.drone.yml

@@ -0,0 +1,18 @@
+kind: pipeline
+type: docker
+name: default
+
+trigger:
+  event:
+    - push
+    - custom
+
+steps:
+  - name: publish
+    pull: if-not-exists
+    image: openjdk:21-jdk
+    environment:
+      PACKAGESKEY:
+        from_secret: GITEA_PACKAGE_PUBLIC_RW
+    commands:
+      - ./gradlew --no-daemon --parallel -Pnetherite.git.packages.token=$PACKAGESKEY build publish

README.md

@@ -40,7 +40,7 @@ Open an issue in the GitHub [issue tracker](https://github.com/Pyrbu/ZNPCsPlus/i
 
 ## Credits
 - [PacketEvents 2.0](https://github.com/retrooper/packetevents) - Packet library
-- [wiki.vg](https://wiki.vg/Main_Page) - Minecraft protocol documentation
+- [Minecraft Wiki Protocol (formally wiki.vg)](https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Main_Page) - Minecraft protocol documentation
 - [gson](https://github.com/google/gson) - JSON parsing library made by Google
 - [Mineskin.org](https://mineskin.org/) - Website for raw skin file uploads
 - [adventure](https://docs.advntr.dev/) - Minecraft text api

api/build.gradle

@@ -1,6 +1,5 @@
 plugins {
     id "java"
-    id "maven-publish"
 }
 
 java {
@@ -21,15 +20,4 @@ publishing {
             }
         }
     }
-    repositories {
-        maven {
-            Map<String, String> systemProperties = System.getenv()
-            credentials {
-                if (systemProperties.containsKey("DIST_USERNAME")) username systemProperties.get("DIST_USERNAME")
-                if (systemProperties.containsKey("DIST_PASSWORD")) password systemProperties.get("DIST_PASSWORD")
-            }
-            // If the BUILD_ID enviroment variable is present that means its a Jenkins build & that it should go into the snapshots repo
-            url = systemProperties.containsKey("BUILD_ID") ? uri("https://repo.pyr.lol/snapshots/") : uri("https://repo.pyr.lol/releases/")
-        }
-    }
 }

api/src/main/java/lol/pyr/znpcsplus/api/NpcApi.java

@@ -5,6 +5,7 @@ import lol.pyr.znpcsplus.api.interaction.ActionFactory;
 import lol.pyr.znpcsplus.api.interaction.ActionRegistry;
 import lol.pyr.znpcsplus.api.npc.NpcRegistry;
 import lol.pyr.znpcsplus.api.npc.NpcTypeRegistry;
+import lol.pyr.znpcsplus.api.serialization.NpcSerializerRegistry;
 import lol.pyr.znpcsplus.api.skin.SkinDescriptorFactory;
 
 /**
@@ -46,4 +47,10 @@ public interface NpcApi {
      * @return the skin descriptor factory
      */
     SkinDescriptorFactory getSkinDescriptorFactory();
+
+    /**
+     * Gets the npc serializer registry.
+     * @return the npc serializer registry
+     */
+    NpcSerializerRegistry getNpcSerializerRegistry();
 }

api/src/main/java/lol/pyr/znpcsplus/api/interaction/ActionRegistry.java

@@ -2,6 +2,7 @@ package lol.pyr.znpcsplus.api.interaction;
 
 public interface ActionRegistry {
     void register(InteractionActionType<?> type);
-
     void unregister(Class<? extends InteractionAction> clazz);
+    <T extends InteractionAction> T deserialize(String str);
+    <T extends InteractionAction> String serialize(T action);
 }

api/src/main/java/lol/pyr/znpcsplus/api/npc/Npc.java

@@ -6,10 +6,12 @@ import lol.pyr.znpcsplus.api.interaction.InteractionAction;
 import lol.pyr.znpcsplus.util.NpcLocation;
 import org.bukkit.World;
 import org.bukkit.entity.Player;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.List;
 import java.util.Set;
 import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
 
 /**
  * Base class for all NPCs
@@ -135,14 +137,16 @@ public interface Npc extends PropertyHolder {
     /**
      * Shows this NPC to a player
      * @param player The {@link Player} to show to
+     * @return A future that completes when the npc is fully shown to the player
      */
-    void show(Player player);
+    CompletableFuture<Void> show(Player player);
 
     /**
      * Respawns this NPC for a player
      * @param player The {@link Player} to respawn for
+     * @return A future that completes when the npc is fully respawned
      */
-    void respawn(Player player);
+    CompletableFuture<Void> respawn(Player player);
 
     /**
      * Sets the head rotation of this NPC for a player
@@ -174,4 +178,35 @@ public interface Npc extends PropertyHolder {
      * @param offHand Should the hand be the offhand
      */
     void swingHand(boolean offHand);
+
+    /**
+     * Gets the passengers of this npc
+     * @return The list of entity ids of the passengers
+     */
+
+    @Nullable List<Integer> getPassengers();
+
+    /**
+     * Adds a passenger to this npc
+     * @param entityId The entity id of the passenger to add
+     */
+    void addPassenger(int entityId);
+
+    /**
+     * Removes a passenger from this npc
+     * @param entityId The entity id of the passenger to remove
+     */
+    void removePassenger(int entityId);
+
+    /**
+     * Gets the vehicle entity id of this npc
+     * @return The entity id of the vehicle
+     */
+    @Nullable Integer getVehicleId();
+
+    /**
+     * Sets the vehicle id of this npc
+     * @param vehicleId The entity id of the vehicle
+     */
+    void setVehicleId(Integer vehicleId);
 }

api/src/main/java/lol/pyr/znpcsplus/api/npc/NpcRegistry.java

@@ -64,4 +64,21 @@ public interface NpcRegistry {
      * @param id The ID of the NPC entry
      */
     void delete(String id);
+
+    /**
+     * Register an NPC to this registry
+     * NpcEntry instances can be obtained through the NpcSerializer classes
+     * @param entry The npc to be registered
+     */
+    void register(NpcEntry entry);
+
+    /**
+     * Reload all saveable npcs from storage
+     */
+    void reload();
+
+    /**
+     * Save all saveable npcs to storage
+     */
+    void save();
 }

api/src/main/java/lol/pyr/znpcsplus/api/serialization/NpcSerializer.java

@@ -0,0 +1,20 @@
+package lol.pyr.znpcsplus.api.serialization;
+
+import lol.pyr.znpcsplus.api.npc.NpcEntry;
+
+public interface NpcSerializer<T> {
+    /**
+     * Serialize an npc into the type of this serializer
+     * @param entry The npc entry
+     * @return The serialized class
+     */
+    T serialize(NpcEntry entry);
+
+    /**
+     * Deserialize an npc from a serialized class
+     * Note: This npc will not be registered, you need to also register it using the NpcRegistry#register(NpcEntry) method
+     * @param model The serialized class
+     * @return The deserialized NpcEntry
+     */
+    NpcEntry deserialize(T model);
+}

api/src/main/java/lol/pyr/znpcsplus/api/serialization/NpcSerializerRegistry.java

@@ -0,0 +1,19 @@
+package lol.pyr.znpcsplus.api.serialization;
+
+public interface NpcSerializerRegistry {
+    /**
+     * Get an NpcSerializer that serializes npcs into the provided class
+     * @param clazz The class to serialize into
+     * @return The npc serializer instance
+     * @param <T> The type of the class that the serializer serializes into
+     */
+    <T> NpcSerializer<T> getSerializer(Class<T> clazz);
+
+    /**
+     * Register an NpcSerializer to be used by other plugins
+     * @param clazz The class that the serializer serializes into
+     * @param serializer The serializer itself
+     * @param <T> The type of the class that the serializer serializes into
+     */
+    <T> void registerSerializer(Class<T> clazz, NpcSerializer<T> serializer);
+}

api/src/main/java/lol/pyr/znpcsplus/api/skin/SkinDescriptorFactory.java

@@ -12,4 +12,5 @@ public interface SkinDescriptorFactory {
     SkinDescriptor createStaticDescriptor(String texture, String signature);
     SkinDescriptor createUrlDescriptor(String url, String variant);
     SkinDescriptor createUrlDescriptor(URL url, String variant);
+    SkinDescriptor createFileDescriptor(String path);
 }

api/src/main/java/lol/pyr/znpcsplus/util/SkeletonType.java

@@ -0,0 +1,11 @@
+package lol.pyr.znpcsplus.util;
+
+public enum SkeletonType {
+    NORMAL,
+    WITHER,
+    STRAY;
+
+    public byte getLegacyId() {
+        return (byte) ordinal();
+    }
+}

build.gradle

@@ -2,13 +2,14 @@ subprojects {
     apply plugin: "java"
 
     group "lol.pyr"
-    version "2.0.0" + (System.getenv().containsKey("BUILD_ID") ? "-SNAPSHOT" : "")
+    version "2.0.0-netherite-SNAPSHOT"
 
     java {
-        toolchain.languageVersion.set(JavaLanguageVersion.of(8))
+        toolchain.languageVersion.set(JavaLanguageVersion.of(21))
     }
 
     dependencies {
+        compileOnly "org.jetbrains:annotations:26.0.1"
         compileOnly "org.spigotmc:spigot-api:1.8.8-R0.1-SNAPSHOT"
     }
 
@@ -20,6 +21,9 @@ subprojects {
         maven {
             url "https://repo.codemc.io/repository/maven-releases/"
         }
+        maven {
+            url "https://repo.codemc.io/repository/maven-snapshots/"
+        }
         maven {
             url "https://libraries.minecraft.net"
         }
@@ -32,5 +36,23 @@ subprojects {
         maven {
             url "https://repo.pyr.lol/releases"
         }
+        maven {
+            url "https://jitpack.io/"
+        }
+    }
+
+    publishing {
+        repositories {
+            maven {
+                url = uri("https://git.netherite.gg/api/packages/Netherite-Public/maven")
+                credentials(HttpHeaderCredentials) {
+                    name "Authorization"
+                    value "token ${project.properties["netherite.git.packages.token"]}"
+                }
+                authentication {
+                    header(HttpHeaderAuthentication)
+                }
+            }
+        }
     }
 }

plugin/build.gradle

@@ -8,32 +8,65 @@ runServer {
     javaLauncher = javaToolchains.launcherFor {
         languageVersion = JavaLanguageVersion.of(21)
     }
-    minecraftVersion "1.21.3"
+    minecraftVersion "1.21.4"
 }
 
 processResources {
     expand("version": version)
 }
 
+publishing {
+    publications {
+        mavenJava(MavenPublication) {
+            from components.java
+            artifactId = "znpcsplus-plugin"
+
+            pom {
+                name.set("znpcsplus-plugin")
+                description.set("The ZNPCsPlus plugin")
+                url.set("https://github.com/Pyrbu/ZNPCsPlus")
+            }
+        }
+    }
+}
+
 dependencies {
     compileOnly "me.clip:placeholderapi:2.11.6" // Placeholder support
     implementation "com.google.code.gson:gson:2.10.1" // JSON parsing
     implementation "org.bstats:bstats-bukkit:3.0.2" // Plugin stats
-    implementation "com.github.retrooper:packetevents-spigot:2.6.0" // Packets
+    implementation "com.github.retrooper:packetevents-spigot:2.7.0" // Packets
     implementation "space.arim.dazzleconf:dazzleconf-ext-snakeyaml:1.2.1" // Configs
     implementation "lol.pyr:director-adventure:2.1.2" // Commands
 
     // Fancy text library
     implementation "net.kyori:adventure-platform-bukkit:4.3.4"
-    implementation "net.kyori:adventure-text-minimessage:4.17.0"
+    implementation "net.kyori:adventure-text-minimessage:4.18.0"
 
     implementation project(":api")
 }
 
+ext {
+    gitBranch = System.getenv('GIT_BRANCH') ?: ''
+    gitCommitHash = System.getenv('GIT_COMMIT') ?: ''
+    buildId = System.getenv('BUILD_ID') ?: ''
+}
+
 shadowJar {
     archivesBaseName = "ZNPCsPlus"
     archiveClassifier.set ""
 
+    manifest {
+        if (gitBranch?.trim()) {
+            attributes('Git-Branch': gitBranch)
+        }
+        if (gitCommitHash?.trim()) {
+            attributes('Git-Commit': gitCommitHash)
+        }
+        if (buildId?.trim()) {
+            attributes('Build-Id': buildId)
+        }
+    }
+
     relocate "org.objectweb.asm", "lol.pyr.znpcsplus.libraries.asm"
     relocate "me.lucko.jarrelocator", "lol.pyr.znpcsplus.libraries.jarrelocator"
 

plugin/src/main/java/lol/pyr/znpcsplus/ZNpcsPlus.java

@@ -38,6 +38,7 @@ import lol.pyr.znpcsplus.parsers.*;
 import lol.pyr.znpcsplus.scheduling.FoliaScheduler;
 import lol.pyr.znpcsplus.scheduling.SpigotScheduler;
 import lol.pyr.znpcsplus.scheduling.TaskScheduler;
+import lol.pyr.znpcsplus.serialization.NpcSerializerRegistryImpl;
 import lol.pyr.znpcsplus.skin.cache.MojangSkinCache;
 import lol.pyr.znpcsplus.skin.cache.SkinCacheCleanTask;
 import lol.pyr.znpcsplus.storage.NpcStorageType;
@@ -93,7 +94,7 @@ public class ZNpcsPlus {
         packetEvents.load();
 
         configManager = new ConfigManager(getDataFolder());
-        skinCache = new MojangSkinCache(configManager);
+        skinCache = new MojangSkinCache(configManager, new File(getDataFolder(), "skins"));
         propertyRegistry = new EntityPropertyRegistryImpl(skinCache, configManager);
 
         NpcPropertyRegistryProvider.register(propertyRegistry);
@@ -135,8 +136,9 @@ public class ZNpcsPlus {
         ActionRegistryImpl actionRegistry = new ActionRegistryImpl();
         ActionFactoryImpl actionFactory = new ActionFactoryImpl(scheduler, adventure, textSerializer, bungeeConnector);
         NpcTypeRegistryImpl typeRegistry = new NpcTypeRegistryImpl();
+        NpcSerializerRegistryImpl serializerRegistry = new NpcSerializerRegistryImpl(packetFactory, configManager, actionRegistry, typeRegistry, propertyRegistry, textSerializer);
         NpcRegistryImpl npcRegistry = new NpcRegistryImpl(configManager, this, packetFactory, actionRegistry,
-                scheduler, typeRegistry, propertyRegistry, textSerializer);
+                scheduler, typeRegistry, propertyRegistry, serializerRegistry, textSerializer);
         shutdownTasks.add(npcRegistry::unload);
 
         UserManager userManager = new UserManager();
@@ -159,7 +161,7 @@ public class ZNpcsPlus {
         pluginManager.registerEvents(new UserListener(userManager), bootstrap);
 
         registerCommands(npcRegistry, skinCache, adventure, actionRegistry,
-                typeRegistry, propertyRegistry, importerRegistry, configManager, packetFactory);
+                typeRegistry, propertyRegistry, importerRegistry, configManager, packetFactory, serializerRegistry);
 
         log(ChatColor.WHITE + " * Starting tasks...");
         if (configManager.getConfig().checkForUpdates()) {
@@ -193,7 +195,7 @@ public class ZNpcsPlus {
             }
         }
 
-        NpcApiProvider.register(bootstrap, new ZNpcsPlusApi(npcRegistry, typeRegistry, propertyRegistry, actionRegistry, actionFactory, skinCache));
+        NpcApiProvider.register(bootstrap, new ZNpcsPlusApi(npcRegistry, typeRegistry, propertyRegistry, actionRegistry, actionFactory, skinCache, serializerRegistry));
         log(ChatColor.WHITE + " * Loading complete! (" + (System.currentTimeMillis() - before) + "ms)");
         log("");
 
@@ -246,7 +248,7 @@ public class ZNpcsPlus {
     private void registerCommands(NpcRegistryImpl npcRegistry, MojangSkinCache skinCache, BukkitAudiences adventure,
                                   ActionRegistryImpl actionRegistry, NpcTypeRegistryImpl typeRegistry,
                                   EntityPropertyRegistryImpl propertyRegistry, DataImporterRegistry importerRegistry,
-                                  ConfigManager configManager, PacketFactory packetFactory) {
+                                  ConfigManager configManager, PacketFactory packetFactory, NpcSerializerRegistryImpl serializerRegistry) {
 
         Message<CommandContext> incorrectUsageMessage = context -> context.send(Component.text("Incorrect usage: /" + context.getUsage(), NamedTextColor.RED));
         CommandManager manager = new CommandManager(bootstrap, adventure, incorrectUsageMessage);
@@ -296,6 +298,7 @@ public class ZNpcsPlus {
         registerEnumParser(manager, ArmadilloState.class, incorrectUsageMessage);
         registerEnumParser(manager, WoldVariant.class, incorrectUsageMessage);
         registerEnumParser(manager, NpcStorageType.class, incorrectUsageMessage);
+        registerEnumParser(manager, SkeletonType.class, incorrectUsageMessage);
 
         manager.registerCommand("npc", new MultiCommand(bootstrap.loadHelpMessage("root"))
                 .addSubcommand("center", new CenterCommand(npcRegistry))
@@ -321,7 +324,7 @@ public class ZNpcsPlus {
                         .addSubcommand("save", new SaveAllCommand(npcRegistry))
                         .addSubcommand("reload", new LoadAllCommand(npcRegistry))
                         .addSubcommand("import", new ImportCommand(npcRegistry, importerRegistry))
-                        .addSubcommand("migrate", new MigrateCommand(configManager, this, packetFactory, actionRegistry, typeRegistry, propertyRegistry, textSerializer, npcRegistry.getStorage(), configManager.getConfig().storageType(), npcRegistry)))
+                        .addSubcommand("migrate", new MigrateCommand(configManager, this, packetFactory, actionRegistry, typeRegistry, propertyRegistry, textSerializer, npcRegistry.getStorage(), configManager.getConfig().storageType(), npcRegistry, serializerRegistry)))
                 .addSubcommand("holo", new MultiCommand(bootstrap.loadHelpMessage("holo"))
                         .addSubcommand("add", new HoloAddCommand(npcRegistry))
                         .addSubcommand("additem", new HoloAddItemCommand(npcRegistry))
@@ -332,13 +335,16 @@ public class ZNpcsPlus {
                         .addSubcommand("set", new HoloSetCommand(npcRegistry))
                         .addSubcommand("setitem", new HoloSetItemCommand(npcRegistry))
                         .addSubcommand("offset", new HoloOffsetCommand(npcRegistry))
-                        .addSubcommand("refreshdelay", new HoloRefreshDelayCommand(npcRegistry)))
+                        .addSubcommand("refreshdelay", new HoloRefreshDelayCommand(npcRegistry))
+                        .addSubcommand("removeduplicate", new HoloRemoveDuplicateCommand(npcRegistry))
+                        .addSubcommand("removeallduplicates", new holoRemoveAllDuplicatesCommand(npcRegistry)))
                 .addSubcommand("action", new MultiCommand(bootstrap.loadHelpMessage("action"))
                         .addSubcommand("add", new ActionAddCommand(npcRegistry, actionRegistry))
                         .addSubcommand("clear", new ActionClearCommand(npcRegistry))
                         .addSubcommand("delete", new ActionDeleteCommand(npcRegistry))
                         .addSubcommand("edit", new ActionEditCommand(npcRegistry, actionRegistry))
                         .addSubcommand("list", new ActionListCommand(npcRegistry)))
+                .addSubcommand("version", new VersionCommand(this))
         );
     }
 

plugin/src/main/java/lol/pyr/znpcsplus/ZNpcsPlusApi.java

@@ -12,6 +12,7 @@ import lol.pyr.znpcsplus.interaction.ActionFactoryImpl;
 import lol.pyr.znpcsplus.interaction.ActionRegistryImpl;
 import lol.pyr.znpcsplus.npc.NpcRegistryImpl;
 import lol.pyr.znpcsplus.npc.NpcTypeRegistryImpl;
+import lol.pyr.znpcsplus.serialization.NpcSerializerRegistryImpl;
 import lol.pyr.znpcsplus.skin.SkinDescriptorFactoryImpl;
 import lol.pyr.znpcsplus.skin.cache.MojangSkinCache;
 
@@ -22,14 +23,16 @@ public class ZNpcsPlusApi implements NpcApi {
     private final ActionRegistryImpl actionRegistry;
     private final ActionFactoryImpl actionFactory;
     private final SkinDescriptorFactoryImpl skinDescriptorFactory;
+    private final NpcSerializerRegistryImpl npcSerializerRegistry;
 
-    public ZNpcsPlusApi(NpcRegistryImpl npcRegistry, NpcTypeRegistryImpl typeRegistry, EntityPropertyRegistryImpl propertyRegistry, ActionRegistryImpl actionRegistry, ActionFactoryImpl actionFactory, MojangSkinCache skinCache) {
+    public ZNpcsPlusApi(NpcRegistryImpl npcRegistry, NpcTypeRegistryImpl typeRegistry, EntityPropertyRegistryImpl propertyRegistry, ActionRegistryImpl actionRegistry, ActionFactoryImpl actionFactory, MojangSkinCache skinCache, NpcSerializerRegistryImpl npcSerializerRegistry) {
         this.npcRegistry = npcRegistry;
         this.typeRegistry = typeRegistry;
         this.propertyRegistry = propertyRegistry;
         this.actionRegistry = actionRegistry;
         this.actionFactory = actionFactory;
         this.skinDescriptorFactory = new SkinDescriptorFactoryImpl(skinCache);
+        this.npcSerializerRegistry = npcSerializerRegistry;
     }
 
     @Override
@@ -62,4 +65,9 @@ public class ZNpcsPlusApi implements NpcApi {
     public SkinDescriptorFactory getSkinDescriptorFactory() {
         return skinDescriptorFactory;
     }
+
+    @Override
+    public NpcSerializerRegistryImpl getNpcSerializerRegistry() {
+        return npcSerializerRegistry;
+    }
 }

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

@@ -26,12 +26,18 @@ public class CreateCommand implements CommandHandler {
 
     @Override
     public void run(CommandContext context) throws CommandExecutionException {
-        context.setUsage(context.getLabel() + " create <id> <type>");
+        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);
+
+        NpcTypeImpl type;
+        if (context.argSize() == 1) {
+            type = context.parse(NpcTypeImpl.class);
+        } else {
+            type = typeRegistry.getByName("player");
+        }
 
         NpcEntryImpl entry = npcRegistry.create(id, player.getWorld(), type, new NpcLocation(player.getLocation()));
         entry.enableEverything();

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

@@ -17,10 +17,14 @@ import lol.pyr.znpcsplus.skin.descriptor.PrefetchedDescriptor;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.format.NamedTextColor;
 
+import java.io.File;
+import java.io.FileNotFoundException;
 import java.net.MalformedURLException;
 import java.net.URL;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.stream.Collectors;
 
 public class SkinCommand implements CommandHandler {
     private final MojangSkinCache skinCache;
@@ -90,6 +94,30 @@ public class SkinCommand implements CommandHandler {
                 context.send(Component.text("Invalid url!", NamedTextColor.RED));
             }
             return;
+        } else if (type.equalsIgnoreCase("file")) {
+            context.ensureArgsNotEmpty();
+            String path = context.dumpAllArgs();
+            context.send(Component.text("Fetching skin from file \"" + path + "\"...", NamedTextColor.GREEN));
+            PrefetchedDescriptor.fromFile(skinCache, path).exceptionally(e -> {
+                if (e instanceof FileNotFoundException || e.getCause() instanceof FileNotFoundException) {
+                    context.send(Component.text("A file at the specified path could not be found!", NamedTextColor.RED));
+                } else {
+                    context.send(Component.text("An error occurred while fetching the skin from file! Check the console for more details.", NamedTextColor.RED));
+                    //noinspection CallToPrintStackTrace
+                    e.printStackTrace();
+                }
+                return null;
+            }).thenAccept(skin -> {
+                if (skin == null) return;
+                if (skin.getSkin() == null) {
+                    context.send(Component.text("Failed to fetch skin, are you sure the file path is valid?", NamedTextColor.RED));
+                    return;
+                }
+                npc.setProperty(propertyRegistry.getByName("skin", SkinDescriptor.class), skin);
+                npc.respawn();
+                context.send(Component.text("The NPC's skin has been set.", NamedTextColor.GREEN));
+            });
+            return;
         }
         context.send(Component.text("Unknown skin type! Please use one of the following: mirror, static, dynamic, url"));
     }
@@ -97,11 +125,19 @@ public class SkinCommand implements CommandHandler {
     @Override
     public List<String> suggest(CommandContext context) throws CommandExecutionException {
         if (context.argSize() == 1) return context.suggestCollection(npcRegistry.getModifiableIds());
-        if (context.argSize() == 2) return context.suggestLiteral("mirror", "static", "dynamic", "url");
+        if (context.argSize() == 2) return context.suggestLiteral("mirror", "static", "dynamic", "url", "file");
         if (context.matchSuggestion("*", "static")) return context.suggestPlayers();
         if (context.argSize() == 3 && context.matchSuggestion("*", "url")) {
             return context.suggestLiteral("slim", "classic");
         }
+        if (context.argSize() == 3 && context.matchSuggestion("*", "file")) {
+            if (skinCache.getSkinsFolder().exists()) {
+                File[] files = skinCache.getSkinsFolder().listFiles();
+                if (files != null) {
+                    return Arrays.stream(files).map(File::getName).collect(Collectors.toList());
+                }
+            }
+        }
         return Collections.emptyList();
     }
 }

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

@@ -21,9 +21,14 @@ public class ToggleCommand implements CommandHandler {
 
     @Override
     public void run(CommandContext context) throws CommandExecutionException {
-        context.setUsage(context.getLabel() + " toggle <id>");
+        context.setUsage(context.getLabel() + " toggle <id> [<enable/disable>]");
         NpcImpl npc = context.parse(NpcEntryImpl.class).getNpc();
-        boolean enabled = !npc.isEnabled();
+        boolean enabled;
+        if (context.argSize() == 1) {
+            enabled = context.popString().equalsIgnoreCase("enable");
+        } else {
+            enabled = !npc.isEnabled();
+        }
         npc.setEnabled(enabled);
         context.send(Component.text("NPC has been " + (enabled ? "enabled" : "disabled"), NamedTextColor.GREEN));
     }
@@ -31,6 +36,7 @@ public class ToggleCommand implements CommandHandler {
     @Override
     public List<String> suggest(CommandContext context) throws CommandExecutionException {
         if (context.argSize() == 1) return context.suggestCollection(npcRegistry.getModifiableIds());
+        if (context.argSize() == 2) return context.suggestLiteral("enable", "disable");
         return Collections.emptyList();
     }
 }

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

@@ -0,0 +1,64 @@
+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.ZNpcsPlus;
+import net.kyori.adventure.text.Component;
+import net.kyori.adventure.text.event.ClickEvent;
+import net.kyori.adventure.text.format.NamedTextColor;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.net.URL;
+import java.util.jar.Attributes;
+import java.util.jar.JarFile;
+
+public class VersionCommand implements CommandHandler {
+
+    private final String pluginVersion;
+    private final String gitBranch;
+    private final String gitCommitHash;
+    private final String buildId;
+
+    public VersionCommand(ZNpcsPlus plugin) {
+        pluginVersion = plugin.getDescription().getVersion();
+        String gitBranch = "";
+        String gitCommitHash = "";
+        String buildId = "";
+        try {
+            URL jarUrl = getClass().getProtectionDomain().getCodeSource().getLocation();
+            JarFile jarFile = new JarFile(jarUrl.toURI().getPath());
+            Attributes attributes = jarFile.getManifest().getMainAttributes();
+            gitBranch = attributes.getValue("Git-Branch");
+            gitCommitHash = attributes.getValue("Git-Commit-Hash");
+            buildId = attributes.getValue("Build-Id");
+        } catch (IOException | URISyntaxException e) {
+            e.printStackTrace();
+        }
+        this.gitBranch = gitBranch;
+        this.gitCommitHash = gitCommitHash;
+        this.buildId = buildId;
+    }
+
+    @Override
+    public void run(CommandContext context) throws CommandExecutionException {
+
+        StringBuilder versionBuilder = new StringBuilder("This server is running ZNPCsPlus version ").append(pluginVersion);
+        if (gitBranch != null && !gitBranch.isEmpty()) {
+            versionBuilder.append("-").append(gitBranch);
+        }
+        if (gitCommitHash != null && !gitCommitHash.isEmpty()) {
+            versionBuilder.append("@").append(gitCommitHash);
+        }
+        if (buildId != null && !buildId.isEmpty()) {
+            versionBuilder.append(" (Build #").append(buildId).append(")");
+        }
+
+        String version = versionBuilder.toString();
+
+        context.send(Component.text(version, NamedTextColor.GREEN)
+                .hoverEvent(Component.text("Click to copy version to clipboard"))
+                .clickEvent(ClickEvent.copyToClipboard(version)));
+    }
+}

plugin/src/main/java/lol/pyr/znpcsplus/commands/hologram/HoloRemoveDuplicateCommand.java

@@ -0,0 +1,58 @@
+package lol.pyr.znpcsplus.commands.hologram;
+
+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.hologram.HologramImpl;
+import lol.pyr.znpcsplus.hologram.HologramLine;
+import lol.pyr.znpcsplus.hologram.HologramText;
+import lol.pyr.znpcsplus.npc.NpcEntryImpl;
+import lol.pyr.znpcsplus.npc.NpcRegistryImpl;
+import net.kyori.adventure.text.Component;
+import net.kyori.adventure.text.format.NamedTextColor;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+
+public class HoloRemoveDuplicateCommand implements CommandHandler {
+    private final NpcRegistryImpl registry;
+
+    public HoloRemoveDuplicateCommand(NpcRegistryImpl registry) {
+        this.registry = registry;
+    }
+
+    @Override
+    public void run(CommandContext context) throws CommandExecutionException {
+        context.setUsage(context.getLabel() + " holo removeduplicates <id>");
+        HologramImpl hologram = context.parse(NpcEntryImpl.class).getNpc().getHologram();
+        List<HologramLine<?>> lines = new ArrayList<>(hologram.getLines());
+        List<HologramText> textLines = new ArrayList<>();
+
+        Iterator<HologramLine<?>> iterator = lines.iterator();
+        while (iterator.hasNext()) {
+            HologramLine<?> line = iterator.next();
+            if (line instanceof HologramText textLine
+                    && !textLine.getValue().equals(Component.empty())
+                    && textLines.contains(textLine)) {
+                iterator.remove();
+                continue;
+            }
+
+            if (line instanceof HologramText textLine) {
+                textLines.add(textLine);
+            }
+        }
+
+        hologram.clearLines();
+        hologram.addLines(lines);
+        context.send(Component.text("NPC lines fixed!", NamedTextColor.GREEN));
+    }
+
+    @Override
+    public List<String> suggest(CommandContext context) throws CommandExecutionException {
+        if (context.argSize() == 1) return context.suggestCollection(registry.getModifiableIds());
+        return Collections.emptyList();
+    }
+}

plugin/src/main/java/lol/pyr/znpcsplus/commands/hologram/holoRemoveAllDuplicatesCommand.java

@@ -0,0 +1,62 @@
+package lol.pyr.znpcsplus.commands.hologram;
+
+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.hologram.HologramImpl;
+import lol.pyr.znpcsplus.hologram.HologramLine;
+import lol.pyr.znpcsplus.hologram.HologramText;
+import lol.pyr.znpcsplus.npc.NpcEntryImpl;
+import lol.pyr.znpcsplus.npc.NpcRegistryImpl;
+import net.kyori.adventure.text.Component;
+import net.kyori.adventure.text.format.NamedTextColor;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+
+public class holoRemoveAllDuplicatesCommand implements CommandHandler {
+    private final NpcRegistryImpl registry;
+
+    public holoRemoveAllDuplicatesCommand(NpcRegistryImpl registry) {
+        this.registry = registry;
+    }
+
+    @Override
+    public void run(CommandContext context) throws CommandExecutionException {
+        context.setUsage(context.getLabel() + " holo removeallduplicates <id>");
+
+        for (NpcEntryImpl npcEntry : registry.getAll()) {
+            HologramImpl hologram = npcEntry.getNpc().getHologram();
+            List<HologramLine<?>> lines = new ArrayList<>(hologram.getLines());
+            List<HologramText> textLines = new ArrayList<>();
+
+            Iterator<HologramLine<?>> iterator = lines.iterator();
+            while (iterator.hasNext()) {
+                HologramLine<?> line = iterator.next();
+                if (line instanceof HologramText textLine
+                        && !textLine.getValue().equals(Component.empty())
+                        && textLines.contains(textLine)) {
+                    iterator.remove();
+                    continue;
+                }
+
+                if (line instanceof HologramText textLine) {
+                    textLines.add(textLine);
+                }
+            }
+
+            hologram.clearLines();
+            hologram.addLines(lines);
+        }
+
+        context.send(Component.text("NPCs fixed!", NamedTextColor.GREEN));
+    }
+
+    @Override
+    public List<String> suggest(CommandContext context) throws CommandExecutionException {
+        if (context.argSize() == 1) return context.suggestCollection(registry.getModifiableIds());
+        return Collections.emptyList();
+    }
+}

plugin/src/main/java/lol/pyr/znpcsplus/commands/property/PropertySetCommand.java

@@ -11,6 +11,7 @@ import lol.pyr.director.adventure.command.CommandHandler;
 import lol.pyr.director.common.command.CommandExecutionException;
 import lol.pyr.znpcsplus.api.entity.EntityProperty;
 import lol.pyr.znpcsplus.entity.EntityPropertyImpl;
+import lol.pyr.znpcsplus.entity.properties.attributes.AttributeProperty;
 import lol.pyr.znpcsplus.npc.NpcEntryImpl;
 import lol.pyr.znpcsplus.npc.NpcImpl;
 import lol.pyr.znpcsplus.npc.NpcRegistryImpl;
@@ -124,6 +125,15 @@ public class PropertySetCommand implements CommandHandler {
             value = context.parse(type);
             valueName = value == null ? "NONE" : ((Vector3i) value).toPrettyString();
         }
+        else if (property instanceof AttributeProperty) {
+            value = context.parse(type);
+            if ((double) value < ((AttributeProperty) property).getMinValue() || (double) value > ((AttributeProperty) property).getMaxValue()) {
+                double sanitizedValue = ((AttributeProperty) property).sanitizeValue((double) value);
+                context.send(Component.text("WARNING: Value " + value + " is out of range for property " + property.getName() + ", setting to " + sanitizedValue, NamedTextColor.YELLOW));
+                value = sanitizedValue;
+            }
+            valueName = String.valueOf(value);
+        }
         else {
             try {
                 value = context.parse(type);

plugin/src/main/java/lol/pyr/znpcsplus/commands/storage/ImportCommand.java

@@ -7,13 +7,13 @@ import lol.pyr.znpcsplus.conversion.DataImporter;
 import lol.pyr.znpcsplus.conversion.DataImporterRegistry;
 import lol.pyr.znpcsplus.npc.NpcEntryImpl;
 import lol.pyr.znpcsplus.npc.NpcRegistryImpl;
+import lol.pyr.znpcsplus.util.FutureUtil;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.format.NamedTextColor;
 
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
-import java.util.concurrent.CompletableFuture;
 
 public class ImportCommand implements CommandHandler {
     private final NpcRegistryImpl npcRegistry;
@@ -33,7 +33,7 @@ public class ImportCommand implements CommandHandler {
         if (importer == null) context.halt(Component.text("Importer not found! Possible importers: " +
                 String.join(", ", importerRegistry.getIds()), NamedTextColor.RED));
 
-        CompletableFuture.runAsync(() -> {
+        FutureUtil.exceptionPrintingRunAsync(() -> {
             if (!importer.isValid()) {
                 context.send(Component.text("There is no data to import from this importer!", NamedTextColor.RED));
                 return;

plugin/src/main/java/lol/pyr/znpcsplus/commands/storage/LoadAllCommand.java

@@ -4,12 +4,12 @@ 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.NpcRegistryImpl;
+import lol.pyr.znpcsplus.util.FutureUtil;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.format.NamedTextColor;
 
 import java.util.Collections;
 import java.util.List;
-import java.util.concurrent.CompletableFuture;
 
 public class LoadAllCommand implements CommandHandler {
     private final NpcRegistryImpl npcRegistry;
@@ -20,7 +20,7 @@ public class LoadAllCommand implements CommandHandler {
 
     @Override
     public void run(CommandContext context) throws CommandExecutionException {
-        CompletableFuture.runAsync(() -> {
+        FutureUtil.exceptionPrintingRunAsync(() -> {
             npcRegistry.reload();
             context.send(Component.text("All NPCs have been re-loaded from storage", NamedTextColor.GREEN));
         });

plugin/src/main/java/lol/pyr/znpcsplus/commands/storage/MigrateCommand.java

@@ -11,6 +11,7 @@ import lol.pyr.znpcsplus.npc.NpcEntryImpl;
 import lol.pyr.znpcsplus.npc.NpcRegistryImpl;
 import lol.pyr.znpcsplus.npc.NpcTypeRegistryImpl;
 import lol.pyr.znpcsplus.packets.PacketFactory;
+import lol.pyr.znpcsplus.serialization.NpcSerializerRegistryImpl;
 import lol.pyr.znpcsplus.storage.NpcStorage;
 import lol.pyr.znpcsplus.storage.NpcStorageType;
 import net.kyori.adventure.text.Component;
@@ -35,8 +36,9 @@ public class MigrateCommand implements CommandHandler {
     private final NpcStorage currentStorage;
     private final NpcStorageType currentStorageType;
     private final NpcRegistryImpl npcRegistry;
+    private final NpcSerializerRegistryImpl serializerRegistry;
 
-    public MigrateCommand(ConfigManager configManager, ZNpcsPlus plugin, PacketFactory packetFactory, ActionRegistryImpl actionRegistry, NpcTypeRegistryImpl typeRegistry, EntityPropertyRegistryImpl propertyRegistry, LegacyComponentSerializer textSerializer, NpcStorage currentStorage, NpcStorageType currentStorageType, NpcRegistryImpl npcRegistry) {
+    public MigrateCommand(ConfigManager configManager, ZNpcsPlus plugin, PacketFactory packetFactory, ActionRegistryImpl actionRegistry, NpcTypeRegistryImpl typeRegistry, EntityPropertyRegistryImpl propertyRegistry, LegacyComponentSerializer textSerializer, NpcStorage currentStorage, NpcStorageType currentStorageType, NpcRegistryImpl npcRegistry, NpcSerializerRegistryImpl serializerRegistry) {
         this.configManager = configManager;
         this.plugin = plugin;
         this.packetFactory = packetFactory;
@@ -47,6 +49,7 @@ public class MigrateCommand implements CommandHandler {
         this.currentStorage = currentStorage;
         this.currentStorageType = currentStorageType;
         this.npcRegistry = npcRegistry;
+        this.serializerRegistry = serializerRegistry;
     }
 
     @Override
@@ -63,7 +66,7 @@ public class MigrateCommand implements CommandHandler {
         if (currentStorageType == from) {
             fromStorage = currentStorage;
         } else {
-            fromStorage = from.create(configManager, plugin, packetFactory, actionRegistry, typeRegistry, propertyRegistry, textSerializer);
+            fromStorage = from.create(configManager, plugin, packetFactory, actionRegistry, typeRegistry, propertyRegistry, textSerializer, serializerRegistry);
             if (fromStorage == null) {
                 context.halt(Component.text("Failed to initialize the source storage. Please check the console for more information.", NamedTextColor.RED));
                 return;
@@ -84,7 +87,7 @@ public class MigrateCommand implements CommandHandler {
         if (currentStorageType == to) {
             toStorage = currentStorage;
         } else {
-            toStorage = to.create(configManager, plugin, packetFactory, actionRegistry, typeRegistry, propertyRegistry, textSerializer);
+            toStorage = to.create(configManager, plugin, packetFactory, actionRegistry, typeRegistry, propertyRegistry, textSerializer, serializerRegistry);
             if (toStorage == null) {
                 context.halt(Component.text("Failed to initialize the destination storage. Please check the console for more information.", NamedTextColor.RED));
                 return;

plugin/src/main/java/lol/pyr/znpcsplus/commands/storage/SaveAllCommand.java

@@ -4,12 +4,12 @@ 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.NpcRegistryImpl;
+import lol.pyr.znpcsplus.util.FutureUtil;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.format.NamedTextColor;
 
 import java.util.Collections;
 import java.util.List;
-import java.util.concurrent.CompletableFuture;
 
 public class SaveAllCommand implements CommandHandler {
     private final NpcRegistryImpl npcRegistry;
@@ -20,7 +20,7 @@ public class SaveAllCommand implements CommandHandler {
 
     @Override
     public void run(CommandContext context) throws CommandExecutionException {
-        CompletableFuture.runAsync(() -> {
+        FutureUtil.exceptionPrintingRunAsync(() -> {
             npcRegistry.save();
             context.send(Component.text("All NPCs have been saved to storage", NamedTextColor.GREEN));
         });

plugin/src/main/java/lol/pyr/znpcsplus/conversion/znpcs/ZNpcImporter.java

@@ -189,12 +189,15 @@ public class ZNpcImporter implements DataImporter {
                 if (toggleValues.containsKey("mirror")) {
                     npc.setProperty(propertyRegistry.getByName("skin", SkinDescriptor.class), new MirrorDescriptor(skinCache));
                 }
-                if (toggleValues.containsKey("glow")) {
+                if (toggleValues.containsKey("glow") && (boolean) toggleValues.get("glow")) {
+                    if (!model.getGlowName().isEmpty())
                         try {
-                        npc.setProperty(propertyRegistry.getByName("glow", DyeColor.class), DyeColor.valueOf((String) toggleValues.get("glow")));
+                            npc.setProperty(propertyRegistry.getByName("glow", DyeColor.class), DyeColor.valueOf(model.getGlowName()));
                         } catch (IllegalArgumentException e) {
                             npc.setProperty(propertyRegistry.getByName("glow", DyeColor.class), DyeColor.WHITE);
                         }
+                    else
+                        npc.setProperty(propertyRegistry.getByName("glow", DyeColor.class), DyeColor.WHITE);
                 }
             }
 

plugin/src/main/java/lol/pyr/znpcsplus/conversion/znpcs/model/ZNpcsModel.java

@@ -84,4 +84,8 @@ public class ZNpcsModel {
     public String getSignature() {
         return signature;
     }
+
+    public String getGlowName() {
+        return glowName;
+    }
 }

plugin/src/main/java/lol/pyr/znpcsplus/entity/ArmorStandVehicleProperties.java

@@ -0,0 +1,76 @@
+package lol.pyr.znpcsplus.entity;
+
+import io.github.retrooper.packetevents.util.SpigotConversionUtil;
+import lol.pyr.znpcsplus.api.entity.EntityProperty;
+import lol.pyr.znpcsplus.api.entity.PropertyHolder;
+import org.bukkit.inventory.ItemStack;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Represents an armor stand vehicle entity.
+ * <p>
+ *     This entity is used to make the NPC sit on an invisible armor stand.
+ * </p>
+ */
+public class ArmorStandVehicleProperties implements PropertyHolder {
+
+    private final Map<EntityPropertyImpl<?>, Object> propertyMap = new HashMap<>();
+
+    public ArmorStandVehicleProperties(EntityPropertyRegistryImpl propertyRegistry) {
+        _setProperty(propertyRegistry.getByName("small", Boolean.class), true);
+        _setProperty(propertyRegistry.getByName("invisible", Boolean.class), true);
+        _setProperty(propertyRegistry.getByName("base_plate", Boolean.class), false);
+    }
+
+    @SuppressWarnings("unchecked")
+    public <T> T getProperty(EntityProperty<T> key) {
+        return hasProperty(key) ? (T) propertyMap.get((EntityPropertyImpl<?>) key) : key.getDefaultValue();
+    }
+
+    @Override
+    public boolean hasProperty(EntityProperty<?> key) {
+        return propertyMap.containsKey((EntityPropertyImpl<?>) key);
+    }
+
+    @SuppressWarnings("unchecked")
+    private <T> void _setProperty(EntityProperty<T> key, T value) {
+        Object val = value;
+        if (val instanceof ItemStack) val = SpigotConversionUtil.fromBukkitItemStack((ItemStack) val);
+
+        setProperty((EntityPropertyImpl<T>) key, (T) val);
+    }
+
+    @Override
+    public <T> void setProperty(EntityProperty<T> key, T value) {
+        throw new UnsupportedOperationException("Cannot set properties on armor stands");
+    }
+
+    @Override
+    public void setItemProperty(EntityProperty<?> key, ItemStack value) {
+        throw new UnsupportedOperationException("Cannot set item properties on armor stands");
+    }
+
+    @Override
+    public ItemStack getItemProperty(EntityProperty<?> key) {
+        throw new UnsupportedOperationException("Cannot get item properties on armor stands");
+    }
+
+    public <T> void setProperty(EntityPropertyImpl<T> key, T value) {
+        if (key == null) return;
+        if (value == null || value.equals(key.getDefaultValue())) propertyMap.remove(key);
+        else propertyMap.put(key, value);
+    }
+
+    public Set<EntityProperty<?>> getAllProperties() {
+        return Collections.unmodifiableSet(propertyMap.keySet());
+    }
+
+    @Override
+    public Set<EntityProperty<?>> getAppliedProperties() {
+        return Collections.unmodifiableSet(propertyMap.keySet());
+    }
+}

plugin/src/main/java/lol/pyr/znpcsplus/entity/EntityPropertyRegistryImpl.java

@@ -2,6 +2,7 @@ package lol.pyr.znpcsplus.entity;
 
 import com.github.retrooper.packetevents.PacketEvents;
 import com.github.retrooper.packetevents.manager.server.ServerVersion;
+import com.github.retrooper.packetevents.protocol.attribute.Attributes;
 import com.github.retrooper.packetevents.protocol.entity.data.EntityDataTypes;
 import com.github.retrooper.packetevents.protocol.entity.pose.EntityPose;
 import com.github.retrooper.packetevents.protocol.nbt.NBTCompound;
@@ -15,6 +16,7 @@ import lol.pyr.znpcsplus.api.entity.EntityPropertyRegistry;
 import lol.pyr.znpcsplus.api.skin.SkinDescriptor;
 import lol.pyr.znpcsplus.config.ConfigManager;
 import lol.pyr.znpcsplus.entity.properties.*;
+import lol.pyr.znpcsplus.entity.properties.attributes.AttributeProperty;
 import lol.pyr.znpcsplus.entity.properties.villager.VillagerLevelProperty;
 import lol.pyr.znpcsplus.entity.properties.villager.VillagerProfessionProperty;
 import lol.pyr.znpcsplus.entity.properties.villager.VillagerTypeProperty;
@@ -32,18 +34,19 @@ import java.util.*;
 import java.util.stream.Collectors;
 
 /**
- * 1.8  <a href="https://wiki.vg/index.php?title=Entity_metadata&oldid=7415">...</a>
+ * 1.8  <a href="https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Entity_metadata?oldid=2767708">...</a>
- * 1.9  <a href="https://wiki.vg/index.php?title=Entity_metadata&oldid=7968">...</a>
+ * 1.9  <a href="https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Entity_metadata?oldid=2768074">...</a>
- * 1.10 <a href="https://wiki.vg/index.php?title=Entity_metadata&oldid=8241">...</a>
+ * 1.10 <a href="https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Entity_metadata?oldid=2768201">...</a>
- * 1.11 <a href="https://wiki.vg/index.php?title=Entity_metadata&oldid=8534">...</a>
+ * 1.11 <a href="https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Entity_metadata?oldid=2768444">...</a>
- * 1.12 <a href="https://wiki.vg/index.php?title=Entity_metadata&oldid=14048">...</a>
+ * 1.12 <a href="https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Entity_metadata?oldid=2768647">...</a>
- * 1.13 <a href="https://wiki.vg/index.php?title=Entity_metadata&oldid=14800">...</a>
+ * 1.13 <a href="https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Entity_metadata?oldid=2768701">...</a>
- * 1.14 <a href="https://wiki.vg/index.php?title=Entity_metadata&oldid=15240">...</a>
+ * 1.14 <a href="https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Entity_metadata?oldid=2768716">...</a>
- * 1.15 <a href="https://wiki.vg/index.php?title=Entity_metadata&oldid=15991">...</a>
+ * 1.15 <a href="https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Entity_metadata?oldid=2768877">...</a>
- * 1.16 <a href="https://wiki.vg/index.php?title=Entity_metadata&oldid=16539">...</a>
+ * 1.16 <a href="https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Entity_metadata?oldid=2769100">...</a>
- * 1.17 <a href="https://wiki.vg/index.php?title=Entity_metadata&oldid=17521">...</a>
+ * 1.17 <a href="https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Entity_metadata?oldid=2769318">...</a>
- * 1.18-1.19 <a href="https://wiki.vg/index.php?title=Entity_metadata&oldid=18191">...</a>
+ * 1.18-1.19 <a href="https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Entity_metadata?oldid=2769409">...</a>
- * 1.20 <a href="https://wiki.vg/index.php?title=Entity_metadata">...</a>
+ * 1.20 <a href="https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Entity_metadata?oldid=2769476">...</a>
+ * 1.21 <a href="https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Entity_metadata">...</a>
  */
 @SuppressWarnings("unchecked")
 public class EntityPropertyRegistryImpl implements EntityPropertyRegistry {
@@ -90,6 +93,7 @@ public class EntityPropertyRegistryImpl implements EntityPropertyRegistry {
         registerEnumSerializer(Sound.class);
         registerEnumSerializer(ArmadilloState.class);
         registerEnumSerializer(WoldVariant.class);
+        registerEnumSerializer(SkeletonType.class);
 
         registerPrimitiveSerializers(Integer.class, Boolean.class, Double.class, Float.class, Long.class, Short.class, Byte.class, String.class);
 
@@ -124,6 +128,7 @@ public class EntityPropertyRegistryImpl implements EntityPropertyRegistry {
 
         register(new DummyProperty<>("look", LookType.FIXED));
         register(new DummyProperty<>("look_distance", configManager.getConfig().lookPropertyDistance()));
+        register(new DummyProperty<>("look_return", false));
         register(new DummyProperty<>("view_distance", configManager.getConfig().viewDistance()));
 
         register(new DummyProperty<>("permission_required", false));
@@ -151,6 +156,16 @@ public class EntityPropertyRegistryImpl implements EntityPropertyRegistry {
         linkProperties("glow", "fire", "invisible");
         register(new BooleanProperty("silent", 4, false, legacyBooleans));
 
+        // Attribute Max Health
+        register(new AttributeProperty(packetFactory, "attribute_max_health", Attributes.MAX_HEALTH));
+
+        // Health - LivingEntity
+        int healthIndex = 6;
+        if (ver.isNewerThanOrEquals(ServerVersion.V_1_17)) healthIndex = 9;
+        else if (ver.isNewerThanOrEquals(ServerVersion.V_1_14)) healthIndex = 8;
+        else if (ver.isNewerThanOrEquals(ServerVersion.V_1_10)) healthIndex = 7;
+        register(new HealthProperty(healthIndex));
+
         final int tameableIndex;
         if (ver.isNewerThanOrEquals(ServerVersion.V_1_17)) tameableIndex = 17;
         else if (ver.isNewerThanOrEquals(ServerVersion.V_1_15)) tameableIndex = 16;
@@ -182,6 +197,8 @@ public class EntityPropertyRegistryImpl implements EntityPropertyRegistry {
             register(new BooleanProperty("baby", babyIndex, false, legacyBooleans));
         }
 
+        register(new EntitySittingProperty(packetFactory, this));
+
         // Player
         register(new DummyProperty<>("skin", SkinDescriptor.class, false));
         final int skinLayersIndex;
@@ -436,6 +453,12 @@ public class EntityPropertyRegistryImpl implements EntityPropertyRegistry {
         witherIndex += 3; // skip the first 3 indexes, will be used for the other properties later
         register(new IntegerProperty("invulnerable_time", witherIndex, 0, false));
 
+        // Skeleton
+        if (ver.isOlderThan(ServerVersion.V_1_11)) {
+            if (legacyBooleans) register(new EncodedByteProperty<>("skeleton_type", SkeletonType.NORMAL, 13, SkeletonType::getLegacyId));
+            else register(new EncodedIntegerProperty<>("skeleton_type", SkeletonType.NORMAL, ver.isOlderThan(ServerVersion.V_1_10) ? 11 : 12, Enum::ordinal));
+        }
+
         if (!ver.isNewerThanOrEquals(ServerVersion.V_1_9)) return;
         // Shulker
         int shulkerIndex;
@@ -483,7 +506,9 @@ public class EntityPropertyRegistryImpl implements EntityPropertyRegistry {
         else if (ver.isNewerThanOrEquals(ServerVersion.V_1_15)) llamaIndex = 20;
         else if (ver.isNewerThanOrEquals(ServerVersion.V_1_14)) llamaIndex = 19;
         else llamaIndex = 17;
-        register(new EncodedIntegerProperty<DyeColor>("carpet_color", DyeColor.class, llamaIndex++, obj -> obj == null ? -1 : obj.ordinal()));
+
+        // Removed in 1.21
+        if (!ver.isNewerThanOrEquals(ServerVersion.V_1_21)) register(new EncodedIntegerProperty<DyeColor>("carpet_color", DyeColor.class, llamaIndex++, obj -> obj == null ? -1 : obj.ordinal()));
         register(new EncodedIntegerProperty<>("llama_variant", LlamaVariant.CREAMY, llamaIndex, Enum::ordinal));
 
         if (!ver.isNewerThanOrEquals(ServerVersion.V_1_12)) return;
@@ -663,8 +688,20 @@ public class EntityPropertyRegistryImpl implements EntityPropertyRegistry {
 
         if (!ver.isNewerThanOrEquals(ServerVersion.V_1_21)) return;
 
+        register(new EquipmentProperty(packetFactory, "body", EquipmentSlot.BODY));
+
         // Bogged
         register(new BooleanProperty("bogged_sheared", 16, false, legacyBooleans));
+
+        if (!ver.isNewerThanOrEquals(ServerVersion.V_1_21_2)) return;
+
+        // Creaking
+        register(new BooleanProperty("creaking_active", 17, false, legacyBooleans));
+
+        if (!ver.isNewerThanOrEquals(ServerVersion.V_1_21_4)) return;
+
+        // Creaking
+        register(new BooleanProperty("creaking_crumbling", 18, false, legacyBooleans));
     }
 
     private void registerSerializer(PropertySerializer<?> serializer) {

plugin/src/main/java/lol/pyr/znpcsplus/entity/PacketEntity.java

@@ -8,27 +8,34 @@ import lol.pyr.znpcsplus.api.entity.EntityProperty;
 import lol.pyr.znpcsplus.api.entity.PropertyHolder;
 import lol.pyr.znpcsplus.packets.PacketFactory;
 import lol.pyr.znpcsplus.reflection.Reflections;
+import lol.pyr.znpcsplus.util.FutureUtil;
 import lol.pyr.znpcsplus.util.NpcLocation;
+import lol.pyr.znpcsplus.util.Viewable;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 
-import java.util.Collection;
+import java.util.*;
-import java.util.Set;
+import java.util.concurrent.CompletableFuture;
-import java.util.UUID;
 
 public class PacketEntity implements PropertyHolder {
     private final PacketFactory packetFactory;
 
     private final PropertyHolder properties;
+    private final Viewable viewable;
     private final int entityId;
     private final UUID uuid;
 
     private final EntityType type;
     private NpcLocation location;
 
-    public PacketEntity(PacketFactory packetFactory, PropertyHolder properties, EntityType type, NpcLocation location) {
+    private PacketEntity vehicle;
+    private Integer vehicleId;
+    private List<Integer> passengers;
+
+    public PacketEntity(PacketFactory packetFactory, PropertyHolder properties, Viewable viewable, EntityType type, NpcLocation location) {
         this.packetFactory = packetFactory;
         this.properties = properties;
+        this.viewable = viewable;
         this.entityId = reserveEntityID();
         this.uuid = UUID.randomUUID();
         this.type = type;
@@ -51,22 +58,117 @@ public class PacketEntity implements PropertyHolder {
         return type;
     }
 
-    public void setLocation(NpcLocation location, Collection<Player> viewers) {
+    public void setLocation(NpcLocation location) {
         this.location = location;
-        for (Player viewer : viewers) packetFactory.teleportEntity(viewer, this);
+        if (vehicle != null) {
+            vehicle.setLocation(location.withY(location.getY() - 0.9));
+            return;
+        }
+        for (Player viewer : viewable.getViewers()) packetFactory.teleportEntity(viewer, this);
     }
 
-    public void spawn(Player player) {
+    public CompletableFuture<Void> spawn(Player player) {
-        if (type == EntityTypes.PLAYER) packetFactory.spawnPlayer(player, this, properties);
+        return FutureUtil.exceptionPrintingRunAsync(() -> {
+            if (type == EntityTypes.PLAYER) packetFactory.spawnPlayer(player, this, properties).join();
             else packetFactory.spawnEntity(player, this, properties);
+            if (vehicleId != null) {
+                packetFactory.setPassengers(player, vehicleId, this.getEntityId());
+            }
+            if (passengers != null) {
+                packetFactory.setPassengers(player, this.getEntityId(), passengers.stream().mapToInt(Integer::intValue).toArray());
+            }
+        });
     }
 
     public void setHeadRotation(Player player, float yaw, float pitch) {
         packetFactory.sendHeadRotation(player, this, yaw, pitch);
     }
 
+    public PacketEntity getVehicle() {
+        return vehicle;
+    }
+
+    public Viewable getViewable() {
+        return viewable;
+    }
+
+    public void setVehicleId(Integer vehicleId) {
+        if (this.vehicle != null) {
+            for (Player player : viewable.getViewers()) {
+                packetFactory.setPassengers(player, this.vehicle.getEntityId());
+                this.vehicle.despawn(player);
+                packetFactory.teleportEntity(player, this);
+            }
+        } else if (this.vehicleId != null) {
+            for (Player player : viewable.getViewers()) {
+                packetFactory.setPassengers(player, this.vehicleId);
+            }
+        }
+        this.vehicleId = vehicleId;
+        if (vehicleId == null) return;
+
+        for (Player player : viewable.getViewers()) {
+            packetFactory.setPassengers(player, this.getEntityId(), vehicleId);
+        }
+    }
+
+    public void setVehicle(PacketEntity vehicle) {
+        // remove old vehicle
+        if (this.vehicle != null) {
+            for (Player player : viewable.getViewers()) {
+                packetFactory.setPassengers(player, this.vehicle.getEntityId());
+                this.vehicle.despawn(player);
+                packetFactory.teleportEntity(player, this);
+            }
+        } else if (this.vehicleId != null) {
+            for (Player player : viewable.getViewers()) {
+                packetFactory.setPassengers(player, this.vehicleId);
+            }
+        }
+
+        this.vehicle = vehicle;
+        if (this.vehicle == null) return;
+
+        vehicle.setLocation(location.withY(location.getY() - 0.9));
+        for (Player player : viewable.getViewers()) {
+            vehicle.spawn(player).thenRun(() -> {
+                packetFactory.setPassengers(player, vehicle.getEntityId(), this.getEntityId());
+            });
+        }
+    }
+
+    public Integer getVehicleId() {
+        return vehicleId;
+    }
+
+    public List<Integer> getPassengers() {
+        return passengers == null ? Collections.emptyList() : passengers;
+    }
+
+    public void addPassenger(int entityId) {
+        if (passengers == null) {
+            passengers = new ArrayList<>();
+        }
+        passengers.add(entityId);
+        for (Player player : viewable.getViewers()) {
+            packetFactory.setPassengers(player, this.getEntityId(), passengers.stream().mapToInt(Integer::intValue).toArray());
+        }
+    }
+
+    public void removePassenger(int entityId) {
+        if (passengers == null) return;
+        passengers.remove(entityId);
+        for (Player player : viewable.getViewers()) {
+            packetFactory.setPassengers(player, this.getEntityId(), passengers.stream().mapToInt(Integer::intValue).toArray());
+        }
+        if (passengers.isEmpty()) {
+            passengers = null;
+        }
+    }
+
     public void despawn(Player player) {
         packetFactory.destroyEntity(player, this, properties);
+        if (vehicle != null) vehicle.despawn(player);
     }
 
     public void refreshMeta(Player player) {

plugin/src/main/java/lol/pyr/znpcsplus/entity/properties/EntitySittingProperty.java

@@ -0,0 +1,37 @@
+package lol.pyr.znpcsplus.entity.properties;
+
+import com.github.retrooper.packetevents.protocol.entity.data.EntityData;
+import com.github.retrooper.packetevents.protocol.entity.type.EntityTypes;
+import lol.pyr.znpcsplus.entity.ArmorStandVehicleProperties;
+import lol.pyr.znpcsplus.entity.EntityPropertyImpl;
+import lol.pyr.znpcsplus.entity.EntityPropertyRegistryImpl;
+import lol.pyr.znpcsplus.entity.PacketEntity;
+import lol.pyr.znpcsplus.packets.PacketFactory;
+import org.bukkit.entity.Player;
+
+import java.util.Map;
+
+public class EntitySittingProperty extends EntityPropertyImpl<Boolean> {
+    private final PacketFactory packetFactory;
+    private final EntityPropertyRegistryImpl propertyRegistry;
+
+    public EntitySittingProperty(PacketFactory packetFactory, EntityPropertyRegistryImpl propertyRegistry) {
+        super("entity_sitting", false, Boolean.class);
+        this.packetFactory = packetFactory;
+        this.propertyRegistry = propertyRegistry;
+    }
+
+    @Override
+    public void apply(Player player, PacketEntity entity, boolean isSpawned, Map<Integer, EntityData> properties) {
+        boolean sitting = entity.getProperty(this);
+        if (sitting) {
+            if (entity.getVehicle() == null) {
+                PacketEntity vehiclePacketEntity = new PacketEntity(packetFactory, new ArmorStandVehicleProperties(propertyRegistry),
+                        entity.getViewable(), EntityTypes.ARMOR_STAND, entity.getLocation().withY(entity.getLocation().getY() - 0.9));
+                entity.setVehicle(vehiclePacketEntity);
+            }
+        } else if (entity.getVehicle() != null) {
+            entity.setVehicle(null);
+        }
+    }
+}

plugin/src/main/java/lol/pyr/znpcsplus/entity/properties/GlowProperty.java

@@ -24,7 +24,10 @@ public class GlowProperty extends EntityPropertyImpl<NamedColor> {
         EntityData oldData = properties.get(0);
         byte oldValue = oldData == null ? 0 : (byte) oldData.getValue();
         properties.put(0, newEntityData(0, EntityDataTypes.BYTE, (byte) (oldValue | (value == null ? 0 : 0x40))));
-        if (isSpawned) packetFactory.removeTeam(player, entity);
+        // the team is already created with the right glow color in the packet factory if the npc isnt spawned yet
+        if (isSpawned) {
+            packetFactory.removeTeam(player, entity);
             packetFactory.createTeam(player, entity, value);
         }
     }
+}

plugin/src/main/java/lol/pyr/znpcsplus/entity/properties/HealthProperty.java

@@ -0,0 +1,27 @@
+package lol.pyr.znpcsplus.entity.properties;
+
+import com.github.retrooper.packetevents.protocol.attribute.Attributes;
+import com.github.retrooper.packetevents.protocol.entity.data.EntityData;
+import com.github.retrooper.packetevents.protocol.entity.data.EntityDataTypes;
+import lol.pyr.znpcsplus.entity.EntityPropertyImpl;
+import lol.pyr.znpcsplus.entity.PacketEntity;
+import org.bukkit.entity.Player;
+
+import java.util.Map;
+
+public class HealthProperty extends EntityPropertyImpl<Float> {
+    private final int index;
+
+    public HealthProperty(int index) {
+        super("health", 20f, Float.class);
+        this.index = index;
+    }
+
+    @Override
+    public void apply(Player player, PacketEntity entity, boolean isSpawned, Map<Integer, EntityData> properties) {
+        float health = entity.getProperty(this);
+        health = (float) Attributes.MAX_HEALTH.sanitizeValue(health);
+        properties.put(index, new EntityData(index, EntityDataTypes.FLOAT, health));
+
+    }
+}

plugin/src/main/java/lol/pyr/znpcsplus/entity/properties/attributes/AttributeProperty.java

@@ -0,0 +1,63 @@
+package lol.pyr.znpcsplus.entity.properties.attributes;
+
+import com.github.retrooper.packetevents.protocol.attribute.Attribute;
+import com.github.retrooper.packetevents.protocol.entity.data.EntityData;
+import com.github.retrooper.packetevents.wrapper.play.server.WrapperPlayServerUpdateAttributes;
+import lol.pyr.znpcsplus.entity.EntityPropertyImpl;
+import lol.pyr.znpcsplus.entity.PacketEntity;
+import lol.pyr.znpcsplus.packets.PacketFactory;
+import org.bukkit.entity.Player;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+public class AttributeProperty extends EntityPropertyImpl<Double> {
+    private final PacketFactory packetFactory;
+    private final Attribute attribute;
+
+    public AttributeProperty(PacketFactory packetFactory, String name, Attribute attribute) {
+        super(name, attribute.getDefaultValue(), Double.class);
+        this.packetFactory = packetFactory;
+        this.attribute = attribute;
+    }
+
+    public double getMinValue() {
+        return attribute.getMinValue();
+    }
+
+    public double getMaxValue() {
+        return attribute.getMaxValue();
+    }
+
+    public double sanitizeValue(double value) {
+        return attribute.sanitizeValue(value);
+    }
+
+    @Override
+    public List<EntityData> applyStandalone(Player player, PacketEntity packetEntity, boolean isSpawned) {
+        apply(player, packetEntity, isSpawned, Collections.emptyList());
+        return Collections.emptyList();
+    }
+
+    @Override
+    public void apply(Player player, PacketEntity entity, boolean isSpawned, Map<Integer, EntityData> properties) {
+    }
+
+    public void apply(Player player, PacketEntity entity, boolean isSpawned, List<WrapperPlayServerUpdateAttributes.Property> properties) {
+        Double value = entity.getProperty(this);
+        if (value == null) {
+            return;
+        }
+        value = attribute.sanitizeValue(value);
+        if (isSpawned) {
+            packetFactory.sendAttribute(player, entity, new WrapperPlayServerUpdateAttributes.Property(attribute, value, Collections.emptyList()));
+        } else {
+            properties.add(new WrapperPlayServerUpdateAttributes.Property(attribute, value, Collections.emptyList()));
+        }
+    }
+
+    public Attribute getAttribute() {
+        return attribute;
+    }
+}

plugin/src/main/java/lol/pyr/znpcsplus/hologram/HologramImpl.java

@@ -6,6 +6,7 @@ import lol.pyr.znpcsplus.api.hologram.Hologram;
 import lol.pyr.znpcsplus.config.ConfigManager;
 import lol.pyr.znpcsplus.entity.EntityPropertyRegistryImpl;
 import lol.pyr.znpcsplus.packets.PacketFactory;
+import lol.pyr.znpcsplus.util.FutureUtil;
 import lol.pyr.znpcsplus.util.NpcLocation;
 import lol.pyr.znpcsplus.util.Viewable;
 import net.kyori.adventure.text.Component;
@@ -16,6 +17,8 @@ import org.bukkit.entity.Player;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.stream.Collectors;
 
 public class HologramImpl extends Viewable implements Hologram {
     private final ConfigManager configManager;
@@ -38,9 +41,9 @@ public class HologramImpl extends Viewable implements Hologram {
     }
 
     public void addTextLineComponent(Component line) {
-        HologramText newLine = new HologramText(propertyRegistry, packetFactory, null, line);
+        HologramText newLine = new HologramText(this, propertyRegistry, packetFactory, null, line);
         lines.add(newLine);
-        relocateLines(newLine);
+        relocateLines();
         for (Player viewer : getViewers()) newLine.show(viewer.getPlayer());
     }
 
@@ -57,9 +60,9 @@ public class HologramImpl extends Viewable implements Hologram {
     }
 
     public void addItemLinePEStack(ItemStack item) {
-        HologramItem newLine = new HologramItem(propertyRegistry, packetFactory, null, item);
+        HologramItem newLine = new HologramItem(this, propertyRegistry, packetFactory, null, item);
         lines.add(newLine);
-        relocateLines(newLine);
+        relocateLines();
         for (Player viewer : getViewers()) newLine.show(viewer.getPlayer());
     }
 
@@ -98,10 +101,16 @@ public class HologramImpl extends Viewable implements Hologram {
         lines.clear();
     }
 
+    public void addLines(List<HologramLine<?>> lines) {
+        this.lines.addAll(lines);
+        relocateLines();
+        for (Player viewer : getViewers()) for (HologramLine<?> line : lines) line.show(viewer);
+    }
+
     public void insertTextLineComponent(int index, Component line) {
-        HologramText newLine = new HologramText(propertyRegistry, packetFactory, null, line);
+        HologramText newLine = new HologramText(this, propertyRegistry, packetFactory, null, line);
         lines.add(index, newLine);
-        relocateLines(newLine);
+        relocateLines();
         for (Player viewer : getViewers()) newLine.show(viewer.getPlayer());
     }
 
@@ -114,9 +123,9 @@ public class HologramImpl extends Viewable implements Hologram {
     }
 
     public void insertItemLinePEStack(int index, ItemStack item) {
-        HologramItem newLine = new HologramItem(propertyRegistry, packetFactory, null, item);
+        HologramItem newLine = new HologramItem(this, propertyRegistry, packetFactory, null, item);
         lines.add(index, newLine);
-        relocateLines(newLine);
+        relocateLines();
         for (Player viewer : getViewers()) newLine.show(viewer.getPlayer());
     }
 
@@ -138,8 +147,10 @@ public class HologramImpl extends Viewable implements Hologram {
     }
 
     @Override
-    protected void UNSAFE_show(Player player) {
+    protected CompletableFuture<Void> UNSAFE_show(Player player) {
-        for (HologramLine<?> line : lines) line.show(player);
+        return FutureUtil.allOf(lines.stream()
+                .map(line -> line.show(player))
+                .collect(Collectors.toList()));
     }
 
     @Override
@@ -172,14 +183,10 @@ public class HologramImpl extends Viewable implements Hologram {
     }
 
     private void relocateLines() {
-        relocateLines(null);
-    }
-
-    private void relocateLines(HologramLine<?> newLine) {
         final double lineSpacing = configManager.getConfig().lineSpacing();
         double height = location.getY() + (lines.size() - 1) * lineSpacing + getOffset();
         for (HologramLine<?> line : lines) {
-            line.setLocation(location.withY(height), line == newLine ? Collections.emptySet() : getViewers());
+            line.setLocation(location.withY(height));
             height -= lineSpacing;
         }
     }

plugin/src/main/java/lol/pyr/znpcsplus/hologram/HologramItem.java

@@ -15,13 +15,11 @@ import lol.pyr.znpcsplus.api.entity.EntityProperty;
 import lol.pyr.znpcsplus.entity.EntityPropertyRegistryImpl;
 import lol.pyr.znpcsplus.packets.PacketFactory;
 import lol.pyr.znpcsplus.util.NpcLocation;
-import org.bukkit.entity.Player;
+import lol.pyr.znpcsplus.util.Viewable;
-
-import java.util.Collection;
 
 public class HologramItem extends HologramLine<ItemStack> {
-    public HologramItem(EntityPropertyRegistryImpl propertyRegistry, PacketFactory packetFactory, NpcLocation location, ItemStack item) {
+    public HologramItem(Viewable viewable,  EntityPropertyRegistryImpl propertyRegistry, PacketFactory packetFactory, NpcLocation location, ItemStack item) {
-        super(item, packetFactory, EntityTypes.ITEM, location);
+        super(viewable, item, packetFactory, EntityTypes.ITEM, location);
         addProperty(propertyRegistry.getByName("holo_item"));
     }
 
@@ -33,8 +31,8 @@ public class HologramItem extends HologramLine<ItemStack> {
     }
 
     @Override
-    public void setLocation(NpcLocation location, Collection<Player> viewers) {
+    public void setLocation(NpcLocation location) {
-        super.setLocation(location.withY(location.getY() + 2.05), viewers);
+        super.setLocation(location.withY(location.getY() + 2.05));
     }
 
     public static boolean ensureValidItemInput(String in) {

plugin/src/main/java/lol/pyr/znpcsplus/hologram/HologramLine.java

@@ -7,21 +7,22 @@ import lol.pyr.znpcsplus.api.entity.PropertyHolder;
 import lol.pyr.znpcsplus.entity.PacketEntity;
 import lol.pyr.znpcsplus.packets.PacketFactory;
 import lol.pyr.znpcsplus.util.NpcLocation;
+import lol.pyr.znpcsplus.util.Viewable;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 
-import java.util.Collection;
 import java.util.HashSet;
 import java.util.Set;
+import java.util.concurrent.CompletableFuture;
 
 public class HologramLine<M> implements PropertyHolder {
     private M value;
     private final PacketEntity entity;
     private final Set<EntityProperty<?>> properties;
 
-    public HologramLine(M value, PacketFactory packetFactory, EntityType type, NpcLocation location) {
+    public HologramLine(Viewable viewable, M value, PacketFactory packetFactory, EntityType type, NpcLocation location) {
         this.value = value;
-        this.entity = new PacketEntity(packetFactory, this, type, location);
+        this.entity = new PacketEntity(packetFactory, this, viewable, type, location);
         this.properties = new HashSet<>();
     }
 
@@ -37,16 +38,16 @@ public class HologramLine<M> implements PropertyHolder {
         entity.refreshMeta(player);
     }
 
-    protected void show(Player player) {
+    protected CompletableFuture<Void> show(Player player) {
-        entity.spawn(player);
+        return entity.spawn(player);
     }
 
     protected void hide(Player player) {
         entity.despawn(player);
     }
 
-    public void setLocation(NpcLocation location, Collection<Player> viewers) {
+    public void setLocation(NpcLocation location) {
-        entity.setLocation(location, viewers);
+        entity.setLocation(location);
     }
 
     public int getEntityId() {

plugin/src/main/java/lol/pyr/znpcsplus/hologram/HologramText.java

@@ -5,24 +5,26 @@ import lol.pyr.znpcsplus.api.entity.EntityProperty;
 import lol.pyr.znpcsplus.entity.EntityPropertyRegistryImpl;
 import lol.pyr.znpcsplus.packets.PacketFactory;
 import lol.pyr.znpcsplus.util.NpcLocation;
+import lol.pyr.znpcsplus.util.Viewable;
 import net.kyori.adventure.text.Component;
 import org.bukkit.entity.Player;
 
+import java.util.concurrent.CompletableFuture;
+
 public class HologramText extends HologramLine<Component> {
 
     private static final Component BLANK  = Component.text("%blank%");
 
-    public HologramText(EntityPropertyRegistryImpl propertyRegistry, PacketFactory packetFactory, NpcLocation location, Component text) {
+    public HologramText(Viewable viewable,  EntityPropertyRegistryImpl propertyRegistry, PacketFactory packetFactory, NpcLocation location, Component text) {
-        super(text, packetFactory, EntityTypes.ARMOR_STAND, location);
+        super(viewable, text, packetFactory, EntityTypes.ARMOR_STAND, location);
         addProperty(propertyRegistry.getByName("name"));
         addProperty(propertyRegistry.getByName("invisible"));
     }
 
     @Override
-    public void show(Player player) {
+    public CompletableFuture<Void> show(Player player) {
-        if (!getValue().equals(BLANK)) {
+        if (getValue().equals(BLANK)) return CompletableFuture.completedFuture(null);
-            super.show(player);
+        return super.show(player);
-        }
     }
 
     @SuppressWarnings("unchecked")
@@ -37,4 +39,12 @@ public class HologramText extends HologramLine<Component> {
     public boolean hasProperty(EntityProperty<?> key) {
         return key.getName().equalsIgnoreCase("name") || key.getName().equalsIgnoreCase("invisible");
     }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        HologramText that = (HologramText) obj;
+        return getValue().equals(that.getValue());
+    }
 }

plugin/src/main/java/lol/pyr/znpcsplus/interaction/switchserver/SwitchServerAction.java

@@ -32,7 +32,7 @@ public class SwitchServerAction extends InteractionActionImpl {
                         .hoverEvent(HoverEvent.hoverEvent(HoverEvent.Action.SHOW_TEXT,
                                 Component.text("Click to edit this action", NamedTextColor.GRAY)))
                         .clickEvent(ClickEvent.clickEvent(ClickEvent.Action.SUGGEST_COMMAND,
-                                "/" + context.getLabel() + " action edit " + id + " " + index + " switcserver " + getInteractionType().name() + " " + getCooldown()/1000 + " " + getDelay() + " " + server))
+                                "/" + context.getLabel() + " action edit " + id + " " + index + " switchserver " + getInteractionType().name() + " " + getCooldown()/1000 + " " + getDelay() + " " + server))
                 .append(Component.text(" | ", NamedTextColor.GRAY))
                 .append(Component.text("[DELETE]", NamedTextColor.RED)
                         .hoverEvent(HoverEvent.hoverEvent(HoverEvent.Action.SHOW_TEXT,

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

@@ -20,9 +20,12 @@ import org.bukkit.Location;
 import org.bukkit.World;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.util.*;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.stream.Collectors;
 
 public class NpcImpl extends Viewable implements Npc {
@@ -38,6 +41,8 @@ public class NpcImpl extends Viewable implements Npc {
     private final Map<EntityPropertyImpl<?>, Object> propertyMap = new HashMap<>();
     private final List<InteractionAction> actions = new ArrayList<>();
 
+    private final Map<UUID, float[]> playerLookMap = new ConcurrentHashMap<>();
+
     protected NpcImpl(UUID uuid, EntityPropertyRegistryImpl propertyRegistry, ConfigManager configManager, LegacyComponentSerializer textSerializer, World world, NpcTypeImpl type, NpcLocation location, PacketFactory packetFactory) {
         this(uuid, propertyRegistry, configManager, packetFactory, textSerializer, world.getName(), type, location);
     }
@@ -48,14 +53,14 @@ public class NpcImpl extends Viewable implements Npc {
         this.type = type;
         this.location = location;
         this.uuid = uuid;
-        entity = new PacketEntity(packetFactory, this, type.getType(), location);
+        entity = new PacketEntity(packetFactory, this, this, type.getType(), location);
         hologram = new HologramImpl(propertyRegistry, configManager, packetFactory, textSerializer, location.withY(location.getY() + type.getHologramOffset()));
     }
 
     public void setType(NpcTypeImpl type) {
         UNSAFE_hideAll();
         this.type = type;
-        entity = new PacketEntity(packetFactory, this, type.getType(), entity.getLocation());
+        entity = new PacketEntity(packetFactory, this, this, type.getType(), entity.getLocation());
         hologram.setLocation(location.withY(location.getY() + type.getHologramOffset()));
         UNSAFE_showAll();
     }
@@ -85,20 +90,34 @@ public class NpcImpl extends Viewable implements Npc {
 
     public void setLocation(NpcLocation location) {
         this.location = location;
-        entity.setLocation(location, getViewers());
+        playerLookMap.clear();
+        playerLookMap.putAll(getViewers().stream().collect(Collectors.toMap(Player::getUniqueId, player -> new float[]{location.getYaw(), location.getPitch()})));
+        entity.setLocation(location);
         hologram.setLocation(location.withY(location.getY() + type.getHologramOffset()));
     }
 
     public void setHeadRotation(Player player, float yaw, float pitch) {
+        if (getHeadYaw(player) == yaw && getHeadPitch(player) == pitch) return;
+        playerLookMap.put(player.getUniqueId(), new float[]{yaw, pitch});
         entity.setHeadRotation(player, yaw, pitch);
     }
 
     public void setHeadRotation(float yaw, float pitch) {
         for (Player player : getViewers()) {
+            if (getHeadYaw(player) == yaw && getHeadPitch(player) == pitch) continue;
+            playerLookMap.put(player.getUniqueId(), new float[]{yaw, pitch});
             entity.setHeadRotation(player, yaw, pitch);
         }
     }
 
+    public float getHeadYaw(Player player) {
+        return playerLookMap.getOrDefault(player.getUniqueId(), new float[]{location.getYaw(), location.getPitch()})[0];
+    }
+
+    public float getHeadPitch(Player player) {
+        return playerLookMap.getOrDefault(player.getUniqueId(), new float[]{location.getYaw(), location.getPitch()})[1];
+    }
+
     public HologramImpl getHologram() {
         return hologram;
     }
@@ -125,13 +144,14 @@ public class NpcImpl extends Viewable implements Npc {
     }
 
     @Override
-    protected void UNSAFE_show(Player player) {
+    protected CompletableFuture<Void> UNSAFE_show(Player player) {
-        entity.spawn(player);
+        playerLookMap.put(player.getUniqueId(), new float[]{location.getYaw(), location.getPitch()});
-        hologram.show(player);
+        return CompletableFuture.allOf(entity.spawn(player), hologram.show(player));
     }
 
     @Override
     protected void UNSAFE_hide(Player player) {
+        playerLookMap.remove(player.getUniqueId());
         entity.despawn(player);
         hologram.hide(player);
     }
@@ -246,4 +266,29 @@ public class NpcImpl extends Viewable implements Npc {
     public void swingHand(boolean offHand) {
         for (Player viewer : getViewers()) entity.swingHand(viewer, offHand);
     }
+
+    @Override
+    public @NotNull List<Integer> getPassengers() {
+        return entity.getPassengers();
+    }
+
+    @Override
+    public void addPassenger(int entityId) {
+        entity.addPassenger(entityId);
+    }
+
+    @Override
+    public void removePassenger(int entityId) {
+        entity.removePassenger(entityId);
+    }
+
+    @Override
+    public @Nullable Integer getVehicleId() {
+        return entity.getVehicleId();
+    }
+
+    @Override
+    public void setVehicleId(Integer vehicleId) {
+        entity.setVehicleId(vehicleId);
+    }
 }

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

@@ -14,6 +14,7 @@ import lol.pyr.znpcsplus.hologram.HologramText;
 import lol.pyr.znpcsplus.interaction.ActionRegistryImpl;
 import lol.pyr.znpcsplus.packets.PacketFactory;
 import lol.pyr.znpcsplus.scheduling.TaskScheduler;
+import lol.pyr.znpcsplus.serialization.NpcSerializerRegistryImpl;
 import lol.pyr.znpcsplus.storage.NpcStorage;
 import lol.pyr.znpcsplus.storage.NpcStorageType;
 import lol.pyr.znpcsplus.util.NpcLocation;
@@ -35,13 +36,13 @@ public class NpcRegistryImpl implements NpcRegistry {
     private final Map<String, NpcEntryImpl> npcIdLookupMap = new HashMap<>();
     private final Map<UUID, NpcEntryImpl> npcUuidLookupMap = new HashMap<>();
 
-    public NpcRegistryImpl(ConfigManager configManager, ZNpcsPlus plugin, PacketFactory packetFactory, ActionRegistryImpl actionRegistry, TaskScheduler scheduler, NpcTypeRegistryImpl typeRegistry, EntityPropertyRegistryImpl propertyRegistry, LegacyComponentSerializer textSerializer) {
+    public NpcRegistryImpl(ConfigManager configManager, ZNpcsPlus plugin, PacketFactory packetFactory, ActionRegistryImpl actionRegistry, TaskScheduler scheduler, NpcTypeRegistryImpl typeRegistry, EntityPropertyRegistryImpl propertyRegistry, NpcSerializerRegistryImpl serializerRegistry, LegacyComponentSerializer textSerializer) {
         this.textSerializer = textSerializer;
         this.propertyRegistry = propertyRegistry;
-        storage = configManager.getConfig().storageType().create(configManager, plugin, packetFactory, actionRegistry, typeRegistry, propertyRegistry, textSerializer);
+        storage = configManager.getConfig().storageType().create(configManager, plugin, packetFactory, actionRegistry, typeRegistry, propertyRegistry, textSerializer, serializerRegistry);
         if (storage == null) {
             Bukkit.getLogger().warning("Failed to initialize storage, falling back to YAML");
-            storage = NpcStorageType.YAML.create(configManager, plugin, packetFactory, actionRegistry, typeRegistry, propertyRegistry, textSerializer);
+            storage = NpcStorageType.YAML.create(configManager, plugin, packetFactory, actionRegistry, typeRegistry, propertyRegistry, textSerializer, serializerRegistry);
         }
         this.packetFactory = packetFactory;
         this.configManager = configManager;
@@ -52,7 +53,13 @@ public class NpcRegistryImpl implements NpcRegistry {
         }
     }
 
+    @Override
+    public void register(NpcEntry entry) {
+        register((NpcEntryImpl) entry);
+    }
+
     private void register(NpcEntryImpl entry) {
+        if (entry == null) throw new NullPointerException();
         unregister(npcIdLookupMap.put(entry.getId(), entry));
         unregister(npcUuidLookupMap.put(entry.getNpc().getUuid(), entry));
         npcList.add(entry);

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

@@ -114,12 +114,15 @@ public class NpcTypeImpl implements NpcType {
 
         public NpcTypeImpl build() {
             ServerVersion version = PacketEvents.getAPI().getServerManager().getVersion();
-            addProperties("fire", "invisible", "silent", "look", "look_distance", "view_distance",
+            addProperties("fire", "invisible", "silent", "look", "look_distance", "look_return", "view_distance",
                     "potion_color", "potion_ambient", "display_name", "permission_required",
                     "player_knockback", "player_knockback_exempt_permission", "player_knockback_distance", "player_knockback_vertical",
                     "player_knockback_horizontal", "player_knockback_cooldown", "player_knockback_sound", "player_knockback_sound_name",
                     "player_knockback_sound_volume", "player_knockback_sound_pitch");
             if (!type.equals(EntityTypes.PLAYER)) addProperties("dinnerbone");
+            if (EntityTypes.isTypeInstanceOf(type, EntityTypes.LIVINGENTITY)) {
+                addProperties("health", "attribute_max_health");
+            }
             // TODO: make this look nicer after completing the rest of the properties
             if (version.isNewerThanOrEquals(ServerVersion.V_1_9)) addProperties("glow");
             if (version.isNewerThanOrEquals(ServerVersion.V_1_14)) {
@@ -143,6 +146,9 @@ public class NpcTypeImpl implements NpcType {
             } else if (version.isOlderThan(ServerVersion.V_1_11) && type.equals(EntityTypes.HORSE)) {
                 addProperties("has_chest");
             }
+            if (version.isOlderThan(ServerVersion.V_1_11) && EntityTypes.isTypeInstanceOf(type, EntityTypes.SKELETON)) {
+                addProperties("skeleton_type");
+            }
             if (EntityTypes.isTypeInstanceOf(type, EntityTypes.ABSTRACT_EVO_ILLU_ILLAGER)) {
                 addProperties("spell");
             }
@@ -176,6 +182,11 @@ public class NpcTypeImpl implements NpcType {
                     addProperties("wolf_variant");
                 }
             }
+            if (version.isNewerThanOrEquals(ServerVersion.V_1_21_4)) {
+                if (EntityTypes.isTypeInstanceOf(type, EntityTypes.CREAKING)) {
+                    addProperties("creaking_crumbling");
+                }
+            }
             return new NpcTypeImpl(name, type, hologramOffset, new HashSet<>(allowedProperties), defaultProperties);
         }
     }

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

@@ -36,7 +36,7 @@ public class NpcTypeRegistryImpl implements NpcTypeRegistry {
         register(builder(p, "player", EntityTypes.PLAYER)
                 .setHologramOffset(-0.15D)
                 .addEquipmentProperties()
-                .addProperties("skin_cape", "skin_jacket", "skin_left_sleeve", "skin_right_sleeve", "skin_left_leg", "skin_right_leg", "skin_hat", "shoulder_entity_left", "shoulder_entity_right", "force_body_rotation")
+                .addProperties("skin_cape", "skin_jacket", "skin_left_sleeve", "skin_right_sleeve", "skin_left_leg", "skin_right_leg", "skin_hat", "shoulder_entity_left", "shoulder_entity_right", "force_body_rotation", "entity_sitting")
                 .addDefaultProperty("skin_cape", true)
                 .addDefaultProperty("skin_jacket", true)
                 .addDefaultProperty("skin_left_sleeve", true)
@@ -82,7 +82,7 @@ public class NpcTypeRegistryImpl implements NpcTypeRegistry {
 
         register(builder(p, "enderman", EntityTypes.ENDERMAN)
                 .setHologramOffset(0.925)
-                .addProperties("enderman_held_block", "enderman_screaming", "enderman_staring"));
+                .addProperties("enderman_held_block", "enderman_screaming", "enderman_staring", "entity_sitting"));
 
         register(builder(p, "endermite", EntityTypes.ENDERMITE)
                 .setHologramOffset(-1.675));
@@ -93,7 +93,8 @@ public class NpcTypeRegistryImpl implements NpcTypeRegistry {
 
         register(builder(p, "giant", EntityTypes.GIANT)
                 .setHologramOffset(10.025)
-                .addEquipmentProperties());
+                .addEquipmentProperties()
+                .addProperties("entity_sitting"));
 
         register(builder(p, "guardian", EntityTypes.GUARDIAN)
                 .setHologramOffset(-1.125)
@@ -133,7 +134,8 @@ public class NpcTypeRegistryImpl implements NpcTypeRegistry {
 
         register(builder(p, "skeleton", EntityTypes.SKELETON)
                 .setHologramOffset(0.015)
-                .addEquipmentProperties());
+                .addEquipmentProperties()
+                .addProperties("entity_sitting"));
 
         register(builder(p, "skeleton_horse", EntityTypes.SKELETON_HORSE)
                 .setHologramOffset(-0.375));
@@ -169,14 +171,16 @@ public class NpcTypeRegistryImpl implements NpcTypeRegistry {
 
         register(builder(p, "zombie", EntityTypes.ZOMBIE)
                 .setHologramOffset(-0.025)
-                .addEquipmentProperties());
+                .addEquipmentProperties()
+                .addProperties("entity_sitting"));
 
         register(builder(p, "zombie_horse", EntityTypes.ZOMBIE_HORSE)
                 .setHologramOffset(-0.375));
 
         register(builder(p, "zombified_piglin", EntityTypes.ZOMBIFIED_PIGLIN)
                 .setHologramOffset(-0.025)
-                .addEquipmentProperties());
+                .addEquipmentProperties()
+                .addProperties("entity_sitting"));
 
         if (!version.isNewerThanOrEquals(ServerVersion.V_1_9)) return;
 
@@ -203,21 +207,21 @@ public class NpcTypeRegistryImpl implements NpcTypeRegistry {
 
         register(builder(p, "husk", EntityTypes.HUSK)
                 .setHologramOffset(-0.025)
-                .addEquipmentProperties());
+                .addEquipmentProperties()
-
+                .addProperties("entity_sitting"));
-        register(builder(p, "polar_bear", EntityTypes.POLAR_BEAR)
-                .setHologramOffset(-0.575));
 
         register(builder(p, "stray", EntityTypes.STRAY)
                 .setHologramOffset(0.015)
-                .addEquipmentProperties());
+                .addEquipmentProperties()
+                .addProperties("entity_sitting"));
 
         register(builder(p, "evoker", EntityTypes.EVOKER)
-                .setHologramOffset(-0.025));
+                .setHologramOffset(-0.025)
+                .addProperties("entity_sitting"));
 
         register(builder(p, "llama", EntityTypes.LLAMA)
                 .setHologramOffset(-0.105)
-                .addProperties("carpet_color", "llama_variant"));
+                .addProperties("carpet_color", "llama_variant", "body"));
 
         register(builder(p, "vex", EntityTypes.VEX)
                 .setHologramOffset(-1.175)
@@ -225,20 +229,23 @@ public class NpcTypeRegistryImpl implements NpcTypeRegistry {
 
         register(builder(p, "vindicator", EntityTypes.VINDICATOR)
                 .setHologramOffset(-0.025)
-                .addProperties("celebrating"));
+                .addProperties("celebrating", "entity_sitting"));
 
         register(builder(p, "wither_skeleton", EntityTypes.WITHER_SKELETON)
                 .setHologramOffset(0.425)
-                .addEquipmentProperties());
+                .addEquipmentProperties()
+                .addProperties("entity_sitting"));
 
         register(builder(p, "zombie_villager", EntityTypes.ZOMBIE_VILLAGER)
                 .setHologramOffset(-0.025)
-                .addEquipmentProperties());
+                .addEquipmentProperties()
+                .addProperties("entity_sitting"));
 
         if (!version.isNewerThanOrEquals(ServerVersion.V_1_12)) return;
 
         register(builder(p, "illusioner", EntityTypes.ILLUSIONER)
-                .setHologramOffset(-0.025));
+                .setHologramOffset(-0.025)
+                .addProperties("entity_sitting"));
 
         register(builder(p, "parrot", EntityTypes.PARROT)
                 .setHologramOffset(-1.075)
@@ -255,7 +262,8 @@ public class NpcTypeRegistryImpl implements NpcTypeRegistry {
 
         register(builder(p, "drowned", EntityTypes.DROWNED)
                 .setHologramOffset(-0.025)
-                .addEquipmentProperties());
+                .addEquipmentProperties()
+                .addProperties("entity_sitting"));
 
         register(builder(p, "phantom", EntityTypes.PHANTOM)
                 .setHologramOffset(-1.475));
@@ -291,7 +299,7 @@ public class NpcTypeRegistryImpl implements NpcTypeRegistry {
         register(builder(p, "pillager", EntityTypes.PILLAGER)
                 .setHologramOffset(-0.025)
                 .addHandProperties()
-                .addProperties("pillager_charging"));
+                .addProperties("pillager_charging", "entity_sitting"));
 
         register(builder(p, "ravager", EntityTypes.RAVAGER)
                 .setHologramOffset(0.225));
@@ -319,11 +327,12 @@ public class NpcTypeRegistryImpl implements NpcTypeRegistry {
         register(builder(p, "piglin", EntityTypes.PIGLIN)
                 .setHologramOffset(-0.025)
                 .addEquipmentProperties()
-                .addProperties("piglin_baby", "piglin_charging_crossbow", "piglin_dancing"));
+                .addProperties("piglin_baby", "piglin_charging_crossbow", "piglin_dancing", "entity_sitting"));
 
         register(builder(p, "piglin_brute", EntityTypes.PIGLIN_BRUTE)
                 .setHologramOffset(-0.025)
-                .addEquipmentProperties());
+                .addEquipmentProperties()
+                .addProperties("entity_sitting"));
 
         register(builder(p, "strider", EntityTypes.STRIDER)
                 .setHologramOffset(-0.275)
@@ -372,6 +381,7 @@ public class NpcTypeRegistryImpl implements NpcTypeRegistry {
                 .setHologramOffset(0.4)
                 .addProperties("bashing", "camel_sitting"));
 
+
         if (!version.isNewerThanOrEquals(ServerVersion.V_1_20_5)) return;
 
         register(builder(p, "armadillo", EntityTypes.ARMADILLO)
@@ -382,10 +392,16 @@ public class NpcTypeRegistryImpl implements NpcTypeRegistry {
 
         register(builder(p, "bogged", EntityTypes.BOGGED)
                 .setHologramOffset(0.015)
-                .addProperties("bogged_sheared"));
+                .addProperties("bogged_sheared", "entity_sitting"));
 
         register(builder(p, "breeze", EntityTypes.BREEZE)
                 .setHologramOffset(-0.205));
+
+        if (!version.isNewerThanOrEquals(ServerVersion.V_1_21_2)) return;
+
+        register(builder(p, "creaking", EntityTypes.CREAKING)
+                .setHologramOffset(0.725)
+                .addProperties("creaking_active"));
     }
 
     public Collection<NpcType> getAll() {

plugin/src/main/java/lol/pyr/znpcsplus/packets/PacketFactory.java

@@ -2,6 +2,7 @@ package lol.pyr.znpcsplus.packets;
 
 import com.github.retrooper.packetevents.protocol.entity.data.EntityData;
 import com.github.retrooper.packetevents.protocol.player.Equipment;
+import com.github.retrooper.packetevents.wrapper.play.server.WrapperPlayServerUpdateAttributes;
 import lol.pyr.znpcsplus.api.entity.PropertyHolder;
 import lol.pyr.znpcsplus.entity.PacketEntity;
 import lol.pyr.znpcsplus.util.NamedColor;
@@ -11,7 +12,7 @@ import java.util.List;
 import java.util.concurrent.CompletableFuture;
 
 public interface PacketFactory {
-    void spawnPlayer(Player player, PacketEntity entity, PropertyHolder properties);
+    CompletableFuture<Void> spawnPlayer(Player player, PacketEntity entity, PropertyHolder properties);
     void spawnEntity(Player player, PacketEntity entity, PropertyHolder properties);
     void destroyEntity(Player player, PacketEntity entity, PropertyHolder properties);
     void teleportEntity(Player player, PacketEntity entity);
@@ -24,4 +25,7 @@ public interface PacketFactory {
     void sendMetadata(Player player, PacketEntity entity, List<EntityData> data);
     void sendHeadRotation(Player player, PacketEntity entity, float yaw, float pitch);
     void sendHandSwing(Player player, PacketEntity entity, boolean offHand);
+    void setPassengers(Player player, int vehicle, int... passengers);
+    void sendAllAttributes(Player player, PacketEntity entity, PropertyHolder properties);
+    void sendAttribute(Player player, PacketEntity entity, WrapperPlayServerUpdateAttributes.Property property);
 }

plugin/src/main/java/lol/pyr/znpcsplus/packets/V1_17PacketFactory.java

@@ -1,6 +1,7 @@
 package lol.pyr.znpcsplus.packets;
 
 import com.github.retrooper.packetevents.PacketEventsAPI;
+import com.github.retrooper.packetevents.protocol.entity.type.EntityTypes;
 import com.github.retrooper.packetevents.util.Vector3d;
 import com.github.retrooper.packetevents.wrapper.play.server.WrapperPlayServerSpawnEntity;
 import lol.pyr.znpcsplus.api.entity.PropertyHolder;
@@ -27,6 +28,7 @@ public class V1_17PacketFactory extends V1_8PacketFactory {
         sendPacket(player, new WrapperPlayServerSpawnEntity(entity.getEntityId(), Optional.of(entity.getUuid()), entity.getType(),
                 npcLocationToVector(location), location.getPitch(), location.getYaw(), location.getYaw(), 0, Optional.of(new Vector3d())));
         sendAllMetadata(player, entity, properties);
+        if (EntityTypes.isTypeInstanceOf(entity.getType(), EntityTypes.LIVINGENTITY)) sendAllAttributes(player, entity, properties);
         createTeam(player, entity, properties.getProperty(propertyRegistry.getByName("glow", NamedColor.class)));
     }
 }

plugin/src/main/java/lol/pyr/znpcsplus/packets/V1_20_2PacketFactory.java

@@ -16,6 +16,7 @@ import org.bukkit.entity.Player;
 import org.bukkit.plugin.Plugin;
 
 import java.util.Optional;
+import java.util.concurrent.CompletableFuture;
 
 public class V1_20_2PacketFactory extends V1_19_3PacketFactory {
 
@@ -27,14 +28,15 @@ public class V1_20_2PacketFactory extends V1_19_3PacketFactory {
     }
 
     @Override
-    public void spawnPlayer(Player player, PacketEntity entity, PropertyHolder properties) {
+    public CompletableFuture<Void> spawnPlayer(Player player, PacketEntity entity, PropertyHolder properties) {
-        addTabPlayer(player, entity, properties).thenAccept(ignored -> {
+        return addTabPlayer(player, entity, properties).thenAccept(ignored -> {
             createTeam(player, entity, properties.getProperty(propertyRegistry.getByName("glow", NamedColor.class)));
             NpcLocation location = entity.getLocation();
             sendPacket(player, new WrapperPlayServerSpawnEntity(entity.getEntityId(), Optional.of(entity.getUuid()), entity.getType(),
                     npcLocationToVector(location), location.getPitch(), location.getYaw(), location.getYaw(), 0, Optional.of(new Vector3d())));
             sendPacket(player, new WrapperPlayServerEntityHeadLook(entity.getEntityId(), location.getYaw()));
             sendAllMetadata(player, entity, properties);
+            sendAllAttributes(player, entity, properties);
             scheduler.runLaterAsync(() -> removeTabPlayer(player, entity), configManager.getConfig().tabHideDelay());
         });
     }

plugin/src/main/java/lol/pyr/znpcsplus/packets/V1_8PacketFactory.java

@@ -18,6 +18,7 @@ import lol.pyr.znpcsplus.config.ConfigManager;
 import lol.pyr.znpcsplus.entity.EntityPropertyImpl;
 import lol.pyr.znpcsplus.entity.EntityPropertyRegistryImpl;
 import lol.pyr.znpcsplus.entity.PacketEntity;
+import lol.pyr.znpcsplus.entity.properties.attributes.AttributeProperty;
 import lol.pyr.znpcsplus.scheduling.TaskScheduler;
 import lol.pyr.znpcsplus.skin.BaseSkinDescriptor;
 import lol.pyr.znpcsplus.util.NamedColor;
@@ -47,14 +48,15 @@ public class V1_8PacketFactory implements PacketFactory {
     }
 
     @Override
-    public void spawnPlayer(Player player, PacketEntity entity, PropertyHolder properties) {
+    public CompletableFuture<Void> spawnPlayer(Player player, PacketEntity entity, PropertyHolder properties) {
-        addTabPlayer(player, entity, properties).thenAccept(ignored -> {
+        return addTabPlayer(player, entity, properties).thenAccept(ignored -> {
             createTeam(player, entity, properties.getProperty(propertyRegistry.getByName("glow", NamedColor.class)));
             NpcLocation location = entity.getLocation();
             sendPacket(player, new WrapperPlayServerSpawnPlayer(entity.getEntityId(),
                     entity.getUuid(), npcLocationToVector(location), location.getYaw(), location.getPitch(), Collections.emptyList()));
             sendPacket(player, new WrapperPlayServerEntityHeadLook(entity.getEntityId(), location.getYaw()));
             sendAllMetadata(player, entity, properties);
+            sendAllAttributes(player, entity, properties);
             scheduler.runLaterAsync(() -> removeTabPlayer(player, entity), configManager.getConfig().tabHideDelay());
         });
     }
@@ -70,6 +72,7 @@ public class V1_8PacketFactory implements PacketFactory {
                 new WrapperPlayServerSpawnEntity(entity.getEntityId(), Optional.of(entity.getUuid()), entity.getType(), npcLocationToVector(location),
                         location.getPitch(), location.getYaw(), location.getYaw(), 0, Optional.empty()));
         sendAllMetadata(player, entity, properties);
+        if (EntityTypes.isTypeInstanceOf(type, EntityTypes.LIVINGENTITY)) sendAllAttributes(player, entity, properties);
         createTeam(player, entity, properties.getProperty(propertyRegistry.getByName("glow", NamedColor.class)));
     }
 
@@ -153,6 +156,11 @@ public class V1_8PacketFactory implements PacketFactory {
         sendPacket(player, new WrapperPlayServerEntityEquipment(entity.getEntityId(), Collections.singletonList(equipment)));
     }
 
+    @Override
+    public void setPassengers(Player player, int vehicleEntityId, int... passengers) {
+        sendPacket(player, new WrapperPlayServerSetPassengers(vehicleEntityId, passengers));
+    }
+
     protected void sendPacket(Player player, PacketWrapper<?> packet) {
         packetEvents.getPlayerManager().sendPacket(player, packet);
     }
@@ -182,4 +190,19 @@ public class V1_8PacketFactory implements PacketFactory {
                 WrapperPlayServerEntityAnimation.EntityAnimationType.SWING_OFF_HAND :
                 WrapperPlayServerEntityAnimation.EntityAnimationType.SWING_MAIN_ARM));
     }
+
+    @Override
+    public void sendAllAttributes(Player player, PacketEntity entity, PropertyHolder properties) {
+        List<WrapperPlayServerUpdateAttributes.Property> attributesList = new ArrayList<>();
+        properties.getAppliedProperties()
+                .stream()
+                .filter(property -> property instanceof AttributeProperty)
+                .forEach(property -> ((AttributeProperty) property).apply(player, entity, false, attributesList));
+        sendPacket(player, new WrapperPlayServerUpdateAttributes(entity.getEntityId(), attributesList));
+    }
+
+    @Override
+    public void sendAttribute(Player player, PacketEntity entity, WrapperPlayServerUpdateAttributes.Property property) {
+        sendPacket(player, new WrapperPlayServerUpdateAttributes(entity.getEntityId(), Collections.singletonList(property)));
+    }
 }

plugin/src/main/java/lol/pyr/znpcsplus/serialization/NpcSerializerRegistryImpl.java

@@ -0,0 +1,33 @@
+package lol.pyr.znpcsplus.serialization;
+
+import lol.pyr.znpcsplus.api.serialization.NpcSerializer;
+import lol.pyr.znpcsplus.api.serialization.NpcSerializerRegistry;
+import lol.pyr.znpcsplus.config.ConfigManager;
+import lol.pyr.znpcsplus.entity.EntityPropertyRegistryImpl;
+import lol.pyr.znpcsplus.interaction.ActionRegistryImpl;
+import lol.pyr.znpcsplus.npc.NpcTypeRegistryImpl;
+import lol.pyr.znpcsplus.packets.PacketFactory;
+import net.kyori.adventure.text.serializer.legacy.LegacyComponentSerializer;
+import org.bukkit.configuration.file.YamlConfiguration;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class NpcSerializerRegistryImpl implements NpcSerializerRegistry {
+    private final Map<Class<?>, NpcSerializer<?>> serializerMap = new HashMap<>();
+
+    public NpcSerializerRegistryImpl(PacketFactory packetFactory, ConfigManager configManager, ActionRegistryImpl actionRegistry, NpcTypeRegistryImpl typeRegistry, EntityPropertyRegistryImpl propertyRegistry, LegacyComponentSerializer textSerializer) {
+        registerSerializer(YamlConfiguration.class, new YamlSerializer(packetFactory, configManager, actionRegistry, typeRegistry, propertyRegistry, textSerializer));
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public <T> NpcSerializer<T> getSerializer(Class<T> clazz) {
+        return (NpcSerializer<T>) serializerMap.get(clazz);
+    }
+
+    @Override
+    public <T> void registerSerializer(Class<T> clazz, NpcSerializer<T> serializer) {
+        serializerMap.put(clazz, serializer);
+    }
+}

plugin/src/main/java/lol/pyr/znpcsplus/serialization/YamlSerializer.java

@@ -0,0 +1,154 @@
+package lol.pyr.znpcsplus.serialization;
+
+import lol.pyr.znpcsplus.api.entity.EntityProperty;
+import lol.pyr.znpcsplus.api.npc.NpcEntry;
+import lol.pyr.znpcsplus.api.serialization.NpcSerializer;
+import lol.pyr.znpcsplus.config.ConfigManager;
+import lol.pyr.znpcsplus.entity.EntityPropertyImpl;
+import lol.pyr.znpcsplus.entity.EntityPropertyRegistryImpl;
+import lol.pyr.znpcsplus.entity.PropertySerializer;
+import lol.pyr.znpcsplus.hologram.HologramImpl;
+import lol.pyr.znpcsplus.interaction.ActionRegistryImpl;
+import lol.pyr.znpcsplus.npc.NpcEntryImpl;
+import lol.pyr.znpcsplus.npc.NpcImpl;
+import lol.pyr.znpcsplus.npc.NpcTypeRegistryImpl;
+import lol.pyr.znpcsplus.packets.PacketFactory;
+import lol.pyr.znpcsplus.util.NpcLocation;
+import net.kyori.adventure.text.serializer.legacy.LegacyComponentSerializer;
+import org.bukkit.Bukkit;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.configuration.file.YamlConfiguration;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.UUID;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import java.util.stream.Collectors;
+
+public class YamlSerializer implements NpcSerializer<YamlConfiguration> {
+    private final static Logger logger = Logger.getLogger("YamlSerializer");
+
+    private final PacketFactory packetFactory;
+    private final ConfigManager configManager;
+    private final ActionRegistryImpl actionRegistry;
+    private final NpcTypeRegistryImpl typeRegistry;
+    private final EntityPropertyRegistryImpl propertyRegistry;
+    private final LegacyComponentSerializer textSerializer;
+
+    public YamlSerializer(PacketFactory packetFactory, ConfigManager configManager, ActionRegistryImpl actionRegistry, NpcTypeRegistryImpl typeRegistry, EntityPropertyRegistryImpl propertyRegistry, LegacyComponentSerializer textSerializer) {
+        this.packetFactory = packetFactory;
+        this.configManager = configManager;
+        this.actionRegistry = actionRegistry;
+        this.typeRegistry = typeRegistry;
+        this.propertyRegistry = propertyRegistry;
+        this.textSerializer = textSerializer;
+    }
+
+    @Override
+    public YamlConfiguration serialize(NpcEntry entry) {
+        YamlConfiguration config = new YamlConfiguration();
+        config.set("id", entry.getId());
+        config.set("is-processed", entry.isProcessed());
+        config.set("allow-commands", entry.isAllowCommandModification());
+        config.set("save", entry.isSave());
+
+        NpcImpl npc = (NpcImpl) entry.getNpc();
+        config.set("enabled", npc.isEnabled());
+        config.set("uuid", npc.getUuid().toString());
+        config.set("world", npc.getWorldName());
+        config.set("location", serializeLocation(npc.getLocation()));
+        config.set("type", npc.getType().getName());
+
+        for (EntityProperty<?> property : npc.getAllProperties()) try {
+            PropertySerializer<?> serializer = propertyRegistry.getSerializer(((EntityPropertyImpl<?>) property).getType());
+            if (serializer == null) {
+                Bukkit.getLogger().log(Level.WARNING, "Unknown serializer for property '" + property.getName() + "' for npc '" + entry.getId() + "'. skipping ...");
+                continue;
+            }
+            config.set("properties." + property.getName(), serializer.UNSAFE_serialize(npc.getProperty(property)));
+        } catch (Exception exception) {
+            logger.severe("Failed to serialize property " + property.getName() + " for npc with id " + entry.getId());
+            exception.printStackTrace();
+        }
+
+        HologramImpl hologram = npc.getHologram();
+        if (hologram.getOffset() != 0.0) config.set("hologram.offset", hologram.getOffset());
+        if (hologram.getRefreshDelay() != -1) config.set("hologram.refresh-delay", hologram.getRefreshDelay());
+        List<String> lines = new ArrayList<>(npc.getHologram().getLines().size());
+        for (int i = 0; i < hologram.getLines().size(); i++) {
+            lines.add(hologram.getLine(i));
+        }
+        config.set("hologram.lines", lines);
+        config.set("actions", npc.getActions().stream()
+                .map(actionRegistry::serialize)
+                .filter(Objects::nonNull)
+                .collect(Collectors.toList()));
+
+        return config;
+    }
+
+    @Override
+    public NpcEntry deserialize(YamlConfiguration config) {
+        UUID uuid = config.contains("uuid") ? UUID.fromString(config.getString("uuid")) : UUID.randomUUID();
+        NpcImpl npc = new NpcImpl(uuid, propertyRegistry, configManager, packetFactory, textSerializer, config.getString("world"),
+                typeRegistry.getByName(config.getString("type")), deserializeLocation(config.getConfigurationSection("location")));
+
+        if (config.isBoolean("enabled")) npc.setEnabled(config.getBoolean("enabled"));
+
+        ConfigurationSection properties = config.getConfigurationSection("properties");
+        if (properties != null) {
+            for (String key : properties.getKeys(false)) {
+                EntityPropertyImpl<?> property = propertyRegistry.getByName(key);
+                if (property == null) {
+                    Bukkit.getLogger().log(Level.WARNING, "Unknown property '" + key + "' for npc '" + config.getString("id") + "'. skipping ...");
+                    continue;
+                }
+                PropertySerializer<?> serializer = propertyRegistry.getSerializer(property.getType());
+                if (serializer == null) {
+                    Bukkit.getLogger().log(Level.WARNING, "Unknown serializer for property '" + key + "' for npc '" + config.getString("id") + "'. skipping ...");
+                    continue;
+                }
+                Object value = serializer.deserialize(properties.getString(key));
+                if (value == null) {
+                    Bukkit.getLogger().log(Level.WARNING, "Failed to deserialize property '" + key + "' for npc '" + config.getString("id") + "'. Resetting to default ...");
+                    value = property.getDefaultValue();
+                }
+                npc.UNSAFE_setProperty(property, value);
+            }
+        }
+        HologramImpl hologram = npc.getHologram();
+        hologram.setOffset(config.getDouble("hologram.offset", 0.0));
+        hologram.setRefreshDelay(config.getLong("hologram.refresh-delay", -1));
+        for (String line : config.getStringList("hologram.lines")) hologram.addLine(line);
+        for (String s : config.getStringList("actions")) npc.addAction(actionRegistry.deserialize(s));
+
+        NpcEntryImpl entry = new NpcEntryImpl(config.getString("id"), npc);
+        entry.setProcessed(config.getBoolean("is-processed"));
+        entry.setAllowCommandModification(config.getBoolean("allow-commands"));
+        entry.setSave(config.getBoolean("save", true));
+
+        return entry;
+    }
+
+    public NpcLocation deserializeLocation(ConfigurationSection section) {
+        return new NpcLocation(
+                section.getDouble("x"),
+                section.getDouble("y"),
+                section.getDouble("z"),
+                (float) section.getDouble("yaw"),
+                (float) section.getDouble("pitch")
+        );
+    }
+
+    public YamlConfiguration serializeLocation(NpcLocation location) {
+        YamlConfiguration config = new YamlConfiguration();
+        config.set("x", location.getX());
+        config.set("y", location.getY());
+        config.set("z", location.getZ());
+        config.set("yaw", location.getYaw());
+        config.set("pitch", location.getPitch());
+        return config;
+    }
+}

plugin/src/main/java/lol/pyr/znpcsplus/skin/SkinDescriptorFactoryImpl.java

@@ -52,4 +52,9 @@ public class SkinDescriptorFactoryImpl implements SkinDescriptorFactory {
     public SkinDescriptor createUrlDescriptor(URL url, String variant) {
         return PrefetchedDescriptor.fromUrl(skinCache, url, variant).join();
     }
+
+    @Override
+    public SkinDescriptor createFileDescriptor(String path) {
+        return PrefetchedDescriptor.fromFile(skinCache, path).join();
+    }
 }

plugin/src/main/java/lol/pyr/znpcsplus/skin/cache/MojangSkinCache.java

@@ -5,6 +5,7 @@ import com.google.gson.JsonParser;
 import lol.pyr.znpcsplus.config.ConfigManager;
 import lol.pyr.znpcsplus.reflection.Reflections;
 import lol.pyr.znpcsplus.skin.SkinImpl;
+import lol.pyr.znpcsplus.util.FutureUtil;
 import org.bukkit.Bukkit;
 import org.bukkit.entity.Player;
 
@@ -14,6 +15,7 @@ import java.net.HttpURLConnection;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ConcurrentHashMap;
@@ -26,9 +28,12 @@ public class MojangSkinCache {
 
     private final Map<String, SkinImpl> cache = new ConcurrentHashMap<>();
     private final Map<String, CachedId> idCache = new ConcurrentHashMap<>();
+    private final File skinsFolder;
 
-    public MojangSkinCache(ConfigManager configManager) {
+    public MojangSkinCache(ConfigManager configManager, File skinsFolder) {
         this.configManager = configManager;
+        this.skinsFolder = skinsFolder;
+        if (!skinsFolder.exists()) skinsFolder.mkdirs();
     }
 
     public void cleanCache() {
@@ -42,7 +47,7 @@ public class MojangSkinCache {
 
         if (idCache.containsKey(name.toLowerCase())) return fetchByUUID(idCache.get(name.toLowerCase()).getId());
 
-        return CompletableFuture.supplyAsync(() -> {
+        return FutureUtil.exceptionPrintingSupplyAsync(() -> {
             URL url = parseUrl("https://api.mojang.com/users/profiles/minecraft/" + name);
             HttpURLConnection connection = null;
             try {
@@ -75,7 +80,7 @@ public class MojangSkinCache {
 
         if (idCache.containsKey(name.toLowerCase())) return fetchByUUID(idCache.get(name.toLowerCase()).getId());
 
-        return CompletableFuture.supplyAsync(() -> {
+        return FutureUtil.exceptionPrintingSupplyAsync(() -> {
             URL url = parseUrl("https://api.ashcon.app/mojang/v2/user/" + name);
             HttpURLConnection connection = null;
             try {
@@ -106,7 +111,7 @@ public class MojangSkinCache {
     }
 
     public CompletableFuture<SkinImpl> fetchByUrl(URL url, String variant) {
-        return CompletableFuture.supplyAsync(() -> {
+        return FutureUtil.exceptionPrintingSupplyAsync(() -> {
             URL apiUrl = parseUrl("https://api.mineskin.org/generate/url");
             HttpURLConnection connection = null;
             try {
@@ -142,6 +147,58 @@ public class MojangSkinCache {
         });
     }
 
+    public CompletableFuture<SkinImpl> fetchFromFile(String path) throws FileNotFoundException {
+        File file = new File(skinsFolder, path);
+        if (!file.exists()) throw new FileNotFoundException("File not found: " + path);
+        return CompletableFuture.supplyAsync(() -> {
+            URL apiUrl = parseUrl("https://api.mineskin.org/generate/upload");
+            HttpURLConnection connection = null;
+            try {
+                String boundary = "*****";
+                String CRLF = "\r\n";
+
+                connection = (HttpURLConnection) apiUrl.openConnection();
+                connection.setRequestMethod("POST");
+                connection.setReadTimeout(10000);
+                connection.setConnectTimeout(15000);
+                connection.setUseCaches(false);
+                connection.setRequestProperty("Cache-Control", "no-cache");
+                connection.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);
+                connection.setDoInput(true);
+                connection.setDoOutput(true);
+                OutputStream outputStream = connection.getOutputStream();
+                DataOutputStream out = new DataOutputStream(outputStream);
+                out.writeBytes("--" + boundary + CRLF);
+                out.writeBytes("Content-Disposition: form-data; name=\"file\"; filename=\"" + file.getName() + "\"" + CRLF);
+                out.writeBytes("Content-Type: image/png" + CRLF);
+                out.writeBytes(CRLF);
+                out.write(Files.readAllBytes(file.toPath()));
+                out.writeBytes(CRLF);
+                out.writeBytes("--" + boundary + "--" + CRLF);
+                out.flush();
+                out.close();
+                outputStream.close();
+
+                try (Reader reader = new InputStreamReader(connection.getInputStream(), StandardCharsets.UTF_8)) {
+                    JsonObject obj = JsonParser.parseReader(reader).getAsJsonObject();
+                    if (obj.has("error")) return null;
+                    if (!obj.has("data")) return null;
+                    JsonObject texture = obj.get("data").getAsJsonObject().get("texture").getAsJsonObject();
+                    return new SkinImpl(texture.get("value").getAsString(), texture.get("signature").getAsString());
+                }
+
+            } catch (IOException exception) {
+                if (!configManager.getConfig().disableSkinFetcherWarnings()) {
+                    logger.warning("Failed to get skin from file:");
+                    exception.printStackTrace();
+                }
+            } finally {
+                if (connection != null) connection.disconnect();
+            }
+            return null;
+        });
+    }
+
     public boolean isNameFullyCached(String s) {
         String name = s.toLowerCase();
         if (!idCache.containsKey(name)) return false;
@@ -170,7 +227,7 @@ public class MojangSkinCache {
             if (!skin.isExpired()) return CompletableFuture.completedFuture(skin);
         }
 
-        return CompletableFuture.supplyAsync(() -> {
+        return FutureUtil.exceptionPrintingSupplyAsync(() -> {
             URL url = parseUrl("https://sessionserver.mojang.com/session/minecraft/profile/" + uuid + "?unsigned=false");
             HttpURLConnection connection = null;
             try {
@@ -213,4 +270,8 @@ public class MojangSkinCache {
             throw new RuntimeException(exception);
         }
     }
+
+    public File getSkinsFolder() {
+        return skinsFolder;
+    }
 }

plugin/src/main/java/lol/pyr/znpcsplus/skin/descriptor/PrefetchedDescriptor.java

@@ -5,8 +5,10 @@ import lol.pyr.znpcsplus.api.skin.SkinDescriptor;
 import lol.pyr.znpcsplus.skin.BaseSkinDescriptor;
 import lol.pyr.znpcsplus.skin.SkinImpl;
 import lol.pyr.znpcsplus.skin.cache.MojangSkinCache;
+import lol.pyr.znpcsplus.util.FutureUtil;
 import org.bukkit.entity.Player;
 
+import java.io.FileNotFoundException;
 import java.net.URL;
 import java.util.concurrent.CompletableFuture;
 
@@ -18,11 +20,21 @@ public class PrefetchedDescriptor implements BaseSkinDescriptor, SkinDescriptor
     }
 
     public static CompletableFuture<PrefetchedDescriptor> forPlayer(MojangSkinCache cache, String name) {
-        return CompletableFuture.supplyAsync(() -> new PrefetchedDescriptor(cache.fetchByName(name).join()));
+        return FutureUtil.exceptionPrintingSupplyAsync(() -> new PrefetchedDescriptor(cache.fetchByName(name).join()));
     }
 
     public static CompletableFuture<PrefetchedDescriptor> fromUrl(MojangSkinCache cache, URL url, String variant) {
-        return CompletableFuture.supplyAsync(() -> new PrefetchedDescriptor(cache.fetchByUrl(url, variant).join()));
+        return FutureUtil.exceptionPrintingSupplyAsync(() -> new PrefetchedDescriptor(cache.fetchByUrl(url, variant).join()));
+    }
+
+    public static CompletableFuture<PrefetchedDescriptor> fromFile(MojangSkinCache cache, String path) {
+        return CompletableFuture.supplyAsync(() -> {
+            try {
+                return new PrefetchedDescriptor(cache.fetchFromFile(path).join());
+            } catch (FileNotFoundException e) {
+                throw new RuntimeException(e);
+            }
+        });
     }
 
     @Override

plugin/src/main/java/lol/pyr/znpcsplus/storage/NpcStorageType.java

@@ -6,6 +6,7 @@ import lol.pyr.znpcsplus.entity.EntityPropertyRegistryImpl;
 import lol.pyr.znpcsplus.interaction.ActionRegistryImpl;
 import lol.pyr.znpcsplus.npc.NpcTypeRegistryImpl;
 import lol.pyr.znpcsplus.packets.PacketFactory;
+import lol.pyr.znpcsplus.serialization.NpcSerializerRegistryImpl;
 import lol.pyr.znpcsplus.storage.mysql.MySQLStorage;
 import lol.pyr.znpcsplus.storage.sqlite.SQLiteStorage;
 import lol.pyr.znpcsplus.storage.yaml.YamlStorage;
@@ -16,13 +17,13 @@ import java.io.File;
 public enum NpcStorageType {
     YAML {
         @Override
-        public NpcStorage create(ConfigManager configManager, ZNpcsPlus plugin, PacketFactory packetFactory, ActionRegistryImpl actionRegistry, NpcTypeRegistryImpl typeRegistry, EntityPropertyRegistryImpl propertyRegistry, LegacyComponentSerializer textSerializer) {
+        public NpcStorage create(ConfigManager configManager, ZNpcsPlus plugin, PacketFactory packetFactory, ActionRegistryImpl actionRegistry, NpcTypeRegistryImpl typeRegistry, EntityPropertyRegistryImpl propertyRegistry, LegacyComponentSerializer textSerializer, NpcSerializerRegistryImpl serializerRegistry) {
-            return new YamlStorage(packetFactory, configManager, actionRegistry, typeRegistry, propertyRegistry, textSerializer, new File(plugin.getDataFolder(), "data"));
+            return new YamlStorage(serializerRegistry, new File(plugin.getDataFolder(), "data"));
         }
     },
     SQLITE {
         @Override
-        public NpcStorage create(ConfigManager configManager, ZNpcsPlus plugin, PacketFactory packetFactory, ActionRegistryImpl actionRegistry, NpcTypeRegistryImpl typeRegistry, EntityPropertyRegistryImpl propertyRegistry, LegacyComponentSerializer textSerializer) {
+        public NpcStorage create(ConfigManager configManager, ZNpcsPlus plugin, PacketFactory packetFactory, ActionRegistryImpl actionRegistry, NpcTypeRegistryImpl typeRegistry, EntityPropertyRegistryImpl propertyRegistry, LegacyComponentSerializer textSerializer, NpcSerializerRegistryImpl serializerRegistry) {
             try {
                 return new SQLiteStorage(packetFactory, configManager, actionRegistry, typeRegistry, propertyRegistry, textSerializer, new File(plugin.getDataFolder(), "znpcsplus.sqlite"));
             } catch (Exception e) {
@@ -33,7 +34,7 @@ public enum NpcStorageType {
     },
     MYSQL {
         @Override
-        public NpcStorage create(ConfigManager configManager, ZNpcsPlus plugin, PacketFactory packetFactory, ActionRegistryImpl actionRegistry, NpcTypeRegistryImpl typeRegistry, EntityPropertyRegistryImpl propertyRegistry, LegacyComponentSerializer textSerializer) {
+        public NpcStorage create(ConfigManager configManager, ZNpcsPlus plugin, PacketFactory packetFactory, ActionRegistryImpl actionRegistry, NpcTypeRegistryImpl typeRegistry, EntityPropertyRegistryImpl propertyRegistry, LegacyComponentSerializer textSerializer, NpcSerializerRegistryImpl serializerRegistry) {
             try {
                 return new MySQLStorage(packetFactory, configManager, actionRegistry, typeRegistry, propertyRegistry, textSerializer);
             } catch (Exception e) {
@@ -43,5 +44,5 @@ public enum NpcStorageType {
         }
     };
 
-    public abstract NpcStorage create(ConfigManager configManager, ZNpcsPlus plugin, PacketFactory packetFactory, ActionRegistryImpl actionRegistry, NpcTypeRegistryImpl typeRegistry, EntityPropertyRegistryImpl propertyRegistry, LegacyComponentSerializer textSerializer);
+    public abstract NpcStorage create(ConfigManager configManager, ZNpcsPlus plugin, PacketFactory packetFactory, ActionRegistryImpl actionRegistry, NpcTypeRegistryImpl typeRegistry, EntityPropertyRegistryImpl propertyRegistry, LegacyComponentSerializer textSerializer, NpcSerializerRegistryImpl serializerRegistry);
 }

plugin/src/main/java/lol/pyr/znpcsplus/storage/yaml/YamlStorage.java

@@ -1,47 +1,28 @@
 package lol.pyr.znpcsplus.storage.yaml;
 
-import lol.pyr.znpcsplus.api.entity.EntityProperty;
+import lol.pyr.znpcsplus.api.serialization.NpcSerializer;
-import lol.pyr.znpcsplus.config.ConfigManager;
-import lol.pyr.znpcsplus.entity.EntityPropertyImpl;
-import lol.pyr.znpcsplus.entity.EntityPropertyRegistryImpl;
-import lol.pyr.znpcsplus.entity.PropertySerializer;
-import lol.pyr.znpcsplus.hologram.HologramImpl;
-import lol.pyr.znpcsplus.interaction.ActionRegistryImpl;
 import lol.pyr.znpcsplus.npc.NpcEntryImpl;
-import lol.pyr.znpcsplus.npc.NpcImpl;
+import lol.pyr.znpcsplus.serialization.NpcSerializerRegistryImpl;
-import lol.pyr.znpcsplus.npc.NpcTypeRegistryImpl;
-import lol.pyr.znpcsplus.packets.PacketFactory;
 import lol.pyr.znpcsplus.storage.NpcStorage;
 import lol.pyr.znpcsplus.util.NpcLocation;
-import net.kyori.adventure.text.serializer.legacy.LegacyComponentSerializer;
-import org.bukkit.Bukkit;
 import org.bukkit.configuration.ConfigurationSection;
 import org.bukkit.configuration.file.YamlConfiguration;
 
 import java.io.File;
-import java.util.*;
+import java.util.ArrayList;
-import java.util.logging.Level;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
 import java.util.logging.Logger;
-import java.util.stream.Collectors;
 
 public class YamlStorage implements NpcStorage {
     private final static Logger logger = Logger.getLogger("YamlStorage");
 
-    private final PacketFactory packetFactory;
-    private final ConfigManager configManager;
-    private final ActionRegistryImpl actionRegistry;
-    private final NpcTypeRegistryImpl typeRegistry;
-    private final EntityPropertyRegistryImpl propertyRegistry;
-    private final LegacyComponentSerializer textSerializer;
     private final File folder;
+    private final NpcSerializer<YamlConfiguration> yamlSerializer;
 
-    public YamlStorage(PacketFactory packetFactory, ConfigManager configManager, ActionRegistryImpl actionRegistry, NpcTypeRegistryImpl typeRegistry, EntityPropertyRegistryImpl propertyRegistry, LegacyComponentSerializer textSerializer, File folder) {
+    public YamlStorage(NpcSerializerRegistryImpl serializerRegistry, File folder) {
-        this.packetFactory = packetFactory;
+        this.yamlSerializer = serializerRegistry.getSerializer(YamlConfiguration.class);
-        this.configManager = configManager;
-        this.actionRegistry = actionRegistry;
-        this.typeRegistry = typeRegistry;
-        this.propertyRegistry = propertyRegistry;
-        this.textSerializer = textSerializer;
         this.folder = folder;
         if (!this.folder.exists()) this.folder.mkdirs();
     }
@@ -53,45 +34,7 @@ public class YamlStorage implements NpcStorage {
         List<NpcEntryImpl> npcs = new ArrayList<>(files.length);
         for (File file : files) if (file.isFile() && file.getName().toLowerCase().endsWith(".yml")) try {
             YamlConfiguration config = YamlConfiguration.loadConfiguration(file);
-            UUID uuid = config.contains("uuid") ? UUID.fromString(config.getString("uuid")) : UUID.randomUUID();
+            npcs.add((NpcEntryImpl) yamlSerializer.deserialize(config));
-            NpcImpl npc = new NpcImpl(uuid, propertyRegistry, configManager, packetFactory, textSerializer, config.getString("world"),
-                    typeRegistry.getByName(config.getString("type")), deserializeLocation(config.getConfigurationSection("location")));
-
-            if (config.isBoolean("enabled")) npc.setEnabled(config.getBoolean("enabled"));
-
-            ConfigurationSection properties = config.getConfigurationSection("properties");
-            if (properties != null) {
-                for (String key : properties.getKeys(false)) {
-                    EntityPropertyImpl<?> property = propertyRegistry.getByName(key);
-                    if (property == null) {
-                        Bukkit.getLogger().log(Level.WARNING, "Unknown property '" + key + "' for npc '" + config.getString("id") + "'. skipping ...");
-                        continue;
-                    }
-                    PropertySerializer<?> serializer = propertyRegistry.getSerializer(property.getType());
-                    if (serializer == null) {
-                        Bukkit.getLogger().log(Level.WARNING, "Unknown serializer for property '" + key + "' for npc '" + config.getString("id") + "'. skipping ...");
-                        continue;
-                    }
-                    Object value = serializer.deserialize(properties.getString(key));
-                    if (value == null) {
-                        Bukkit.getLogger().log(Level.WARNING, "Failed to deserialize property '" + key + "' for npc '" + config.getString("id") + "'. Resetting to default ...");
-                        value = property.getDefaultValue();
-                    }
-                    npc.UNSAFE_setProperty(property, value);
-                }
-            }
-            HologramImpl hologram = npc.getHologram();
-            hologram.setOffset(config.getDouble("hologram.offset", 0.0));
-            hologram.setRefreshDelay(config.getLong("hologram.refresh-delay", -1));
-            for (String line : config.getStringList("hologram.lines")) hologram.addLine(line);
-            for (String s : config.getStringList("actions")) npc.addAction(actionRegistry.deserialize(s));
-
-            NpcEntryImpl entry = new NpcEntryImpl(config.getString("id"), npc);
-            entry.setProcessed(config.getBoolean("is-processed"));
-            entry.setAllowCommandModification(config.getBoolean("allow-commands"));
-            entry.setSave(true);
-
-            npcs.add(entry);
         } catch (Throwable t) {
             logger.severe("Failed to load npc file: " + file.getName());
             t.printStackTrace();
@@ -102,43 +45,7 @@ public class YamlStorage implements NpcStorage {
     @Override
     public void saveNpcs(Collection<NpcEntryImpl> npcs) {
         for (NpcEntryImpl entry : npcs) try {
-            YamlConfiguration config = new YamlConfiguration();
+            YamlConfiguration config = yamlSerializer.serialize(entry);
-            config.set("id", entry.getId());
-            config.set("is-processed", entry.isProcessed());
-            config.set("allow-commands", entry.isAllowCommandModification());
-
-            NpcImpl npc = entry.getNpc();
-            config.set("enabled", npc.isEnabled());
-            config.set("uuid", npc.getUuid().toString());
-            config.set("world", npc.getWorldName());
-            config.set("location", serializeLocation(npc.getLocation()));
-            config.set("type", npc.getType().getName());
-
-            for (EntityProperty<?> property : npc.getAllProperties()) try {
-                PropertySerializer<?> serializer = propertyRegistry.getSerializer(((EntityPropertyImpl<?>) property).getType());
-                if (serializer == null) {
-                    Bukkit.getLogger().log(Level.WARNING, "Unknown serializer for property '" + property.getName() + "' for npc '" + entry.getId() + "'. skipping ...");
-                    continue;
-                }
-                config.set("properties." + property.getName(), serializer.UNSAFE_serialize(npc.getProperty(property)));
-            } catch (Exception exception) {
-                logger.severe("Failed to serialize property " + property.getName() + " for npc with id " + entry.getId());
-                exception.printStackTrace();
-            }
-
-            HologramImpl hologram = npc.getHologram();
-            if (hologram.getOffset() != 0.0) config.set("hologram.offset", hologram.getOffset());
-            if (hologram.getRefreshDelay() != -1) config.set("hologram.refresh-delay", hologram.getRefreshDelay());
-            List<String> lines = new ArrayList<>(npc.getHologram().getLines().size());
-            for (int i = 0; i < hologram.getLines().size(); i++) {
-                lines.add(hologram.getLine(i));
-            }
-            config.set("hologram.lines", lines);
-            config.set("actions", npc.getActions().stream()
-                    .map(actionRegistry::serialize)
-                    .filter(Objects::nonNull)
-                    .collect(Collectors.toList()));
-
             config.save(fileFor(entry));
         } catch (Exception exception) {
             logger.severe("Failed to save npc with id " + entry.getId());

plugin/src/main/java/lol/pyr/znpcsplus/tasks/NpcProcessorTask.java

@@ -33,6 +33,7 @@ public class NpcProcessorTask extends BukkitRunnable {
         EntityPropertyImpl<Integer> viewDistanceProperty = propertyRegistry.getByName("view_distance", Integer.class); // Not sure why this is an Integer, but it is
         EntityPropertyImpl<LookType> lookProperty = propertyRegistry.getByName("look", LookType.class);
         EntityPropertyImpl<Double> lookDistanceProperty = propertyRegistry.getByName("look_distance", Double.class);
+        EntityPropertyImpl<Boolean> lookReturnProperty = propertyRegistry.getByName("look_return", Boolean.class);
         EntityPropertyImpl<Boolean> permissionRequiredProperty = propertyRegistry.getByName("permission_required", Boolean.class);
         EntityPropertyImpl<Boolean> playerKnockbackProperty = propertyRegistry.getByName("player_knockback", Boolean.class);
         EntityPropertyImpl<String> playerKnockbackExemptPermissionProperty = propertyRegistry.getByName("player_knockback_exempt_permission", String.class);
@@ -45,6 +46,7 @@ public class NpcProcessorTask extends BukkitRunnable {
         EntityPropertyImpl<Float> playerKnockbackSoundVolumeProperty = propertyRegistry.getByName("player_knockback_sound_volume", Float.class);
         EntityPropertyImpl<Float> playerKnockbackSoundPitchProperty = propertyRegistry.getByName("player_knockback_sound_pitch", Float.class);
         double lookDistance;
+        boolean lookReturn;
         boolean permissionRequired;
         boolean playerKnockback;
         String playerKnockbackExemptPermission = null;
@@ -64,6 +66,7 @@ public class NpcProcessorTask extends BukkitRunnable {
             Player closest = null;
             LookType lookType = npc.getProperty(lookProperty);
             lookDistance =  NumberConversions.square(npc.getProperty(lookDistanceProperty));
+            lookReturn = npc.getProperty(lookReturnProperty);
             permissionRequired = npc.getProperty(permissionRequiredProperty);
             playerKnockback = npc.getProperty(playerKnockbackProperty);
             if (playerKnockback) {
@@ -106,9 +109,13 @@ public class NpcProcessorTask extends BukkitRunnable {
                         closestDist = distance;
                         closest = player;
                     }
-                    if (lookType.equals(LookType.PER_PLAYER) && lookDistance >= distance) {
+                    if (lookType.equals(LookType.PER_PLAYER)) {
+                        if (lookDistance >= distance) {
                             NpcLocation expected = npc.getLocation().lookingAt(player.getLocation().add(0, -npc.getType().getHologramOffset(), 0));
-                        if (!expected.equals(npc.getLocation())) npc.setHeadRotation(player, expected.getYaw(), expected.getPitch());
+                            npc.setHeadRotation(player, expected.getYaw(), expected.getPitch());
+                        } else if (lookReturn) {
+                            npc.setHeadRotation(player, npc.getLocation().getYaw(), npc.getLocation().getPitch());
+                        }
                     }
 
                     // player knockback
@@ -132,7 +139,11 @@ public class NpcProcessorTask extends BukkitRunnable {
                 if (closest != null && lookDistance >= closestDist) {
                     NpcLocation expected = npc.getLocation().lookingAt(closest.getLocation().add(0, -npc.getType().getHologramOffset(), 0));
                     if (!expected.equals(npc.getLocation())) npc.setHeadRotation(expected.getYaw(), expected.getPitch());
-                }
+                } else if (lookReturn) {
+                    npc.setHeadRotation(npc.getLocation().getYaw(), npc.getLocation().getPitch());
+                }
+            } else if (lookType.equals(LookType.FIXED)) {
+                npc.setHeadRotation(npc.getLocation().getYaw(), npc.getLocation().getPitch());
             }
         }
     }

plugin/src/main/java/lol/pyr/znpcsplus/util/FutureUtil.java

@@ -0,0 +1,34 @@
+package lol.pyr.znpcsplus.util;
+
+import java.util.Collection;
+import java.util.concurrent.CompletableFuture;
+import java.util.function.Supplier;
+
+public class FutureUtil {
+    public static CompletableFuture<Void> allOf(Collection<CompletableFuture<?>> futures) {
+        return exceptionPrintingRunAsync(() -> {
+            for (CompletableFuture<?> future : futures) future.join();
+        });
+    }
+
+    public static <T> CompletableFuture<T> newExceptionPrintingFuture() {
+        return new CompletableFuture<T>().exceptionally(throwable -> {
+            throwable.printStackTrace();
+            return null;
+        });
+    }
+
+    public static CompletableFuture<Void> exceptionPrintingRunAsync(Runnable runnable) {
+        return CompletableFuture.runAsync(runnable).exceptionally(throwable -> {
+            throwable.printStackTrace();
+            return null;
+        });
+    }
+
+    public static <T> CompletableFuture<T> exceptionPrintingSupplyAsync(Supplier<T> supplier) {
+        return CompletableFuture.supplyAsync(supplier).exceptionally(throwable -> {
+            throwable.printStackTrace();
+            return null;
+        });
+    }
+}

plugin/src/main/java/lol/pyr/znpcsplus/util/Viewable.java

@@ -4,11 +4,10 @@ import org.bukkit.entity.Player;
 
 import java.lang.ref.Reference;
 import java.lang.ref.WeakReference;
-import java.util.ArrayList;
+import java.util.*;
-import java.util.Collections;
+import java.util.concurrent.CompletableFuture;
-import java.util.List;
-import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.stream.Collectors;
 
 public abstract class Viewable {
@@ -21,38 +20,74 @@ public abstract class Viewable {
                 .collect(Collectors.toList());
     }
 
+    private boolean queueRunning = false;
+    private final Queue<Runnable> visibilityTaskQueue = new ConcurrentLinkedQueue<>();
     private final Set<Player> viewers = ConcurrentHashMap.newKeySet();
 
     public Viewable() {
         all.add(new WeakReference<>(this));
     }
 
+    private void tryRunQueue() {
+        if (visibilityTaskQueue.isEmpty() || queueRunning) return;
+        queueRunning = true;
+        FutureUtil.exceptionPrintingRunAsync(() -> {
+            while (!visibilityTaskQueue.isEmpty()) try {
+                visibilityTaskQueue.remove().run();
+            } catch (Exception e) {
+                e.printStackTrace();
+            }
+            queueRunning = false;
+        });
+    }
+
+    private void queueVisibilityTask(Runnable runnable) {
+        visibilityTaskQueue.add(runnable);
+        tryRunQueue();
+    }
+
     public void delete() {
+        queueVisibilityTask(() -> {
             UNSAFE_hideAll();
             viewers.clear();
+        });
     }
 
-    public void respawn() {
+    public CompletableFuture<Void> respawn() {
+        CompletableFuture<Void> future = new CompletableFuture<>();
+        queueVisibilityTask(() -> {
             UNSAFE_hideAll();
-        UNSAFE_showAll();
+            UNSAFE_showAll().join();
+            future.complete(null);
+        });
+        return future;
     }
 
-    public void respawn(Player player) {
+    public CompletableFuture<Void> respawn(Player player) {
-        if (!viewers.contains(player)) return;
+        hide(player);
-        UNSAFE_hide(player);
+        return show(player);
-        UNSAFE_show(player);
     }
 
-    public void show(Player player) {
+    public CompletableFuture<Void> show(Player player) {
-        if (viewers.contains(player)) return;
+        CompletableFuture<Void> future = new CompletableFuture<>();
+        queueVisibilityTask(() -> {
+            if (viewers.contains(player)) {
+                future.complete(null);
+                return;
+            }
             viewers.add(player);
-        UNSAFE_show(player);
+            UNSAFE_show(player).join();
+            future.complete(null);
+        });
+        return future;
     }
 
     public void hide(Player player) {
+        queueVisibilityTask(() -> {
             if (!viewers.contains(player)) return;
             viewers.remove(player);
             UNSAFE_hide(player);
+        });
     }
 
     public void UNSAFE_removeViewer(Player player) {
@@ -63,8 +98,10 @@ public abstract class Viewable {
         for (Player viewer : viewers) UNSAFE_hide(viewer);
     }
 
-    protected void UNSAFE_showAll() {
+    protected CompletableFuture<Void> UNSAFE_showAll() {
-        for (Player viewer : viewers) UNSAFE_show(viewer);
+        return FutureUtil.allOf(viewers.stream()
+                .map(this::UNSAFE_show)
+                .collect(Collectors.toList()));
     }
 
     public Set<Player> getViewers() {
@@ -75,7 +112,7 @@ public abstract class Viewable {
         return viewers.contains(player);
     }
 
-    protected abstract void UNSAFE_show(Player player);
+    protected abstract CompletableFuture<Void> UNSAFE_show(Player player);
 
     protected abstract void UNSAFE_hide(Player player);
 }

plugin/src/main/resources/plugin.yml

@@ -11,6 +11,9 @@ api-version: 1.13
 
 folia-supported: true
 
+depend:
+  - packetevents
+
 softdepend:
   - PlaceholderAPI
   - ServersNPC