fix multiple null errors with unloaded worlds

plugin/src/main/java/lol/pyr/znpcsplus/commands/CloneCommand.java

@@ -0,0 +1,48 @@
+package lol.pyr.znpcsplus.commands;
+
+import lol.pyr.director.adventure.command.CommandContext;
+import lol.pyr.director.adventure.command.CommandHandler;
+import lol.pyr.director.common.command.CommandExecutionException;
+import lol.pyr.znpcsplus.npc.NpcEntryImpl;
+import lol.pyr.znpcsplus.npc.NpcRegistryImpl;
+import lol.pyr.znpcsplus.npc.NpcTypeImpl;
+import lol.pyr.znpcsplus.npc.NpcTypeRegistryImpl;
+import lol.pyr.znpcsplus.util.NpcLocation;
+import net.kyori.adventure.text.Component;
+import net.kyori.adventure.text.format.NamedTextColor;
+import org.bukkit.entity.Player;
+
+import java.util.Collections;
+import java.util.List;
+
+public class CloneCommand implements CommandHandler {
+    private final NpcRegistryImpl npcRegistry;
+    private final NpcTypeRegistryImpl typeRegistry;
+
+    public CloneCommand(NpcRegistryImpl npcRegistry, NpcTypeRegistryImpl typeRegistry) {
+        this.npcRegistry = npcRegistry;
+        this.typeRegistry = typeRegistry;
+    }
+
+    @Override
+    public void run(CommandContext context) throws  CommandExecutionException {
+        context.setUsage(context.getLabel() + " create <id> <type>");
+        Player player = context.ensureSenderIsPlayer();
+
+        String id = context.popString();
+        if (npcRegistry.getById(id) != null) context.halt(Component.text("NPC with that ID already exists.", NamedTextColor.RED));
+        NpcTypeImpl type = context.parse(NpcTypeImpl.class);
+
+        NpcEntryImpl entry = npcRegistry.create(id, player.getWorld(), type, new NpcLocation(player.getLocation()));
+        entry.enableEverything();
+
+        context.send(Component.text("Created a " + type.getName() + " NPC with ID " + id + ".", NamedTextColor.GREEN));
+    }
+
+    @Override
+    public List<String> suggest(CommandContext context) throws CommandExecutionException {
+        if (context.argSize() == 1) return context.suggestCollection(npcRegistry.getModifiableIds());
+        if (context.argSize() == 2) return context.suggestStream(typeRegistry.getAllImpl().stream().map(NpcTypeImpl::getName));
+        return Collections.emptyList();
+    }
+}

plugin/src/main/java/lol/pyr/znpcsplus/commands/MoveCommand.java

@@ -13,6 +13,7 @@ import org.bukkit.entity.Player;
 
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 
 public class MoveCommand implements CommandHandler {
     private final NpcRegistryImpl npcRegistry;
@@ -27,7 +28,7 @@ public class MoveCommand implements CommandHandler {
         Player player = context.ensureSenderIsPlayer();
         NpcImpl npc = context.parse(NpcEntryImpl.class).getNpc();
         npc.setLocation(new NpcLocation(player.getLocation()));
-        if (!npc.getWorld().equals(player.getWorld())) npc.setWorld(player.getWorld());
+        if (!Objects.equals(npc.getWorld(), player.getWorld())) npc.setWorld(player.getWorld());
         context.send(Component.text("NPC moved to your current location.", NamedTextColor.GREEN));
     }
 

plugin/src/main/java/lol/pyr/znpcsplus/commands/NearCommand.java

@@ -10,6 +10,7 @@ import lol.pyr.znpcsplus.util.NpcLocation;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.event.ClickEvent;
 import net.kyori.adventure.text.format.NamedTextColor;
+import org.bukkit.Location;
 import org.bukkit.entity.Player;
 
 import java.util.List;
@@ -32,7 +33,10 @@ public class NearCommand implements CommandHandler {
 
         List<NpcEntryImpl> entries = npcRegistry.getAllModifiable().stream()
                 .filter(entry -> Objects.equals(entry.getNpc().getWorld(), player.getWorld()))
-                .filter(entry -> entry.getNpc().getBukkitLocation().distanceSquared(player.getLocation()) < radius)
+                .filter(entry -> {
+                    Location loc = entry.getNpc().getBukkitLocation();
+                    return loc != null && loc.distanceSquared(player.getLocation()) < radius;
+                })
                 .collect(Collectors.toList());
 
         if (entries.isEmpty()) context.halt(Component.text("There are no npcs within " + raw + " blocks around you.", NamedTextColor.RED));

plugin/src/main/java/lol/pyr/znpcsplus/npc/NpcImpl.java

@@ -20,6 +20,7 @@ import org.bukkit.Location;
 import org.bukkit.World;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.*;
 import java.util.stream.Collectors;
@@ -75,8 +76,10 @@ public class NpcImpl extends Viewable implements Npc {
         return location;
     }
 
-    public Location getBukkitLocation() {
+    public @Nullable Location getBukkitLocation() {
-        return location.toBukkitLocation(getWorld());
+        World world = getWorld();
+        if (world == null) return null;
+        return location.toBukkitLocation(world);
     }
 
     public void setLocation(NpcLocation location) {
@@ -112,7 +115,7 @@ public class NpcImpl extends Viewable implements Npc {
         return uuid;
     }
 
-    public World getWorld() {
+    public @Nullable World getWorld() {
         return Bukkit.getWorld(worldName);
     }
 
@@ -182,6 +185,11 @@ public class NpcImpl extends Viewable implements Npc {
         setProperty((EntityPropertyImpl<T>) property, (T) value);
     }
 
+    @SuppressWarnings("unchecked")
+    public <T> void UNSAFE_setProperty(EntityProperty<?> property, Object value) {
+        setProperty((EntityPropertyImpl<T>) property, (T) value);
+    }
+
     public Set<EntityProperty<?>> getAllProperties() {
         return Collections.unmodifiableSet(propertyMap.keySet());
     }

plugin/src/main/java/lol/pyr/znpcsplus/npc/NpcRegistryImpl.java

@@ -1,12 +1,17 @@
 package lol.pyr.znpcsplus.npc;
 
 import lol.pyr.znpcsplus.ZNpcsPlus;
+import lol.pyr.znpcsplus.api.entity.EntityProperty;
 import lol.pyr.znpcsplus.api.npc.NpcEntry;
 import lol.pyr.znpcsplus.api.npc.NpcRegistry;
 import lol.pyr.znpcsplus.api.npc.NpcType;
 import lol.pyr.znpcsplus.config.ConfigManager;
 import lol.pyr.znpcsplus.entity.EntityPropertyRegistryImpl;
+import lol.pyr.znpcsplus.hologram.HologramItem;
+import lol.pyr.znpcsplus.hologram.HologramLine;
+import lol.pyr.znpcsplus.hologram.HologramText;
 import lol.pyr.znpcsplus.interaction.ActionRegistry;
+import lol.pyr.znpcsplus.interaction.InteractionActionImpl;
 import lol.pyr.znpcsplus.packets.PacketFactory;
 import lol.pyr.znpcsplus.scheduling.TaskScheduler;
 import lol.pyr.znpcsplus.storage.NpcStorage;
@@ -153,6 +158,35 @@ public class NpcRegistryImpl implements NpcRegistry {
         return entry;
     }
 
+    public NpcEntryImpl clone(String id, String newId, World newWorld, NpcLocation newLocation) {
+        NpcEntryImpl oldNpc = getById(id);
+        if (oldNpc == null) return null;
+        NpcEntryImpl newNpc = create(newId, newWorld, oldNpc.getNpc().getType(), newLocation);
+        newNpc.enableEverything();
+
+        for (EntityProperty<?> property : oldNpc.getNpc().getAllProperties()) {
+            newNpc.getNpc().UNSAFE_setProperty(property, oldNpc.getNpc().getProperty(property));
+        }
+
+        for (InteractionActionImpl action : oldNpc.getNpc().getActions()) {
+            newNpc.getNpc().addAction(action);
+        }
+
+        for (HologramLine<?> line : oldNpc.getNpc().getHologram().getLines()) {
+            if (line instanceof HologramText) {
+                HologramText text = (HologramText) line;
+                newNpc.getNpc().getHologram().addTextLineComponent(text.getValue());
+            }
+            else if (line instanceof HologramItem) {
+                HologramItem item = (HologramItem) line;
+                newNpc.getNpc().getHologram().addItemLinePEStack(item.getValue());
+            }
+            else throw new IllegalArgumentException("Unknown hologram line type during clone");
+        }
+
+        return newNpc;
+    }
+
     @Override
     public void delete(String id) {
         NpcEntryImpl entry = npcIdLookupMap.get(id.toLowerCase());