Wait for Terraplusminus cache priming on tpll

Bukkit/src/main/java/de/btegermany/teleportation/TeleportationBukkit/message/executor/TeleportExecutor.java

@@ -56,8 +56,14 @@ public void execute(ByteArrayDataInput dataInput) {
             Float pitch = Optional.of(dataInput.readUTF()).filter(str -> !str.equals("null")).map(Float::parseFloat).orElse(null);
             String worldName = Optional.of(dataInput.readUTF()).filter(str -> !str.equals("null")).orElse(null);
             String originServerName = dataInput.readUTF();
-
-            this.teleportationHandler.handle(new PendingTpLocation(playerUUID, x, y, z, yaw, pitch, worldName, originServerName, this.plugin));
+            boolean prepareRegion = false;
+            try {
+                prepareRegion = Boolean.parseBoolean(dataInput.readUTF());
+            } catch (IllegalStateException ignored) {
+                // Older Velocity messages do not include the optional preparation flag.
+            }
+
+            this.teleportationHandler.handle(new PendingTpLocation(playerUUID, x, y, z, yaw, pitch, worldName, originServerName, prepareRegion, this.plugin));
         }
 
     }

Bukkit/src/main/java/de/btegermany/teleportation/TeleportationBukkit/tp/PendingTpLocation.java

@@ -17,16 +17,22 @@ public class PendingTpLocation extends PendingTeleportationAbstract {
     private final Float yaw;
     private final Float pitch;
     private final String worldName;
+    private final boolean prepareRegion;
     private final TeleportationBukkit plugin;
 
     public PendingTpLocation(UUID playerUUID, double x, double y, double z, Float yaw, Float pitch, String worldName, String originServerName, TeleportationBukkit plugin) {
+        this(playerUUID, x, y, z, yaw, pitch, worldName, originServerName, false, plugin);
+    }
+
+    public PendingTpLocation(UUID playerUUID, double x, double y, double z, Float yaw, Float pitch, String worldName, String originServerName, boolean prepareRegion, TeleportationBukkit plugin) {
         super(playerUUID, originServerName);
         this.x = x;
         this.y = y;
         this.z = z;
         this.yaw = yaw;
         this.pitch = pitch;
         this.worldName = worldName;
+        this.prepareRegion = prepareRegion;
         this.plugin = plugin;
     }
 
@@ -38,11 +44,41 @@ public boolean canTeleport() {
 
     @Override
     public void teleport() {
+        Bukkit.getScheduler().runTask(this.plugin, () -> {
+            Player player = Bukkit.getPlayer(this.playerUUID);
+            if (player == null || !player.isOnline()) {
+                return;
+            }
+
+            World world = (worldName == null) ? player.getWorld() : Bukkit.getWorld(worldName);
+            if (world == null) {
+                world = Bukkit.getWorld("world");
+            }
+            if (world == null) {
+                player.sendMessage(TeleportationBukkit.getFormattedErrorMessage("Target world not found."));
+                return;
+            }
+
+            World targetWorld = world;
+            if (!this.prepareRegion) {
+                this.teleportPrepared(targetWorld);
+                return;
+            }
+
+            TerraplusminusRegionPreparer.prepare(this.plugin, player, targetWorld, x, z)
+                    .thenAccept(prepared -> {
+                        if (!Boolean.TRUE.equals(prepared)) {
+                            return;
+                        }
+                        Bukkit.getScheduler().runTask(this.plugin, () -> this.teleportPrepared(targetWorld));
+                    });
+        });
+    }
+
+    private void teleportPrepared(World world) {
         Player player = Bukkit.getPlayer(this.playerUUID);
-        assert player != null; // canTeleport() checked
-        World world = (worldName == null) ? player.getWorld() : Bukkit.getWorld(worldName);
-        if (world == null) {
-            world = Bukkit.getWorld("world");
+        if (player == null || !player.isOnline()) {
+            return;
         }
 
         double yWorld = y;
@@ -53,7 +89,7 @@ public void teleport() {
         location.setYaw(yaw != null ? yaw : player.getLocation().getYaw());
         location.setPitch(pitch != null ? pitch : player.getLocation().getPitch());
 
-        Bukkit.getScheduler().runTask(this.plugin, () -> player.teleport(location));
+        player.teleport(location);
     }
 
 }

Bukkit/src/main/java/de/btegermany/teleportation/TeleportationBukkit/tp/TerraplusminusRegionPreparer.java

@@ -0,0 +1,87 @@
+package de.btegermany.teleportation.TeleportationBukkit.tp;
+
+import de.btegermany.teleportation.TeleportationBukkit.TeleportationBukkit;
+import org.bukkit.Bukkit;
+import org.bukkit.World;
+import org.bukkit.entity.Player;
+import org.bukkit.plugin.Plugin;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionStage;
+
+final class TerraplusminusRegionPreparer {
+
+    private static final String PLUGIN_NAME = "Terraplusminus";
+    private static final int TELEPORT_PREP_RADIUS_CHUNKS = 16;
+
+    private TerraplusminusRegionPreparer() {
+    }
+
+    static CompletableFuture<Boolean> prepare(TeleportationBukkit owner, Player player, World world, double x, double z) {
+        Plugin terraplusminus = Bukkit.getPluginManager().getPlugin(PLUGIN_NAME);
+        if (terraplusminus == null || !terraplusminus.isEnabled()) {
+            return CompletableFuture.completedFuture(true);
+        }
+
+        try {
+            Method isTeleportRegionGenerated = terraplusminus.getClass().getMethod(
+                    "isTeleportRegionGenerated",
+                    World.class,
+                    double.class,
+                    double.class,
+                    int.class
+            );
+            boolean alreadyGenerated = (boolean) isTeleportRegionGenerated.invoke(
+                    terraplusminus,
+                    world,
+                    x,
+                    z,
+                    TELEPORT_PREP_RADIUS_CHUNKS
+            );
+            if (alreadyGenerated) {
+                return CompletableFuture.completedFuture(true);
+            }
+
+            player.sendMessage(TeleportationBukkit.getFormattedMessage("Die Zielregion wird gerade generiert. Du wirst teleportiert, sobald sie bereit ist."));
+            Method primeTeleportRegionCache = terraplusminus.getClass().getMethod(
+                    "primeTeleportRegionCache",
+                    World.class,
+                    double.class,
+                    double.class,
+                    int.class
+            );
+            Object result = primeTeleportRegionCache.invoke(
+                    terraplusminus,
+                    world,
+                    x,
+                    z,
+                    TELEPORT_PREP_RADIUS_CHUNKS
+            );
+
+            if (!(result instanceof CompletionStage<?> completionStage)) {
+                owner.getLogger().warning("Terraplusminus primeTeleportRegionCache did not return a CompletionStage.");
+                return CompletableFuture.completedFuture(false);
+            }
+
+            return completionStage
+                    .thenApply(ignored -> true)
+                    .exceptionally(ex -> {
+                        owner.getLogger().warning("Terraplusminus failed to prepare the target teleport region: " + ex.getMessage());
+                        Bukkit.getScheduler().runTask(owner, () ->
+                                player.sendMessage(TeleportationBukkit.getFormattedErrorMessage("Die Zielregion konnte nicht generiert werden. Bitte versuche es spaeter erneut.")));
+                        return false;
+                    })
+                    .toCompletableFuture();
+        } catch (NoSuchMethodException e) {
+            owner.getLogger().fine("Terraplusminus is installed without teleport region preparation API; continuing without cache priming.");
+            return CompletableFuture.completedFuture(true);
+        } catch (IllegalAccessException | InvocationTargetException | ClassCastException e) {
+            owner.getLogger().warning("Could not call Terraplusminus teleport region preparation API: " + e.getMessage());
+            Bukkit.getScheduler().runTask(owner, () ->
+                    player.sendMessage(TeleportationBukkit.getFormattedErrorMessage("Die Zielregion konnte nicht generiert werden. Bitte versuche es spaeter erneut.")));
+            return CompletableFuture.completedFuture(false);
+        }
+    }
+}

Velocity/src/main/java/de/btegermany/teleportation/TeleportationVelocity/command/TpllCommand.java

@@ -136,7 +136,7 @@ public void execute(Invocation invocation) {
         // send teleport data and the player to the target server
         RequestLastLocationMessage requestLastLocationMessage = new RequestLastLocationMessage(player, this.registriesProvider, () -> {
             sendMessage(player, Component.text("Teleporting to " + coordinates.getLat() + ", " + coordinates.getLng() + ".", NamedTextColor.GOLD));
-            this.pluginMessenger.teleportToCoords(player, targetServer, mcCoordinatesFinal[0], mcCoordinatesY, mcCoordinatesFinal[1], yawFinal, pitchFinal, worldFinal);
+            this.pluginMessenger.teleportToCoords(player, targetServer, mcCoordinatesFinal[0], mcCoordinatesY, mcCoordinatesFinal[1], yawFinal, pitchFinal, worldFinal, true);
         });
         if (player.getCurrentServer().isEmpty()) {
             return;

Velocity/src/main/java/de/btegermany/teleportation/TeleportationVelocity/message/PluginMessenger.java

@@ -69,6 +69,11 @@ public void teleportToCoords(Player player, RegisteredServer server, double x, d
         this.sendAndConnect(player, server, new TeleportToCoordsMessage(player, x, y, z, yaw, pitch, world));
     }
 
+    // teleports a player to the specified coordinates after the backend prepared the target region if supported
+    public void teleportToCoords(Player player, RegisteredServer server, double x, double y, double z, Float yaw, Float pitch, String world, boolean prepareRegion) {
+        this.sendAndConnect(player, server, new TeleportToCoordsMessage(player, x, y, z, yaw, pitch, world, prepareRegion));
+    }
+
     // teleports a player to the normen world on the specified server
     public void teleportToNormen(Player player, RegisteredServer server, String normenWorld, float yaw, float pitch) {
         this.sendAndConnect(player, server, new TeleportToNormenMessage(player, normenWorld, yaw, pitch));

Velocity/src/main/java/de/btegermany/teleportation/TeleportationVelocity/message/TeleportToCoordsMessage.java

@@ -8,6 +8,10 @@
 public class TeleportToCoordsMessage extends PluginMessage {
 
     public TeleportToCoordsMessage(Player player, double x, double y, double z, Float yaw, Float pitch, String world) {
+        this(player, x, y, z, yaw, pitch, world, false);
+    }
+
+    public TeleportToCoordsMessage(Player player, double x, double y, double z, Float yaw, Float pitch, String world, boolean prepareRegion) {
         super("teleport_coords", MessageType.NORMAL);
         if (player.getCurrentServer().isEmpty()) {
             return;
@@ -20,7 +24,8 @@ public TeleportToCoordsMessage(Player player, double x, double y, double z, Floa
                 pitch == null ? "null" : pitch.toString(),
                 // null to use the player's current world
                 world == null ? "null" : world,
-                player.getCurrentServer().get().getServerInfo().getName()));
+                player.getCurrentServer().get().getServerInfo().getName(),
+                Boolean.toString(prepareRegion)));
     }
 
 }