filtering + server lock

src/main/java/net/kewwbec/networkcore/NetworkCore.java

@@ -4,6 +4,7 @@ import com.hypixel.hytale.logger.HytaleLogger;
 import com.hypixel.hytale.server.core.event.events.ShutdownEvent;
 import com.hypixel.hytale.server.core.event.events.player.PlayerConnectEvent;
 import com.hypixel.hytale.server.core.event.events.player.PlayerDisconnectEvent;
+import com.hypixel.hytale.server.core.event.events.player.PlayerSetupConnectEvent;
 import com.hypixel.hytale.server.core.plugin.JavaPlugin;
 import com.hypixel.hytale.server.core.plugin.JavaPluginInit;
 import net.kewwbec.networkcore.api.DatabaseService;
@@ -18,6 +19,8 @@ import net.kewwbec.networkcore.command.NetworkCoreCommand;
 import net.kewwbec.networkcore.command.network.AlertCommand;
 import net.kewwbec.networkcore.command.network.GlistCommand;
 import net.kewwbec.networkcore.command.network.HubCommand;
+import net.kewwbec.networkcore.command.network.LockServerCommand;
+import net.kewwbec.networkcore.command.network.SendAllCommand;
 import net.kewwbec.networkcore.command.network.SendCommand;
 import net.kewwbec.networkcore.config.ConfigLoader;
 import net.kewwbec.networkcore.config.CoreConfig;
@@ -30,6 +33,8 @@ import net.kewwbec.networkcore.metrics.BuiltInMetrics;
 import net.kewwbec.networkcore.metrics.MetricsServiceImpl;
 import net.kewwbec.networkcore.metrics.PrometheusExporter;
 import net.kewwbec.networkcore.network.AlertService;
+import net.kewwbec.networkcore.network.LockEnforcer;
+import net.kewwbec.networkcore.network.LockService;
 import net.kewwbec.networkcore.network.RefRequestService;
 import net.kewwbec.networkcore.network.ShutdownHandoff;
 import net.kewwbec.networkcore.presence.PlayerPresenceService;
@@ -61,6 +66,7 @@ public final class NetworkCore extends JavaPlugin {
     @Nullable private PlayerPresenceService presenceService;
     @Nullable private AlertService alertService;
     @Nullable private RefRequestService refRequestService;
+    @Nullable private LockService lockService;
     @Nullable private ShutdownHandoff shutdownHandoff;
 
     public NetworkCore(@Nonnull JavaPluginInit init) {
@@ -157,6 +163,11 @@ public final class NetworkCore extends JavaPlugin {
         LobbyPicker lobbyPicker = new LobbyPicker(serverRegistry, config.server);
         this.shutdownHandoff = new ShutdownHandoff(lobbyPicker, serverId);
 
+        this.lockService = new LockService(serverId, serverRegistry, lobbyPicker, messageBus, getDataDirectory());
+        lockService.start();
+        LockEnforcer lockEnforcer = new LockEnforcer(lockService);
+        getEventRegistry().registerGlobal(PlayerSetupConnectEvent.class, lockEnforcer::onSetupConnect);
+
         getEventRegistry().registerGlobal(
             (short) (ShutdownEvent.DISCONNECT_PLAYERS - 1),
             ShutdownEvent.class,
@@ -170,6 +181,8 @@ public final class NetworkCore extends JavaPlugin {
         getCommandRegistry().registerCommand(new GlistCommand(serverRegistry, presenceService));
         getCommandRegistry().registerCommand(new HubCommand(lobbyPicker, refRequestService, serverId));
         getCommandRegistry().registerCommand(new SendCommand(serverRegistry, presenceService, refRequestService));
+        getCommandRegistry().registerCommand(new SendAllCommand(serverRegistry, presenceService, refRequestService, serverId));
+        getCommandRegistry().registerCommand(new LockServerCommand(lockService, serverRegistry, serverId));
 
         LOGGER.at(Level.INFO).log("NetworkCore started");
     }
@@ -177,6 +190,10 @@ public final class NetworkCore extends JavaPlugin {
     @Override
     protected void shutdown() {
         shutdownHandoff = null;
+        if (lockService != null) {
+            try { lockService.stop(); } catch (RuntimeException ignored) {}
+            lockService = null;
+        }
         if (refRequestService != null) {
             try { refRequestService.stop(); } catch (RuntimeException ignored) {}
             refRequestService = null;

src/main/java/net/kewwbec/networkcore/NetworkCorePermissions.java

@@ -11,6 +11,9 @@ public final class NetworkCorePermissions {
     public static final String GLIST    = ROOT + ".glist";
     public static final String HUB      = ROOT + ".hub";
     public static final String SEND     = ROOT + ".send";
+    public static final String SENDALL  = ROOT + ".sendall";
+    public static final String LOCKSERVER        = ROOT + ".lockserver";
+    public static final String LOCKSERVER_BYPASS = ROOT + ".lockserver.bypass";
 
     private NetworkCorePermissions() {
     }

src/main/java/net/kewwbec/networkcore/command/network/GlistCommand.java

@@ -4,6 +4,8 @@ import com.hypixel.hytale.component.Ref;
 import com.hypixel.hytale.component.Store;
 import com.hypixel.hytale.server.core.Message;
 import com.hypixel.hytale.server.core.command.system.CommandContext;
+import com.hypixel.hytale.server.core.command.system.arguments.system.OptionalArg;
+import com.hypixel.hytale.server.core.command.system.arguments.types.ArgTypes;
 import com.hypixel.hytale.server.core.command.system.basecommands.AbstractPlayerCommand;
 import com.hypixel.hytale.server.core.universe.PlayerRef;
 import com.hypixel.hytale.server.core.universe.world.World;
@@ -19,16 +21,25 @@ import java.awt.Color;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
+/**
+ * /glist [filter]
+ *
+ * No filter: every server is listed.
+ * Filter matches with this priority: exact server id, then role name.
+ */
 public final class GlistCommand extends AbstractPlayerCommand {
 
     private final ServerRegistry registry;
     private final PlayerPresence presence;
+    private final OptionalArg<String> filterArg = withOptionalArg("filter", "Server id or role to filter by", ArgTypes.STRING);
 
     public GlistCommand(@Nonnull ServerRegistry registry, @Nonnull PlayerPresence presence) {
-        super("glist", "List all online players across all servers");
+        super("glist", "List online players, optionally filtered by server id or role");
         this.registry = registry;
         this.presence = presence;
         requirePermission(NetworkCorePermissions.GLIST);
@@ -38,16 +49,32 @@ public final class GlistCommand extends AbstractPlayerCommand {
 
     @Override
     protected void execute(@Nonnull CommandContext ctx, @Nonnull Store<EntityStore> store, @Nonnull Ref<EntityStore> ref, @Nonnull PlayerRef sender, @Nonnull World world) {
-        Collection<ServerInfo> servers = registry.getServers();
+        String filter = filterArg.get(ctx);
-        ctx.sendMessage(Message.raw("=== Network ===").color(Color.YELLOW));
+        Collection<ServerInfo> servers = resolveServers(filter);
-        ctx.sendMessage(Message.raw("Servers: " + servers.size() + " | Online: " + presence.onlineCount()).color(Color.WHITE));
+
+        if (filter != null && !filter.isBlank() && servers.isEmpty()) {
+            ctx.sendMessage(Message.raw("No server matches id or role '" + filter + "'.").color(Color.RED));
+            return;
+        }
+
+        Set<String> includedIds = new LinkedHashSet<>();
+        for (ServerInfo s : servers) includedIds.add(s.id());
 
         Map<String, List<PlayerLocation>> grouped = new LinkedHashMap<>();
         for (ServerInfo s : servers) grouped.put(s.id(), new ArrayList<>());
+        int filteredOnline = 0;
         for (PlayerLocation loc : presence.all()) {
+            if (!includedIds.contains(loc.serverId())) continue;
             grouped.computeIfAbsent(loc.serverId(), k -> new ArrayList<>()).add(loc);
+            filteredOnline++;
         }
 
+        String header = (filter == null || filter.isBlank())
+            ? "=== Network ==="
+            : "=== Network (filter: " + filter + ") ===";
+        ctx.sendMessage(Message.raw(header).color(Color.YELLOW));
+        ctx.sendMessage(Message.raw("Servers: " + servers.size() + " | Online: " + filteredOnline).color(Color.WHITE));
+
         for (Map.Entry<String, List<PlayerLocation>> e : grouped.entrySet()) {
             ServerInfo s = registry.getServer(e.getKey());
             String role = (s == null) ? "?" : s.role();
@@ -66,4 +93,12 @@ public final class GlistCommand extends AbstractPlayerCommand {
             }
         }
     }
+
+    @Nonnull
+    private Collection<ServerInfo> resolveServers(String filter) {
+        if (filter == null || filter.isBlank()) return registry.getServers();
+        ServerInfo exact = registry.getServer(filter);
+        if (exact != null) return List.of(exact);
+        return registry.getServersByRole(filter);
+    }
 }

src/main/java/net/kewwbec/networkcore/command/network/LockServerCommand.java

@@ -0,0 +1,115 @@
+package net.kewwbec.networkcore.command.network;
+
+import com.hypixel.hytale.component.Ref;
+import com.hypixel.hytale.component.Store;
+import com.hypixel.hytale.server.core.Message;
+import com.hypixel.hytale.server.core.command.system.CommandContext;
+import com.hypixel.hytale.server.core.command.system.arguments.system.OptionalArg;
+import com.hypixel.hytale.server.core.command.system.arguments.system.RequiredArg;
+import com.hypixel.hytale.server.core.command.system.arguments.types.ArgTypes;
+import com.hypixel.hytale.server.core.command.system.basecommands.AbstractPlayerCommand;
+import com.hypixel.hytale.server.core.universe.PlayerRef;
+import com.hypixel.hytale.server.core.universe.world.World;
+import com.hypixel.hytale.server.core.universe.world.storage.EntityStore;
+import net.kewwbec.networkcore.NetworkCorePermissions;
+import net.kewwbec.networkcore.api.ServerInfo;
+import net.kewwbec.networkcore.api.ServerRegistry;
+import net.kewwbec.networkcore.network.LockService;
+
+import javax.annotation.Nonnull;
+import java.awt.Color;
+
+/**
+ * /lockserver <on|off|status> [serverId] [reason...]
+ *
+ * - on / lock: lock the target server (default: this server). Drains non-bypass players to a
+ *   lobby (or any other server, falling back to disconnect).
+ * - off / unlock: unlock the target server.
+ * - status: print this server's current lock state.
+ */
+public final class LockServerCommand extends AbstractPlayerCommand {
+
+    private final LockService locks;
+    private final ServerRegistry registry;
+    private final String selfServerId;
+
+    private final RequiredArg<String> actionArg = withRequiredArg("action", "on | off | status", ArgTypes.STRING);
+    private final OptionalArg<String> targetArg = withOptionalArg("server", "Server id (default: this server)", ArgTypes.STRING);
+    private final OptionalArg<String> reasonArg = withOptionalArg("reason", "Lock reason (optional)", ArgTypes.GREEDY_STRING);
+
+    public LockServerCommand(@Nonnull LockService locks,
+                             @Nonnull ServerRegistry registry,
+                             @Nonnull String selfServerId) {
+        super("lockserver", "Lock or unlock a server to non-bypass players");
+        this.locks = locks;
+        this.registry = registry;
+        this.selfServerId = selfServerId;
+        requirePermission(NetworkCorePermissions.LOCKSERVER);
+    }
+
+    @Override protected boolean canGeneratePermission() { return false; }
+
+    @Override
+    protected void execute(@Nonnull CommandContext ctx, @Nonnull Store<EntityStore> store, @Nonnull Ref<EntityStore> ref, @Nonnull PlayerRef sender, @Nonnull World world) {
+        String action = actionArg.get(ctx);
+        if (action == null) {
+            ctx.sendMessage(Message.raw("Usage: /lockserver <on|off|status> [serverId] [reason...]").color(Color.YELLOW));
+            return;
+        }
+        String target = targetArg.get(ctx);
+        String reason = reasonArg.get(ctx);
+        String resolvedTarget = (target == null || target.isBlank()) ? selfServerId : target;
+
+        switch (action.toLowerCase()) {
+            case "on", "lock" -> doLock(ctx, sender, resolvedTarget, reason);
+            case "off", "unlock" -> doUnlock(ctx, sender, resolvedTarget);
+            case "status" -> doStatus(ctx);
+            default -> ctx.sendMessage(Message.raw("Unknown action '" + action + "'. Use on, off, or status.").color(Color.YELLOW));
+        }
+    }
+
+    private void doLock(@Nonnull CommandContext ctx, @Nonnull PlayerRef sender, @Nonnull String targetId, String reason) {
+        ServerInfo info = registry.getServer(targetId);
+        if (info == null && !targetId.equals(selfServerId)) {
+            ctx.sendMessage(Message.raw("Unknown server id '" + targetId + "'.").color(Color.RED));
+            return;
+        }
+        if (targetId.equals(selfServerId)) {
+            locks.setLocal(true, reason, sender.getUsername());
+            ctx.sendMessage(Message.raw("This server is now LOCKED.").color(Color.GREEN));
+        } else {
+            locks.requestRemote(targetId, true, reason, sender.getUsername());
+            ctx.sendMessage(Message.raw("Lock request sent to " + targetId + ".").color(Color.GREEN));
+        }
+    }
+
+    private void doUnlock(@Nonnull CommandContext ctx, @Nonnull PlayerRef sender, @Nonnull String targetId) {
+        ServerInfo info = registry.getServer(targetId);
+        if (info == null && !targetId.equals(selfServerId)) {
+            ctx.sendMessage(Message.raw("Unknown server id '" + targetId + "'.").color(Color.RED));
+            return;
+        }
+        if (targetId.equals(selfServerId)) {
+            locks.setLocal(false, null, sender.getUsername());
+            ctx.sendMessage(Message.raw("This server is now UNLOCKED.").color(Color.GREEN));
+        } else {
+            locks.requestRemote(targetId, false, null, sender.getUsername());
+            ctx.sendMessage(Message.raw("Unlock request sent to " + targetId + ".").color(Color.GREEN));
+        }
+    }
+
+    private void doStatus(@Nonnull CommandContext ctx) {
+        ctx.sendMessage(Message.raw("=== Lock status (this server) ===").color(Color.YELLOW));
+        ctx.sendMessage(Message.raw("Server: " + selfServerId).color(Color.WHITE));
+        if (locks.isLocked()) {
+            String r = locks.lockReason();
+            String by = locks.lockedByName();
+            ctx.sendMessage(Message.raw("State: LOCKED").color(Color.RED));
+            if (r != null && !r.isBlank()) ctx.sendMessage(Message.raw("Reason: " + r).color(Color.WHITE));
+            if (by != null && !by.isBlank()) ctx.sendMessage(Message.raw("Locked by: " + by).color(Color.WHITE));
+        } else {
+            ctx.sendMessage(Message.raw("State: open").color(Color.GREEN));
+        }
+        ctx.sendMessage(Message.raw("Status of other servers is not tracked in v1. Run /lockserver status on each.").color(Color.GRAY));
+    }
+}

src/main/java/net/kewwbec/networkcore/command/network/SendAllCommand.java

@@ -0,0 +1,151 @@
+package net.kewwbec.networkcore.command.network;
+
+import com.hypixel.hytale.component.Ref;
+import com.hypixel.hytale.component.Store;
+import com.hypixel.hytale.server.core.Message;
+import com.hypixel.hytale.server.core.command.system.CommandContext;
+import com.hypixel.hytale.server.core.command.system.arguments.system.RequiredArg;
+import com.hypixel.hytale.server.core.command.system.arguments.types.ArgTypes;
+import com.hypixel.hytale.server.core.command.system.basecommands.AbstractPlayerCommand;
+import com.hypixel.hytale.server.core.universe.PlayerRef;
+import com.hypixel.hytale.server.core.universe.Universe;
+import com.hypixel.hytale.server.core.universe.world.World;
+import com.hypixel.hytale.server.core.universe.world.storage.EntityStore;
+import net.kewwbec.networkcore.NetworkCorePermissions;
+import net.kewwbec.networkcore.api.PlayerLocation;
+import net.kewwbec.networkcore.api.PlayerPresence;
+import net.kewwbec.networkcore.api.ServerInfo;
+import net.kewwbec.networkcore.api.ServerRegistry;
+import net.kewwbec.networkcore.network.RefRequestService;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import java.awt.Color;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * /sendall <source> <target>
+ *
+ * Sends every player on the source server(s) to the target server.
+ *
+ * Each argument resolves with this priority:
+ *  1. literal "here" (source only) - this server
+ *  2. exact server id
+ *  3. role name (any server with that role)
+ *
+ * If source resolves to a role, every server with that role is drained.
+ * Target must resolve to a single server; if a role matches multiple, the least-loaded referrable
+ * one is picked. Players already on the target server are skipped.
+ */
+public final class SendAllCommand extends AbstractPlayerCommand {
+
+    private final ServerRegistry registry;
+    private final PlayerPresence presence;
+    private final RefRequestService refRequest;
+    private final String selfServerId;
+
+    private final RequiredArg<String> sourceArg = withRequiredArg("source", "here, server id, or role", ArgTypes.STRING);
+    private final RequiredArg<String> targetArg = withRequiredArg("target", "Server id or role", ArgTypes.STRING);
+
+    public SendAllCommand(@Nonnull ServerRegistry registry,
+                          @Nonnull PlayerPresence presence,
+                          @Nonnull RefRequestService refRequest,
+                          @Nonnull String selfServerId) {
+        super("sendall", "Send every player from a server/role to another server/role");
+        this.registry = registry;
+        this.presence = presence;
+        this.refRequest = refRequest;
+        this.selfServerId = selfServerId;
+        requirePermission(NetworkCorePermissions.SENDALL);
+    }
+
+    @Override protected boolean canGeneratePermission() { return false; }
+
+    @Override
+    protected void execute(@Nonnull CommandContext ctx, @Nonnull Store<EntityStore> store, @Nonnull Ref<EntityStore> ref, @Nonnull PlayerRef sender, @Nonnull World world) {
+        String sourceRaw = sourceArg.get(ctx);
+        String targetRaw = targetArg.get(ctx);
+        if (sourceRaw == null || targetRaw == null) {
+            ctx.sendMessage(Message.raw("Usage: /sendall <here|serverId|role> <serverId|role>").color(Color.YELLOW));
+            return;
+        }
+
+        Set<String> sourceServers = resolveSource(sourceRaw);
+        if (sourceServers.isEmpty()) {
+            ctx.sendMessage(Message.raw("No source server matches '" + sourceRaw + "'.").color(Color.RED));
+            return;
+        }
+
+        ServerInfo target = resolveTarget(targetRaw);
+        if (target == null) {
+            ctx.sendMessage(Message.raw("No target server matches '" + targetRaw + "'.").color(Color.RED));
+            return;
+        }
+        if (!target.isReferrable()) {
+            ctx.sendMessage(Message.raw("Target server " + target.id() + " has no public address configured.").color(Color.RED));
+            return;
+        }
+        sourceServers.remove(target.id());
+        if (sourceServers.isEmpty()) {
+            ctx.sendMessage(Message.raw("Source and target resolve to the same server; nothing to do.").color(Color.YELLOW));
+            return;
+        }
+
+        int localCount = 0;
+        int remoteCount = 0;
+        Universe universe = Universe.get();
+        for (String srcId : sourceServers) {
+            Collection<PlayerLocation> on = presence.onServer(srcId);
+            for (PlayerLocation pl : on) {
+                if (srcId.equals(selfServerId) && universe != null) {
+                    PlayerRef local = universe.getPlayer(pl.uuid());
+                    if (local != null) {
+                        if (refRequest.referLocal(local, target)) localCount++;
+                        continue;
+                    }
+                }
+                refRequest.requestRemote(pl.uuid(), target);
+                remoteCount++;
+            }
+        }
+
+        int total = localCount + remoteCount;
+        ctx.sendMessage(Message.raw(
+            "Sending " + total + " player(s) from " + sourceServers + " to " + target.id()
+                + " (" + localCount + " local, " + remoteCount + " remote)."
+        ).color(Color.GREEN));
+    }
+
+    @Nonnull
+    private Set<String> resolveSource(@Nonnull String input) {
+        if ("here".equalsIgnoreCase(input)) {
+            return new LinkedHashSet<>(List.of(selfServerId));
+        }
+        Set<String> out = new LinkedHashSet<>();
+        ServerInfo exact = registry.getServer(input);
+        if (exact != null) {
+            out.add(exact.id());
+            return out;
+        }
+        for (ServerInfo s : registry.getServersByRole(input)) {
+            out.add(s.id());
+        }
+        return out;
+    }
+
+    @Nullable
+    private ServerInfo resolveTarget(@Nonnull String input) {
+        ServerInfo exact = registry.getServer(input);
+        if (exact != null) return exact;
+        List<ServerInfo> byRole = new ArrayList<>(registry.getServersByRole(input));
+        return byRole.stream()
+            .filter(ServerInfo::isReferrable)
+            .min(Comparator.comparingInt(ServerInfo::players))
+            .orElse(null);
+    }
+}

src/main/java/net/kewwbec/networkcore/network/LockEnforcer.java

@@ -0,0 +1,30 @@
+package net.kewwbec.networkcore.network;
+
+import com.hypixel.hytale.server.core.Message;
+import com.hypixel.hytale.server.core.event.events.player.PlayerSetupConnectEvent;
+
+import javax.annotation.Nonnull;
+
+/**
+ * Cancels PlayerSetupConnectEvent if this server is locked and the connecting player lacks the
+ * LOCKSERVER_BYPASS permission.
+ */
+public final class LockEnforcer {
+
+    private final LockService locks;
+
+    public LockEnforcer(@Nonnull LockService locks) {
+        this.locks = locks;
+    }
+
+    public void onSetupConnect(@Nonnull PlayerSetupConnectEvent event) {
+        if (!locks.isLocked()) return;
+        if (locks.hasBypass(event.getUuid())) return;
+        event.setCancelled(true);
+        String reason = locks.lockReason();
+        String text = (reason != null && !reason.isBlank())
+            ? "Server locked: " + reason
+            : "Server is locked. Please try again later.";
+        event.setReason(Message.raw(text));
+    }
+}

src/main/java/net/kewwbec/networkcore/network/LockServerPayload.java

@@ -0,0 +1,32 @@
+package net.kewwbec.networkcore.network;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * Cross-server lock/unlock instruction. Only the server whose id matches targetServerId acts.
+ */
+public final class LockServerPayload {
+
+    public static final String CHANNEL = "network.lock";
+
+    public String targetServerId;
+    public boolean lock;
+    public String reason;
+    public String issuedByName;
+    public String fromServerId;
+
+    public LockServerPayload() {}
+
+    public LockServerPayload(@Nonnull String targetServerId,
+                             boolean lock,
+                             @Nullable String reason,
+                             @Nullable String issuedByName,
+                             @Nullable String fromServerId) {
+        this.targetServerId = targetServerId;
+        this.lock = lock;
+        this.reason = reason;
+        this.issuedByName = issuedByName;
+        this.fromServerId = fromServerId;
+    }
+}

src/main/java/net/kewwbec/networkcore/network/LockService.java

@@ -0,0 +1,223 @@
+package net.kewwbec.networkcore.network;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.hypixel.hytale.logger.HytaleLogger;
+import com.hypixel.hytale.server.core.Message;
+import com.hypixel.hytale.server.core.permissions.PermissionsModule;
+import com.hypixel.hytale.server.core.universe.PlayerRef;
+import com.hypixel.hytale.server.core.universe.Universe;
+import net.kewwbec.networkcore.NetworkCorePermissions;
+import net.kewwbec.networkcore.api.MessageBus;
+import net.kewwbec.networkcore.api.ServerInfo;
+import net.kewwbec.networkcore.api.ServerRegistry;
+import net.kewwbec.networkcore.internal.LobbyPicker;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+import java.util.UUID;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.logging.Level;
+
+/**
+ * Owns the local lock state for this server: whether non-bypass players can connect.
+ *
+ * Persistence: a JSON file in the plugin data dir. Lock state survives restarts so an admin's
+ * lock isn't accidentally cleared when the server reboots.
+ *
+ * Bus: subscribes to {@link LockServerPayload#CHANNEL}; if the message targets this server id,
+ * applies the change locally. The {@link #setLocked(boolean, String, String)} method handles both
+ * the local-command case (no bus publish) and post-bus-receive (also no further publish).
+ *
+ * Drain: when transitioning to LOCKED, walks online non-bypass players and refers each to a lobby
+ * (via {@link LobbyPicker}); falls back to any other referrable server. If nothing is available,
+ * the player is disconnected with the lock reason.
+ */
+public final class LockService {
+
+    private static final HytaleLogger LOGGER = HytaleLogger.forEnclosingClass();
+    private static final Gson GSON = new GsonBuilder().setPrettyPrinting().create();
+
+    private final String selfServerId;
+    private final ServerRegistry registry;
+    private final LobbyPicker lobbyPicker;
+    private final MessageBus bus;
+    private final Path stateFile;
+
+    private final AtomicBoolean locked = new AtomicBoolean(false);
+    @Nullable private volatile String lockReason;
+    @Nullable private volatile String lockedByName;
+    @Nullable private MessageBus.Subscription sub;
+
+    public LockService(@Nonnull String selfServerId,
+                       @Nonnull ServerRegistry registry,
+                       @Nonnull LobbyPicker lobbyPicker,
+                       @Nonnull MessageBus bus,
+                       @Nonnull Path dataDirectory) {
+        this.selfServerId = selfServerId;
+        this.registry = registry;
+        this.lobbyPicker = lobbyPicker;
+        this.bus = bus;
+        this.stateFile = dataDirectory.resolve("lock-state.json");
+    }
+
+    public void start() {
+        loadFromDisk();
+        sub = bus.subscribe(LockServerPayload.CHANNEL, LockServerPayload.class, this::onBus);
+        if (locked.get()) {
+            LOGGER.at(Level.INFO).log("Server is LOCKED (restored from disk). Reason: %s", lockReason);
+        }
+    }
+
+    public void stop() {
+        if (sub != null) {
+            try { sub.close(); } catch (RuntimeException ignored) {}
+            sub = null;
+        }
+    }
+
+    public boolean isLocked() {
+        return locked.get();
+    }
+
+    @Nullable
+    public String lockReason() {
+        return lockReason;
+    }
+
+    @Nullable
+    public String lockedByName() {
+        return lockedByName;
+    }
+
+    public boolean hasBypass(@Nonnull UUID uuid) {
+        PermissionsModule module = PermissionsModule.get();
+        return module != null && module.hasPermission(uuid, NetworkCorePermissions.LOCKSERVER_BYPASS);
+    }
+
+    /**
+     * Lock or unlock another server in the network. Returns immediately; the target server applies
+     * the change asynchronously after receiving the bus message.
+     */
+    public void requestRemote(@Nonnull String targetServerId, boolean lock,
+                              @Nullable String reason, @Nullable String issuedByName) {
+        bus.publish(LockServerPayload.CHANNEL, new LockServerPayload(
+            targetServerId, lock, reason, issuedByName, selfServerId));
+    }
+
+    /**
+     * Lock or unlock THIS server. Persists, drains, and broadcasts (so other plugins or future
+     * status readers can observe even though only this server enforces).
+     */
+    public void setLocal(boolean lock, @Nullable String reason, @Nullable String issuedByName) {
+        applyLocal(lock, reason, issuedByName);
+        bus.publish(LockServerPayload.CHANNEL, new LockServerPayload(
+            selfServerId, lock, reason, issuedByName, selfServerId));
+    }
+
+    private void applyLocal(boolean lock, @Nullable String reason, @Nullable String issuedByName) {
+        boolean was = locked.getAndSet(lock);
+        this.lockReason = reason;
+        this.lockedByName = issuedByName;
+        saveToDisk();
+        if (lock && !was) {
+            LOGGER.at(Level.INFO).log("Server LOCKED by %s. Reason: %s", issuedByName, reason);
+            drainNonBypass(reason);
+        } else if (!lock && was) {
+            LOGGER.at(Level.INFO).log("Server UNLOCKED by %s.", issuedByName);
+        }
+    }
+
+    private void onBus(@Nonnull LockServerPayload p) {
+        if (p.targetServerId == null || !p.targetServerId.equals(selfServerId)) return;
+        if (p.fromServerId != null && p.fromServerId.equals(selfServerId)) return; // our own echo
+        applyLocal(p.lock, p.reason, p.issuedByName);
+    }
+
+    private void drainNonBypass(@Nullable String reason) {
+        Universe universe = Universe.get();
+        if (universe == null) return;
+
+        Message kickMsg = Message.raw(reason != null && !reason.isBlank()
+            ? "Server locked: " + reason
+            : "Server locked. Please reconnect later.");
+
+        List<PlayerRef> snapshot = new ArrayList<>(universe.getPlayers());
+        ServerInfo lobby = lobbyPicker.pick(selfServerId);
+        ServerInfo fallback = pickFallback(lobby);
+
+        for (PlayerRef ref : snapshot) {
+            try {
+                if (hasBypass(ref.getUuid())) continue;
+                ServerInfo dest = lobby;
+                if (dest == null) dest = fallback;
+                if (dest != null && dest.isReferrable()) {
+                    try {
+                        ref.referToServer(dest.host(), dest.port());
+                        continue;
+                    } catch (RuntimeException e) {
+                        LOGGER.at(Level.WARNING).log("Drain refer of %s failed: %s", ref.getUsername(), e.getMessage());
+                    }
+                }
+                try { ref.getPacketHandler().disconnect(kickMsg); } catch (RuntimeException ignored) {}
+            } catch (RuntimeException e) {
+                ((HytaleLogger.Api) LOGGER.at(Level.WARNING).withCause(e))
+                    .log("Drain failed for %s", ref.getUsername());
+            }
+        }
+    }
+
+    @Nullable
+    private ServerInfo pickFallback(@Nullable ServerInfo excludeLobby) {
+        List<ServerInfo> pool = new ArrayList<>();
+        for (ServerInfo s : registry.getServers()) {
+            if (s.id().equals(selfServerId)) continue;
+            if (excludeLobby != null && s.id().equals(excludeLobby.id())) continue;
+            if (!s.isReferrable()) continue;
+            pool.add(s);
+        }
+        if (pool.isEmpty()) return null;
+        pool.sort(Comparator.comparingInt(ServerInfo::players));
+        return pool.get(0);
+    }
+
+    private void loadFromDisk() {
+        if (!Files.exists(stateFile)) return;
+        try {
+            String json = Files.readString(stateFile, StandardCharsets.UTF_8);
+            State s = GSON.fromJson(json, State.class);
+            if (s == null) return;
+            locked.set(s.locked);
+            lockReason = s.reason;
+            lockedByName = s.lockedByName;
+        } catch (IOException e) {
+            LOGGER.at(Level.WARNING).log("Failed to read lock state: %s", e.getMessage());
+        }
+    }
+
+    private void saveToDisk() {
+        try {
+            Files.createDirectories(stateFile.getParent());
+            State s = new State();
+            s.locked = locked.get();
+            s.reason = lockReason;
+            s.lockedByName = lockedByName;
+            Files.writeString(stateFile, GSON.toJson(s), StandardCharsets.UTF_8);
+        } catch (IOException e) {
+            LOGGER.at(Level.WARNING).log("Failed to write lock state: %s", e.getMessage());
+        }
+    }
+
+    private static final class State {
+        boolean locked;
+        String reason;
+        String lockedByName;
+    }
+}