {
         super(new CreatedState());
@@ -29,22 +32,32 @@ public class Player extends Context<ClientState, Player> {
     }
 
     public void onMessage(ClientMessage message) {
-
+        execute(s -> s.onMessage(this, message));
-        try {
-            execute(s -> s.onMessage(this, message));
-        } catch (NackException e) {
-            send(new NackMessage(e.getCode(), e.getMessage()));
-        }
     }
 
     public void onClose(CloseStatus status) {
         execute(s -> s.onClose(this, status));
     }
 
+    public void buffer() {
+        shouldBuffer = Response.class;
+    }
+
     @SneakyThrows
     public void send(ServerMessage message) {
         synchronized (session) {
-            session.sendMessage(new TextMessage(message.toString()));
+            if (shouldBuffer != null && shouldBuffer.isInstance(message)) {
+                session.sendMessage(new TextMessage(message.toString()));
+                shouldBuffer = null;
+                for (ServerMessage serverMessage : buffer) {
+                    session.sendMessage(new TextMessage(serverMessage.toString()));
+                }
+                buffer.clear();
+            } else if (shouldBuffer != null) {
+                buffer.add(message);
+            } else {
+                session.sendMessage(new TextMessage(message.toString()));
+            }
         }
     }
 }

wizard-server/src/main/java/eu/jonahbauer/wizard/server/machine/states/InGame.java

@@ -1,46 +0,0 @@
-package eu.jonahbauer.wizard.server.machine.states;
-
-import eu.jonahbauer.wizard.common.messages.client.ClientMessage;
-import eu.jonahbauer.wizard.common.messages.client.LeaveSessionMessage;
-import eu.jonahbauer.wizard.common.messages.server.NackMessage;
-import eu.jonahbauer.wizard.common.messages.server.StartingGameMessage;
-import eu.jonahbauer.wizard.server.machine.ClientState;
-import eu.jonahbauer.wizard.server.machine.Player;
-import org.springframework.web.socket.CloseStatus;
-
-import java.util.Optional;
-
-public class InGame implements ClientState {
-    @Override
-    public Optional<ClientState> onEnter(Player context) {
-        context.send(new StartingGameMessage());
-
-        return ClientState.super.onEnter(context);
-    }
-
-    @Override
-    public void onExit(Player context) {
-        ClientState.super.onExit(context);
-    }
-
-    @Override
-    public Optional<ClientState> onOpen(Player player) {
-        return Optional.empty();
-    }
-
-    @Override
-    public Optional<ClientState> onMessage(Player player, ClientMessage message) {
-        if(message instanceof LeaveSessionMessage) {
-            //?
-            return Optional.empty();
-        } else {
-            player.send(new NackMessage(0, "Error: Invalid Message!"));
-            return Optional.empty();
-        }
-    }
-
-    @Override
-    public Optional<ClientState> onClose(Player player, CloseStatus status) {
-        return Optional.empty();
-    }
-}

wizard-server/src/main/java/eu/jonahbauer/wizard/server/machine/states/LobbyState.java

@@ -23,16 +23,33 @@ public class LobbyState implements ClientState {
     public Optional<ClientState> onMessage(Player player, ClientMessage message) {
         if (message instanceof CreateSessionMessage create) {
             Lobby.getInstance().leave(player);
-            var session = Lobby.getInstance().createSession(create);
+            try {
-            var uuid = session.join(player, create.getPlayerName());
+                player.buffer();
-            return Optional.of(new SessionState(session.getUuid(), uuid, create.getPlayerName()));
+                var session = Lobby.getInstance().createSession(create);
+                var uuid = session.join(player, create.getPlayerName());
+                return Optional.of(new SessionState(session.getUuid(), uuid, create.getPlayerName()));
+            } catch (NackException nack) {
+                // nack must be sent before joinlobby
+                player.send(nack.toMessage());
+                Lobby.getInstance().join(player);
+                return Optional.empty();
+            }
         } else if (message instanceof JoinSessionMessage join) {
-            var session = Lobby.getInstance().getSession(join.getSession());
+            Lobby.getInstance().leave(player);
-            if (session == null) {
+            try {
-                throw new NackException(NackMessage.NOT_FOUND, "Session not found.");
+                player.buffer();
-            } else {
+                var session = Lobby.getInstance().getSession(join.getSession());
-                var uuid = session.join(player, join.getPlayerName());
+                if (session == null) {
-                return Optional.of(new SessionState(session.getUuid(), uuid, join.getPlayerName()));
+                    throw new NackException(NackMessage.NOT_FOUND, "Session not found.");
+                } else {
+                    var uuid = session.join(player, join.getPlayerName());
+                    return Optional.of(new SessionState(session.getUuid(), uuid, join.getPlayerName()));
+                }
+            } catch (NackException nack) {
+                // nack must be sent before joinlobby
+                player.send(nack.toMessage());
+                Lobby.getInstance().join(player);
+                return Optional.empty();
             }
         } else {
             return ClientState.super.onMessage(player, message);

wizard-server/src/main/java/eu/jonahbauer/wizard/server/machine/states/SessionState.java

@@ -4,7 +4,6 @@ import eu.jonahbauer.wizard.common.messages.client.ClientMessage;
 import eu.jonahbauer.wizard.common.messages.client.InteractionMessage;
 import eu.jonahbauer.wizard.common.messages.client.LeaveSessionMessage;
 import eu.jonahbauer.wizard.common.messages.client.ReadyMessage;
-import eu.jonahbauer.wizard.common.messages.server.NackMessage;
 import eu.jonahbauer.wizard.server.Lobby;
 import eu.jonahbauer.wizard.server.machine.ClientState;
 import eu.jonahbauer.wizard.server.machine.Player;
@@ -42,8 +41,7 @@ public class SessionState implements ClientState {
             Lobby.getInstance().getSession(session).handlePlayerMessage(self, playerMessage);
             return Optional.empty();
         } else {
-            player.send(new NackMessage(NackMessage.UNEXPECTED_MESSAGE, "Invalid Message!"));
+            return ClientState.super.onMessage(player, message);
-            return Optional.empty();
         }
     }
 

wizard-server/src/main/java/eu/jonahbauer/wizard/server/socket/WizardSocketHandler.java

@@ -1,6 +1,9 @@
 package eu.jonahbauer.wizard.server.socket;
 
+import com.google.gson.JsonParseException;
 import eu.jonahbauer.wizard.common.messages.client.ClientMessage;
+import eu.jonahbauer.wizard.common.messages.server.NackMessage;
+import eu.jonahbauer.wizard.server.NackException;
 import eu.jonahbauer.wizard.server.machine.Player;
 import lombok.extern.log4j.Log4j2;
 import org.jetbrains.annotations.NotNull;
@@ -29,7 +32,14 @@ public class WizardSocketHandler extends TextWebSocketHandler {
 
     @Override
     protected void handleTextMessage(@NotNull WebSocketSession session, @NotNull TextMessage text) {
-        players.get(session.getId()).onMessage(ClientMessage.parse(text.getPayload()));
+        var player = players.get(session.getId());
+        try {
+            player.onMessage(ClientMessage.parse(text.getPayload()));
+        } catch (NackException e) {
+            player.send(e.toMessage());
+        } catch (JsonParseException e) {
+            player.send(new NackMessage(NackMessage.MALFORMED_MESSAGE, "Could not parse " + text.getPayload() + "."));
+        }
     }
 
     @Override