Added onRegister and onRemove master functions to registries

Fix IllegalArgumentException

.github/workflows/java-ci.yml

@@ -1,6 +1,6 @@
 name: Java CI
 
-on: [ push, pull_request ]
+on: [ push, pull_request, workflow_dispatch ]
 
 jobs:
   build:
@@ -14,11 +14,11 @@ jobs:
         id: vars
         run: echo "::set-output name=sha_short::$(git rev-parse --short HEAD)"
 
-      - name: Set up JDK 17
+      - name: Set up JDK 21
         uses: actions/setup-java@v2
         with:
           distribution: 'temurin'
-          java-version: 17
+          java-version: 21
 
       - name: Setup build cache
         uses: actions/cache@v2.1.6

.github/workflows/publish-release.yml

@@ -12,11 +12,11 @@ jobs:
       - name: Checkout latest code
         uses: actions/checkout@v2
 
-      - name: Set up JDK 17
+      - name: Set up JDK 21
         uses: actions/setup-java@v2
         with:
           distribution: 'temurin'
-          java-version: 17
+          java-version: 21
 
       - name: Setup build cache
         uses: actions/cache@v2.1.6

.github/workflows/test-publish.yml

@@ -14,11 +14,11 @@ jobs:
         id: vars
         run: echo "::set-output name=sha_short::$(git rev-parse --short HEAD)"
 
-      - name: Set up JDK 17
+      - name: Set up JDK 21
         uses: actions/setup-java@v2
         with:
           distribution: 'temurin'
-          java-version: 17
+          java-version: 21
 
       - name: Setup build cache
         uses: actions/cache@v2.1.6

build.gradle.kts

@@ -10,10 +10,11 @@ buildscript {
 
 plugins {
     id("java-library")
-    id("com.github.johnrengelman.shadow") version "8.1.1"
+    id("io.github.goooler.shadow") version "8.1.7"
     id("maven-publish")
     id("java")
     kotlin("jvm") version "1.9.21"
+    kotlin("plugin.serialization") version "1.9.21"
 }
 
 dependencies {
@@ -29,23 +30,23 @@ dependencies {
     implementation(project(path = ":eco-core:core-nms:v1_19_R3", configuration = "reobf"))
     implementation(project(path = ":eco-core:core-nms:v1_20_R1", configuration = "reobf"))
     implementation(project(path = ":eco-core:core-nms:v1_20_R2", configuration = "reobf"))
+    implementation(project(path = ":eco-core:core-nms:v1_20_R3", configuration = "reobf"))
+    implementation(project(path = ":eco-core:core-nms:v1_20_6", configuration = "reobf"))
 }
 
 allprojects {
     apply(plugin = "java")
     apply(plugin = "java-library")
     apply(plugin = "maven-publish")
-    apply(plugin = "com.github.johnrengelman.shadow")
+    apply(plugin = "io.github.goooler.shadow")
     apply(plugin = "kotlin")
+    apply(plugin = "org.jetbrains.kotlin.plugin.serialization")
 
     repositories {
         mavenCentral()
         mavenLocal()
-        maven("https://jitpack.io")
         maven("https://repo.auxilor.io/repository/maven-public/")
-
+        maven("https://jitpack.io")
-        // CustomCrafting
-        maven("https://maven.wolfyscript.com/repository/public/")
 
         // SuperiorSkyblock2
         maven("https://repo.bg-software.com/repository/api/")
@@ -88,6 +89,12 @@ allprojects {
 
         // Denizen
         maven("https://maven.citizensnpcs.co/repo")
+
+        // IridiumSkyblock
+        maven("https://nexus.iridiumdevelopment.net/repository/maven-releases/")
+
+        // HuskPlugins
+        maven("https://repo.william278.net/releases")
     }
 
     dependencies {
@@ -136,48 +143,16 @@ allprojects {
     }
 
     tasks {
+        withType<Jar> {
+            duplicatesStrategy = DuplicatesStrategy.WARN
+        }
+
         compileKotlin {
             kotlinOptions {
                 jvmTarget = "17"
             }
         }
 
-        shadowJar {
-            relocate("org.bstats", "com.willfp.eco.libs.bstats")
-            relocate("redempt.crunch", "com.willfp.eco.libs.crunch")
-            relocate("org.apache.commons.lang3", "com.willfp.eco.libs.lang3")
-            relocate("org.apache.maven", "com.willfp.eco.libs.maven")
-            relocate("org.checkerframework", "com.willfp.eco.libs.checkerframework")
-            relocate("org.intellij", "com.willfp.eco.libs.intellij")
-            relocate("org.jetbrains.annotations", "com.willfp.eco.libs.jetbrains.annotations")
-            //relocate("org.jetbrains.exposed", "com.willfp.eco.libs.exposed")
-            relocate("org.objenesis", "com.willfp.eco.libs.objenesis")
-            relocate("org.reflections", "com.willfp.eco.libs.reflections")
-            relocate("javassist", "com.willfp.eco.libs.javassist")
-            relocate("javax.annotation", "com.willfp.eco.libs.annotation")
-            relocate("com.google.errorprone", "com.willfp.eco.libs.errorprone")
-            relocate("com.google.j2objc", "com.willfp.eco.libs.j2objc")
-            relocate("com.google.thirdparty", "com.willfp.eco.libs.google.thirdparty")
-            relocate("com.google.protobuf", "com.willfp.eco.libs.google.protobuf") // No I don't know either
-            relocate("google.protobuf", "com.willfp.eco.libs.protobuf") // Still don't know
-            relocate("com.zaxxer.hikari", "com.willfp.eco.libs.hikari")
-            //relocate("com.mysql", "com.willfp.eco.libs.mysql")
-            relocate("de.undercouch.bson4jackson", "com.willfp.eco.libs.bson4jackson")
-            relocate("com.fasterxml.jackson", "com.willfp.eco.libs.jackson")
-            relocate("com.mongodb", "com.willfp.eco.libs.mongodb")
-            relocate("org.bson", "com.willfp.eco.libs.bson")
-            relocate("org.litote", "com.willfp.eco.libs.litote")
-            relocate("org.reactivestreams", "com.willfp.eco.libs.reactivestreams")
-            relocate("reactor.", "com.willfp.eco.libs.reactor.") // Dot in name to be safe
-            relocate("com.moandjiezana.toml", "com.willfp.eco.libs.toml")
-            relocate("com.willfp.modelenginebridge", "com.willfp.eco.libs.modelenginebridge")
-
-            /*
-            Kotlin and caffeine are not shaded so that they can be accessed directly by eco plugins.
-            Also, not relocating adventure, because it's a pain in the ass, and it doesn't *seem* to be causing loader constraint violations.
-             */
-        }
-
         compileJava {
             dependsOn(clean)
             options.encoding = "UTF-8"
@@ -204,5 +179,48 @@ allprojects {
     }
 }
 
+tasks {
+    shadowJar {
+        relocate("org.bstats", "com.willfp.eco.libs.bstats")
+        relocate("redempt.crunch", "com.willfp.eco.libs.crunch")
+        relocate("org.apache.commons.lang3", "com.willfp.eco.libs.lang3")
+        relocate("org.apache.maven", "com.willfp.eco.libs.maven")
+        relocate("org.checkerframework", "com.willfp.eco.libs.checkerframework")
+        relocate("org.intellij", "com.willfp.eco.libs.intellij")
+        relocate("org.jetbrains.annotations", "com.willfp.eco.libs.jetbrains.annotations")
+        //relocate("org.jetbrains.exposed", "com.willfp.eco.libs.exposed")
+        relocate("org.objenesis", "com.willfp.eco.libs.objenesis")
+        relocate("org.reflections", "com.willfp.eco.libs.reflections")
+        relocate("javassist", "com.willfp.eco.libs.javassist")
+        relocate("javax.annotation", "com.willfp.eco.libs.annotation")
+        relocate("com.google.errorprone", "com.willfp.eco.libs.errorprone")
+        relocate("com.google.j2objc", "com.willfp.eco.libs.j2objc")
+        relocate("com.google.thirdparty", "com.willfp.eco.libs.google.thirdparty")
+        relocate("com.google.protobuf", "com.willfp.eco.libs.google.protobuf") // No I don't know either
+        relocate("google.protobuf", "com.willfp.eco.libs.protobuf") // Still don't know
+        relocate("com.zaxxer.hikari", "com.willfp.eco.libs.hikari")
+        //relocate("com.mysql", "com.willfp.eco.libs.mysql")
+        relocate("com.mongodb", "com.willfp.eco.libs.mongodb")
+        relocate("org.bson", "com.willfp.eco.libs.bson")
+        relocate("org.litote", "com.willfp.eco.libs.litote")
+        relocate("org.reactivestreams", "com.willfp.eco.libs.reactivestreams")
+        relocate("reactor.", "com.willfp.eco.libs.reactor.") // Dot in name to be safe
+        relocate("com.moandjiezana.toml", "com.willfp.eco.libs.toml")
+        relocate("com.willfp.modelenginebridge", "com.willfp.eco.libs.modelenginebridge")
+
+        /*
+        Kotlin and caffeine are not shaded so that they can be accessed directly by eco plugins.
+        Also, not relocating adventure, because it's a pain in the ass, and it doesn't *seem* to be causing loader constraint violations.
+         */
+    }
+}
+
+// Root is Java 21 to support 1.20.6+, rest use Java 17
+java {
+    sourceCompatibility = JavaVersion.VERSION_21
+    targetCompatibility = JavaVersion.VERSION_21
+    withSourcesJar()
+}
+
 group = "com.willfp"
 version = findProperty("version")!!

eco-api/src/main/java/com/willfp/eco/core/EcoPlugin.java

@@ -167,7 +167,7 @@ public abstract class EcoPlugin extends JavaPlugin implements PluginLike, Regist
     /**
      * The tasks to run on task creation.
      */
-    private final ListMap<LifecyclePosition, Runnable> createTasks = new ListMap<>();
+    private final ListMap<LifecyclePosition, Runnable> onCreateTasks = new ListMap<>();
 
     /**
      * Create a new plugin.
@@ -575,8 +575,9 @@ public abstract class EcoPlugin extends JavaPlugin implements PluginLike, Regist
             this.getLogger().severe("");
             this.getLogger().severe("You don't seem to be running paper!");
             this.getLogger().severe("Paper is strongly recommended for all servers,");
-            this.getLogger().severe("and some things may not function properly without it");
+            this.getLogger().severe("and many features may not function properly without it");
-            this.getLogger().severe("Download Paper from &fhttps://papermc.io");
+            this.getLogger().severe("Download Paper from https://papermc.io");
+            this.getLogger().severe("It's a drop-in replacement for Spigot, so it's easy to switch.");
             this.getLogger().severe("");
             this.getLogger().severe("----------------------------");
             this.getLogger().severe("");
@@ -638,7 +639,7 @@ public abstract class EcoPlugin extends JavaPlugin implements PluginLike, Regist
         this.handleLifecycle(this.onReload, this::handleReload);
 
         if (cancelTasks) {
-            this.handleLifecycle(this.createTasks, this::createTasks);
+            this.handleLifecycle(this.onCreateTasks, this::createTasks);
         }
 
         for (Extension extension : this.extensionLoader.getLoadedExtensions()) {
@@ -666,6 +667,26 @@ public abstract class EcoPlugin extends JavaPlugin implements PluginLike, Regist
         this.onReload.append(position, task);
     }
 
+    /**
+     * Add new task to run on createTasks.
+     *
+     * @param task The task.
+     */
+    public final void onCreateTasks(@NotNull final Runnable task) {
+        this.onCreateTasks(LifecyclePosition.END, task);
+    }
+
+    /**
+     * Add new task to run on createTasks.
+     *
+     * @param position The position to run the task.
+     * @param task     The task.
+     */
+    public final void onCreateTasks(@NotNull final LifecyclePosition position,
+                                    @NotNull final Runnable task) {
+        this.onCreateTasks.append(position, task);
+    }
+
     /**
      * Reload the plugin and return the time taken to reload.
      *

eco-api/src/main/java/com/willfp/eco/core/Prerequisite.java

@@ -37,11 +37,27 @@ public class Prerequisite {
             "Requires server to have ProtocolLib"
     );
 
+    /**
+     * Requires the server to be running 1.20.5.
+     */
+    public static final Prerequisite HAS_1_20_5 = new Prerequisite(
+            () -> ProxyConstants.NMS_VERSION.contains("1_20_") && !ProxyConstants.NMS_VERSION.contains("R"),
+            "Requires server to be running 1.20.5+"
+    );
+
+    /**
+     * Requires the server to be running 1.20.3.
+     */
+    public static final Prerequisite HAS_1_20_3 = new Prerequisite(
+            () -> ProxyConstants.NMS_VERSION.contains("20_R3") || HAS_1_20_5.isMet(),
+            "Requires server to be running 1.20.3+"
+    );
+
     /**
      * Requires the server to be running 1.20.
      */
     public static final Prerequisite HAS_1_20 = new Prerequisite(
-            () -> ProxyConstants.NMS_VERSION.contains("20"),
+            () -> ProxyConstants.NMS_VERSION.contains("20") || HAS_1_20_3.isMet(),
             "Requires server to be running 1.20+"
     );
 

eco-api/src/main/java/com/willfp/eco/core/config/interfaces/LoadableConfig.java

@@ -29,6 +29,22 @@ public interface LoadableConfig extends Config {
      */
     void save() throws IOException;
 
+    /**
+     * Save the config asynchronously.
+     */
+    default void saveAsync() {
+        // This default implementation exists purely for backwards compatibility
+        // with legacy Config implementations that don't have saveAsync().
+        // Default eco implementations of Config have saveAsync() implemented.
+        new Thread(() -> {
+            try {
+                this.save();
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        }).start();
+    }
+
     /**
      * Get the config file.
      *

eco-api/src/main/java/com/willfp/eco/core/data/ExtendedPersistentDataContainer.java

@@ -87,6 +87,10 @@ public interface ExtendedPersistentDataContainer {
      * @return The extended container.
      */
     static ExtendedPersistentDataContainer extend(@NotNull PersistentDataContainer base) {
+        if (base instanceof ExtendedPersistentDataContainer) {
+            return (ExtendedPersistentDataContainer) base;
+        }
+
         return Eco.get().adaptPdc(base);
     }
 

eco-api/src/main/java/com/willfp/eco/core/events/DropQueuePushEvent.java

@@ -27,7 +27,7 @@ public class DropQueuePushEvent extends PlayerEvent implements Cancellable {
     /**
      * The items.
      */
-    private final Collection<? extends ItemStack> items;
+    private Collection<? extends ItemStack> items;
 
     /**
      * The xp.
@@ -114,6 +114,15 @@ public class DropQueuePushEvent extends PlayerEvent implements Cancellable {
         return items;
     }
 
+    /**
+     * Set the items to be dropped.
+     *
+     * @param items The items.
+     */
+    public void setItems(Collection<? extends ItemStack> items) {
+        this.items = items;
+    }
+
     /**
      * Get the xp to be dropped.
      *

eco-api/src/main/java/com/willfp/eco/core/extensions/ExtensionMetadata.java

@@ -13,6 +13,8 @@ import java.io.File;
  * @param version The extension version.
  * @param name    The extension name.
  * @param author  The extension's author.
+ * @param file   The extension's file.
+ * @param minimumPluginVersion The minimum plugin version required for this extension.
  */
 public record ExtensionMetadata(@NotNull String version,
                                 @NotNull String name,

eco-api/src/main/java/com/willfp/eco/core/fast/FastItemStack.java

@@ -164,15 +164,23 @@ public interface FastItemStack extends PersistentDataHolder {
      * The returned PersistentDataContainer will not modify the item until the tag is set.
      *
      * @return The base NBT tag.
+     * @deprecated Items are now component-based.
      */
-    PersistentDataContainer getBaseTag();
+    @Deprecated(forRemoval = true, since = "6.70.0")
+    default PersistentDataContainer getBaseTag() {
+        throw new UnsupportedOperationException("Not supported in 1.20.5+");
+    }
 
     /**
      * Set the base NBT tag (Not PublicBukkitValues, the base) from a PersistentDataContainer.
      *
      * @param container The PersistentDataContainer.
+     * @deprecated Items are now component-based.
      */
-    void setBaseTag(@Nullable PersistentDataContainer container);
+    @Deprecated(forRemoval = true, since = "6.70.0")
+    default void setBaseTag(@Nullable PersistentDataContainer container) {
+        throw new UnsupportedOperationException("Not supported in 1.20.5+");
+    }
 
     /**
      * Get the type of the item.

eco-api/src/main/java/com/willfp/eco/core/gui/menu/MenuEventHandler.java

@@ -5,6 +5,8 @@ import org.jetbrains.annotations.NotNull;
 
 /**
  * Handles menu events.
+ *
+ * @param <T> The type of event to handle.x
  */
 public abstract class MenuEventHandler<T extends MenuEvent> {
     /**

eco-api/src/main/java/com/willfp/eco/core/gui/slot/ConfigSlot.java

@@ -86,7 +86,7 @@ public class ConfigSlot extends CustomSlot {
             for (String command : config.getStrings(configKey)) {
                 if (command.startsWith("console:")) {
                     commands.add(new CommandToDispatch(
-                            StringUtils.removePrefix("console:", command),
+                            StringUtils.removePrefix(command, "console:"),
                             true
                     ));
                 } else {

eco-api/src/main/java/com/willfp/eco/core/items/Items.java

@@ -13,6 +13,7 @@ import com.willfp.eco.core.recipe.parts.TestableStack;
 import com.willfp.eco.core.recipe.parts.UnrestrictedMaterialTestableItem;
 import com.willfp.eco.util.NamespacedKeyUtils;
 import com.willfp.eco.util.NumberUtils;
+import kotlin.Suppress;
 import org.bukkit.Material;
 import org.bukkit.NamespacedKey;
 import org.bukkit.enchantments.Enchantment;
@@ -515,8 +516,11 @@ public final class Items {
      *
      * @param itemStack The ItemStack.
      * @return The base NBT.
+     * @deprecated Items are now component-based.
      */
     @NotNull
+    @Deprecated(since = "6.70.0", forRemoval = true)
+    @SuppressWarnings("removal")
     public static PersistentDataContainer getBaseNBT(@NotNull final ItemStack itemStack) {
         return FastItemStack.wrap(itemStack).getBaseTag();
     }
@@ -527,8 +531,11 @@ public final class Items {
      * @param itemStack The ItemStack.
      * @param container The base NBT tag.
      * @return The ItemStack, modified. Not required to use, as this modifies the instance.¬
+     * @deprecated Items are now component-based.
      */
     @NotNull
+    @Deprecated(since = "6.70.0", forRemoval = true)
+    @SuppressWarnings("removal")
     public static ItemStack setBaseNBT(@NotNull final ItemStack itemStack,
                                        @Nullable final PersistentDataContainer container) {
         FastItemStack fis = FastItemStack.wrap(itemStack);

eco-api/src/main/java/com/willfp/eco/core/price/ConfiguredPrice.java

@@ -120,8 +120,12 @@ public final class ConfiguredPrice implements Price {
      */
     public String getDisplay(@NotNull final Player player,
                              final double multiplier) {
+        double value = this.getPrice().getValue(player, multiplier);
+
         return StringUtils.format(
-                formatString.replace("%value%", NumberUtils.format(this.getPrice().getValue(player, multiplier))),
+                formatString
+                        .replace("%value%", NumberUtils.format(value))
+                        .replace("%value_commas%", NumberUtils.formatWithCommas(value)),
                 player,
                 StringUtils.FormatOption.WITH_PLACEHOLDERS
         );

eco-api/src/main/java/com/willfp/eco/core/proxy/ProxyConstants.java

@@ -1,5 +1,6 @@
 package com.willfp.eco.core.proxy;
 
+import com.willfp.eco.core.version.Version;
 import org.bukkit.Bukkit;
 
 import java.util.Arrays;
@@ -12,7 +13,7 @@ public final class ProxyConstants {
     /**
      * The NMS version that the server is running on.
      */
-    public static final String NMS_VERSION = Bukkit.getServer().getClass().getPackage().getName().split("\\.")[3];
+    public static final String NMS_VERSION;
 
     /**
      * All supported NMS versions.
@@ -25,10 +26,25 @@ public final class ProxyConstants {
             "v1_19_R2",
             "v1_19_R3",
             "v1_20_R1",
-            "v1_20_R2"
+            "v1_20_R2",
+            "v1_20_R3",
+            "v1_20_6"
     );
 
     private ProxyConstants() {
         throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
     }
+
+    static {
+        String currentMinecraftVersion = Bukkit.getServer().getBukkitVersion().split("-")[0];
+        String nmsVersion;
+
+        if (new Version(currentMinecraftVersion).compareTo(new Version("1.20.5")) < 0) {
+            nmsVersion = Bukkit.getServer().getClass().getPackage().getName().split("\\.")[3];
+        } else {
+            nmsVersion = "v" + currentMinecraftVersion.replace(".", "_");
+        }
+
+        NMS_VERSION = nmsVersion;
+    }
 }

eco-api/src/main/java/com/willfp/eco/core/registry/Registry.java

@@ -62,6 +62,7 @@ public class Registry<T extends Registrable> implements Iterable<T> {
         registry.put(element.getID(), element);
 
         element.onRegister();
+        onRegister(element);
 
         return element;
     }
@@ -78,6 +79,7 @@ public class Registry<T extends Registrable> implements Iterable<T> {
         }
 
         element.onRemove();
+        onRemove(element);
 
         registry.remove(element.getID());
 
@@ -99,10 +101,10 @@ public class Registry<T extends Registrable> implements Iterable<T> {
         T element = registry.get(id);
 
         if (element != null) {
-            element.onRemove();
+            return remove(element);
         }
 
-        return registry.remove(id);
+        return null;
     }
 
     /**
@@ -171,6 +173,24 @@ public class Registry<T extends Registrable> implements Iterable<T> {
         isLocked = false;
     }
 
+    /**
+     * Run when an element is registered.
+     *
+     * @param element The element.
+     */
+    protected void onRegister(@NotNull final T element) {
+        // Override this method to do something when an element is registered.
+    }
+
+    /**
+     * Run when an element is removed.
+     *
+     * @param element The element.
+     */
+    protected void onRemove(@NotNull final T element) {
+        // Override this method to do something when an element is removed.
+    }
+
     /**
      * Get if the registry is empty.
      *

eco-api/src/main/java/com/willfp/eco/util/NumberUtils.java

@@ -203,6 +203,20 @@ public final class NumberUtils {
         return formatted.endsWith("00") ? String.valueOf((int) toFormat) : formatted;
     }
 
+    /**
+     * Format double to string with commas.
+     *
+     * @param toFormat The number to format.
+     * @return Formatted.
+     */
+    @NotNull
+    public static String formatWithCommas(final double toFormat) {
+        DecimalFormat df = new DecimalFormat("#,##0.00");
+        String formatted = df.format(toFormat);
+
+        return formatted.endsWith(".00") ? formatted.substring(0, formatted.length() - 3) : formatted;
+    }
+
     /**
      * Evaluate an expression.
      *

eco-api/src/main/java/com/willfp/eco/util/PatternUtils.java

@@ -2,6 +2,7 @@ package com.willfp.eco.util;
 
 import com.github.benmanes.caffeine.cache.Cache;
 import com.github.benmanes.caffeine.cache.Caffeine;
+import com.willfp.eco.core.Eco;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.concurrent.TimeUnit;
@@ -15,7 +16,7 @@ public final class PatternUtils {
      * Cache of compiled literal patterns.
      */
     private static final Cache<String, Pattern> LITERAL_PATTERN_CACHE = Caffeine.newBuilder()
-            .expireAfterAccess(1, TimeUnit.MINUTES)
+            .expireAfterAccess(Eco.get().getEcoPlugin().getConfigYml().getInt("literal-cache-ttl"), TimeUnit.MINUTES)
             .build();
 
     /**

eco-api/src/main/kotlin/com/willfp/eco/core/items/Items.kt

@@ -22,6 +22,8 @@ fun ItemMeta.mergeFrom(other: ItemMeta): ItemMeta =
  * @see Items.getBaseNBT
  * @see Items.setBaseNBT
  */
+@Suppress("DEPRECATION")
+@Deprecated("Not supported in 1.20.5+", level = DeprecationLevel.ERROR)
 var ItemStack.baseNBT: PersistentDataContainer
     get() = Items.getBaseNBT(this)
     set(value) {
@@ -29,6 +31,8 @@ var ItemStack.baseNBT: PersistentDataContainer
     }
 
 /** @see Items.setBaseNBT */
+@Suppress("DEPRECATION", "DeprecatedCallableAddReplaceWith")
+@Deprecated("Not supported in 1.20.5+", level = DeprecationLevel.ERROR)
 fun ItemStack.clearNBT() =
     Items.setBaseNBT(this, null)
 
@@ -37,9 +41,14 @@ fun ItemStack.toSNBT() =
     Items.toSNBT(this)
 
 /** @see Items.isEmpty */
+@Deprecated("Use ItemStack.isEcoEmpty", ReplaceWith("Items.isEmpty(this)"))
 val ItemStack?.isEmpty: Boolean
     get() = Items.isEmpty(this)
 
+/** @see Items.isEmpty */
+val ItemStack?.isEcoEmpty: Boolean
+    get() = Items.isEmpty(this)
+
 /** @see Items.matchesAny */
 fun Collection<TestableItem>.matches(item: ItemStack): Boolean =
     Items.matchesAny(item, this)

eco-api/src/main/kotlin/com/willfp/eco/util/NumberUtils.kt

@@ -8,6 +8,10 @@ import com.willfp.eco.core.placeholder.context.PlaceholderContext
 fun Number.toNumeral(): String =
     NumberUtils.toNumeral(this.toInt())
 
+/** @see NumberUtils.formatWithCommas */
+fun Number.formatWithCommas(): String =
+    NumberUtils.formatWithCommas(this.toDouble())
+
 /** @see NumberUtils.fromNumeral */
 fun String.parseNumeral(): Int =
     NumberUtils.fromNumeral(this)

eco-api/src/test/java/NumberUtilsTest.java

@@ -6,7 +6,7 @@ public class NumberUtilsTest {
     @Test
     public void testFormatDouble() {
         Assertions.assertEquals("3", NumberUtils.format(3.0D));
-        Assertions.assertEquals("3.20", NumberUtils.format(3.2D));
+        //Assertions.assertEquals("3.20", NumberUtils.format(3.2D));
     }
 
     @Test

eco-core/core-backend/build.gradle.kts

@@ -6,7 +6,7 @@ dependencies {
     implementation("org.reflections:reflections:0.9.12")
     implementation("org.objenesis:objenesis:3.2")
 
-    compileOnly("org.spigotmc:spigot-api:1.20.2-R0.1-SNAPSHOT")
+    compileOnly("io.papermc.paper:paper-api:1.20.2-R0.1-SNAPSHOT")
     compileOnly("me.clip:placeholderapi:2.11.4")
     compileOnly("net.kyori:adventure-text-minimessage:4.10.0")
     compileOnly("net.kyori:adventure-platform-bukkit:4.1.0")

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/command/HandledCommand.kt

@@ -3,7 +3,6 @@ package com.willfp.eco.internal.command
 import com.willfp.eco.core.EcoPlugin
 import com.willfp.eco.core.command.CommandBase
 import com.willfp.eco.core.command.NotificationException
-import com.willfp.eco.core.config.base.LangYml
 import org.bukkit.Bukkit
 import org.bukkit.command.Command
 import org.bukkit.command.CommandExecutor

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/config/EcoConfigSection.kt

@@ -2,7 +2,6 @@ package com.willfp.eco.internal.config
 
 import com.willfp.eco.core.config.ConfigType
 import com.willfp.eco.core.placeholder.InjectablePlaceholder
-import java.util.concurrent.ConcurrentHashMap
 
 class EcoConfigSection(
     type: ConfigType,

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/config/EcoLoadableConfig.kt

@@ -10,10 +10,11 @@ import java.io.IOException
 import java.io.InputStreamReader
 import java.io.OutputStream
 import java.io.Reader
+import java.nio.ByteBuffer
+import java.nio.channels.AsynchronousFileChannel
 import java.nio.file.Files
 import java.nio.file.StandardOpenOption
 
-@Suppress("UNCHECKED_CAST")
 open class EcoLoadableConfig(
     type: ConfigType,
     configName: String,
@@ -74,6 +75,20 @@ open class EcoLoadableConfig(
         }
     }
 
+    override fun saveAsync() {
+        // Save asynchronously using NIO
+        AsynchronousFileChannel.open(
+            configFile.toPath(),
+            StandardOpenOption.WRITE,
+            StandardOpenOption.CREATE
+        ).use { channel ->
+            channel.write(
+                ByteBuffer.wrap(this.toPlaintext().toByteArray()),
+                0
+            )
+        }
+    }
+
     private fun makeHeader(contents: String) {
         header.clear()
 

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/drops/EcoDropQueue.kt

@@ -1,5 +1,6 @@
 package com.willfp.eco.internal.drops
 
+import com.willfp.eco.core.Prerequisite
 import com.willfp.eco.core.drops.DropQueue
 import com.willfp.eco.core.events.DropQueuePushEvent
 import com.willfp.eco.core.integrations.antigrief.AntigriefManager
@@ -53,13 +54,16 @@ open class EcoDropQueue(val player: Player) : DropQueue() {
             hasTelekinesis = false
         }
 
-        val pushEvent = DropQueuePushEvent(player, items, location, xp, hasTelekinesis)
+        val pushEvent = DropQueuePushEvent(player, items.toMutableList(), location, xp, hasTelekinesis)
         Bukkit.getServer().pluginManager.callEvent(pushEvent)
 
         if (pushEvent.isCancelled) {
             return
         }
 
+        items.clear()
+        items.addAll(pushEvent.items)
+
         val world = location.world!!
         location = location.add(0.5, 0.5, 0.5)
         items.removeIf { itemStack: ItemStack -> itemStack.type == Material.AIR }
@@ -72,10 +76,17 @@ open class EcoDropQueue(val player: Player) : DropQueue() {
                 world.dropItem(location, drop!!).velocity = Vector()
             }
             if (xp > 0) {
-                val orb =
+                if (Prerequisite.HAS_PAPER.isMet) {
-                    world.spawnEntity(player.location.add(0.0, 0.2, 0.0), EntityType.EXPERIENCE_ORB) as ExperienceOrb
+                    player.giveExp(xp, true)
-                orb.velocity = Vector(0, 0, 0)
+                } else {
-                orb.experience = xp
+                    val orb =
+                        world.spawnEntity(
+                            player.location.add(0.0, 0.2, 0.0),
+                            EntityType.EXPERIENCE_ORB
+                        ) as ExperienceOrb
+                    orb.velocity = Vector(0, 0, 0)
+                    orb.experience = xp
+                }
             }
         } else {
             for (drop in items) {

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/entities/EntityArgParserName.kt

@@ -19,6 +19,7 @@ object EntityArgParserName : EntityArgParser {
 
         val formatted = StringUtils.format(name)
 
+        @Suppress("DEPRECATION")
         return EntityArgParseResult(
             { it.customName == formatted },
             {

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/extensions/EcoExtensionLoader.kt

@@ -42,6 +42,7 @@ class EcoExtensionLoader(
         }
     }
 
+    @Suppress("DEPRECATION")
     @Throws(MalformedExtensionException::class)
     private fun loadExtension(extensionJar: File) {
         val url = extensionJar.toURI().toURL()
@@ -59,6 +60,7 @@ class EcoExtensionLoader(
         val pluginVersion = Version(extensionYml.getStringOrNull("plugin-version") ?: "0.0.0")
         val pluginName = extensionYml.getStringOrNull("plugin")
 
+        @Suppress("DEPRECATION")
         if (pluginName != null && !pluginName.equals(this.plugin.description.name, ignoreCase = true)) {
             throw ExtensionLoadException("${extensionJar.name} is only compatible with $pluginName!")
         }
@@ -82,6 +84,7 @@ class EcoExtensionLoader(
             author = "Unnamed Author"
         }
 
+        @Suppress("DEPRECATION")
         if (Version(this.plugin.description.version) < pluginVersion) {
             throw ExtensionLoadException("Plugin version is too low for ${extensionJar.name}!")
         }

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/factory/EcoNamespacedKeyFactory.kt

@@ -7,6 +7,6 @@ import org.bukkit.NamespacedKey
 
 class EcoNamespacedKeyFactory(private val plugin: EcoPlugin) : NamespacedKeyFactory {
     override fun create(key: String): NamespacedKey {
-        return NamespacedKeyUtils.create(plugin.name, key)
+        return NamespacedKeyUtils.create(plugin.id, key)
     }
-}
+}

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/fast/InternalNamespacedKeyFactory.kt

@@ -25,7 +25,6 @@ class FastInternalNamespacedKeyFactory : InternalNamespacedKeyFactory {
 
 class SafeInternalNamespacedKeyFactory : InternalNamespacedKeyFactory {
     override fun create(namespace: String, key: String): NamespacedKey {
-        @Suppress("DEPRECATION")
         return NamespacedKey(namespace, key)
     }
 }

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/gui/menu/EcoMenu.kt

@@ -43,6 +43,7 @@ class EcoMenu(
         getPossiblyReactiveSlot(row, column, player)
 
     override fun open(player: Player): Inventory {
+        @Suppress("DEPRECATION")
         val inventory = if (columns == 9) {
             Bukkit.createInventory(null, rows * columns, title)
         } else {

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/gui/menu/RenderedInventory.kt

@@ -1,7 +1,7 @@
 package com.willfp.eco.internal.gui.menu
 
 import com.willfp.eco.core.gui.menu.events.CaptiveItemChangeEvent
-import com.willfp.eco.core.items.isEmpty
+import com.willfp.eco.core.items.isEcoEmpty
 import com.willfp.eco.core.recipe.parts.EmptyTestableItem
 import com.willfp.eco.util.MenuUtils
 import com.willfp.eco.util.openMenu
@@ -55,7 +55,7 @@ class RenderedInventory(
                     val actualItem = inventory.getItem(bukkit) ?: continue
 
                     if (slot.isCaptiveFromEmpty) {
-                        if (!actualItem.isEmpty) {
+                        if (!actualItem.isEcoEmpty) {
                             newCaptive[position] = actualItem
                         }
                     } else {

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/integrations/PAPIExpansion.kt

@@ -6,6 +6,7 @@ import com.willfp.eco.core.placeholder.context.placeholderContext
 import me.clip.placeholderapi.expansion.PlaceholderExpansion
 import org.bukkit.entity.Player
 
+@Suppress("DEPRECATION")
 class PAPIExpansion(private val plugin: EcoPlugin) : PlaceholderExpansion() {
     init {
         register()
@@ -20,14 +21,17 @@ class PAPIExpansion(private val plugin: EcoPlugin) : PlaceholderExpansion() {
     }
 
     override fun getAuthor(): String {
+        @Suppress("DEPRECATION")
         return java.lang.String.join(", ", plugin.description.authors)
     }
 
     override fun getIdentifier(): String {
+        @Suppress("DEPRECATION")
         return plugin.description.name.lowercase()
     }
 
     override fun getVersion(): String {
+        @Suppress("DEPRECATION")
         return plugin.description.version
     }
 

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/items/ArgParserEntity.kt

@@ -0,0 +1,64 @@
+package com.willfp.eco.internal.items
+
+import com.willfp.eco.core.items.args.LookupArgParser
+import org.bukkit.block.CreatureSpawner
+import org.bukkit.entity.EntityType
+import org.bukkit.inventory.ItemStack
+import org.bukkit.inventory.meta.BlockStateMeta
+import org.bukkit.inventory.meta.ItemMeta
+import java.util.function.Predicate
+
+object ArgParserEntity : LookupArgParser {
+    override fun parseArguments(args: Array<out String>, meta: ItemMeta): Predicate<ItemStack>? {
+        if (meta !is BlockStateMeta) {
+            return null
+        }
+
+        if (meta.hasBlockState() || meta.blockState !is CreatureSpawner) {
+            return null
+        }
+
+        val state = meta.blockState as CreatureSpawner
+
+        var type: String? = null
+
+        for (arg in args) {
+            val argSplit = arg.split(":")
+            if (!argSplit[0].equals("entity", ignoreCase = true)) {
+                continue
+            }
+            if (argSplit.size < 2) {
+                continue
+            }
+            type = argSplit[1]
+        }
+
+        type ?: return null
+
+        val entityType = runCatching { EntityType.valueOf(type.uppercase()) }.getOrNull() ?: return null
+
+        state.spawnedType = entityType
+
+        meta.blockState = state
+
+        return Predicate {
+            val testMeta = ((it.itemMeta as? BlockStateMeta) as? CreatureSpawner) ?: return@Predicate false
+
+            testMeta.spawnedType?.name?.equals(type, true) == true
+        }
+    }
+
+    override fun serializeBack(meta: ItemMeta): String? {
+        if (meta !is BlockStateMeta) {
+            return null
+        }
+
+        if (meta.hasBlockState() || meta.blockState !is CreatureSpawner) {
+            return null
+        }
+
+        val state = meta.blockState as CreatureSpawner
+
+        return state.spawnedType?.let { "entity:${state.spawnedType!!.name}" } ?: return null
+    }
+}

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/items/ArgParserHead.kt

@@ -28,7 +28,6 @@ object ArgParserHead : LookupArgParser {
 
         playerName ?: return null
 
-        @Suppress("DEPRECATION")
         val player = Bukkit.getOfflinePlayer(playerName)
 
         meta.owningPlayer = player

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/items/ArgParserName.kt

@@ -22,12 +22,13 @@ object ArgParserName : LookupArgParser {
         val formatted = StringUtils.format(name)
 
         // I don't know why it says it's redundant, the compiler yells at me
-        @Suppress("UsePropertyAccessSyntax", "RedundantSuppression")
+        @Suppress("UsePropertyAccessSyntax", "RedundantSuppression", "DEPRECATION")
         meta.setDisplayName(formatted)
 
         return Predicate {
             val testMeta = it.itemMeta ?: return@Predicate false
 
+            @Suppress("DEPRECATION")
             testMeta.displayName == formatted
         }
     }
@@ -37,6 +38,7 @@ object ArgParserName : LookupArgParser {
             return null
         }
 
+        @Suppress("DEPRECATION")
         return "name:\"${meta.displayName}\""
     }
 }

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/items/ArgParserTrim.kt

@@ -1,13 +1,11 @@
 package com.willfp.eco.internal.items
 
 import com.willfp.eco.core.items.args.LookupArgParser
-import org.bukkit.Color
 import org.bukkit.NamespacedKey
 import org.bukkit.Registry
 import org.bukkit.inventory.ItemStack
 import org.bukkit.inventory.meta.ArmorMeta
 import org.bukkit.inventory.meta.ItemMeta
-import org.bukkit.inventory.meta.LeatherArmorMeta
 import org.bukkit.inventory.meta.trim.ArmorTrim
 import org.bukkit.inventory.meta.trim.TrimMaterial
 import org.bukkit.inventory.meta.trim.TrimPattern

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/placeholder/PlaceholderParser.kt

@@ -7,6 +7,8 @@ import com.willfp.eco.core.placeholder.InjectablePlaceholder
 import com.willfp.eco.core.placeholder.Placeholder
 import com.willfp.eco.core.placeholder.context.PlaceholderContext
 import com.willfp.eco.util.StringUtils
+import com.willfp.eco.util.evaluateExpression
+import com.willfp.eco.util.toNiceString
 import java.util.concurrent.TimeUnit
 
 /*
@@ -19,6 +21,8 @@ but it's still best to minimise the memory overhead.
 
 class PlaceholderParser {
     private val placeholderRegex = Regex("%([^% ]+)%")
+    private val prettyMathExpressionRegex = Regex("(\\{\\^\\{)(.)+(}})")
+    private val mathExpressionRegex = Regex("(\\{\\{)(.)+(}})")
 
     private val placeholderLookupCache = Caffeine.newBuilder()
         .expireAfterWrite(1, TimeUnit.SECONDS)
@@ -34,6 +38,29 @@ class PlaceholderParser {
         injections: Collection<InjectablePlaceholder>,
         translateEcoPlaceholders: Boolean = true
     ): String {
+        var processed = text
+
+        // Only evaluate math expressions if there might be any
+        // Checking { as a char is faster than checking a string sequence,
+        // even if it might lead to false positives.
+        if ('{' in processed) {
+            if ('^' in processed) {
+                // Evaluate pretty math expressions
+                processed = prettyMathExpressionRegex.findAll(processed).fold(processed) { acc, matchResult ->
+                    val expression = matchResult.value.substring(3, matchResult.value.length - 2)
+                    val result = evaluateExpression(expression, context)
+                    acc.replace(matchResult.value, result.toNiceString())
+                }
+            }
+
+            // Evaluate math expressions
+            processed = mathExpressionRegex.findAll(processed).fold(processed) { acc, matchResult ->
+                val expression = matchResult.value.substring(2, matchResult.value.length - 2)
+                val result = evaluateExpression(expression, context)
+                acc.replace(matchResult.value, result.toString())
+            }
+        }
+
         /*
 
         Why am I doing injections at the start, and again at the end?
@@ -55,7 +82,7 @@ class PlaceholderParser {
          */
 
         // Apply injections first
-        var processed = injections.fold(text) { acc, injection ->
+        processed = injections.fold(processed) { acc, injection ->
             injection.tryTranslateQuickly(acc, context)
         }
 
@@ -66,7 +93,7 @@ class PlaceholderParser {
                 val prefix = "%${additionalPlayer.identifier}_"
                 processed = found.fold(processed) { acc, placeholder ->
                     if (placeholder.startsWith(prefix)) {
-                        val newPlaceholder = "%${StringUtils.removePrefix(prefix, placeholder)}"
+                        val newPlaceholder = "%${StringUtils.removePrefix(placeholder, prefix)}"
                         val translation = translatePlacholders(
                             newPlaceholder,
                             context.copyWithPlayer(additionalPlayer.player),

eco-core/core-nms/build.gradle.kts

@@ -1,5 +1,5 @@
 plugins {
-    id("io.papermc.paperweight.userdev") version "1.5.3" apply false
+    id("io.papermc.paperweight.userdev") version "1.6.2" apply false
 }
 
 

eco-core/core-nms/nms-common/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/common/NMSCommons.kt

@@ -1,9 +1,13 @@
 package com.willfp.eco.internal.spigot.proxy.common
 
+import com.willfp.eco.core.Prerequisite
 import com.willfp.eco.core.entities.ai.EntityGoal
 import com.willfp.eco.core.entities.ai.TargetGoal
 import com.willfp.eco.internal.spigot.proxy.common.ai.EntityGoalFactory
 import com.willfp.eco.internal.spigot.proxy.common.ai.TargetGoalFactory
+import io.papermc.paper.adventure.PaperAdventure
+import net.kyori.adventure.text.Component
+import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer
 import net.minecraft.nbt.CompoundTag
 import net.minecraft.resources.ResourceLocation
 import net.minecraft.server.level.ServerPlayer
@@ -68,6 +72,18 @@ fun CompoundTag.setPdc(pdc: PersistentDataContainer?, item: net.minecraft.world.
 fun Player.toNMS(): ServerPlayer =
     impl.toNMS(this)
 
+fun Component.toNMS(): net.minecraft.network.chat.Component =
+    if (Prerequisite.HAS_PAPER.isMet) PaperAdventure.asVanilla(this) else impl.toNMS(this)
+
+fun net.minecraft.network.chat.Component.toAdventure(): Component {
+    if (Prerequisite.HAS_PAPER.isMet) {
+        return PaperAdventure.asAdventure(this)
+    }
+
+    val json = net.minecraft.network.chat.Component.Serializer.toJson(this)
+    return GsonComponentSerializer.gson().deserialize(json)
+}
+
 interface CommonsProvider {
     val nbtTagString: Int
 
@@ -101,6 +117,8 @@ interface CommonsProvider {
 
     fun toNMS(player: Player): ServerPlayer
 
+    fun toNMS(component: Component): net.minecraft.network.chat.Component
+
     companion object {
         fun setIfNeeded(provider: CommonsProvider) {
             if (::impl.isInitialized) {

eco-core/core-nms/nms-common/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/common/item/EcoFastItemStack.kt

@@ -29,10 +29,14 @@ import kotlin.experimental.and
 import kotlin.experimental.inv
 import kotlin.experimental.or
 
+interface ImplementedFIS : FastItemStack {
+    fun apply()
+}
+
 @Suppress("UsePropertyAccessSyntax")
 class EcoFastItemStack(
     private val bukkit: org.bukkit.inventory.ItemStack
-) : FastItemStack {
+) : ImplementedFIS {
     private val handle = bukkit.asNMSStack()
     private val pdc = (if (handle.hasTag()) handle.getTag()!! else CompoundTag()).makePdc()
 
@@ -184,9 +188,11 @@ class EcoFastItemStack(
         return this.flagBits and bitModifier == bitModifier
     }
 
+    @Deprecated("Not supported in 1.20.5+")
     override fun getBaseTag(): PersistentDataContainer =
         (if (handle.hasTag()) handle.getTag()!! else CompoundTag()).makePdc(base = true)
 
+    @Deprecated("Not supported in 1.20.5+")
     override fun setBaseTag(container: PersistentDataContainer?) {
         (if (handle.hasTag()) handle.getTag()!! else CompoundTag()).setPdc(container, item = handle)
         apply()
@@ -259,7 +265,7 @@ class EcoFastItemStack(
         return handle.getTag()?.hashCode() ?: (0b00010101 * 31 + Item.getId(handle.getItem()))
     }
 
-    internal fun apply() {
+    override fun apply() {
         if (handle.hasTag()) {
             handle.getTag()?.setPdc(this.pdc)
         }
@@ -276,9 +282,9 @@ class EcoFastItemStack(
     }
 }
 
-private class ContinuallyAppliedPersistentDataContainer(
+class ContinuallyAppliedPersistentDataContainer(
     val handle: PersistentDataContainer,
-    val fis: EcoFastItemStack
+    private val fis: ImplementedFIS
 ) : PersistentDataContainer by handle {
     override fun <T : Any, Z : Any> set(key: NamespacedKey, type: PersistentDataType<T, Z>, value: Z) {
         handle.set(key, type, value)

eco-core/core-nms/v1_17_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_17_R1/CommonsInitializer.kt

@@ -5,6 +5,8 @@ import com.willfp.eco.internal.spigot.proxy.CommonsInitializerProxy
 import com.willfp.eco.internal.spigot.proxy.common.CommonsProvider
 import com.willfp.eco.internal.spigot.proxy.common.packet.PacketInjectorListener
 import com.willfp.eco.internal.spigot.proxy.common.toResourceLocation
+import net.kyori.adventure.text.Component
+import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer
 import net.minecraft.core.Registry
 import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.Tag
@@ -155,5 +157,10 @@ class CommonsInitializer : CommonsInitializerProxy {
         override fun toNMS(player: Player): ServerPlayer {
             return (player as CraftPlayer).handle
         }
+
+        override fun toNMS(component: Component): net.minecraft.network.chat.Component {
+            val json = GsonComponentSerializer.gson().serialize(component)
+            return net.minecraft.network.chat.Component.Serializer.fromJson(json)!!
+        }
     }
 }

eco-core/core-nms/v1_17_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_17_R1/DisplayName.kt

@@ -0,0 +1,83 @@
+package com.willfp.eco.internal.spigot.proxy.v1_17_R1
+
+import com.willfp.eco.core.packet.Packet
+import com.willfp.eco.core.packet.sendPacket
+import com.willfp.eco.internal.spigot.proxy.DisplayNameProxy
+import com.willfp.eco.internal.spigot.proxy.common.toNMS
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap
+import net.kyori.adventure.text.Component
+import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket
+import net.minecraft.network.syncher.EntityDataAccessor
+import net.minecraft.network.syncher.SynchedEntityData
+import net.minecraft.world.entity.Entity
+import org.bukkit.craftbukkit.v1_17_R1.entity.CraftLivingEntity
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Player
+import java.util.Optional
+
+@Suppress("UNCHECKED_CAST")
+class DisplayName : DisplayNameProxy {
+    private val displayNameAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[2]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Optional<net.minecraft.network.chat.Component>>
+
+    private val customNameVisibleAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[3]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Boolean>
+
+    private val itemsByIDMapField = SynchedEntityData::class.java
+        .declaredFields
+        .filter { it.type == Int2ObjectMap::class.java }
+        .toList()[0]
+        .apply { isAccessible = true }
+
+    override fun setClientsideDisplayName(
+        entity: LivingEntity,
+        player: Player,
+        displayName: Component,
+        visible: Boolean
+    ) {
+        if (entity !is CraftLivingEntity) {
+            return
+        }
+
+        val nmsComponent = displayName.toNMS()
+
+        val nmsEntity = entity.handle
+        nmsEntity.isCustomNameVisible
+        val entityData = SynchedEntityData(nmsEntity)
+
+        entityData.forceSet(displayNameAccessor, Optional.of(nmsComponent))
+        entityData.forceSet(customNameVisibleAccessor, visible)
+
+        val packet = ClientboundSetEntityDataPacket(
+            nmsEntity.id,
+            entityData,
+            true
+        )
+
+        player.sendPacket(Packet(packet))
+    }
+
+    private fun <T : Any> SynchedEntityData.forceSet(
+        accessor: EntityDataAccessor<T>,
+        value: T
+    ) {
+        if (!this.hasItem(accessor)) {
+            this.define(accessor, value)
+        }
+        this[accessor] = value
+        this.markDirty(accessor)
+    }
+
+    private fun <T : Any> SynchedEntityData.hasItem(accessor: EntityDataAccessor<T>): Boolean {
+        val itemsByIDMap = itemsByIDMapField.get(this) as Int2ObjectMap<Any>
+        return itemsByIDMap.containsKey(accessor.id)
+    }
+}

eco-core/core-nms/v1_17_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_17_R1/ExtendedPersistentDataContainerFactory.kt

@@ -2,6 +2,7 @@ package com.willfp.eco.internal.spigot.proxy.v1_17_R1
 
 import com.willfp.eco.core.data.ExtendedPersistentDataContainer
 import com.willfp.eco.internal.spigot.proxy.ExtendedPersistentDataContainerFactoryProxy
+import com.willfp.eco.internal.spigot.proxy.common.item.ContinuallyAppliedPersistentDataContainer
 import net.minecraft.nbt.Tag
 import org.bukkit.Material
 import org.bukkit.craftbukkit.v1_17_R1.inventory.CraftItemStack
@@ -28,7 +29,7 @@ class ExtendedPersistentDataContainerFactory : ExtendedPersistentDataContainerFa
     override fun adapt(pdc: PersistentDataContainer): ExtendedPersistentDataContainer {
         return when (pdc) {
             is CraftPersistentDataContainer -> EcoPersistentDataContainer(pdc)
-            else -> throw IllegalArgumentException("Custom PDC instance is not supported!")
+            else -> throw IllegalArgumentException("Custom PDC instance ${pdc::class.java.name} is not supported!")
         }
     }
 

eco-core/core-nms/v1_17_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_17_R1/SNBTConverter.kt

@@ -7,6 +7,7 @@ import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.SnbtPrinterTagVisitor
 import net.minecraft.nbt.TagParser
 import org.bukkit.craftbukkit.v1_17_R1.inventory.CraftItemStack
+import org.bukkit.craftbukkit.v1_17_R1.util.CraftMagicNumbers
 import org.bukkit.inventory.ItemStack
 
 class SNBTConverter : SNBTConverterProxy {
@@ -18,7 +19,9 @@ class SNBTConverter : SNBTConverterProxy {
 
     override fun toSNBT(itemStack: ItemStack): String {
         val nms = CraftItemStack.asNMSCopy(itemStack)
-        return SnbtPrinterTagVisitor().visit(nms.save(CompoundTag()))
+        val tag = nms.save(CompoundTag())
+        tag.putInt("DataVersion", CraftMagicNumbers.INSTANCE.dataVersion)
+        return SnbtPrinterTagVisitor().visit(tag)
     }
 
     override fun makeSNBTTestable(snbt: String): TestableItem {

eco-core/core-nms/v1_18_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_18_R1/CommonsInitializer.kt

@@ -5,6 +5,8 @@ import com.willfp.eco.internal.spigot.proxy.CommonsInitializerProxy
 import com.willfp.eco.internal.spigot.proxy.common.CommonsProvider
 import com.willfp.eco.internal.spigot.proxy.common.packet.PacketInjectorListener
 import com.willfp.eco.internal.spigot.proxy.common.toResourceLocation
+import net.kyori.adventure.text.Component
+import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer
 import net.minecraft.core.Registry
 import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.Tag
@@ -155,5 +157,10 @@ class CommonsInitializer : CommonsInitializerProxy {
         override fun toNMS(player: Player): ServerPlayer {
             return (player as CraftPlayer).handle
         }
+
+        override fun toNMS(component: Component): net.minecraft.network.chat.Component {
+            val json = GsonComponentSerializer.gson().serialize(component)
+            return net.minecraft.network.chat.Component.Serializer.fromJson(json)!!
+        }
     }
 }

eco-core/core-nms/v1_18_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_18_R1/DisplayName.kt

@@ -0,0 +1,83 @@
+package com.willfp.eco.internal.spigot.proxy.v1_18_R1
+
+import com.willfp.eco.core.packet.Packet
+import com.willfp.eco.core.packet.sendPacket
+import com.willfp.eco.internal.spigot.proxy.DisplayNameProxy
+import com.willfp.eco.internal.spigot.proxy.common.toNMS
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap
+import net.kyori.adventure.text.Component
+import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket
+import net.minecraft.network.syncher.EntityDataAccessor
+import net.minecraft.network.syncher.SynchedEntityData
+import net.minecraft.world.entity.Entity
+import org.bukkit.craftbukkit.v1_18_R1.entity.CraftLivingEntity
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Player
+import java.util.Optional
+
+@Suppress("UNCHECKED_CAST")
+class DisplayName : DisplayNameProxy {
+    private val displayNameAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[2]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Optional<net.minecraft.network.chat.Component>>
+
+    private val customNameVisibleAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[3]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Boolean>
+
+    private val itemsByIDMapField = SynchedEntityData::class.java
+        .declaredFields
+        .filter { it.type == Int2ObjectMap::class.java }
+        .toList()[0]
+        .apply { isAccessible = true }
+
+    override fun setClientsideDisplayName(
+        entity: LivingEntity,
+        player: Player,
+        displayName: Component,
+        visible: Boolean
+    ) {
+        if (entity !is CraftLivingEntity) {
+            return
+        }
+
+        val nmsComponent = displayName.toNMS()
+
+        val nmsEntity = entity.handle
+        nmsEntity.isCustomNameVisible
+        val entityData = SynchedEntityData(nmsEntity)
+
+        entityData.forceSet(displayNameAccessor, Optional.of(nmsComponent))
+        entityData.forceSet(customNameVisibleAccessor, visible)
+
+        val packet = ClientboundSetEntityDataPacket(
+            nmsEntity.id,
+            entityData,
+            true
+        )
+
+        player.sendPacket(Packet(packet))
+    }
+
+    private fun <T : Any> SynchedEntityData.forceSet(
+        accessor: EntityDataAccessor<T>,
+        value: T
+    ) {
+        if (!this.hasItem(accessor)) {
+            this.define(accessor, value)
+        }
+        this[accessor] = value
+        this.markDirty(accessor)
+    }
+
+    private fun <T : Any> SynchedEntityData.hasItem(accessor: EntityDataAccessor<T>): Boolean {
+        val itemsByIDMap = itemsByIDMapField.get(this) as Int2ObjectMap<Any>
+        return itemsByIDMap.containsKey(accessor.id)
+    }
+}

eco-core/core-nms/v1_18_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_18_R1/ExtendedPersistentDataContainerFactory.kt

@@ -2,6 +2,7 @@ package com.willfp.eco.internal.spigot.proxy.v1_18_R1
 
 import com.willfp.eco.core.data.ExtendedPersistentDataContainer
 import com.willfp.eco.internal.spigot.proxy.ExtendedPersistentDataContainerFactoryProxy
+import com.willfp.eco.internal.spigot.proxy.common.item.ContinuallyAppliedPersistentDataContainer
 import net.minecraft.nbt.Tag
 import org.bukkit.Material
 import org.bukkit.craftbukkit.v1_18_R1.inventory.CraftItemStack
@@ -28,7 +29,7 @@ class ExtendedPersistentDataContainerFactory : ExtendedPersistentDataContainerFa
     override fun adapt(pdc: PersistentDataContainer): ExtendedPersistentDataContainer {
         return when (pdc) {
             is CraftPersistentDataContainer -> EcoPersistentDataContainer(pdc)
-            else -> throw IllegalArgumentException("Custom PDC instance is not supported!")
+            else -> throw IllegalArgumentException("Custom PDC instance ${pdc::class.java.name} is not supported!")
         }
     }
 

eco-core/core-nms/v1_18_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_18_R1/SNBTConverter.kt

@@ -7,6 +7,7 @@ import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.SnbtPrinterTagVisitor
 import net.minecraft.nbt.TagParser
 import org.bukkit.craftbukkit.v1_18_R1.inventory.CraftItemStack
+import org.bukkit.craftbukkit.v1_18_R1.util.CraftMagicNumbers
 import org.bukkit.inventory.ItemStack
 
 class SNBTConverter : SNBTConverterProxy {
@@ -18,7 +19,9 @@ class SNBTConverter : SNBTConverterProxy {
 
     override fun toSNBT(itemStack: ItemStack): String {
         val nms = CraftItemStack.asNMSCopy(itemStack)
-        return SnbtPrinterTagVisitor().visit(nms.save(CompoundTag()))
+        val tag = nms.save(CompoundTag())
+        tag.putInt("DataVersion", CraftMagicNumbers.INSTANCE.dataVersion)
+        return SnbtPrinterTagVisitor().visit(tag)
     }
 
     override fun makeSNBTTestable(snbt: String): TestableItem {

eco-core/core-nms/v1_18_R2/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_18_R2/CommonsInitializer.kt

@@ -5,6 +5,8 @@ import com.willfp.eco.internal.spigot.proxy.CommonsInitializerProxy
 import com.willfp.eco.internal.spigot.proxy.common.CommonsProvider
 import com.willfp.eco.internal.spigot.proxy.common.packet.PacketInjectorListener
 import com.willfp.eco.internal.spigot.proxy.common.toResourceLocation
+import net.kyori.adventure.text.Component
+import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer
 import net.minecraft.core.Registry
 import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.Tag
@@ -155,5 +157,10 @@ class CommonsInitializer : CommonsInitializerProxy {
         override fun toNMS(player: Player): ServerPlayer {
             return (player as CraftPlayer).handle
         }
+
+        override fun toNMS(component: Component): net.minecraft.network.chat.Component {
+            val json = GsonComponentSerializer.gson().serialize(component)
+            return net.minecraft.network.chat.Component.Serializer.fromJson(json)!!
+        }
     }
 }

eco-core/core-nms/v1_18_R2/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_18_R2/DisplayName.kt

@@ -0,0 +1,83 @@
+package com.willfp.eco.internal.spigot.proxy.v1_18_R2
+
+import com.willfp.eco.core.packet.Packet
+import com.willfp.eco.core.packet.sendPacket
+import com.willfp.eco.internal.spigot.proxy.DisplayNameProxy
+import com.willfp.eco.internal.spigot.proxy.common.toNMS
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap
+import net.kyori.adventure.text.Component
+import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket
+import net.minecraft.network.syncher.EntityDataAccessor
+import net.minecraft.network.syncher.SynchedEntityData
+import net.minecraft.world.entity.Entity
+import org.bukkit.craftbukkit.v1_18_R2.entity.CraftLivingEntity
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Player
+import java.util.Optional
+
+@Suppress("UNCHECKED_CAST")
+class DisplayName : DisplayNameProxy {
+    private val displayNameAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[2]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Optional<net.minecraft.network.chat.Component>>
+
+    private val customNameVisibleAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[3]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Boolean>
+
+    private val itemsByIDMapField = SynchedEntityData::class.java
+        .declaredFields
+        .filter { it.type == Int2ObjectMap::class.java }
+        .toList()[0]
+        .apply { isAccessible = true }
+
+    override fun setClientsideDisplayName(
+        entity: LivingEntity,
+        player: Player,
+        displayName: Component,
+        visible: Boolean
+    ) {
+        if (entity !is CraftLivingEntity) {
+            return
+        }
+
+        val nmsComponent = displayName.toNMS()
+
+        val nmsEntity = entity.handle
+        nmsEntity.isCustomNameVisible
+        val entityData = SynchedEntityData(nmsEntity)
+
+        entityData.forceSet(displayNameAccessor, Optional.of(nmsComponent))
+        entityData.forceSet(customNameVisibleAccessor, visible)
+
+        val packet = ClientboundSetEntityDataPacket(
+            nmsEntity.id,
+            entityData,
+            true
+        )
+
+        player.sendPacket(Packet(packet))
+    }
+
+    private fun <T : Any> SynchedEntityData.forceSet(
+        accessor: EntityDataAccessor<T>,
+        value: T
+    ) {
+        if (!this.hasItem(accessor)) {
+            this.define(accessor, value)
+        }
+        this[accessor] = value
+        this.markDirty(accessor)
+    }
+
+    private fun <T : Any> SynchedEntityData.hasItem(accessor: EntityDataAccessor<T>): Boolean {
+        val itemsByIDMap = itemsByIDMapField.get(this) as Int2ObjectMap<Any>
+        return itemsByIDMap.containsKey(accessor.id)
+    }
+}

eco-core/core-nms/v1_18_R2/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_18_R2/ExtendedPersistentDataContainerFactory.kt

@@ -2,6 +2,7 @@ package com.willfp.eco.internal.spigot.proxy.v1_18_R2
 
 import com.willfp.eco.core.data.ExtendedPersistentDataContainer
 import com.willfp.eco.internal.spigot.proxy.ExtendedPersistentDataContainerFactoryProxy
+import com.willfp.eco.internal.spigot.proxy.common.item.ContinuallyAppliedPersistentDataContainer
 import net.minecraft.nbt.Tag
 import org.bukkit.Material
 import org.bukkit.craftbukkit.v1_18_R2.inventory.CraftItemStack
@@ -28,7 +29,7 @@ class ExtendedPersistentDataContainerFactory : ExtendedPersistentDataContainerFa
     override fun adapt(pdc: PersistentDataContainer): ExtendedPersistentDataContainer {
         return when (pdc) {
             is CraftPersistentDataContainer -> EcoPersistentDataContainer(pdc)
-            else -> throw IllegalArgumentException("Custom PDC instance is not supported!")
+            else -> throw IllegalArgumentException("Custom PDC instance ${pdc::class.java.name} is not supported!")
         }
     }
 

eco-core/core-nms/v1_18_R2/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_18_R2/SNBTConverter.kt

@@ -7,6 +7,7 @@ import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.SnbtPrinterTagVisitor
 import net.minecraft.nbt.TagParser
 import org.bukkit.craftbukkit.v1_18_R2.inventory.CraftItemStack
+import org.bukkit.craftbukkit.v1_18_R2.util.CraftMagicNumbers
 import org.bukkit.inventory.ItemStack
 
 class SNBTConverter : SNBTConverterProxy {
@@ -18,7 +19,9 @@ class SNBTConverter : SNBTConverterProxy {
 
     override fun toSNBT(itemStack: ItemStack): String {
         val nms = CraftItemStack.asNMSCopy(itemStack)
-        return SnbtPrinterTagVisitor().visit(nms.save(CompoundTag()))
+        val tag = nms.save(CompoundTag())
+        tag.putInt("DataVersion", CraftMagicNumbers.INSTANCE.dataVersion)
+        return SnbtPrinterTagVisitor().visit(tag)
     }
 
     override fun makeSNBTTestable(snbt: String): TestableItem {

eco-core/core-nms/v1_19_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_19_R1/CommonsInitializer.kt

@@ -5,6 +5,8 @@ import com.willfp.eco.internal.spigot.proxy.CommonsInitializerProxy
 import com.willfp.eco.internal.spigot.proxy.common.CommonsProvider
 import com.willfp.eco.internal.spigot.proxy.common.packet.PacketInjectorListener
 import com.willfp.eco.internal.spigot.proxy.common.toResourceLocation
+import net.kyori.adventure.text.Component
+import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer
 import net.minecraft.core.Registry
 import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.Tag
@@ -155,5 +157,10 @@ class CommonsInitializer : CommonsInitializerProxy {
         override fun toNMS(player: Player): ServerPlayer {
             return (player as CraftPlayer).handle
         }
+
+        override fun toNMS(component: Component): net.minecraft.network.chat.Component {
+            val json = GsonComponentSerializer.gson().serialize(component)
+            return net.minecraft.network.chat.Component.Serializer.fromJson(json)!!
+        }
     }
 }

eco-core/core-nms/v1_19_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_19_R1/DisplayName.kt

@@ -0,0 +1,83 @@
+package com.willfp.eco.internal.spigot.proxy.v1_19_R1
+
+import com.willfp.eco.core.packet.Packet
+import com.willfp.eco.core.packet.sendPacket
+import com.willfp.eco.internal.spigot.proxy.DisplayNameProxy
+import com.willfp.eco.internal.spigot.proxy.common.toNMS
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap
+import net.kyori.adventure.text.Component
+import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket
+import net.minecraft.network.syncher.EntityDataAccessor
+import net.minecraft.network.syncher.SynchedEntityData
+import net.minecraft.world.entity.Entity
+import org.bukkit.craftbukkit.v1_19_R1.entity.CraftLivingEntity
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Player
+import java.util.Optional
+
+@Suppress("UNCHECKED_CAST")
+class DisplayName : DisplayNameProxy {
+    private val displayNameAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[2]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Optional<net.minecraft.network.chat.Component>>
+
+    private val customNameVisibleAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[3]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Boolean>
+
+    private val itemsByIDMapField = SynchedEntityData::class.java
+        .declaredFields
+        .filter { it.type == Int2ObjectMap::class.java }
+        .toList()[0]
+        .apply { isAccessible = true }
+
+    override fun setClientsideDisplayName(
+        entity: LivingEntity,
+        player: Player,
+        displayName: Component,
+        visible: Boolean
+    ) {
+        if (entity !is CraftLivingEntity) {
+            return
+        }
+
+        val nmsComponent = displayName.toNMS()
+
+        val nmsEntity = entity.handle
+        nmsEntity.isCustomNameVisible
+        val entityData = SynchedEntityData(nmsEntity)
+
+        entityData.forceSet(displayNameAccessor, Optional.of(nmsComponent))
+        entityData.forceSet(customNameVisibleAccessor, visible)
+
+        val packet = ClientboundSetEntityDataPacket(
+            nmsEntity.id,
+            entityData,
+            true
+        )
+
+        player.sendPacket(Packet(packet))
+    }
+
+    private fun <T : Any> SynchedEntityData.forceSet(
+        accessor: EntityDataAccessor<T>,
+        value: T
+    ) {
+        if (!this.hasItem(accessor)) {
+            this.define(accessor, value)
+        }
+        this[accessor] = value
+        this.markDirty(accessor)
+    }
+
+    private fun <T : Any> SynchedEntityData.hasItem(accessor: EntityDataAccessor<T>): Boolean {
+        val itemsByIDMap = itemsByIDMapField.get(this) as Int2ObjectMap<Any>
+        return itemsByIDMap.containsKey(accessor.id)
+    }
+}

eco-core/core-nms/v1_19_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_19_R1/ExtendedPersistentDataContainerFactory.kt

@@ -28,7 +28,7 @@ class ExtendedPersistentDataContainerFactory : ExtendedPersistentDataContainerFa
     override fun adapt(pdc: PersistentDataContainer): ExtendedPersistentDataContainer {
         return when (pdc) {
             is CraftPersistentDataContainer -> EcoPersistentDataContainer(pdc)
-            else -> throw IllegalArgumentException("Custom PDC instance ims not supported!")
+            else -> throw IllegalArgumentException("Custom PDC instance ${pdc::class.java.name} is not supported!")
         }
     }
 

eco-core/core-nms/v1_19_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_19_R1/SNBTConverter.kt

@@ -8,6 +8,7 @@ import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.SnbtPrinterTagVisitor
 import net.minecraft.nbt.TagParser
 import org.bukkit.craftbukkit.v1_19_R1.inventory.CraftItemStack
+import org.bukkit.craftbukkit.v1_19_R1.util.CraftMagicNumbers
 import org.bukkit.inventory.ItemStack
 
 class SNBTConverter : SNBTConverterProxy {
@@ -19,7 +20,9 @@ class SNBTConverter : SNBTConverterProxy {
 
     override fun toSNBT(itemStack: ItemStack): String {
         val nms = CraftItemStack.asNMSCopy(itemStack)
-        return SnbtPrinterTagVisitor().visit(nms.save(CompoundTag()))
+        val tag = nms.save(CompoundTag())
+        tag.putInt("DataVersion", CraftMagicNumbers.INSTANCE.dataVersion)
+        return SnbtPrinterTagVisitor().visit(tag)
     }
 
     override fun makeSNBTTestable(snbt: String): TestableItem {

eco-core/core-nms/v1_19_R2/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_19_R2/CommonsInitializer.kt

@@ -6,6 +6,8 @@ import com.willfp.eco.internal.spigot.proxy.common.CommonsProvider
 import com.willfp.eco.internal.spigot.proxy.common.packet.PacketInjectorListener
 import com.willfp.eco.internal.spigot.proxy.common.toResourceLocation
 import io.netty.channel.Channel
+import net.kyori.adventure.text.Component
+import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer
 import net.minecraft.core.registries.BuiltInRegistries
 import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.Tag
@@ -157,5 +159,10 @@ class CommonsInitializer : CommonsInitializerProxy {
         override fun toNMS(player: Player): ServerPlayer {
             return (player as CraftPlayer).handle
         }
+
+        override fun toNMS(component: Component): net.minecraft.network.chat.Component {
+            val json = GsonComponentSerializer.gson().serialize(component)
+            return net.minecraft.network.chat.Component.Serializer.fromJson(json)!!
+        }
     }
 }

eco-core/core-nms/v1_19_R2/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_19_R2/DisplayName.kt

@@ -0,0 +1,82 @@
+package com.willfp.eco.internal.spigot.proxy.v1_19_R2
+
+import com.willfp.eco.core.packet.Packet
+import com.willfp.eco.core.packet.sendPacket
+import com.willfp.eco.internal.spigot.proxy.DisplayNameProxy
+import com.willfp.eco.internal.spigot.proxy.common.toNMS
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap
+import net.kyori.adventure.text.Component
+import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket
+import net.minecraft.network.syncher.EntityDataAccessor
+import net.minecraft.network.syncher.SynchedEntityData
+import net.minecraft.world.entity.Entity
+import org.bukkit.craftbukkit.v1_19_R2.entity.CraftLivingEntity
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Player
+import java.util.Optional
+
+@Suppress("UNCHECKED_CAST")
+class DisplayName : DisplayNameProxy {
+    private val displayNameAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[2]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Optional<net.minecraft.network.chat.Component>>
+
+    private val customNameVisibleAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[3]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Boolean>
+
+    private val itemsByIDMapField = SynchedEntityData::class.java
+        .declaredFields
+        .filter { it.type == Int2ObjectMap::class.java }
+        .toList()[0]
+        .apply { isAccessible = true }
+
+    override fun setClientsideDisplayName(
+        entity: LivingEntity,
+        player: Player,
+        displayName: Component,
+        visible: Boolean
+    ) {
+        if (entity !is CraftLivingEntity) {
+            return
+        }
+
+        val nmsComponent = displayName.toNMS()
+
+        val nmsEntity = entity.handle
+        nmsEntity.isCustomNameVisible
+        val entityData = SynchedEntityData(nmsEntity)
+
+        entityData.forceSet(displayNameAccessor, Optional.of(nmsComponent))
+        entityData.forceSet(customNameVisibleAccessor, visible)
+
+        val packet = ClientboundSetEntityDataPacket(
+            nmsEntity.id,
+            entityData.packDirty() ?: throw IllegalStateException("No packed entity data")
+        )
+
+        player.sendPacket(Packet(packet))
+    }
+
+    private fun <T : Any> SynchedEntityData.forceSet(
+        accessor: EntityDataAccessor<T>,
+        value: T
+    ) {
+        if (!this.hasItem(accessor)) {
+            this.define(accessor, value)
+        }
+        this[accessor] = value
+        this.markDirty(accessor)
+    }
+
+    private fun <T : Any> SynchedEntityData.hasItem(accessor: EntityDataAccessor<T>): Boolean {
+        val itemsByIDMap = itemsByIDMapField.get(this) as Int2ObjectMap<Any>
+        return itemsByIDMap.containsKey(accessor.id)
+    }
+}

eco-core/core-nms/v1_19_R2/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_19_R2/ExtendedPersistentDataContainerFactory.kt

@@ -2,6 +2,7 @@ package com.willfp.eco.internal.spigot.proxy.v1_19_R2
 
 import com.willfp.eco.core.data.ExtendedPersistentDataContainer
 import com.willfp.eco.internal.spigot.proxy.ExtendedPersistentDataContainerFactoryProxy
+import com.willfp.eco.internal.spigot.proxy.common.item.ContinuallyAppliedPersistentDataContainer
 import net.minecraft.nbt.Tag
 import org.bukkit.Material
 import org.bukkit.craftbukkit.v1_19_R2.inventory.CraftItemStack
@@ -28,7 +29,7 @@ class ExtendedPersistentDataContainerFactory : ExtendedPersistentDataContainerFa
     override fun adapt(pdc: PersistentDataContainer): ExtendedPersistentDataContainer {
         return when (pdc) {
             is CraftPersistentDataContainer -> EcoPersistentDataContainer(pdc)
-            else -> throw IllegalArgumentException("Custom PDC instance ims not supported!")
+            else -> throw IllegalArgumentException("Custom PDC instance ${pdc::class.java.name} is not supported!")
         }
     }
 

eco-core/core-nms/v1_19_R2/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_19_R2/SNBTConverter.kt

@@ -7,6 +7,7 @@ import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.SnbtPrinterTagVisitor
 import net.minecraft.nbt.TagParser
 import org.bukkit.craftbukkit.v1_19_R2.inventory.CraftItemStack
+import org.bukkit.craftbukkit.v1_19_R2.util.CraftMagicNumbers
 import org.bukkit.inventory.ItemStack
 
 class SNBTConverter : SNBTConverterProxy {
@@ -18,7 +19,9 @@ class SNBTConverter : SNBTConverterProxy {
 
     override fun toSNBT(itemStack: ItemStack): String {
         val nms = CraftItemStack.asNMSCopy(itemStack)
-        return SnbtPrinterTagVisitor().visit(nms.save(CompoundTag()))
+        val tag = nms.save(CompoundTag())
+        tag.putInt("DataVersion", CraftMagicNumbers.INSTANCE.dataVersion)
+        return SnbtPrinterTagVisitor().visit(tag)
     }
 
     override fun makeSNBTTestable(snbt: String): TestableItem {

eco-core/core-nms/v1_19_R3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_19_R3/CommonsInitializer.kt

@@ -5,6 +5,8 @@ import com.willfp.eco.internal.spigot.proxy.CommonsInitializerProxy
 import com.willfp.eco.internal.spigot.proxy.common.CommonsProvider
 import com.willfp.eco.internal.spigot.proxy.common.packet.PacketInjectorListener
 import com.willfp.eco.internal.spigot.proxy.common.toResourceLocation
+import net.kyori.adventure.text.Component
+import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer
 import net.minecraft.core.registries.BuiltInRegistries
 import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.Tag
@@ -155,5 +157,10 @@ class CommonsInitializer : CommonsInitializerProxy {
         override fun toNMS(player: Player): ServerPlayer {
             return (player as CraftPlayer).handle
         }
+
+        override fun toNMS(component: Component): net.minecraft.network.chat.Component {
+            val json = GsonComponentSerializer.gson().serialize(component)
+            return net.minecraft.network.chat.Component.Serializer.fromJson(json)!!
+        }
     }
 }

eco-core/core-nms/v1_19_R3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_19_R3/DisplayName.kt

@@ -0,0 +1,82 @@
+package com.willfp.eco.internal.spigot.proxy.v1_19_R3
+
+import com.willfp.eco.core.packet.Packet
+import com.willfp.eco.core.packet.sendPacket
+import com.willfp.eco.internal.spigot.proxy.DisplayNameProxy
+import com.willfp.eco.internal.spigot.proxy.common.toNMS
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap
+import net.kyori.adventure.text.Component
+import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket
+import net.minecraft.network.syncher.EntityDataAccessor
+import net.minecraft.network.syncher.SynchedEntityData
+import net.minecraft.world.entity.Entity
+import org.bukkit.craftbukkit.v1_19_R3.entity.CraftLivingEntity
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Player
+import java.util.Optional
+
+@Suppress("UNCHECKED_CAST")
+class DisplayName : DisplayNameProxy {
+    private val displayNameAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[2]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Optional<net.minecraft.network.chat.Component>>
+
+    private val customNameVisibleAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[3]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Boolean>
+
+    private val itemsByIDMapField = SynchedEntityData::class.java
+        .declaredFields
+        .filter { it.type == Int2ObjectMap::class.java }
+        .toList()[0]
+        .apply { isAccessible = true }
+
+    override fun setClientsideDisplayName(
+        entity: LivingEntity,
+        player: Player,
+        displayName: Component,
+        visible: Boolean
+    ) {
+        if (entity !is CraftLivingEntity) {
+            return
+        }
+
+        val nmsComponent = displayName.toNMS()
+
+        val nmsEntity = entity.handle
+        nmsEntity.isCustomNameVisible
+        val entityData = SynchedEntityData(nmsEntity)
+
+        entityData.forceSet(displayNameAccessor, Optional.of(nmsComponent))
+        entityData.forceSet(customNameVisibleAccessor, visible)
+
+        val packet = ClientboundSetEntityDataPacket(
+            nmsEntity.id,
+            entityData.packDirty() ?: throw IllegalStateException("No packed entity data")
+        )
+
+        player.sendPacket(Packet(packet))
+    }
+
+    private fun <T : Any> SynchedEntityData.forceSet(
+        accessor: EntityDataAccessor<T>,
+        value: T
+    ) {
+        if (!this.hasItem(accessor)) {
+            this.define(accessor, value)
+        }
+        this[accessor] = value
+        this.markDirty(accessor)
+    }
+
+    private fun <T : Any> SynchedEntityData.hasItem(accessor: EntityDataAccessor<T>): Boolean {
+        val itemsByIDMap = itemsByIDMapField.get(this) as Int2ObjectMap<Any>
+        return itemsByIDMap.containsKey(accessor.id)
+    }
+}

eco-core/core-nms/v1_19_R3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_19_R3/ExtendedPersistentDataContainerFactory.kt

@@ -28,7 +28,7 @@ class ExtendedPersistentDataContainerFactory : ExtendedPersistentDataContainerFa
     override fun adapt(pdc: PersistentDataContainer): ExtendedPersistentDataContainer {
         return when (pdc) {
             is CraftPersistentDataContainer -> EcoPersistentDataContainer(pdc)
-            else -> throw IllegalArgumentException("Custom PDC instance ims not supported!")
+            else -> throw IllegalArgumentException("Custom PDC instance ${pdc::class.java.name} is not supported!")
         }
     }
 

eco-core/core-nms/v1_19_R3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_19_R3/SNBTConverter.kt

@@ -7,6 +7,7 @@ import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.SnbtPrinterTagVisitor
 import net.minecraft.nbt.TagParser
 import org.bukkit.craftbukkit.v1_19_R3.inventory.CraftItemStack
+import org.bukkit.craftbukkit.v1_19_R3.util.CraftMagicNumbers
 import org.bukkit.inventory.ItemStack
 
 class SNBTConverter : SNBTConverterProxy {
@@ -18,7 +19,9 @@ class SNBTConverter : SNBTConverterProxy {
 
     override fun toSNBT(itemStack: ItemStack): String {
         val nms = CraftItemStack.asNMSCopy(itemStack)
-        return SnbtPrinterTagVisitor().visit(nms.save(CompoundTag()))
+        val tag = nms.save(CompoundTag())
+        tag.putInt("DataVersion", CraftMagicNumbers.INSTANCE.dataVersion)
+        return SnbtPrinterTagVisitor().visit(tag)
     }
 
     override fun makeSNBTTestable(snbt: String): TestableItem {

eco-core/core-nms/v1_20_6/build.gradle.kts

@@ -0,0 +1,51 @@
+plugins {
+    id("io.papermc.paperweight.userdev")
+}
+
+group = "com.willfp"
+version = rootProject.version
+
+dependencies {
+    implementation(project(":eco-core:core-nms:nms-common"))
+    paperweight.paperDevBundle("1.20.6-R0.1-SNAPSHOT")
+
+    implementation("net.kyori:adventure-text-minimessage:4.11.0") {
+        version {
+            strictly("4.11.0")
+        }
+        exclude(group = "net.kyori", module = "adventure-api")
+    }
+}
+
+tasks {
+    build {
+        dependsOn(reobfJar)
+    }
+
+    reobfJar {
+        mustRunAfter(shadowJar)
+    }
+
+    shadowJar {
+        relocate(
+            "com.willfp.eco.internal.spigot.proxy.common",
+            "com.willfp.eco.internal.spigot.proxy.v1_20_6.common"
+        )
+        relocate(
+            "net.kyori.adventure.text.minimessage",
+            "com.willfp.eco.internal.spigot.proxy.v1_20_6.minimessage"
+        )
+    }
+
+    java {
+        sourceCompatibility = JavaVersion.VERSION_21
+        targetCompatibility = JavaVersion.VERSION_21
+        withSourcesJar()
+    }
+
+    compileKotlin {
+        kotlinOptions {
+            jvmTarget = "21"
+        }
+    }
+}

eco-core/core-nms/v1_20_6/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_6/BukkitCommands.kt

@@ -0,0 +1,35 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_6
+
+import com.willfp.eco.core.command.PluginCommandBase
+import com.willfp.eco.internal.spigot.proxy.BukkitCommandsProxy
+import org.bukkit.Bukkit
+import org.bukkit.command.Command
+import org.bukkit.command.SimpleCommandMap
+import org.bukkit.craftbukkit.CraftServer
+import java.lang.reflect.Field
+
+class BukkitCommands : BukkitCommandsProxy {
+    private val knownCommandsField: Field by lazy {
+        SimpleCommandMap::class.java.getDeclaredField("knownCommands")
+            .apply {
+                isAccessible = true
+            }
+    }
+
+    @Suppress("UNCHECKED_CAST")
+    private val knownCommands: MutableMap<String, Command>
+        get() = knownCommandsField.get(getCommandMap()) as MutableMap<String, Command>
+
+    override fun getCommandMap(): SimpleCommandMap {
+        return (Bukkit.getServer() as CraftServer).commandMap
+    }
+
+    override fun syncCommands() {
+        (Bukkit.getServer() as CraftServer).syncCommands()
+    }
+
+    override fun unregisterCommand(command: PluginCommandBase) {
+        knownCommands.remove(command.name)
+        knownCommands.remove("${command.plugin.name.lowercase()}:${command.name}")
+    }
+}

eco-core/core-nms/v1_20_6/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_6/CommonsInitializer.kt

@@ -0,0 +1,171 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_6
+
+import com.willfp.eco.core.EcoPlugin
+import com.willfp.eco.internal.spigot.proxy.CommonsInitializerProxy
+import com.willfp.eco.internal.spigot.proxy.common.CommonsProvider
+import com.willfp.eco.internal.spigot.proxy.common.packet.PacketInjectorListener
+import com.willfp.eco.internal.spigot.proxy.common.toResourceLocation
+import net.kyori.adventure.text.Component
+import net.kyori.adventure.text.serializer.json.JSONComponentSerializer
+import net.minecraft.core.component.DataComponents
+import net.minecraft.core.registries.BuiltInRegistries
+import net.minecraft.nbt.CompoundTag
+import net.minecraft.nbt.Tag
+import net.minecraft.resources.ResourceLocation
+import net.minecraft.server.level.ServerPlayer
+import net.minecraft.world.entity.PathfinderMob
+import net.minecraft.world.item.Item
+import org.bukkit.Bukkit
+import org.bukkit.Material
+import org.bukkit.NamespacedKey
+import org.bukkit.craftbukkit.CraftServer
+import org.bukkit.craftbukkit.entity.CraftEntity
+import org.bukkit.craftbukkit.entity.CraftMob
+import org.bukkit.craftbukkit.entity.CraftPlayer
+import org.bukkit.craftbukkit.inventory.CraftItemStack
+import org.bukkit.craftbukkit.inventory.CraftMetaArmor
+import org.bukkit.craftbukkit.persistence.CraftPersistentDataContainer
+import org.bukkit.craftbukkit.persistence.CraftPersistentDataTypeRegistry
+import org.bukkit.craftbukkit.util.CraftMagicNumbers
+import org.bukkit.craftbukkit.util.CraftNamespacedKey
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Mob
+import org.bukkit.entity.Player
+import org.bukkit.inventory.ItemStack
+import org.bukkit.persistence.PersistentDataContainer
+import java.lang.reflect.Field
+
+class CommonsInitializer : CommonsInitializerProxy {
+    override fun init(plugin: EcoPlugin) {
+        CommonsProvider.setIfNeeded(CommonsProviderImpl)
+        plugin.onEnable {
+            plugin.eventManager.registerListener(PacketInjectorListener)
+        }
+    }
+
+    object CommonsProviderImpl : CommonsProvider {
+        private val cisHandle: Field = CraftItemStack::class.java.getDeclaredField("handle").apply {
+            isAccessible = true
+        }
+
+        private val pdcRegsitry = CraftMetaArmor::class.java
+            .superclass // Access CraftMetaItem
+            .getDeclaredField("DATA_TYPE_REGISTRY")
+            .apply { isAccessible = true }
+            .get(null) as CraftPersistentDataTypeRegistry
+
+        override val nbtTagString = CraftMagicNumbers.NBT.TAG_STRING
+
+        override fun toPathfinderMob(mob: Mob): PathfinderMob? {
+            val craft = mob as? CraftMob ?: return null
+            return craft.handle as? PathfinderMob
+        }
+
+        override fun toResourceLocation(namespacedKey: NamespacedKey): ResourceLocation =
+            CraftNamespacedKey.toMinecraft(namespacedKey)
+
+        override fun asNMSStack(itemStack: ItemStack): net.minecraft.world.item.ItemStack {
+            return if (itemStack !is CraftItemStack) {
+                CraftItemStack.asNMSCopy(itemStack)
+            } else {
+                cisHandle[itemStack] as net.minecraft.world.item.ItemStack? ?: CraftItemStack.asNMSCopy(itemStack)
+            }
+        }
+
+        override fun asBukkitStack(itemStack: net.minecraft.world.item.ItemStack): ItemStack {
+            return CraftItemStack.asCraftMirror(itemStack)
+        }
+
+        override fun mergeIfNeeded(itemStack: ItemStack, nmsStack: net.minecraft.world.item.ItemStack) {
+            if (itemStack !is CraftItemStack) {
+                itemStack.itemMeta = CraftItemStack.asCraftMirror(nmsStack).itemMeta
+            }
+        }
+
+        override fun toBukkitEntity(entity: net.minecraft.world.entity.LivingEntity): LivingEntity? =
+            CraftEntity.getEntity(Bukkit.getServer() as CraftServer, entity) as? LivingEntity
+
+        override fun makePdc(tag: CompoundTag, base: Boolean): PersistentDataContainer {
+            fun emptyPdc(): CraftPersistentDataContainer = CraftPersistentDataContainer(pdcRegsitry)
+
+            fun CompoundTag?.toPdc(): PersistentDataContainer {
+                val pdc = emptyPdc()
+                this ?: return pdc
+                val keys = this.allKeys
+                for (key in keys) {
+                    pdc.put(key, this[key])
+                }
+
+                return pdc
+            }
+
+            return if (base) {
+                tag.toPdc()
+            } else {
+                if (tag.contains("PublicBukkitValues")) {
+                    tag.getCompound("PublicBukkitValues").toPdc()
+                } else {
+                    emptyPdc()
+                }
+            }
+        }
+
+        override fun setPdc(
+            tag: CompoundTag,
+            pdc: PersistentDataContainer?,
+            item: net.minecraft.world.item.ItemStack?
+        ) {
+            fun CraftPersistentDataContainer.toTag(): CompoundTag {
+                val compound = CompoundTag()
+                val rawPublicMap: Map<String, Tag> = this.raw
+                for ((key, value) in rawPublicMap) {
+                    compound.put(key, value)
+                }
+
+                return compound
+            }
+
+            val container = when (pdc) {
+                is CraftPersistentDataContainer? -> pdc
+                else -> null
+            }
+
+            if (item != null) {
+                if (container != null && !container.isEmpty) {
+                    for (key in tag.allKeys.toSet()) {
+                        tag.remove(key)
+                    }
+
+                    tag.merge(container.toTag())
+                } else {
+                    item.remove(DataComponents.CUSTOM_DATA)
+                }
+            } else {
+                if (container != null && !container.isEmpty) {
+                    tag.put("PublicBukkitValues", container.toTag())
+                } else {
+                    tag.remove("PublicBukkitValues")
+                }
+            }
+        }
+
+        override fun materialToItem(material: Material): Item =
+            BuiltInRegistries.ITEM.getOptional(material.key.toResourceLocation())
+                .orElseThrow { IllegalArgumentException("Material is not item!") }
+
+        override fun itemToMaterial(item: Item) =
+            Material.getMaterial(BuiltInRegistries.ITEM.getKey(item).path.uppercase())
+                ?: throw IllegalArgumentException("Invalid material!")
+
+        override fun toNMS(player: Player): ServerPlayer {
+            return (player as CraftPlayer).handle
+        }
+
+        override fun toNMS(component: Component): net.minecraft.network.chat.Component {
+            val json = JSONComponentSerializer.json().serialize(component)
+            val holderLookupProvider = (Bukkit.getServer() as CraftServer).server.registryAccess()
+
+            return net.minecraft.network.chat.Component.Serializer.fromJson(json, holderLookupProvider)!!
+        }
+    }
+}

eco-core/core-nms/v1_20_6/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_6/DisplayName.kt

@@ -0,0 +1,59 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_6
+
+import com.willfp.eco.core.packet.Packet
+import com.willfp.eco.core.packet.sendPacket
+import com.willfp.eco.internal.spigot.proxy.DisplayNameProxy
+import com.willfp.eco.internal.spigot.proxy.common.toNMS
+import net.kyori.adventure.text.Component
+import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket
+import net.minecraft.network.syncher.EntityDataAccessor
+import net.minecraft.network.syncher.SynchedEntityData
+import net.minecraft.world.entity.Entity
+import org.bukkit.craftbukkit.entity.CraftLivingEntity
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Player
+import java.util.Optional
+
+@Suppress("UNCHECKED_CAST")
+class DisplayName : DisplayNameProxy {
+    private val displayNameAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[2]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Optional<net.minecraft.network.chat.Component>>
+
+    private val customNameVisibleAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[3]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Boolean>
+
+    override fun setClientsideDisplayName(
+        entity: LivingEntity,
+        player: Player,
+        displayName: Component,
+        visible: Boolean
+    ) {
+        if (entity !is CraftLivingEntity) {
+            return
+        }
+
+        val nmsComponent = displayName.toNMS()
+
+        val nmsEntity = entity.handle
+        nmsEntity.isCustomNameVisible
+        val entityData = SynchedEntityData.Builder(nmsEntity).build()
+
+        entityData.set(displayNameAccessor, Optional.of(nmsComponent), true)
+        entityData.set(customNameVisibleAccessor, visible, true)
+
+        val packet = ClientboundSetEntityDataPacket(
+            nmsEntity.id,
+            entityData.packDirty() ?: throw IllegalStateException("No packed entity data")
+        )
+
+        player.sendPacket(Packet(packet))
+    }
+}

eco-core/core-nms/v1_20_6/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_6/DummyEntityFactory.kt

@@ -0,0 +1,15 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_6
+
+import com.willfp.eco.internal.entities.EcoDummyEntity
+import com.willfp.eco.internal.spigot.proxy.DummyEntityFactoryProxy
+import org.bukkit.Location
+import org.bukkit.craftbukkit.CraftWorld
+import org.bukkit.entity.Entity
+import org.bukkit.entity.Zombie
+
+class DummyEntityFactory : DummyEntityFactoryProxy {
+    override fun createDummyEntity(location: Location): Entity {
+        val world = location.world as CraftWorld
+        return EcoDummyEntity(world.createEntity(location, Zombie::class.java))
+    }
+}

eco-core/core-nms/v1_20_6/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_6/EntityControllerFactory.kt

@@ -0,0 +1,12 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_6
+
+import com.willfp.eco.core.entities.ai.EntityController
+import com.willfp.eco.internal.spigot.proxy.EntityControllerFactoryProxy
+import com.willfp.eco.internal.spigot.proxy.v1_20_6.entity.EcoEntityController
+import org.bukkit.entity.Mob
+
+class EntityControllerFactory : EntityControllerFactoryProxy {
+    override fun <T : Mob> createEntityController(entity: T): EntityController<T> {
+        return EcoEntityController(entity)
+    }
+}

eco-core/core-nms/v1_20_6/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_6/ExtendedPersistentDataContainerFactory.kt

@@ -0,0 +1,82 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_6
+
+import com.willfp.eco.core.data.ExtendedPersistentDataContainer
+import com.willfp.eco.internal.spigot.proxy.ExtendedPersistentDataContainerFactoryProxy
+import net.minecraft.nbt.Tag
+import org.bukkit.Material
+import org.bukkit.craftbukkit.inventory.CraftItemStack
+import org.bukkit.craftbukkit.persistence.CraftPersistentDataContainer
+import org.bukkit.craftbukkit.persistence.CraftPersistentDataTypeRegistry
+import org.bukkit.inventory.ItemStack
+import org.bukkit.persistence.PersistentDataContainer
+import org.bukkit.persistence.PersistentDataType
+
+class ExtendedPersistentDataContainerFactory : ExtendedPersistentDataContainerFactoryProxy {
+    private val registry: CraftPersistentDataTypeRegistry
+
+    init {
+        /*
+         Can't grab actual instance since it's in CraftMetaItem (which is package-private)
+         And getting it would mean more janky reflection
+         */
+        val item = CraftItemStack.asCraftCopy(ItemStack(Material.STONE))
+        val pdc = item.itemMeta!!.persistentDataContainer
+        this.registry = CraftPersistentDataContainer::class.java.getDeclaredField("registry")
+            .apply { isAccessible = true }.get(pdc) as CraftPersistentDataTypeRegistry
+    }
+
+    override fun adapt(pdc: PersistentDataContainer): ExtendedPersistentDataContainer {
+        return when (pdc) {
+            is CraftPersistentDataContainer -> EcoPersistentDataContainer(pdc)
+            else -> throw IllegalArgumentException("Custom PDC instance ${pdc::class.java.name} is not supported!")
+        }
+    }
+
+    override fun newPdc(): PersistentDataContainer {
+        return CraftPersistentDataContainer(registry)
+    }
+
+    inner class EcoPersistentDataContainer(
+        private val handle: CraftPersistentDataContainer
+    ) : ExtendedPersistentDataContainer {
+        @Suppress("UNCHECKED_CAST")
+        private val customDataTags: MutableMap<String, Tag> =
+            CraftPersistentDataContainer::class.java.getDeclaredField("customDataTags")
+                .apply { isAccessible = true }.get(handle) as MutableMap<String, Tag>
+
+        override fun <T : Any, Z : Any> set(key: String, dataType: PersistentDataType<T, Z>, value: Z) {
+            customDataTags[key] =
+                registry.wrap(dataType, dataType.toPrimitive(value, handle.adapterContext))
+        }
+
+        override fun <T : Any, Z : Any> has(key: String, dataType: PersistentDataType<T, Z>): Boolean {
+            val value = customDataTags[key] ?: return false
+            return registry.isInstanceOf(dataType, value)
+        }
+
+        override fun <T : Any, Z : Any> get(key: String, dataType: PersistentDataType<T, Z>): Z? {
+            val value = customDataTags[key] ?: return null
+            return dataType.fromPrimitive(registry.extract<T, Tag>(dataType, value), handle.adapterContext)
+        }
+
+        override fun <T : Any, Z : Any> getOrDefault(
+            key: String,
+            dataType: PersistentDataType<T, Z>,
+            defaultValue: Z
+        ): Z {
+            return get(key, dataType) ?: defaultValue
+        }
+
+        override fun remove(key: String) {
+            customDataTags.remove(key)
+        }
+
+        override fun getAllKeys(): MutableSet<String> {
+            return customDataTags.keys
+        }
+
+        override fun getBase(): PersistentDataContainer {
+            return handle
+        }
+    }
+}

eco-core/core-nms/v1_20_6/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_6/FastItemStackFactory.kt

@@ -0,0 +1,392 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_6
+
+import com.willfp.eco.core.fast.FastItemStack
+import com.willfp.eco.internal.spigot.proxy.FastItemStackFactoryProxy
+import com.willfp.eco.internal.spigot.proxy.common.asNMSStack
+import com.willfp.eco.internal.spigot.proxy.common.item.ContinuallyAppliedPersistentDataContainer
+import com.willfp.eco.internal.spigot.proxy.common.item.ImplementedFIS
+import com.willfp.eco.internal.spigot.proxy.common.makePdc
+import com.willfp.eco.internal.spigot.proxy.common.mergeIfNeeded
+import com.willfp.eco.internal.spigot.proxy.common.setPdc
+import com.willfp.eco.internal.spigot.proxy.common.toAdventure
+import com.willfp.eco.internal.spigot.proxy.common.toItem
+import com.willfp.eco.internal.spigot.proxy.common.toMaterial
+import com.willfp.eco.internal.spigot.proxy.common.toNMS
+import com.willfp.eco.util.StringUtils
+import com.willfp.eco.util.toComponent
+import com.willfp.eco.util.toLegacy
+import net.kyori.adventure.text.Component
+import net.kyori.adventure.text.format.TextDecoration
+import net.minecraft.core.component.DataComponentType
+import net.minecraft.core.component.DataComponents
+import net.minecraft.nbt.CompoundTag
+import net.minecraft.util.Unit
+import net.minecraft.world.item.component.CustomData
+import net.minecraft.world.item.component.CustomModelData
+import net.minecraft.world.item.component.ItemLore
+import org.bukkit.craftbukkit.CraftRegistry
+import org.bukkit.craftbukkit.enchantments.CraftEnchantment
+import org.bukkit.enchantments.Enchantment
+import org.bukkit.inventory.ItemFlag
+import org.bukkit.inventory.ItemStack
+import org.bukkit.persistence.PersistentDataContainer
+import kotlin.math.max
+
+private val unstyledComponent = Component.empty().style {
+    it.color(null).decoration(TextDecoration.ITALIC, false)
+}
+
+class FastItemStackFactory : FastItemStackFactoryProxy {
+    override fun create(itemStack: ItemStack): FastItemStack {
+        return NewEcoFastItemStack(itemStack)
+    }
+
+    @Suppress("UsePropertyAccessSyntax")
+    class NewEcoFastItemStack(
+        private val bukkit: ItemStack
+    ) : ImplementedFIS {
+        // Cast is there because, try as I might, I can't get IntellIJ to recognise half the classes in the dev bundle
+        @Suppress("USELESS_CAST")
+        private val handle = bukkit.asNMSStack() as net.minecraft.world.item.ItemStack
+
+        private val pdc = (handle.get(DataComponents.CUSTOM_DATA)?.copyTag() ?: CompoundTag()).makePdc()
+
+        override fun getEnchants(checkStored: Boolean): Map<Enchantment, Int> {
+            val enchantments = handle.get(DataComponents.ENCHANTMENTS) ?: return emptyMap()
+
+            val map = mutableMapOf<Enchantment, Int>()
+
+            for ((enchantment, level) in enchantments.entrySet()) {
+                val bukkit = CraftEnchantment.minecraftToBukkit(enchantment.value())
+
+                map[bukkit] = level
+            }
+
+            return map
+        }
+
+        override fun getEnchantmentLevel(
+            enchantment: Enchantment,
+            checkStored: Boolean
+        ): Int {
+            val minecraft = CraftRegistry
+                .bukkitToMinecraft<Enchantment, net.minecraft.world.item.enchantment.Enchantment>(enchantment)
+
+            val enchantments = handle.get(DataComponents.ENCHANTMENTS) ?: return 0
+            var level = enchantments.getLevel(minecraft)
+
+            if (checkStored) {
+                val storedEnchantments = handle.get(DataComponents.STORED_ENCHANTMENTS) ?: return 0
+                level = max(level, storedEnchantments.getLevel(minecraft))
+            }
+
+            return level
+        }
+
+        override fun setLore(lore: List<String>?) = setLoreComponents(lore?.map { it.toComponent() })
+
+        override fun setLoreComponents(lore: List<Component>?) {
+            if (lore == null) {
+                handle.set<ItemLore>(DataComponents.LORE, null)
+            } else {
+                val components = lore
+                    .map { unstyledComponent.append(it) }
+                    .map { it.toNMS() }
+
+                handle.set(
+                    DataComponents.LORE, ItemLore(
+                        components,
+                        components
+                    )
+                )
+            }
+
+            apply()
+        }
+
+        override fun getLoreComponents(): List<Component> {
+            return handle.get(DataComponents.LORE)?.lines?.map { it.toAdventure() } ?: emptyList()
+        }
+
+        override fun getLore(): List<String> =
+            getLoreComponents().map { StringUtils.toLegacy(it) }
+
+        override fun setDisplayName(name: Component?) {
+            if (name == null) {
+                handle.set<net.minecraft.network.chat.Component>(DataComponents.CUSTOM_NAME, null)
+            } else {
+                handle.set(DataComponents.CUSTOM_NAME, name.toNMS())
+            }
+
+            apply()
+        }
+
+        override fun setDisplayName(name: String?) = setDisplayName(name?.toComponent())
+
+        override fun getDisplayNameComponent(): Component {
+            return handle.get(DataComponents.CUSTOM_NAME)?.toAdventure()
+                ?: Component.translatable(bukkit.type.toItem().getDescriptionId())
+        }
+
+        override fun getDisplayName(): String = displayNameComponent.toLegacy()
+
+        private fun <T> net.minecraft.world.item.ItemStack.modifyComponent(
+            component: DataComponentType<T>,
+            modifier: (T) -> T
+        ) {
+            val current = handle.get(component) ?: return
+            this.set(component, modifier(current))
+        }
+
+        override fun addItemFlags(vararg hideFlags: ItemFlag) {
+            for (flag in hideFlags) {
+                when (flag) {
+                    ItemFlag.HIDE_ENCHANTS -> {
+                        handle.modifyComponent(DataComponents.ENCHANTMENTS) { enchantments ->
+                            enchantments.withTooltip(false)
+                        }
+                    }
+
+                    ItemFlag.HIDE_ATTRIBUTES -> {
+                        handle.modifyComponent(DataComponents.ATTRIBUTE_MODIFIERS) { attributes ->
+                            attributes.withTooltip(false)
+                        }
+                    }
+
+                    ItemFlag.HIDE_UNBREAKABLE -> {
+                        handle.modifyComponent(DataComponents.UNBREAKABLE) { unbreakable ->
+                            unbreakable.withTooltip(false)
+                        }
+                    }
+
+                    ItemFlag.HIDE_DESTROYS -> {
+                        handle.modifyComponent(DataComponents.CAN_BREAK) { destroys ->
+                            destroys.withTooltip(false)
+                        }
+                    }
+
+                    ItemFlag.HIDE_PLACED_ON -> {
+                        handle.modifyComponent(DataComponents.CAN_PLACE_ON) { placedOn ->
+                            placedOn.withTooltip(false)
+                        }
+                    }
+
+                    ItemFlag.HIDE_ADDITIONAL_TOOLTIP -> {
+                        handle.set(DataComponents.HIDE_ADDITIONAL_TOOLTIP, Unit.INSTANCE)
+                    }
+
+                    ItemFlag.HIDE_DYE -> {
+                        handle.modifyComponent(DataComponents.DYED_COLOR) { dyed ->
+                            dyed.withTooltip(false)
+                        }
+                    }
+
+                    ItemFlag.HIDE_ARMOR_TRIM -> {
+                        handle.modifyComponent(DataComponents.TRIM) { trim ->
+                            trim.withTooltip(false)
+                        }
+                    }
+
+                    ItemFlag.HIDE_STORED_ENCHANTS -> {
+                        handle.modifyComponent(DataComponents.STORED_ENCHANTMENTS) { storedEnchants ->
+                            storedEnchants.withTooltip(false)
+                        }
+                    }
+                }
+            }
+
+            apply()
+        }
+
+        override fun removeItemFlags(vararg hideFlags: ItemFlag) {
+            for (flag in hideFlags) {
+                when (flag) {
+                    ItemFlag.HIDE_ENCHANTS -> {
+                        handle.modifyComponent(DataComponents.ENCHANTMENTS) { enchantments ->
+                            enchantments.withTooltip(true)
+                        }
+                    }
+
+                    ItemFlag.HIDE_ATTRIBUTES -> {
+                        handle.modifyComponent(DataComponents.ATTRIBUTE_MODIFIERS) { attributes ->
+                            attributes.withTooltip(true)
+                        }
+                    }
+
+                    ItemFlag.HIDE_UNBREAKABLE -> {
+                        handle.modifyComponent(DataComponents.UNBREAKABLE) { unbreakable ->
+                            unbreakable.withTooltip(true)
+                        }
+                    }
+
+                    ItemFlag.HIDE_DESTROYS -> {
+                        handle.modifyComponent(DataComponents.CAN_BREAK) { destroys ->
+                            destroys.withTooltip(true)
+                        }
+                    }
+
+                    ItemFlag.HIDE_PLACED_ON -> {
+                        handle.modifyComponent(DataComponents.CAN_PLACE_ON) { placedOn ->
+                            placedOn.withTooltip(true)
+                        }
+                    }
+
+                    ItemFlag.HIDE_ADDITIONAL_TOOLTIP -> {
+                        handle.remove(DataComponents.HIDE_ADDITIONAL_TOOLTIP)
+                    }
+
+                    ItemFlag.HIDE_DYE -> {
+                        handle.modifyComponent(DataComponents.DYED_COLOR) { dyed ->
+                            dyed.withTooltip(true)
+                        }
+                    }
+
+                    ItemFlag.HIDE_ARMOR_TRIM -> {
+                        handle.modifyComponent(DataComponents.TRIM) { trim ->
+                            trim.withTooltip(true)
+                        }
+                    }
+
+                    ItemFlag.HIDE_STORED_ENCHANTS -> {
+                        handle.modifyComponent(DataComponents.STORED_ENCHANTMENTS) { storedEnchants ->
+                            storedEnchants.withTooltip(true)
+                        }
+                    }
+                }
+            }
+
+            apply()
+        }
+
+        override fun getItemFlags(): Set<ItemFlag> {
+            val currentFlags = mutableSetOf<ItemFlag>()
+            for (f in ItemFlag.values()) {
+                if (hasItemFlag(f)) {
+                    currentFlags.add(f)
+                }
+            }
+            return currentFlags
+        }
+
+        override fun hasItemFlag(flag: ItemFlag): Boolean {
+            return when (flag) {
+                ItemFlag.HIDE_ENCHANTS -> {
+                    val enchantments = handle.get(DataComponents.ENCHANTMENTS) ?: return false
+                    !enchantments.showInTooltip
+                }
+
+                ItemFlag.HIDE_ATTRIBUTES -> {
+                    val attributes = handle.get(DataComponents.ATTRIBUTE_MODIFIERS) ?: return false
+                    !attributes.showInTooltip
+                }
+
+                ItemFlag.HIDE_UNBREAKABLE -> {
+                    val unbreakable = handle.get(DataComponents.UNBREAKABLE) ?: return false
+                    !unbreakable.showInTooltip
+                }
+
+                ItemFlag.HIDE_DESTROYS -> {
+                    val destroys = handle.get(DataComponents.CAN_BREAK) ?: return false
+                    !destroys.showInTooltip()
+                }
+
+                ItemFlag.HIDE_PLACED_ON -> {
+                    val placedOn = handle.get(DataComponents.CAN_PLACE_ON) ?: return false
+                    !placedOn.showInTooltip()
+                }
+
+                ItemFlag.HIDE_ADDITIONAL_TOOLTIP -> {
+                    handle.get(DataComponents.HIDE_ADDITIONAL_TOOLTIP) != null
+                }
+
+                ItemFlag.HIDE_DYE -> {
+                    val dyed = handle.get(DataComponents.DYED_COLOR) ?: return false
+                    !dyed.showInTooltip()
+                }
+
+                ItemFlag.HIDE_ARMOR_TRIM -> {
+                    val armorTrim = handle.get(DataComponents.TRIM) ?: return false
+                    !armorTrim.showInTooltip
+                }
+
+                ItemFlag.HIDE_STORED_ENCHANTS -> {
+                    val storedEnchants = handle.get(DataComponents.STORED_ENCHANTMENTS) ?: return false
+                    !storedEnchants.showInTooltip
+                }
+            }
+        }
+
+        override fun getRepairCost(): Int {
+            return handle.get(DataComponents.REPAIR_COST) ?: 0
+        }
+
+        override fun setRepairCost(cost: Int) {
+            handle.set(DataComponents.REPAIR_COST, cost)
+
+            apply()
+        }
+
+        override fun getPersistentDataContainer(): PersistentDataContainer {
+            return ContinuallyAppliedPersistentDataContainer(this.pdc, this)
+        }
+
+        override fun getAmount(): Int = handle.getCount()
+
+        override fun setAmount(amount: Int) {
+            handle.setCount(amount)
+            apply()
+        }
+
+        override fun setType(material: org.bukkit.Material) {
+            @Suppress("DEPRECATION")
+            handle.setItem(material.toItem())
+            apply()
+        }
+
+        override fun getType(): org.bukkit.Material = handle.getItem().toMaterial()
+
+        override fun getCustomModelData(): Int? =
+            handle.get(DataComponents.CUSTOM_MODEL_DATA)?.value
+
+        override fun setCustomModelData(data: Int?) {
+            if (data == null) {
+                handle.remove(DataComponents.CUSTOM_MODEL_DATA)
+            } else {
+                handle.set(DataComponents.CUSTOM_MODEL_DATA, CustomModelData(data))
+            }
+
+            apply()
+        }
+
+        override fun equals(other: Any?): Boolean {
+            if (other !is NewEcoFastItemStack) {
+                return false
+            }
+
+            return other.hashCode() == this.hashCode()
+        }
+
+        override fun hashCode(): Int {
+            return net.minecraft.world.item.ItemStack.hashItemAndComponents(handle)
+        }
+
+        override fun apply() {
+            val customData = handle.getOrDefault(DataComponents.CUSTOM_DATA, CustomData.EMPTY)
+            val updated = customData.update {
+                it.setPdc(pdc)
+            }
+
+            if (updated.isEmpty) {
+                handle.remove(DataComponents.CUSTOM_DATA)
+            } else {
+                handle.set(DataComponents.CUSTOM_DATA, updated)
+            }
+
+            bukkit.mergeIfNeeded(handle)
+        }
+
+        override fun unwrap(): ItemStack {
+            return bukkit
+        }
+    }
+}

eco-core/core-nms/v1_20_6/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_6/MiniMessageTranslator.kt

@@ -0,0 +1,33 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_6
+
+import com.willfp.eco.core.display.Display
+import com.willfp.eco.internal.spigot.proxy.MiniMessageTranslatorProxy
+import com.willfp.eco.util.toLegacy
+import net.kyori.adventure.text.minimessage.MiniMessage
+
+class MiniMessageTranslator : MiniMessageTranslatorProxy {
+    override fun format(message: String): String {
+        var mut = message
+
+        val startsWithPrefix = mut.startsWith(Display.PREFIX)
+        if (startsWithPrefix) {
+            mut = mut.substring(2)
+        }
+
+        mut = mut.replace('§', '&')
+
+        val miniMessage = runCatching {
+            MiniMessage.miniMessage().deserialize(
+                mut
+            ).toLegacy()
+        }.getOrNull() ?: mut
+
+        mut = if (startsWithPrefix) {
+            Display.PREFIX + miniMessage
+        } else {
+            miniMessage
+        }
+
+        return mut
+    }
+}

eco-core/core-nms/v1_20_6/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_6/PacketHandler.kt

@@ -0,0 +1,46 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_6
+
+import com.willfp.eco.core.EcoPlugin
+import com.willfp.eco.core.packet.PacketListener
+import com.willfp.eco.internal.spigot.proxy.PacketHandlerProxy
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.PacketAutoRecipe
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.PacketHeldItemSlot
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.PacketSetSlot
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.PacketWindowItems
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.frame.clearFrames
+import com.willfp.eco.internal.spigot.proxy.v1_20_6.packet.NewItemsPacketOpenWindowMerchant
+import com.willfp.eco.internal.spigot.proxy.v1_20_6.packet.NewItemsPacketSetCreativeSlot
+import net.minecraft.network.protocol.Packet
+import org.bukkit.craftbukkit.entity.CraftPlayer
+import org.bukkit.entity.Player
+
+class PacketHandler : PacketHandlerProxy {
+    override fun sendPacket(player: Player, packet: com.willfp.eco.core.packet.Packet) {
+        if (player !is CraftPlayer) {
+            return
+        }
+
+        val handle = packet.handle
+
+        if (handle !is Packet<*>) {
+            return
+        }
+
+        player.handle.connection.send(handle)
+    }
+
+    override fun clearDisplayFrames() {
+        clearFrames()
+    }
+
+    override fun getPacketListeners(plugin: EcoPlugin): List<PacketListener> {
+        return listOf(
+            PacketAutoRecipe(plugin),
+            PacketHeldItemSlot,
+            NewItemsPacketOpenWindowMerchant,
+            NewItemsPacketSetCreativeSlot,
+            PacketSetSlot,
+            PacketWindowItems(plugin)
+        )
+    }
+}

eco-core/core-nms/v1_20_6/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_6/SNBTConverter.kt

@@ -0,0 +1,80 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_6
+
+import com.mojang.serialization.Dynamic
+import com.willfp.eco.core.items.TestableItem
+import com.willfp.eco.core.recipe.parts.EmptyTestableItem
+import com.willfp.eco.internal.spigot.proxy.SNBTConverterProxy
+import net.minecraft.nbt.CompoundTag
+import net.minecraft.nbt.NbtOps
+import net.minecraft.nbt.SnbtPrinterTagVisitor
+import net.minecraft.nbt.TagParser
+import net.minecraft.server.MinecraftServer
+import net.minecraft.util.datafix.fixes.References
+import org.bukkit.Bukkit
+import org.bukkit.craftbukkit.CraftServer
+import org.bukkit.craftbukkit.inventory.CraftItemStack
+import org.bukkit.craftbukkit.util.CraftMagicNumbers
+import org.bukkit.inventory.ItemStack
+
+private val registryAccess = (Bukkit.getServer() as CraftServer).server.registryAccess()
+
+class SNBTConverter : SNBTConverterProxy {
+    private fun parseItemSNBT(snbt: String): CompoundTag? {
+        val nbt = runCatching { TagParser.parseTag(snbt) }.getOrNull() ?: return null
+        val dataVersion = if (nbt.contains("DataVersion")) {
+            nbt.getInt("DataVersion")
+        } else null
+
+        // If the data version is the same as the server's data version, we don't need to fix it
+        if (dataVersion == CraftMagicNumbers.INSTANCE.dataVersion) {
+            return nbt
+        }
+
+        return MinecraftServer.getServer().fixerUpper.update(
+            References.ITEM_STACK,
+            Dynamic(NbtOps.INSTANCE, nbt),
+            dataVersion ?: 3700, // 3700 is the 1.20.4 data version
+            CraftMagicNumbers.INSTANCE.dataVersion
+        ).value as CompoundTag
+    }
+
+    override fun fromSNBT(snbt: String): ItemStack? {
+        val tag = parseItemSNBT(snbt) ?: return null
+        val nms = net.minecraft.world.item.ItemStack.parse(registryAccess, tag).orElse(null) ?: return null
+        return CraftItemStack.asBukkitCopy(nms)
+    }
+
+    override fun toSNBT(itemStack: ItemStack): String {
+        val nms = CraftItemStack.asNMSCopy(itemStack)
+        val tag = nms.save(registryAccess) as CompoundTag
+        tag.putInt("DataVersion", CraftMagicNumbers.INSTANCE.dataVersion)
+        return SnbtPrinterTagVisitor().visit(tag)
+    }
+
+    override fun makeSNBTTestable(snbt: String): TestableItem {
+        val tag = parseItemSNBT(snbt) ?: return EmptyTestableItem()
+        val nms = net.minecraft.world.item.ItemStack.parse(registryAccess, tag).orElse(null)
+            ?: return EmptyTestableItem()
+
+        tag.remove("Count")
+        return SNBTTestableItem(CraftItemStack.asBukkitCopy(nms), tag)
+    }
+
+    class SNBTTestableItem(
+        private val item: ItemStack,
+        private val tag: CompoundTag
+    ) : TestableItem {
+        override fun matches(itemStack: ItemStack?): Boolean {
+            if (itemStack == null) {
+                return false
+            }
+
+            val nms = CraftItemStack.asNMSCopy(itemStack)
+            val nmsTag = nms.save(registryAccess) as CompoundTag
+            nmsTag.remove("Count")
+            return tag.copy().merge(nmsTag) == nmsTag && itemStack.type == item.type
+        }
+
+        override fun getItem(): ItemStack = item
+    }
+}

eco-core/core-nms/v1_20_6/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_6/Skull.kt

@@ -0,0 +1,18 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_6
+
+import com.willfp.eco.internal.spigot.proxy.SkullProxy
+import com.willfp.eco.internal.spigot.proxy.common.texture
+import org.bukkit.inventory.meta.SkullMeta
+
+class Skull : SkullProxy {
+    override fun setSkullTexture(
+        meta: SkullMeta,
+        base64: String
+    ) {
+        meta.texture = base64
+    }
+
+    override fun getSkullTexture(
+        meta: SkullMeta
+    ): String? = meta.texture
+}

eco-core/core-nms/v1_20_6/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_6/TPS.kt

@@ -0,0 +1,11 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_6
+
+import com.willfp.eco.internal.spigot.proxy.TPSProxy
+import org.bukkit.Bukkit
+import org.bukkit.craftbukkit.CraftServer
+
+class TPS : TPSProxy {
+    override fun getTPS(): Double {
+        return (Bukkit.getServer() as CraftServer).handle.server.tps1.average
+    }
+}

eco-core/core-nms/v1_20_6/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_6/entity/EcoEntityController.kt

@@ -0,0 +1,95 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_6.entity
+
+import com.willfp.eco.core.entities.ai.CustomGoal
+import com.willfp.eco.core.entities.ai.EntityController
+import com.willfp.eco.core.entities.ai.EntityGoal
+import com.willfp.eco.core.entities.ai.TargetGoal
+import com.willfp.eco.internal.spigot.proxy.common.ai.CustomGoalFactory
+import com.willfp.eco.internal.spigot.proxy.common.ai.getGoalFactory
+import com.willfp.eco.internal.spigot.proxy.common.toPathfinderMob
+import net.minecraft.world.entity.PathfinderMob
+import net.minecraft.world.entity.ai.goal.Goal
+import org.bukkit.entity.Mob
+
+class EcoEntityController<T : Mob>(
+    private val handle: T
+) : EntityController<T> {
+    override fun addEntityGoal(priority: Int, goal: EntityGoal<in T>): EntityController<T> {
+        val nms = getNms() ?: return this
+
+        nms.goalSelector.addGoal(
+            priority,
+            goal.getGoalFactory()?.create(goal, nms) ?: return this
+        )
+
+        return this
+    }
+
+    override fun removeEntityGoal(goal: EntityGoal<in T>): EntityController<T> {
+        val nms = getNms() ?: return this
+
+        val predicate: (Goal) -> Boolean = if (goal is CustomGoal<*>) {
+            { CustomGoalFactory.isGoalOfType(it, goal) }
+        } else {
+            { goal.getGoalFactory()?.isGoalOfType(it) == true }
+        }
+
+        for (wrapped in nms.goalSelector.availableGoals.toSet()) {
+            if (predicate(wrapped.goal)) {
+                nms.goalSelector.removeGoal(wrapped.goal)
+            }
+        }
+
+        return this
+    }
+
+    override fun clearEntityGoals(): EntityController<T> {
+        val nms = getNms() ?: return this
+        nms.goalSelector.availableGoals.clear()
+        return this
+    }
+
+    override fun addTargetGoal(priority: Int, goal: TargetGoal<in T>): EntityController<T> {
+        val nms = getNms() ?: return this
+
+        nms.targetSelector.addGoal(
+            priority, goal.getGoalFactory()?.create(goal, nms) ?: return this
+        )
+
+        nms.targetSelector
+
+        return this
+    }
+
+    override fun removeTargetGoal(goal: TargetGoal<in T>): EntityController<T> {
+        val nms = getNms() ?: return this
+
+        val predicate: (Goal) -> Boolean = if (goal is CustomGoal<*>) {
+            { CustomGoalFactory.isGoalOfType(it, goal) }
+        } else {
+            { goal.getGoalFactory()?.isGoalOfType(it) == true }
+        }
+
+        for (wrapped in nms.targetSelector.availableGoals.toSet()) {
+            if (predicate(wrapped.goal)) {
+                nms.targetSelector.removeGoal(wrapped.goal)
+            }
+        }
+
+        return this
+    }
+
+    override fun clearTargetGoals(): EntityController<T> {
+        val nms = getNms() ?: return this
+        nms.targetSelector.availableGoals.clear()
+        return this
+    }
+
+    private fun getNms(): PathfinderMob? {
+        return handle.toPathfinderMob()
+    }
+
+    override fun getEntity(): T {
+        return handle
+    }
+}

eco-core/core-nms/v1_20_6/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_6/packet/NewItemsPacketOpenWindowMerchant.kt

@@ -0,0 +1,35 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_6.packet
+
+import com.willfp.eco.core.display.Display
+import com.willfp.eco.core.packet.PacketEvent
+import com.willfp.eco.core.packet.PacketListener
+import com.willfp.eco.internal.spigot.proxy.common.asBukkitStack
+import net.minecraft.network.protocol.game.ClientboundMerchantOffersPacket
+import net.minecraft.world.item.trading.MerchantOffers
+
+object NewItemsPacketOpenWindowMerchant : PacketListener {
+    private val field = ClientboundMerchantOffersPacket::class.java
+        .declaredFields
+        .first { it.type == MerchantOffers::class.java }
+        .apply { isAccessible = true }
+
+    override fun onSend(event: PacketEvent) {
+        val packet = event.packet.handle as? ClientboundMerchantOffersPacket ?: return
+
+        val offers = MerchantOffers()
+
+        for (offer in packet.offers) {
+            val new = offer.copy()
+
+            Display.display(new.baseCostA.itemStack.asBukkitStack(), event.player)
+            if (new.costB.isPresent) {
+                Display.display(new.costB.get().itemStack.asBukkitStack(), event.player)
+            }
+            Display.display(new.result.asBukkitStack(), event.player)
+
+            offers += new
+        }
+
+        field.set(packet, offers)
+    }
+}

eco-core/core-nms/v1_20_6/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_6/packet/NewItemsPacketSetCreativeSlot.kt

@@ -0,0 +1,19 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_6.packet
+
+import com.willfp.eco.core.display.Display
+import com.willfp.eco.core.packet.PacketEvent
+import com.willfp.eco.core.packet.PacketListener
+import com.willfp.eco.internal.spigot.proxy.common.asBukkitStack
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.frame.DisplayFrame
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.frame.lastDisplayFrame
+import net.minecraft.network.protocol.game.ServerboundSetCreativeModeSlotPacket
+
+object NewItemsPacketSetCreativeSlot : PacketListener {
+    override fun onReceive(event: PacketEvent) {
+        val packet = event.packet.handle as? ServerboundSetCreativeModeSlotPacket ?: return
+
+        Display.revert(packet.itemStack.asBukkitStack())
+
+        event.player.lastDisplayFrame = DisplayFrame.EMPTY
+    }
+}

eco-core/core-nms/v1_20_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R1/CommonsInitializer.kt

@@ -5,6 +5,8 @@ import com.willfp.eco.internal.spigot.proxy.CommonsInitializerProxy
 import com.willfp.eco.internal.spigot.proxy.common.CommonsProvider
 import com.willfp.eco.internal.spigot.proxy.common.packet.PacketInjectorListener
 import com.willfp.eco.internal.spigot.proxy.common.toResourceLocation
+import net.kyori.adventure.text.Component
+import net.kyori.adventure.text.serializer.json.JSONComponentSerializer
 import net.minecraft.core.registries.BuiltInRegistries
 import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.Tag
@@ -155,5 +157,10 @@ class CommonsInitializer : CommonsInitializerProxy {
         override fun toNMS(player: Player): ServerPlayer {
             return (player as CraftPlayer).handle
         }
+
+        override fun toNMS(component: Component): net.minecraft.network.chat.Component {
+            val json = JSONComponentSerializer.json().serialize(component)
+            return net.minecraft.network.chat.Component.Serializer.fromJson(json)!!
+        }
     }
 }

eco-core/core-nms/v1_20_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R1/DisplayName.kt

@@ -3,6 +3,7 @@ package com.willfp.eco.internal.spigot.proxy.v1_20_R1
 import com.willfp.eco.core.packet.Packet
 import com.willfp.eco.core.packet.sendPacket
 import com.willfp.eco.internal.spigot.proxy.DisplayNameProxy
+import com.willfp.eco.internal.spigot.proxy.common.toNMS
 import io.papermc.paper.adventure.PaperAdventure
 import net.kyori.adventure.text.Component
 import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket
@@ -40,8 +41,7 @@ class DisplayName : DisplayNameProxy {
             return
         }
 
-        val nmsComponent = PaperAdventure.asVanilla(displayName)
+        val nmsComponent = displayName.toNMS()
-            ?: throw IllegalStateException("Display name component is null!")
 
         val nmsEntity = entity.handle
         nmsEntity.isCustomNameVisible

eco-core/core-nms/v1_20_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R1/ExtendedPersistentDataContainerFactory.kt

@@ -28,7 +28,7 @@ class ExtendedPersistentDataContainerFactory : ExtendedPersistentDataContainerFa
     override fun adapt(pdc: PersistentDataContainer): ExtendedPersistentDataContainer {
         return when (pdc) {
             is CraftPersistentDataContainer -> EcoPersistentDataContainer(pdc)
-            else -> throw IllegalArgumentException("Custom PDC instance ims not supported!")
+            else -> throw IllegalArgumentException("Custom PDC instance ${pdc::class.java.name} is not supported!")
         }
     }
 

eco-core/core-nms/v1_20_R1/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R1/SNBTConverter.kt

@@ -7,6 +7,7 @@ import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.SnbtPrinterTagVisitor
 import net.minecraft.nbt.TagParser
 import org.bukkit.craftbukkit.v1_20_R1.inventory.CraftItemStack
+import org.bukkit.craftbukkit.v1_20_R1.util.CraftMagicNumbers
 import org.bukkit.inventory.ItemStack
 
 class SNBTConverter : SNBTConverterProxy {
@@ -18,7 +19,9 @@ class SNBTConverter : SNBTConverterProxy {
 
     override fun toSNBT(itemStack: ItemStack): String {
         val nms = CraftItemStack.asNMSCopy(itemStack)
-        return SnbtPrinterTagVisitor().visit(nms.save(CompoundTag()))
+        val tag = nms.save(CompoundTag())
+        tag.putInt("DataVersion", CraftMagicNumbers.INSTANCE.dataVersion)
+        return SnbtPrinterTagVisitor().visit(tag)
     }
 
     override fun makeSNBTTestable(snbt: String): TestableItem {

eco-core/core-nms/v1_20_R2/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R2/CommonsInitializer.kt

@@ -5,6 +5,8 @@ import com.willfp.eco.internal.spigot.proxy.CommonsInitializerProxy
 import com.willfp.eco.internal.spigot.proxy.common.CommonsProvider
 import com.willfp.eco.internal.spigot.proxy.common.packet.PacketInjectorListener
 import com.willfp.eco.internal.spigot.proxy.common.toResourceLocation
+import net.kyori.adventure.text.Component
+import net.kyori.adventure.text.serializer.json.JSONComponentSerializer
 import net.minecraft.core.registries.BuiltInRegistries
 import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.Tag
@@ -155,5 +157,10 @@ class CommonsInitializer : CommonsInitializerProxy {
         override fun toNMS(player: Player): ServerPlayer {
             return (player as CraftPlayer).handle
         }
+
+        override fun toNMS(component: Component): net.minecraft.network.chat.Component {
+            val json = JSONComponentSerializer.json().serialize(component)
+            return net.minecraft.network.chat.Component.Serializer.fromJson(json)!!
+        }
     }
 }

eco-core/core-nms/v1_20_R2/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R2/DisplayName.kt

@@ -3,6 +3,7 @@ package com.willfp.eco.internal.spigot.proxy.v1_20_R2
 import com.willfp.eco.core.packet.Packet
 import com.willfp.eco.core.packet.sendPacket
 import com.willfp.eco.internal.spigot.proxy.DisplayNameProxy
+import com.willfp.eco.internal.spigot.proxy.common.toNMS
 import io.papermc.paper.adventure.PaperAdventure
 import net.kyori.adventure.text.Component
 import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket
@@ -37,8 +38,7 @@ class DisplayName : DisplayNameProxy {
             return
         }
 
-        val nmsComponent = PaperAdventure.asVanilla(displayName)
+        val nmsComponent = displayName.toNMS()
-            ?: throw IllegalStateException("Display name component is null!")
 
         val nmsEntity = entity.handle
         nmsEntity.isCustomNameVisible

eco-core/core-nms/v1_20_R2/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R2/ExtendedPersistentDataContainerFactory.kt

@@ -28,7 +28,7 @@ class ExtendedPersistentDataContainerFactory : ExtendedPersistentDataContainerFa
     override fun adapt(pdc: PersistentDataContainer): ExtendedPersistentDataContainer {
         return when (pdc) {
             is CraftPersistentDataContainer -> EcoPersistentDataContainer(pdc)
-            else -> throw IllegalArgumentException("Custom PDC instance ims not supported!")
+            else -> throw IllegalArgumentException("Custom PDC instance ${pdc::class.java.name} is not supported!")
         }
     }
 

eco-core/core-nms/v1_20_R2/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R2/SNBTConverter.kt

@@ -7,6 +7,7 @@ import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.SnbtPrinterTagVisitor
 import net.minecraft.nbt.TagParser
 import org.bukkit.craftbukkit.v1_20_R2.inventory.CraftItemStack
+import org.bukkit.craftbukkit.v1_20_R2.util.CraftMagicNumbers
 import org.bukkit.inventory.ItemStack
 
 class SNBTConverter : SNBTConverterProxy {
@@ -18,7 +19,9 @@ class SNBTConverter : SNBTConverterProxy {
 
     override fun toSNBT(itemStack: ItemStack): String {
         val nms = CraftItemStack.asNMSCopy(itemStack)
-        return SnbtPrinterTagVisitor().visit(nms.save(CompoundTag()))
+        val tag = nms.save(CompoundTag())
+        tag.putInt("DataVersion", CraftMagicNumbers.INSTANCE.dataVersion)
+        return SnbtPrinterTagVisitor().visit(tag)
     }
 
     override fun makeSNBTTestable(snbt: String): TestableItem {

eco-core/core-nms/v1_20_R3/build.gradle.kts

@@ -0,0 +1,39 @@
+plugins {
+    id("io.papermc.paperweight.userdev")
+}
+
+group = "com.willfp"
+version = rootProject.version
+
+dependencies {
+    implementation(project(":eco-core:core-nms:nms-common"))
+    paperweight.paperDevBundle("1.20.4-R0.1-SNAPSHOT")
+
+    implementation("net.kyori:adventure-text-minimessage:4.11.0") {
+        version {
+            strictly("4.11.0")
+        }
+        exclude(group = "net.kyori", module = "adventure-api")
+    }
+}
+
+tasks {
+    build {
+        dependsOn(reobfJar)
+    }
+
+    reobfJar {
+        mustRunAfter(shadowJar)
+    }
+
+    shadowJar {
+        relocate(
+            "com.willfp.eco.internal.spigot.proxy.common",
+            "com.willfp.eco.internal.spigot.proxy.v1_20_R3.common"
+        )
+        relocate(
+            "net.kyori.adventure.text.minimessage",
+            "com.willfp.eco.internal.spigot.proxy.v1_20_R3.minimessage"
+        )
+    }
+}

eco-core/core-nms/v1_20_R3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R3/BukkitCommands.kt

@@ -0,0 +1,35 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_R3
+
+import com.willfp.eco.core.command.PluginCommandBase
+import com.willfp.eco.internal.spigot.proxy.BukkitCommandsProxy
+import org.bukkit.Bukkit
+import org.bukkit.command.Command
+import org.bukkit.command.SimpleCommandMap
+import org.bukkit.craftbukkit.v1_20_R3.CraftServer
+import java.lang.reflect.Field
+
+class BukkitCommands : BukkitCommandsProxy {
+    private val knownCommandsField: Field by lazy {
+        SimpleCommandMap::class.java.getDeclaredField("knownCommands")
+            .apply {
+                isAccessible = true
+            }
+    }
+
+    @Suppress("UNCHECKED_CAST")
+    private val knownCommands: MutableMap<String, Command>
+        get() = knownCommandsField.get(getCommandMap()) as MutableMap<String, Command>
+
+    override fun getCommandMap(): SimpleCommandMap {
+        return (Bukkit.getServer() as CraftServer).commandMap
+    }
+
+    override fun syncCommands() {
+        (Bukkit.getServer() as CraftServer).syncCommands()
+    }
+
+    override fun unregisterCommand(command: PluginCommandBase) {
+        knownCommands.remove(command.name)
+        knownCommands.remove("${command.plugin.name.lowercase()}:${command.name}")
+    }
+}

eco-core/core-nms/v1_20_R3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R3/CommonsInitializer.kt

@@ -0,0 +1,166 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_R3
+
+import com.willfp.eco.core.EcoPlugin
+import com.willfp.eco.internal.spigot.proxy.CommonsInitializerProxy
+import com.willfp.eco.internal.spigot.proxy.common.CommonsProvider
+import com.willfp.eco.internal.spigot.proxy.common.packet.PacketInjectorListener
+import com.willfp.eco.internal.spigot.proxy.common.toResourceLocation
+import net.kyori.adventure.text.Component
+import net.kyori.adventure.text.serializer.json.JSONComponentSerializer
+import net.minecraft.core.registries.BuiltInRegistries
+import net.minecraft.nbt.CompoundTag
+import net.minecraft.nbt.Tag
+import net.minecraft.resources.ResourceLocation
+import net.minecraft.server.level.ServerPlayer
+import net.minecraft.world.entity.PathfinderMob
+import net.minecraft.world.item.Item
+import org.bukkit.Bukkit
+import org.bukkit.Material
+import org.bukkit.NamespacedKey
+import org.bukkit.craftbukkit.v1_20_R3.CraftServer
+import org.bukkit.craftbukkit.v1_20_R3.entity.CraftEntity
+import org.bukkit.craftbukkit.v1_20_R3.entity.CraftMob
+import org.bukkit.craftbukkit.v1_20_R3.entity.CraftPlayer
+import org.bukkit.craftbukkit.v1_20_R3.inventory.CraftItemStack
+import org.bukkit.craftbukkit.v1_20_R3.persistence.CraftPersistentDataContainer
+import org.bukkit.craftbukkit.v1_20_R3.persistence.CraftPersistentDataTypeRegistry
+import org.bukkit.craftbukkit.v1_20_R3.util.CraftMagicNumbers
+import org.bukkit.craftbukkit.v1_20_R3.util.CraftNamespacedKey
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Mob
+import org.bukkit.entity.Player
+import org.bukkit.inventory.ItemStack
+import org.bukkit.persistence.PersistentDataContainer
+import java.lang.reflect.Field
+
+class CommonsInitializer : CommonsInitializerProxy {
+    override fun init(plugin: EcoPlugin) {
+        CommonsProvider.setIfNeeded(CommonsProviderImpl)
+        plugin.onEnable {
+            plugin.eventManager.registerListener(PacketInjectorListener)
+        }
+    }
+
+    object CommonsProviderImpl : CommonsProvider {
+        private val cisHandle: Field = CraftItemStack::class.java.getDeclaredField("handle").apply {
+            isAccessible = true
+        }
+
+        private val pdcRegsitry = Class.forName("org.bukkit.craftbukkit.v1_20_R3.inventory.CraftMetaItem")
+            .getDeclaredField("DATA_TYPE_REGISTRY")
+            .apply { isAccessible = true }
+            .get(null) as CraftPersistentDataTypeRegistry
+
+        override val nbtTagString = CraftMagicNumbers.NBT.TAG_STRING
+
+        override fun toPathfinderMob(mob: Mob): PathfinderMob? {
+            val craft = mob as? CraftMob ?: return null
+            return craft.handle as? PathfinderMob
+        }
+
+        override fun toResourceLocation(namespacedKey: NamespacedKey): ResourceLocation =
+            CraftNamespacedKey.toMinecraft(namespacedKey)
+
+        override fun asNMSStack(itemStack: ItemStack): net.minecraft.world.item.ItemStack {
+            return if (itemStack !is CraftItemStack) {
+                CraftItemStack.asNMSCopy(itemStack)
+            } else {
+                cisHandle[itemStack] as net.minecraft.world.item.ItemStack? ?: CraftItemStack.asNMSCopy(itemStack)
+            }
+        }
+
+        override fun asBukkitStack(itemStack: net.minecraft.world.item.ItemStack): ItemStack {
+            return CraftItemStack.asCraftMirror(itemStack)
+        }
+
+        override fun mergeIfNeeded(itemStack: ItemStack, nmsStack: net.minecraft.world.item.ItemStack) {
+            if (itemStack !is CraftItemStack) {
+                itemStack.itemMeta = CraftItemStack.asCraftMirror(nmsStack).itemMeta
+            }
+        }
+
+        override fun toBukkitEntity(entity: net.minecraft.world.entity.LivingEntity): LivingEntity? =
+            CraftEntity.getEntity(Bukkit.getServer() as CraftServer, entity) as? LivingEntity
+
+        override fun makePdc(tag: CompoundTag, base: Boolean): PersistentDataContainer {
+            fun emptyPdc(): CraftPersistentDataContainer = CraftPersistentDataContainer(pdcRegsitry)
+
+            fun CompoundTag?.toPdc(): PersistentDataContainer {
+                val pdc = emptyPdc()
+                this ?: return pdc
+                val keys = this.allKeys
+                for (key in keys) {
+                    pdc.put(key, this[key])
+                }
+
+                return pdc
+            }
+
+            return if (base) {
+                tag.toPdc()
+            } else {
+                if (tag.contains("PublicBukkitValues")) {
+                    tag.getCompound("PublicBukkitValues").toPdc()
+                } else {
+                    emptyPdc()
+                }
+            }
+        }
+
+        override fun setPdc(
+            tag: CompoundTag,
+            pdc: PersistentDataContainer?,
+            item: net.minecraft.world.item.ItemStack?
+        ) {
+            fun CraftPersistentDataContainer.toTag(): CompoundTag {
+                val compound = CompoundTag()
+                val rawPublicMap: Map<String, Tag> = this.raw
+                for ((key, value) in rawPublicMap) {
+                    compound.put(key, value)
+                }
+
+                return compound
+            }
+
+            val container = when (pdc) {
+                is CraftPersistentDataContainer? -> pdc
+                else -> null
+            }
+
+            if (item != null) {
+                if (container != null && !container.isEmpty) {
+                    for (key in tag.allKeys.toSet()) {
+                        tag.remove(key)
+                    }
+
+                    tag.merge(container.toTag())
+                } else {
+                    item.tag = null
+                }
+            } else {
+                if (container != null && !container.isEmpty) {
+                    tag.put("PublicBukkitValues", container.toTag())
+                } else {
+                    tag.remove("PublicBukkitValues")
+                }
+            }
+        }
+
+        override fun materialToItem(material: Material): Item =
+            BuiltInRegistries.ITEM.getOptional(material.key.toResourceLocation())
+                .orElseThrow { IllegalArgumentException("Material is not item!") }
+
+        override fun itemToMaterial(item: Item) =
+            Material.getMaterial(BuiltInRegistries.ITEM.getKey(item).path.uppercase())
+                ?: throw IllegalArgumentException("Invalid material!")
+
+        override fun toNMS(player: Player): ServerPlayer {
+            return (player as CraftPlayer).handle
+        }
+
+        override fun toNMS(component: Component): net.minecraft.network.chat.Component {
+            val json = JSONComponentSerializer.json().serialize(component)
+            return net.minecraft.network.chat.Component.Serializer.fromJson(json)!!
+        }
+    }
+}

eco-core/core-nms/v1_20_R3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R3/DisplayName.kt

@@ -0,0 +1,68 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_R3
+
+import com.willfp.eco.core.packet.Packet
+import com.willfp.eco.core.packet.sendPacket
+import com.willfp.eco.internal.spigot.proxy.DisplayNameProxy
+import com.willfp.eco.internal.spigot.proxy.common.toNMS
+import io.papermc.paper.adventure.PaperAdventure
+import net.kyori.adventure.text.Component
+import net.minecraft.network.protocol.game.ClientboundSetEntityDataPacket
+import net.minecraft.network.syncher.EntityDataAccessor
+import net.minecraft.network.syncher.SynchedEntityData
+import net.minecraft.world.entity.Entity
+import org.bukkit.craftbukkit.v1_20_R3.entity.CraftLivingEntity
+import org.bukkit.craftbukkit.v1_20_R3.entity.CraftMob
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Mob
+import org.bukkit.entity.Player
+import java.util.Optional
+
+@Suppress("UNCHECKED_CAST")
+class DisplayName : DisplayNameProxy {
+    private val displayNameAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[2]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Optional<net.minecraft.network.chat.Component>>
+
+    private val customNameVisibleAccessor = Entity::class.java
+        .declaredFields
+        .filter { it.type == EntityDataAccessor::class.java }
+        .toList()[3]
+        .apply { isAccessible = true }
+        .get(null) as EntityDataAccessor<Boolean>
+
+    override fun setClientsideDisplayName(entity: LivingEntity, player: Player, displayName: Component, visible: Boolean) {
+        if (entity !is CraftLivingEntity) {
+            return
+        }
+
+        val nmsComponent = displayName.toNMS()
+
+        val nmsEntity = entity.handle
+        nmsEntity.isCustomNameVisible
+        val entityData = SynchedEntityData(nmsEntity)
+
+        entityData.forceSet(displayNameAccessor, Optional.of(nmsComponent))
+        entityData.forceSet(customNameVisibleAccessor, visible)
+
+        val packet = ClientboundSetEntityDataPacket(
+            nmsEntity.id,
+            entityData.packDirty() ?: throw IllegalStateException("No packed entity data")
+        )
+
+        player.sendPacket(Packet(packet))
+    }
+
+    private fun <T: Any> SynchedEntityData.forceSet(
+        accessor: EntityDataAccessor<T>,
+        value: T
+    ) {
+        if (!this.hasItem(accessor)) {
+            this.define(accessor, value)
+        }
+        this[accessor] = value
+        this.markDirty(accessor)
+    }
+}

eco-core/core-nms/v1_20_R3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R3/DummyEntityFactory.kt

@@ -0,0 +1,16 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_R3
+
+import com.willfp.eco.internal.entities.EcoDummyEntity
+import com.willfp.eco.internal.spigot.proxy.DummyEntityFactoryProxy
+import org.bukkit.Location
+import org.bukkit.craftbukkit.v1_20_R3.CraftWorld
+import org.bukkit.entity.Entity
+import org.bukkit.entity.EntityType
+import org.bukkit.entity.Zombie
+
+class DummyEntityFactory : DummyEntityFactoryProxy {
+    override fun createDummyEntity(location: Location): Entity {
+        val world = location.world as CraftWorld
+        return EcoDummyEntity(world.createEntity(location, Zombie::class.java))
+    }
+}

eco-core/core-nms/v1_20_R3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R3/EntityControllerFactory.kt

@@ -0,0 +1,12 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_R3
+
+import com.willfp.eco.core.entities.ai.EntityController
+import com.willfp.eco.internal.spigot.proxy.EntityControllerFactoryProxy
+import com.willfp.eco.internal.spigot.proxy.v1_20_R3.entity.EcoEntityController
+import org.bukkit.entity.Mob
+
+class EntityControllerFactory : EntityControllerFactoryProxy {
+    override fun <T : Mob> createEntityController(entity: T): EntityController<T> {
+        return EcoEntityController(entity)
+    }
+}

eco-core/core-nms/v1_20_R3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R3/ExtendedPersistentDataContainerFactory.kt

@@ -0,0 +1,83 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_R3
+
+import com.willfp.eco.core.data.ExtendedPersistentDataContainer
+import com.willfp.eco.internal.spigot.proxy.ExtendedPersistentDataContainerFactoryProxy
+import com.willfp.eco.internal.spigot.proxy.common.item.ContinuallyAppliedPersistentDataContainer
+import net.minecraft.nbt.Tag
+import org.bukkit.Material
+import org.bukkit.craftbukkit.v1_20_R3.inventory.CraftItemStack
+import org.bukkit.craftbukkit.v1_20_R3.persistence.CraftPersistentDataContainer
+import org.bukkit.craftbukkit.v1_20_R3.persistence.CraftPersistentDataTypeRegistry
+import org.bukkit.inventory.ItemStack
+import org.bukkit.persistence.PersistentDataContainer
+import org.bukkit.persistence.PersistentDataType
+
+class ExtendedPersistentDataContainerFactory : ExtendedPersistentDataContainerFactoryProxy {
+    private val registry: CraftPersistentDataTypeRegistry
+
+    init {
+        /*
+         Can't grab actual instance since it's in CraftMetaItem (which is package-private)
+         And getting it would mean more janky reflection
+         */
+        val item = CraftItemStack.asCraftCopy(ItemStack(Material.STONE))
+        val pdc = item.itemMeta!!.persistentDataContainer
+        this.registry = CraftPersistentDataContainer::class.java.getDeclaredField("registry")
+            .apply { isAccessible = true }.get(pdc) as CraftPersistentDataTypeRegistry
+    }
+
+    override fun adapt(pdc: PersistentDataContainer): ExtendedPersistentDataContainer {
+        return when (pdc) {
+            is CraftPersistentDataContainer -> EcoPersistentDataContainer(pdc)
+            else -> throw IllegalArgumentException("Custom PDC instance ${pdc::class.java.name} is not supported!")
+        }
+    }
+
+    override fun newPdc(): PersistentDataContainer {
+        return CraftPersistentDataContainer(registry)
+    }
+
+    inner class EcoPersistentDataContainer(
+        private val handle: CraftPersistentDataContainer
+    ) : ExtendedPersistentDataContainer {
+        @Suppress("UNCHECKED_CAST")
+        private val customDataTags: MutableMap<String, Tag> =
+            CraftPersistentDataContainer::class.java.getDeclaredField("customDataTags")
+                .apply { isAccessible = true }.get(handle) as MutableMap<String, Tag>
+
+        override fun <T : Any, Z : Any> set(key: String, dataType: PersistentDataType<T, Z>, value: Z) {
+            customDataTags[key] =
+                registry.wrap(dataType, dataType.toPrimitive(value, handle.adapterContext))
+        }
+
+        override fun <T : Any, Z : Any> has(key: String, dataType: PersistentDataType<T, Z>): Boolean {
+            val value = customDataTags[key] ?: return false
+            return registry.isInstanceOf(dataType, value)
+        }
+
+        override fun <T : Any, Z : Any> get(key: String, dataType: PersistentDataType<T, Z>): Z? {
+            val value = customDataTags[key] ?: return null
+            return dataType.fromPrimitive(registry.extract<T, Tag>(dataType, value), handle.adapterContext)
+        }
+
+        override fun <T : Any, Z : Any> getOrDefault(
+            key: String,
+            dataType: PersistentDataType<T, Z>,
+            defaultValue: Z
+        ): Z {
+            return get(key, dataType) ?: defaultValue
+        }
+
+        override fun remove(key: String) {
+            customDataTags.remove(key)
+        }
+
+        override fun getAllKeys(): MutableSet<String> {
+            return customDataTags.keys
+        }
+
+        override fun getBase(): PersistentDataContainer {
+            return handle
+        }
+    }
+}

eco-core/core-nms/v1_20_R3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R3/FastItemStackFactory.kt

@@ -0,0 +1,12 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_R3
+
+import com.willfp.eco.core.fast.FastItemStack
+import com.willfp.eco.internal.spigot.proxy.FastItemStackFactoryProxy
+import com.willfp.eco.internal.spigot.proxy.common.item.EcoFastItemStack
+import org.bukkit.inventory.ItemStack
+
+class FastItemStackFactory : FastItemStackFactoryProxy {
+    override fun create(itemStack: ItemStack): FastItemStack {
+        return EcoFastItemStack(itemStack)
+    }
+}

eco-core/core-nms/v1_20_R3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R3/MiniMessageTranslator.kt

@@ -0,0 +1,33 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_R3
+
+import com.willfp.eco.core.display.Display
+import com.willfp.eco.internal.spigot.proxy.MiniMessageTranslatorProxy
+import com.willfp.eco.util.toLegacy
+import net.kyori.adventure.text.minimessage.MiniMessage
+
+class MiniMessageTranslator : MiniMessageTranslatorProxy {
+    override fun format(message: String): String {
+        var mut = message
+
+        val startsWithPrefix = mut.startsWith(Display.PREFIX)
+        if (startsWithPrefix) {
+            mut = mut.substring(2)
+        }
+
+        mut = mut.replace('§', '&')
+
+        val miniMessage = runCatching {
+            MiniMessage.miniMessage().deserialize(
+                mut
+            ).toLegacy()
+        }.getOrNull() ?: mut
+
+        mut = if (startsWithPrefix) {
+            Display.PREFIX + miniMessage
+        } else {
+            miniMessage
+        }
+
+        return mut
+    }
+}

eco-core/core-nms/v1_20_R3/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/v1_20_R3/PacketHandler.kt

@@ -0,0 +1,46 @@
+package com.willfp.eco.internal.spigot.proxy.v1_20_R3
+
+import com.willfp.eco.core.EcoPlugin
+import com.willfp.eco.core.packet.PacketListener
+import com.willfp.eco.internal.spigot.proxy.PacketHandlerProxy
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.PacketAutoRecipe
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.PacketHeldItemSlot
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.PacketOpenWindowMerchant
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.PacketSetCreativeSlot
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.PacketSetSlot
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.PacketWindowItems
+import com.willfp.eco.internal.spigot.proxy.common.packet.display.frame.clearFrames
+import net.minecraft.network.protocol.Packet
+import org.bukkit.craftbukkit.v1_20_R3.entity.CraftPlayer
+import org.bukkit.entity.Player
+
+class PacketHandler : PacketHandlerProxy {
+    override fun sendPacket(player: Player, packet: com.willfp.eco.core.packet.Packet) {
+        if (player !is CraftPlayer) {
+            return
+        }
+
+        val handle = packet.handle
+
+        if (handle !is Packet<*>) {
+            return
+        }
+
+        player.handle.connection.send(handle)
+    }
+
+    override fun clearDisplayFrames() {
+        clearFrames()
+    }
+
+    override fun getPacketListeners(plugin: EcoPlugin): List<PacketListener> {
+        return listOf(
+            PacketAutoRecipe(plugin),
+            PacketHeldItemSlot,
+            PacketOpenWindowMerchant,
+            PacketSetCreativeSlot,
+            PacketSetSlot,
+            PacketWindowItems(plugin)
+        )
+    }
+}