.

core-bukkit-impl/src/main/java/de/kentoj/scrow/bukkit/CoreImplPlugin.java

@@ -3,6 +3,7 @@ package de.kentoj.scrow.bukkit;
 import de.kentoj.scrow.bukkit.crown.CrownCommand;
 import de.kentoj.scrow.bukkit.economy.CoinsCommand;
 import de.kentoj.scrow.bukkit.friends.command.FriendCommand;
+import de.kentoj.scrow.bukkit.server.PlayCommand;
 import org.bukkit.Bukkit;
 import org.bukkit.plugin.java.JavaPlugin;
 
@@ -18,6 +19,7 @@ public class CoreImplPlugin extends JavaPlugin {
             ScrowAPI.getCommandManager().register(new FriendCommand().getRootNode());
             ScrowAPI.getCommandManager().register(new CoinsCommand().getRootNode());
             ScrowAPI.getCommandManager().register(new CrownCommand().getRootNode());
+            ScrowAPI.getCommandManager().register(new PlayCommand().getRootNode());
         }
 
         registerServer();

core-bukkit-impl/src/main/java/de/kentoj/scrow/bukkit/ScrowAPISurface.java

@@ -11,7 +11,7 @@ import de.kentoj.scrow.bukkit.friends.friendship.InMemoryFriendshipService;
 import de.kentoj.scrow.bukkit.friends.friendship.MongoFriendshipService;
 import de.kentoj.scrow.bukkit.friends.request.InMemoryFriendRequestService;
 import de.kentoj.scrow.bukkit.friends.request.MongoFriendRequestService;
-import de.kentoj.scrowlib.servermanager.CrownServerManager;
+import de.kentoj.scrowlib.servermanager.ServerManagerImpl;
 import io.nats.client.Nats;
 import io.nats.client.Options;
 import lombok.AccessLevel;
@@ -64,7 +64,7 @@ public class ScrowAPISurface {
             ScrowAPI.setDatabase(mongoClient.getDatabase("scrow"));
         }
 
-        ScrowAPI.setServerManager(new CrownServerManager(ScrowAPI.getNats()));
+        ScrowAPI.setServerManager(new ServerManagerImpl(ScrowAPI.getNats()));
 
         ScrowAPI.setEconomyService(ScrowAPI.getDatabase() != null ?
                 new MongoEconomyService(ScrowAPI.getDatabase()) : new InMemoryEconomyService());

core-bukkit-impl/src/main/java/de/kentoj/scrow/bukkit/crown/CrownDeployServerLiteral.java

@@ -28,8 +28,8 @@ public class CrownDeployServerLiteral implements CommandExecutor<CommandSender,
     public void execute(BukkitCommandContext ctx) {
         var template = ctx.getArg(templateArg);
         ScrowAPI.getServerManager().deployServer(template)
-                .subscribe(server -> {
-                    ctx.getSender().sendMessage("Deployed instance of " + template + " with handle " + server.getHandle());
-                });
+                .subscribe(server ->
+                        ctx.getSender().sendMessage("Deployed instance of " + template + " with handle " + server.getHandle())
+                );
     }
 }

core-bukkit-impl/src/main/java/de/kentoj/scrow/bukkit/crown/CrownDestroyServerLiteral.java

@@ -38,8 +38,8 @@ public class CrownDestroyServerLiteral implements CommandExecutor<CommandSender,
     public void execute(BukkitCommandContext ctx) {
         var handle = ctx.getArg(handleArg);
         ScrowAPI.getServerManager().destroyServer(handle)
-                .subscribe(__ -> {
-                    ctx.getSender().sendMessage("Destroyed server with handle " + handle);
-                });
+                .subscribe(__ ->
+                    ctx.getSender().sendMessage("Destroyed server with handle " + handle)
+                );
     }
 }

core-bukkit-impl/src/main/java/de/kentoj/scrow/bukkit/crown/CrownListServersLiteral.java

@@ -28,8 +28,8 @@ public class CrownListServersLiteral implements CommandExecutor<CommandSender, B
                         .append(cur.getState())
                         .append('\n')
                 )
-                .subscribe(msg -> {
-                    ctx.getPlayerSender().sendMessage(msg.toString());
-                });
+                .subscribe(msg ->
+                        ctx.getPlayerSender().sendMessage(msg.toString())
+                );
     }
 }

core-bukkit-impl/src/main/java/de/kentoj/scrow/bukkit/server/PlayCommand.java

@@ -0,0 +1,41 @@
+package de.kentoj.scrow.bukkit.server;
+
+import de.kentoj.kencommandapi.BukkitCommandContext;
+import de.kentoj.kencommandapi.api.processing.CommandExecutor;
+import de.kentoj.kencommandapi.api.structure.argument.CommandArgument;
+import de.kentoj.kencommandapi.api.structure.argument.types.StringArgumentType;
+import de.kentoj.kencommandapi.api.structure.node.CommandNode;
+import de.kentoj.scrow.bukkit.ScrowAPI;
+import de.kentoj.scrowlib.servermanager.ServerInstance;
+import lombok.Getter;
+import org.bukkit.command.CommandSender;
+
+public class PlayCommand implements CommandExecutor<CommandSender, BukkitCommandContext> {
+
+    @Getter
+    private final CommandNode<CommandSender, BukkitCommandContext> rootNode;
+    private final CommandArgument<CommandSender, BukkitCommandContext, String> gamemodeArg;
+
+    public PlayCommand() {
+        this.rootNode = ScrowAPI.getCommandManager().createNode("play", "queue");
+        this.gamemodeArg = ScrowAPI.getCommandManager().createArgument("gamemode", new StringArgumentType<>());
+        this.rootNode.addArgument(this.gamemodeArg);
+        this.rootNode.setExecutor(this);
+    }
+
+    @Override
+    public void execute(BukkitCommandContext ctx) {
+        var gamemode = ctx.getArg(gamemodeArg);
+        ScrowAPI.getServerManager().getRunningServers().filter(
+                        inst -> inst.getTemplateName().equals(gamemode) && inst.getState().equals("UP")
+                )
+                .single()
+                .map(ServerInstance::getHandle)
+                .flatMap(handle ->
+                        ScrowAPI.getServerManager().sendPlayer(ctx.getPlayerSender().getUniqueId(), handle)
+                )
+                .subscribe(null, ex -> {
+                    ctx.getPlayerSender().sendMessage("failed sending you to " + gamemode + ": " + ex.getMessage());
+                });
+    }
+}

core-lib/build.gradle.kts

@@ -8,7 +8,7 @@ plugins {
 }
 
 group = "de.kentoj.scrow"
-version = "0.2"
+version = "0.3"
 
 repositories {
     mavenCentral()

core-lib/src/main/java/de/kentoj/scrowlib/messaging/NatsRepository.java

@@ -1,8 +1,10 @@
 package de.kentoj.scrowlib.messaging;
 
+import de.kentoj.scrowlib.messaging.respose.SafeResult;
 import io.nats.client.Connection;
 import io.nats.client.Dispatcher;
 import io.nats.client.Message;
+import org.bson.Document;
 import org.jetbrains.annotations.NotNull;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -18,23 +20,34 @@ public class NatsRepository {
         this.dispatcher = nats.createDispatcher();
     }
 
-    public Mono<@NotNull Void> publish(String subject, byte[] data) {
+    public Mono<@NotNull Void> publishSafeResult(String subject, SafeResult safeResult) {
+        return this.publish(subject, safeResult.toDocument());
+    }
+
+    public Mono<@NotNull Void> publish(String subject, Document document) {
+        return publishRaw(subject, DocumentRepository.toBytes(document));
+    }
+
+    public Mono<@NotNull Void> publishRaw(String subject, byte[] data) {
         return Mono.fromRunnable(() -> nats.publish(subject, data));
     }
 
     public Flux<@NotNull Message> subscribe(String subject) {
         return Flux.create(sink -> {
-                    var handler = dispatcher.subscribe(subject, msg -> {
-                        try {
-                            sink.next(msg);
-                        } catch (Throwable e) {
-                            sink.error(e);
-                        }
-                    });
+            var handler = dispatcher.subscribe(subject, msg -> {
+                try {
+                    sink.next(msg);
+                } catch (Throwable e) {
+                    sink.error(e);
+                }
+            });
+            sink.onCancel(handler::unsubscribe);
+            sink.onDispose(handler::unsubscribe);
+        });
+    }
 
-                    sink.onCancel(handler::unsubscribe);
-                    sink.onDispose(handler::unsubscribe);
-                });
+    public Mono<@NotNull Message> request(String subject, Document document) {
+        return Mono.fromFuture(nats.request(subject, DocumentRepository.toBytes(document)));
     }
 
     public Mono<@NotNull Message> request(String subject, byte[] data) {

core-lib/src/main/java/de/kentoj/scrowlib/messaging/respose/SafeErrorResult.java

@@ -0,0 +1,34 @@
+package de.kentoj.scrowlib.messaging.respose;
+
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import org.bson.Document;
+
+@Getter
+@AllArgsConstructor(access = AccessLevel.PACKAGE)
+public final class SafeErrorResult extends SafeResult {
+    private final String type;
+    private final String message;
+
+    public SafeErrorResult(Throwable throwable) {
+        this.type = throwable.getClass().getCanonicalName();
+        this.message = throwable.getMessage();
+    }
+
+    @Override
+    public Document unwrap() {
+        throw this.toException();
+    }
+
+    public RuntimeException toException() {
+        return new RuntimeException(message);
+    }
+
+    @Override
+    public Document toDocument() {
+        return new Document("error", new Document()
+                .append("type", this.type)
+                .append("message", this.getMessage()));
+    }
+}

core-lib/src/main/java/de/kentoj/scrowlib/messaging/respose/SafeResult.java

@@ -0,0 +1,64 @@
+package de.kentoj.scrowlib.messaging.respose;
+
+import de.kentoj.scrowlib.messaging.DocumentRepository;
+import io.nats.client.Message;
+import org.bson.Document;
+
+public abstract sealed class SafeResult permits SafeErrorResult, SafeSuccessResult {
+
+    /**
+     * @return the SafeResult as a Document for transit
+     */
+    public abstract Document toDocument();
+
+    /**
+     * @return the data stored in the SafeResult
+     * @throws RuntimeException if the SafeResult represents an error
+     */
+    public abstract Document unwrap();
+
+    public boolean isError() {
+        return this instanceof SafeErrorResult;
+    }
+
+    public boolean isSuccess() {
+        return this instanceof SafeSuccessResult;
+    }
+
+    public SafeErrorResult asError() {
+        return (SafeErrorResult) this;
+    }
+
+    public SafeSuccessResult asSuccess() {
+        return (SafeSuccessResult) this;
+    }
+
+    public static Document unwrap(Message message) {
+        return fromMessage(message).unwrap();
+    }
+
+    public static SafeResult wrap(Document document) {
+        return new SafeSuccessResult(document);
+    }
+
+    public static SafeResult wrap(Throwable throwable) {
+        return new SafeErrorResult(throwable);
+    }
+
+    public static SafeResult fromMessage(Message message) {
+        return fromDocument(DocumentRepository.fromMessage(message));
+    }
+
+    public static SafeResult fromDocument(Document document) {
+        if (document.containsKey("error")) {
+            var doc = document.get("error", Document.class);
+            return new SafeErrorResult(
+                    doc.getString("type"),
+                    doc.getString("message")
+            );
+        } else if (document.containsKey("data")) {
+            return new SafeSuccessResult(document.get("data", Document.class));
+        }
+        throw new IllegalArgumentException("document does not conform to SafeDocument format");
+    }
+}

core-lib/src/main/java/de/kentoj/scrowlib/messaging/respose/SafeSuccessResult.java

@@ -0,0 +1,22 @@
+package de.kentoj.scrowlib.messaging.respose;
+
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import org.bson.Document;
+
+@Getter
+@AllArgsConstructor(access = AccessLevel.PACKAGE)
+public final class SafeSuccessResult extends SafeResult {
+    private final Document data;
+
+    @Override
+    public Document unwrap() {
+        return this.getData();
+    }
+
+    @Override
+    public Document toDocument() {
+        return new Document("data", this.getData());
+    }
+}

core-lib/src/main/java/de/kentoj/scrowlib/servermanager/ServerInstance.java

@@ -1,16 +1,26 @@
 package de.kentoj.scrowlib.servermanager;
 
-import lombok.AllArgsConstructor;
+import com.google.common.base.Preconditions;
 import lombok.Value;
 
 @Value
-@AllArgsConstructor
 public class ServerInstance {
+    String templateName;
     String handle;
     int port;
     String state;
 
-    public ServerInstance(String handle, int port) {
-        this(handle, port, "STARTING");
+    public ServerInstance(String templateName, String handle, int port, String state) {
+        Preconditions.checkNotNull(templateName);
+        Preconditions.checkNotNull(handle);
+        Preconditions.checkNotNull(state);
+        this.templateName = templateName;
+        this.handle = handle;
+        this.port = port;
+        this.state = state;
+    }
+
+    public ServerInstance(String templateName, String handle, int port) {
+        this(templateName, handle, port, "STARTING");
     }
 }

core-lib/src/main/java/de/kentoj/scrowlib/servermanager/ServerManager.java

@@ -4,6 +4,8 @@ import org.jetbrains.annotations.NotNull;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
+import java.util.UUID;
+
 public interface ServerManager {
 
     /**
@@ -24,4 +26,6 @@ public interface ServerManager {
     Mono<@NotNull ServerInstance> getInfo(String handle);
 
     Mono<@NotNull Void> setState(String handle, String state);
+
+    Mono<@NotNull Void> sendPlayer(UUID playerId, String serverHandle);
 }

core-lib/src/main/java/de/kentoj/scrowlib/servermanager/ServerManagerImpl.java

@@ -3,17 +3,20 @@ package de.kentoj.scrowlib.servermanager;
 import com.google.common.base.Preconditions;
 import de.kentoj.scrowlib.messaging.DocumentRepository;
 import de.kentoj.scrowlib.messaging.NatsRepository;
+import de.kentoj.scrowlib.messaging.respose.SafeResult;
 import io.nats.client.Connection;
 import org.bson.Document;
 import org.jetbrains.annotations.NotNull;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
-public class CrownServerManager implements ServerManager {
+import java.util.UUID;
+
+public class ServerManagerImpl implements ServerManager {
 
     private final NatsRepository natsRepo;
 
-    public CrownServerManager(Connection nats) {
+    public ServerManagerImpl(Connection nats) {
         this.natsRepo = new NatsRepository(nats);
     }
 
@@ -23,6 +26,7 @@ public class CrownServerManager implements ServerManager {
         return natsRepo.request("crown.deploy-server", payload)
                 .map(DocumentRepository::fromMessage)
                 .map(doc -> new ServerInstance(
+                        template,
                         doc.getString("handle"),
                         doc.getInteger("port")
                 ));
@@ -38,6 +42,7 @@ public class CrownServerManager implements ServerManager {
                 )
                 .flatMapIterable(l -> l)
                 .map(doc -> new ServerInstance(
+                        doc.getString("templateName"),
                         doc.getString("handle"),
                         doc.getInteger("port"),
                         doc.getString("state")
@@ -57,6 +62,7 @@ public class CrownServerManager implements ServerManager {
         return natsRepo.request("crown.get-info", payload)
                 .map(DocumentRepository::fromMessage)
                 .map(doc -> new ServerInstance(
+                        doc.getString("templateName"),
                         handle,
                         doc.getInteger("port"),
                         doc.getString("state")
@@ -72,4 +78,14 @@ public class CrownServerManager implements ServerManager {
         return natsRepo.request("crown.set-state", payload)
                 .then();
     }
+
+    @Override
+    public Mono<@NotNull Void> sendPlayer(UUID playerId, String serverHandle) {
+        var payload = DocumentRepository.toBytes(new Document()
+                .append("playerId", playerId.toString())
+                .append("handle", serverHandle));
+        return natsRepo.request("proxy.send-player", payload)
+                .map(SafeResult::unwrap)
+                .then();
+    }
 }

core-velocity/src/main/java/de/kentoj/scrow/corevelocity/CoreVelocity.java

@@ -1,11 +1,9 @@
 package de.kentoj.scrow.corevelocity;
 
 import com.google.inject.Inject;
-import com.velocitypowered.api.event.Subscribe;
-import com.velocitypowered.api.event.proxy.ProxyInitializeEvent;
 import com.velocitypowered.api.plugin.Plugin;
 import com.velocitypowered.api.proxy.ProxyServer;
-import de.kentoj.scrowlib.servermanager.CrownServerManager;
+import de.kentoj.scrowlib.servermanager.ServerManagerImpl;
 import de.kentoj.scrowlib.servermanager.ServerManager;
 import io.nats.client.Connection;
 import io.nats.client.Nats;
@@ -26,6 +24,7 @@ public class CoreVelocity {
     private final Connection nats;
     private final ServerManager serverManager;
     private final ServerRegisterWatchdog registerWatchdog;
+    private final SendPlayerWatchdog sendPlayerWatchdog;
 
     @Inject
     public CoreVelocity(ProxyServer server) {
@@ -37,11 +36,13 @@ public class CoreVelocity {
                     .pedantic()
                     .server(natsHost)
                     .build());
-            serverManager = new CrownServerManager(nats);
+            serverManager = new ServerManagerImpl(nats);
             registerWatchdog = new ServerRegisterWatchdog(nats, serverManager, server);
+            sendPlayerWatchdog = new SendPlayerWatchdog(nats, server);
 
             log.info("listening on " + natsHost + " for server registrations");
             registerWatchdog.listen();
+            sendPlayerWatchdog.listen();
         } catch (IOException | InterruptedException e) {
             throw new RuntimeException(e);
         }

core-velocity/src/main/java/de/kentoj/scrow/corevelocity/SendPlayerWatchdog.java

@@ -0,0 +1,48 @@
+package de.kentoj.scrow.corevelocity;
+
+import com.velocitypowered.api.proxy.ProxyServer;
+import de.kentoj.scrowlib.messaging.DocumentRepository;
+import de.kentoj.scrowlib.messaging.NatsRepository;
+import de.kentoj.scrowlib.messaging.respose.SafeResult;
+import de.kentoj.scrowlib.messaging.respose.SafeSuccessResult;
+import io.nats.client.Connection;
+import org.bson.Document;
+import org.checkerframework.checker.optional.qual.Present;
+import org.jetbrains.annotations.NotNull;
+import reactor.core.publisher.Mono;
+
+import java.util.UUID;
+
+public class SendPlayerWatchdog {
+
+    private final NatsRepository natsRepo;
+    private final ProxyServer server;
+
+    public SendPlayerWatchdog(Connection nats, ProxyServer server) {
+        this.natsRepo = new NatsRepository(nats);
+        this.server = server;
+    }
+
+    public void listen() {
+        natsRepo.subscribe("proxy.send-player")
+                .flatMap(msg ->
+                        handleSendPlayer(DocumentRepository.fromMessage(msg))
+                                .flatMap(result -> natsRepo.publishSafeResult(msg.getReplyTo(), SafeResult.wrap(result)))
+                                .onErrorResume(err -> natsRepo.publishSafeResult(msg.getReplyTo(), SafeResult.wrap(err)))
+                )
+                .subscribe();
+    }
+
+    private Mono<@NotNull Document> handleSendPlayer(Document doc) {
+        return Mono.fromCallable(() -> {
+                    var player = server.getPlayer(UUID.fromString(doc.getString("playerId"))).orElseThrow();
+                    var targetServer = server.getServer(doc.getString("handle")).orElseThrow();
+                    return player.createConnectionRequest(targetServer).connect();
+                })
+                .flatMap(Mono::fromFuture)
+                .flatMap(res -> res.isSuccessful()
+                        ? Mono.just(new Document())
+                        : Mono.error(new RuntimeException(res.getStatus().name().toLowerCase().replace('_', ' ')))
+                );
+    }
+}