Fixed readme again

Update oraxen dependency

README.md

@@ -31,6 +31,7 @@ eco comes packed with all the tools you need in your plugins:
 - Yaml/JSON/TOML config system
 - Persistent data storage API with Yaml/MySQL/MongoDB support
 - Packet item display system
+- Lightweight event loop based packet API
 - Entity AI API with near-1:1 NMS mappings
 - More events
 - Extension API, essentially plugins for plugins
@@ -52,7 +53,6 @@ eco comes packed with all the tools you need in your plugins:
 - And much more
 
 # For server owners
-- Requires ProtocolLib to be installed: get the latest version [here](https://www.spigotmc.org/resources/protocollib.1997/)
 - Supports 1.17+
 
 ## Downloads

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

@@ -13,27 +13,30 @@ import java.util.Collections;
 
 /**
  * Wrapper class for ProtocolLib packets.
+ *
+ * @deprecated ProtocolLib is no longer used by eco. Use {@link com.willfp.eco.core.packet.PacketListener} instead.
  */
+@Deprecated(since = "6.51.0")
 public abstract class AbstractPacketAdapter extends PacketAdapter {
     /**
-     * The packet type to listen for.
+     * The handle type to listen for.
      */
     private final PacketType type;
 
     /**
-     * Whether the packet adapter should be registered after the server has loaded.
+     * Whether the handle adapter should be registered after the server has loaded.
      * <p>
      * Useful for monitor priority adapters that <b>must</b> be ran last.
      */
     private final boolean postLoad;
 
     /**
-     * Create a new packet adapter for a specified plugin and type.
+     * Create a new handle adapter for a specified plugin and type.
      *
      * @param plugin   The plugin that ProtocolLib should mark as the owner.
      * @param type     The {@link PacketType} to listen for.
-     * @param priority The priority at which the adapter should be ran on packet send/receive.
-     * @param postLoad If the packet adapter should be registered after the server has loaded.
+     * @param priority The priority at which the adapter should be ran on handle send/receive.
+     * @param postLoad If the handle adapter should be registered after the server has loaded.
      */
     protected AbstractPacketAdapter(@NotNull final EcoPlugin plugin,
                                     @NotNull final PacketType type,
@@ -45,11 +48,11 @@ public abstract class AbstractPacketAdapter extends PacketAdapter {
     }
 
     /**
-     * Create a new packet adapter for a specified plugin and type.
+     * Create a new handle adapter for a specified plugin and type.
      *
      * @param plugin   The plugin that ProtocolLib should mark as the owner.
      * @param type     The {@link PacketType} to listen for.
-     * @param postLoad If the packet adapter should be registered after the server has loaded.
+     * @param postLoad If the handle adapter should be registered after the server has loaded.
      */
     protected AbstractPacketAdapter(@NotNull final EcoPlugin plugin,
                                     @NotNull final PacketType type,
@@ -58,9 +61,9 @@ public abstract class AbstractPacketAdapter extends PacketAdapter {
     }
 
     /**
-     * The code that should be executed once the packet has been received.
+     * The code that should be executed once the handle has been received.
      *
-     * @param packet The packet.
+     * @param packet The handle.
      * @param player The player.
      * @param event  The event.
      */
@@ -71,9 +74,9 @@ public abstract class AbstractPacketAdapter extends PacketAdapter {
     }
 
     /**
-     * THe code that should be executed once the packet has been sent.
+     * THe code that should be executed once the handle has been sent.
      *
-     * @param packet The packet.
+     * @param packet The handle.
      * @param player The player.
      * @param event  The event.
      */
@@ -84,7 +87,7 @@ public abstract class AbstractPacketAdapter extends PacketAdapter {
     }
 
     /**
-     * Boilerplate to assert that the packet is of the specified type.
+     * Boilerplate to assert that the handle is of the specified type.
      *
      * @param event The ProtocolLib event.
      */
@@ -102,7 +105,7 @@ public abstract class AbstractPacketAdapter extends PacketAdapter {
     }
 
     /**
-     * Boilerplate to assert that the packet is of the specified type.
+     * Boilerplate to assert that the handle is of the specified type.
      *
      * @param event The ProtocolLib event.
      */
@@ -125,7 +128,7 @@ public abstract class AbstractPacketAdapter extends PacketAdapter {
     }
 
     /**
-     * Register the packet adapter with ProtocolLib.
+     * Register the handle adapter with ProtocolLib.
      */
     public final void register() {
         if (!ProtocolLibrary.getProtocolManager().getPacketListeners().contains(this)) {
@@ -134,7 +137,7 @@ public abstract class AbstractPacketAdapter extends PacketAdapter {
     }
 
     /**
-     * Get if the packet adapter should be loaded last.
+     * Get if the handle adapter should be loaded last.
      *
      * @return If post load.
      */

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

@@ -26,13 +26,13 @@ import com.willfp.eco.core.gui.slot.SlotBuilder;
 import com.willfp.eco.core.gui.slot.functional.SlotProvider;
 import com.willfp.eco.core.items.TestableItem;
 import com.willfp.eco.core.math.MathContext;
+import com.willfp.eco.core.packet.Packet;
 import com.willfp.eco.core.proxy.ProxyFactory;
 import com.willfp.eco.core.scheduling.Scheduler;
 import net.kyori.adventure.platform.bukkit.BukkitAudiences;
 import org.apache.commons.lang.Validate;
 import org.bukkit.Location;
 import org.bukkit.NamespacedKey;
-import org.bukkit.command.CommandMap;
 import org.bukkit.configuration.ConfigurationSection;
 import org.bukkit.entity.Entity;
 import org.bukkit.entity.Mob;
@@ -547,19 +547,21 @@ public interface Eco {
      */
     void syncCommands();
 
-    /**
-     * Get the command map.
-     *
-     * @return The command map.
-     */
-    @NotNull CommandMap getCommandMap();
-
     /**
      * Unregister a command.
      *
      * @param command The command.
      */
-    void unregisterCommand(@NotNull final PluginCommand command);
+    void unregisterCommand(@NotNull PluginCommandBase command);
+
+    /**
+     * Send a packet.
+     *
+     * @param player The player.
+     * @param packet The packet.
+     */
+    void sendPacket(@NotNull Player player,
+                    @NotNull Packet packet);
 
     /**
      * Get the instance of eco; the bridge between the api frontend and the implementation backend.

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

@@ -13,6 +13,7 @@ import com.willfp.eco.core.factory.MetadataValueFactory;
 import com.willfp.eco.core.factory.NamespacedKeyFactory;
 import com.willfp.eco.core.factory.RunnableFactory;
 import com.willfp.eco.core.integrations.IntegrationLoader;
+import com.willfp.eco.core.packet.PacketListener;
 import com.willfp.eco.core.proxy.ProxyFactory;
 import com.willfp.eco.core.scheduling.Scheduler;
 import com.willfp.eco.core.web.UpdateChecker;
@@ -52,7 +53,7 @@ import java.util.stream.Collectors;
  * <b>IMPORTANT: When reloading a plugin, all runnables / tasks will
  * be cancelled.</b>
  */
-@SuppressWarnings("unused")
+@SuppressWarnings({"unused", "DeprecatedIsStillUsed", "deprecation", "RedundantSuppression"})
 public abstract class EcoPlugin extends JavaPlugin implements PluginLike {
     /**
      * The polymart resource ID of the plugin.
@@ -422,13 +423,16 @@ public abstract class EcoPlugin extends JavaPlugin implements PluginLike {
 
         Prerequisite.update();
 
-        this.loadPacketAdapters().forEach(abstractPacketAdapter -> {
-            if (!abstractPacketAdapter.isPostLoad()) {
-                abstractPacketAdapter.register();
-            }
-        });
+        if (Prerequisite.HAS_PROTOCOLLIB.isMet()) {
+            this.loadPacketAdapters().forEach(abstractPacketAdapter -> {
+                if (!abstractPacketAdapter.isPostLoad()) {
+                    abstractPacketAdapter.register();
+                }
+            });
+        }
 
         this.loadListeners().forEach(listener -> this.getEventManager().registerListener(listener));
+        this.loadPacketListeners().forEach(listener -> this.getEventManager().registerPacketListener(listener));
 
         this.loadPluginCommands().forEach(PluginCommand::register);
 
@@ -520,11 +524,13 @@ public abstract class EcoPlugin extends JavaPlugin implements PluginLike {
             Display.registerDisplayModule(this.getDisplayModule());
         }
 
-        this.loadPacketAdapters().forEach(abstractPacketAdapter -> {
-            if (abstractPacketAdapter.isPostLoad()) {
-                abstractPacketAdapter.register();
-            }
-        });
+        if (Prerequisite.HAS_PROTOCOLLIB.isMet()) {
+            this.loadPacketAdapters().forEach(abstractPacketAdapter -> {
+                if (abstractPacketAdapter.isPostLoad()) {
+                    abstractPacketAdapter.register();
+                }
+            });
+        }
 
         if (!Prerequisite.HAS_PAPER.isMet()) {
             this.getLogger().severe("");
@@ -681,16 +687,27 @@ public abstract class EcoPlugin extends JavaPlugin implements PluginLike {
     }
 
     /**
-     * ProtocolLib packet adapters to be registered.
+     * ProtocolLib handle adapters to be registered.
      * <p>
      * If the plugin does not require ProtocolLib this can be left empty.
      *
-     * @return A list of packet adapters.
+     * @return A list of handle adapters.
+     * @deprecated Use {@link #loadPacketListeners()} instead.
      */
+    @Deprecated(since = "6.51.0")
     protected List<AbstractPacketAdapter> loadPacketAdapters() {
         return new ArrayList<>();
     }
 
+    /**
+     * Packet Listeners to be registered.
+     *
+     * @return A list of handle listeners.
+     */
+    protected List<PacketListener> loadPacketListeners() {
+        return new ArrayList<>();
+    }
+
     /**
      * All listeners to be registered.
      *

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

@@ -30,6 +30,14 @@ public class Prerequisite {
             "Requires server to be running paper (or a fork)"
     );
 
+    /**
+     * Requires the server to be running an implementation of paper.
+     */
+    public static final Prerequisite HAS_PROTOCOLLIB = new Prerequisite(
+            () -> ClassUtils.exists("com.comphenix.protocol.events.PacketAdapter"),
+            "Requires server to have ProtocolLib"
+    );
+
     /**
      * Requires the server to have vault installed.
      *

eco-api/src/main/java/com/willfp/eco/core/command/NotificationException.java

@@ -1,5 +1,7 @@
 package com.willfp.eco.core.command;
 
+import org.jetbrains.annotations.NotNull;
+
 /**
  * A notification exception is thrown when {@link org.bukkit.command.CommandSender}s don't
  * specify valid arguments in commands.
@@ -18,7 +20,7 @@ public class NotificationException extends Exception {
      *
      * @param key The lang key of the notification.
      */
-    public NotificationException(String key) {
+    public NotificationException(@NotNull final String key) {
         super(key);
         this.key = key;
     }

eco-api/src/main/java/com/willfp/eco/core/display/Display.java

@@ -1,6 +1,7 @@
 package com.willfp.eco.core.display;
 
 import com.willfp.eco.core.fast.FastItemStack;
+import com.willfp.eco.core.integrations.guidetection.GUIDetectionManager;
 import com.willfp.eco.util.NamespacedKeyUtils;
 import org.bukkit.NamespacedKey;
 import org.bukkit.entity.Player;
@@ -18,6 +19,9 @@ import java.util.TreeMap;
 
 /**
  * Utility class to manage client-side item display.
+ * <p>
+ * Packet display is not done on the main thread, so make sure
+ * all your modules are thread-safe.
  */
 public final class Display {
     /**
@@ -71,7 +75,7 @@ public final class Display {
         ItemStack original = itemStack.clone();
         Inventory inventory = player == null ? null : player.getOpenInventory().getTopInventory();
         boolean inInventory = inventory != null && inventory.contains(original);
-        boolean inGui = inventory != null && inventory.getHolder() == null;
+        boolean inGui = player != null && GUIDetectionManager.hasGUIOpen(player);
 
         DisplayProperties properties = new DisplayProperties(
                 inInventory,

eco-api/src/main/java/com/willfp/eco/core/display/DisplayModule.java

@@ -8,6 +8,8 @@ import org.jetbrains.annotations.Nullable;
 
 /**
  * Class for all plugin-specific client-side item display modules.
+ * <p>
+ * Display modules are called in the netty thread, so make sure they are thread-safe.
  */
 public abstract class DisplayModule {
     /**

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalAvoidEntity.java

@@ -13,10 +13,10 @@ import org.jetbrains.annotations.Nullable;
 /**
  * Avoid entities.
  *
- * @param entity       The entity type to avoid.
- * @param distance The distance to flee to.
- * @param slowSpeed    The slow movement speed.
- * @param fastSpeed    The fast movement speed.
+ * @param entity    The entity type to avoid.
+ * @param distance  The distance to flee to.
+ * @param slowSpeed The slow movement speed.
+ * @param fastSpeed The fast movement speed.
  */
 public record EntityGoalAvoidEntity(
         @NotNull TestableEntity entity,
@@ -45,23 +45,14 @@ public record EntityGoalAvoidEntity(
                 return null;
             }
 
-            try {
-                TestableEntity entity = Entities.lookup(config.getString("entity"));
+            TestableEntity entity = Entities.lookup(config.getString("entity"));
 
-                return new EntityGoalAvoidEntity(
-                        entity,
-                        config.getDouble("distance"),
-                        config.getDouble("slowSpeed"),
-                        config.getDouble("fastSpeed")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalAvoidEntity(
+                    entity,
+                    config.getDouble("distance"),
+                    config.getDouble("slowSpeed"),
+                    config.getDouble("fastSpeed")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalBreakDoors.java

@@ -34,18 +34,9 @@ public record EntityGoalBreakDoors(
                 return null;
             }
 
-            try {
-                return new EntityGoalBreakDoors(
-                        config.getInt("ticks")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalBreakDoors(
+                    config.getInt("ticks")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalBreed.java

@@ -34,18 +34,9 @@ public record EntityGoalBreed(
                 return null;
             }
 
-            try {
-                return new EntityGoalBreed(
-                        config.getDouble("speed")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalBreed(
+                    config.getDouble("speed")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalCatLieOnBed.java

@@ -37,19 +37,10 @@ public record EntityGoalCatLieOnBed(
                 return null;
             }
 
-            try {
-                return new EntityGoalCatLieOnBed(
-                        config.getDouble("speed"),
-                        config.getInt("range")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalCatLieOnBed(
+                    config.getDouble("speed"),
+                    config.getInt("range")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalCatSitOnBed.java

@@ -34,18 +34,9 @@ public record EntityGoalCatSitOnBed(
                 return null;
             }
 
-            try {
-                return new EntityGoalCatSitOnBed(
-                        config.getDouble("speed")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalCatSitOnBed(
+                    config.getDouble("speed")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalFleeSun.java

@@ -34,18 +34,9 @@ public record EntityGoalFleeSun(
                 return null;
             }
 
-            try {
-                return new EntityGoalFleeSun(
-                        config.getDouble("speed")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalFleeSun(
+                    config.getDouble("speed")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalFollowMobs.java

@@ -40,20 +40,11 @@ public record EntityGoalFollowMobs(
                 return null;
             }
 
-            try {
-                return new EntityGoalFollowMobs(
-                        config.getDouble("speed"),
-                        config.getDouble("minDistance"),
-                        config.getDouble("maxDistance")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalFollowMobs(
+                    config.getDouble("speed"),
+                    config.getDouble("minDistance"),
+                    config.getDouble("maxDistance")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalInteract.java

@@ -42,20 +42,11 @@ public record EntityGoalInteract(
                 return null;
             }
 
-            try {
-                return new EntityGoalInteract(
-                        Entities.lookup(config.getString("target")),
-                        config.getDouble("range"),
-                        config.getDouble("chance")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalInteract(
+                    Entities.lookup(config.getString("target")),
+                    config.getDouble("range"),
+                    config.getDouble("chance")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalLeapAtTarget.java

@@ -34,18 +34,9 @@ public record EntityGoalLeapAtTarget(
                 return null;
             }
 
-            try {
-                return new EntityGoalLeapAtTarget(
-                        config.getDouble("velocity")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalLeapAtTarget(
+                    config.getDouble("velocity")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalLookAtPlayer.java

@@ -37,19 +37,10 @@ public record EntityGoalLookAtPlayer(
                 return null;
             }
 
-            try {
-                return new EntityGoalLookAtPlayer(
-                        config.getDouble("range"),
-                        config.getDouble("chance")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalLookAtPlayer(
+                    config.getDouble("range"),
+                    config.getDouble("chance")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalMeleeAttack.java

@@ -37,19 +37,10 @@ public record EntityGoalMeleeAttack(
                 return null;
             }
 
-            try {
-                return new EntityGoalMeleeAttack(
-                        config.getDouble("speed"),
-                        config.getBool("pauseWhenMobIdle")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalMeleeAttack(
+                    config.getDouble("speed"),
+                    config.getBool("pauseWhenMobIdle")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalMoveBackToVillage.java

@@ -37,19 +37,10 @@ public record EntityGoalMoveBackToVillage(
                 return null;
             }
 
-            try {
-                return new EntityGoalMoveBackToVillage(
-                        config.getDouble("speed"),
-                        config.getBool("canDespawn")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalMoveBackToVillage(
+                    config.getDouble("speed"),
+                    config.getBool("canDespawn")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalMoveThroughVillage.java

@@ -43,21 +43,12 @@ public record EntityGoalMoveThroughVillage(
                 return null;
             }
 
-            try {
-                return new EntityGoalMoveThroughVillage(
-                        config.getDouble("speed"),
-                        config.getBool("onlyAtNight"),
-                        config.getInt("distance"),
-                        config.getBool("canPassThroughDoors")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalMoveThroughVillage(
+                    config.getDouble("speed"),
+                    config.getBool("onlyAtNight"),
+                    config.getInt("distance"),
+                    config.getBool("canPassThroughDoors")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalMoveTowardsRestriction.java

@@ -34,18 +34,9 @@ public record EntityGoalMoveTowardsRestriction(
                 return null;
             }
 
-            try {
-                return new EntityGoalMoveTowardsRestriction(
-                        config.getDouble("speed")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalMoveTowardsRestriction(
+                    config.getDouble("speed")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalMoveTowardsTarget.java

@@ -37,19 +37,10 @@ public record EntityGoalMoveTowardsTarget(
                 return null;
             }
 
-            try {
-                return new EntityGoalMoveTowardsTarget(
-                        config.getDouble("speed"),
-                        config.getDouble("maxDistance")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalMoveTowardsTarget(
+                    config.getDouble("speed"),
+                    config.getDouble("maxDistance")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalOpenDoors.java

@@ -34,18 +34,9 @@ public record EntityGoalOpenDoors(
                 return null;
             }
 
-            try {
-                return new EntityGoalOpenDoors(
-                        config.getBool("delayClosing")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalOpenDoors(
+                    config.getBool("delayClosing")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalPanic.java

@@ -34,18 +34,9 @@ public record EntityGoalPanic(
                 return null;
             }
 
-            try {
-                return new EntityGoalPanic(
-                        config.getDouble("speed")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalPanic(
+                    config.getDouble("speed")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalRandomStroll.java

@@ -40,20 +40,11 @@ public record EntityGoalRandomStroll(
                 return null;
             }
 
-            try {
-                return new EntityGoalRandomStroll(
-                        config.getDouble("speed"),
-                        config.getInt("interval"),
-                        config.getBool("canDespawn")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalRandomStroll(
+                    config.getDouble("speed"),
+                    config.getInt("interval"),
+                    config.getBool("canDespawn")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalRandomSwimming.java

@@ -37,19 +37,10 @@ public record EntityGoalRandomSwimming(
                 return null;
             }
 
-            try {
-                return new EntityGoalRandomSwimming(
-                        config.getDouble("speed"),
-                        config.getInt("interval")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalRandomSwimming(
+                    config.getDouble("speed"),
+                    config.getInt("interval")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalRangedAttack.java

@@ -45,21 +45,12 @@ public record EntityGoalRangedAttack(
                 return null;
             }
 
-            try {
-                return new EntityGoalRangedAttack(
-                        config.getDouble("speed"),
-                        config.getInt("minInterval"),
-                        config.getInt("maxInterval"),
-                        config.getDouble("range")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalRangedAttack(
+                    config.getDouble("speed"),
+                    config.getInt("minInterval"),
+                    config.getInt("maxInterval"),
+                    config.getDouble("range")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalRangedBowAttack.java

@@ -13,9 +13,9 @@ import org.jetbrains.annotations.Nullable;
  * <p>
  * Only supports monsters that have bow attacks.
  *
- * @param speed          The speed.
+ * @param speed    The speed.
  * @param interval The interval between attacks (in ticks).
- * @param range          The max range at which to attack.
+ * @param range    The max range at which to attack.
  */
 public record EntityGoalRangedBowAttack(
         double speed,
@@ -42,20 +42,11 @@ public record EntityGoalRangedBowAttack(
                 return null;
             }
 
-            try {
-                return new EntityGoalRangedBowAttack(
-                        config.getDouble("speed"),
-                        config.getInt("interval"),
-                        config.getDouble("range")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalRangedBowAttack(
+                    config.getDouble("speed"),
+                    config.getInt("interval"),
+                    config.getDouble("range")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalRangedCrossbowAttack.java

@@ -39,19 +39,10 @@ public record EntityGoalRangedCrossbowAttack(
                 return null;
             }
 
-            try {
-                return new EntityGoalRangedCrossbowAttack(
-                        config.getDouble("speed"),
-                        config.getDouble("range")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalRangedCrossbowAttack(
+                    config.getDouble("speed"),
+                    config.getDouble("range")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalStrollThroughVillage.java

@@ -34,18 +34,9 @@ public record EntityGoalStrollThroughVillage(
                 return null;
             }
 
-            try {
-                return new EntityGoalStrollThroughVillage(
-                        config.getInt("searchRange")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalStrollThroughVillage(
+                    config.getInt("searchRange")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalTempt.java

@@ -58,25 +58,16 @@ public record EntityGoalTempt(
                 return null;
             }
 
-            try {
-                Collection<TestableItem> items = config.getStrings("items").stream()
-                        .map(Items::lookup)
-                        .filter(it -> !(it instanceof EmptyTestableItem))
-                        .collect(Collectors.toList());
+            Collection<TestableItem> items = config.getStrings("items").stream()
+                    .map(Items::lookup)
+                    .filter(it -> !(it instanceof EmptyTestableItem))
+                    .collect(Collectors.toList());
 
-                return new EntityGoalTempt(
-                        config.getDouble("speed"),
-                        items,
-                        config.getBool("canBeScared")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalTempt(
+                    config.getDouble("speed"),
+                    items,
+                    config.getBool("canBeScared")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalUseItem.java

@@ -48,22 +48,13 @@ public record EntityGoalUseItem(
                 return null;
             }
 
-            try {
-                TestableEntity filter = Entities.lookup(config.getString("condition"));
+            TestableEntity filter = Entities.lookup(config.getString("condition"));
 
-                return new EntityGoalUseItem(
-                        Items.lookup(config.getString("item")).getItem(),
-                        Sound.valueOf(config.getString("sound").toUpperCase()),
-                        filter::matches
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalUseItem(
+                    Items.lookup(config.getString("item")).getItem(),
+                    Sound.valueOf(config.getString("sound").toUpperCase()),
+                    filter::matches
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalWaterAvoidingRandomFlying.java

@@ -34,18 +34,9 @@ public record EntityGoalWaterAvoidingRandomFlying(
                 return null;
             }
 
-            try {
-                return new EntityGoalWaterAvoidingRandomFlying(
-                        config.getDouble("speed")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalWaterAvoidingRandomFlying(
+                    config.getDouble("speed")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalWaterAvoidingRandomStroll.java

@@ -37,19 +37,10 @@ public record EntityGoalWaterAvoidingRandomStroll(
                 return null;
             }
 
-            try {
-                return new EntityGoalWaterAvoidingRandomStroll(
-                        config.getDouble("speed"),
-                        config.getDouble("chance")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalWaterAvoidingRandomStroll(
+                    config.getDouble("speed"),
+                    config.getDouble("chance")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/entity/EntityGoalWolfBeg.java

@@ -34,18 +34,9 @@ public record EntityGoalWolfBeg(
                 return null;
             }
 
-            try {
-                return new EntityGoalWolfBeg(
-                        config.getDouble("distance")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new EntityGoalWolfBeg(
+                    config.getDouble("distance")
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/target/TargetGoalHurtBy.java

@@ -37,18 +37,9 @@ public record TargetGoalHurtBy(
                 return null;
             }
 
-            try {
-                return new TargetGoalHurtBy(
-                        Entities.lookup(config.getString("blacklist"))
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new TargetGoalHurtBy(
+                    Entities.lookup(config.getString("blacklist"))
+            );
         }
 
         @NotNull

eco-api/src/main/java/com/willfp/eco/core/entities/ai/target/TargetGoalNearestAttackable.java

@@ -63,32 +63,23 @@ public record TargetGoalNearestAttackable(
                 return null;
             }
 
-            try {
-                if (config.has("targetFilter")) {
-                    TestableEntity filter = Entities.lookup(config.getString("targetFilter"));
+            if (config.has("targetFilter")) {
+                TestableEntity filter = Entities.lookup(config.getString("targetFilter"));
 
-                    return new TargetGoalNearestAttackable(
-                            Entities.lookup(config.getString("target")),
-                            config.getBool("checkVisibility"),
-                            config.getBool("checkCanNavigate"),
-                            config.getInt("reciprocalChance"),
-                            filter::matches
-                    );
-                } else {
-                    return new TargetGoalNearestAttackable(
-                            Entities.lookup(config.getString("target")),
-                            config.getBool("checkVisibility"),
-                            config.getBool("checkCanNavigate"),
-                            config.getInt("reciprocalChance")
-                    );
-                }
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
+                return new TargetGoalNearestAttackable(
+                        Entities.lookup(config.getString("target")),
+                        config.getBool("checkVisibility"),
+                        config.getBool("checkCanNavigate"),
+                        config.getInt("reciprocalChance"),
+                        filter::matches
+                );
+            } else {
+                return new TargetGoalNearestAttackable(
+                        Entities.lookup(config.getString("target")),
+                        config.getBool("checkVisibility"),
+                        config.getBool("checkCanNavigate"),
+                        config.getInt("reciprocalChance")
+                );
             }
         }
 

eco-api/src/main/java/com/willfp/eco/core/entities/ai/target/TargetGoalNearestAttackableWitch.java

@@ -63,32 +63,23 @@ public record TargetGoalNearestAttackableWitch(
                 return null;
             }
 
-            try {
-                if (config.has("targetFilter")) {
-                    TestableEntity filter = Entities.lookup(config.getString("targetFilter"));
+            if (config.has("targetFilter")) {
+                TestableEntity filter = Entities.lookup(config.getString("targetFilter"));
 
-                    return new TargetGoalNearestAttackableWitch(
-                            Entities.lookup(config.getString("target")),
-                            config.getBool("checkVisibility"),
-                            config.getBool("checkCanNavigate"),
-                            config.getInt("reciprocalChance"),
-                            filter::matches
-                    );
-                } else {
-                    return new TargetGoalNearestAttackableWitch(
-                            Entities.lookup(config.getString("target")),
-                            config.getBool("checkVisibility"),
-                            config.getBool("checkCanNavigate"),
-                            config.getInt("reciprocalChance")
-                    );
-                }
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
+                return new TargetGoalNearestAttackableWitch(
+                        Entities.lookup(config.getString("target")),
+                        config.getBool("checkVisibility"),
+                        config.getBool("checkCanNavigate"),
+                        config.getInt("reciprocalChance"),
+                        filter::matches
+                );
+            } else {
+                return new TargetGoalNearestAttackableWitch(
+                        Entities.lookup(config.getString("target")),
+                        config.getBool("checkVisibility"),
+                        config.getBool("checkCanNavigate"),
+                        config.getInt("reciprocalChance")
+                );
             }
         }
 

eco-api/src/main/java/com/willfp/eco/core/entities/ai/target/TargetGoalNearestHealableRaider.java

@@ -53,28 +53,19 @@ public record TargetGoalNearestHealableRaider(
                 return null;
             }
 
-            try {
-                if (config.has("targetFilter")) {
-                    TestableEntity filter = Entities.lookup(config.getString("targetFilter"));
+            if (config.has("targetFilter")) {
+                TestableEntity filter = Entities.lookup(config.getString("targetFilter"));
 
-                    return new TargetGoalNearestHealableRaider(
-                            Entities.lookup(config.getString("target")),
-                            config.getBool("checkVisibility"),
-                            filter::matches
-                    );
-                } else {
-                    return new TargetGoalNearestHealableRaider(
-                            Entities.lookup(config.getString("target")),
-                            config.getBool("checkVisibility")
-                    );
-                }
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
+                return new TargetGoalNearestHealableRaider(
+                        Entities.lookup(config.getString("target")),
+                        config.getBool("checkVisibility"),
+                        filter::matches
+                );
+            } else {
+                return new TargetGoalNearestHealableRaider(
+                        Entities.lookup(config.getString("target")),
+                        config.getBool("checkVisibility")
+                );
             }
         }
 

eco-api/src/main/java/com/willfp/eco/core/entities/ai/target/TargetGoalNonTameRandom.java

@@ -53,28 +53,19 @@ public record TargetGoalNonTameRandom(
                 return null;
             }
 
-            try {
-                if (config.has("targetFilter")) {
-                    TestableEntity filter = Entities.lookup(config.getString("targetFilter"));
+            if (config.has("targetFilter")) {
+                TestableEntity filter = Entities.lookup(config.getString("targetFilter"));
 
-                    return new TargetGoalNonTameRandom(
-                            Entities.lookup(config.getString("target")),
-                            config.getBool("checkVisibility"),
-                            filter::matches
-                    );
-                } else {
-                    return new TargetGoalNonTameRandom(
-                            Entities.lookup(config.getString("target")),
-                            config.getBool("checkVisibility")
-                    );
-                }
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
+                return new TargetGoalNonTameRandom(
+                        Entities.lookup(config.getString("target")),
+                        config.getBool("checkVisibility"),
+                        filter::matches
+                );
+            } else {
+                return new TargetGoalNonTameRandom(
+                        Entities.lookup(config.getString("target")),
+                        config.getBool("checkVisibility")
+                );
             }
         }
 

eco-api/src/main/java/com/willfp/eco/core/entities/ai/target/TargetGoalResetUniversalAnger.java

@@ -36,18 +36,9 @@ public record TargetGoalResetUniversalAnger(
                 return null;
             }
 
-            try {
-                return new TargetGoalResetUniversalAnger(
-                        config.getBool("triggerOthers")
-                );
-            } catch (Exception e) {
-                /*
-                Exceptions could be caused by configs having values of a wrong type,
-                invalid enum parameters, etc. Serializers shouldn't throw exceptions,
-                so we encapsulate them as null.
-                 */
-                return null;
-            }
+            return new TargetGoalResetUniversalAnger(
+                    config.getBool("triggerOthers")
+            );
         }
 
         @NotNull

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

@@ -1,5 +1,6 @@
 package com.willfp.eco.core.events;
 
+import com.willfp.eco.core.packet.PacketListener;
 import org.bukkit.event.Listener;
 import org.jetbrains.annotations.NotNull;
 
@@ -25,4 +26,11 @@ public interface EventManager {
      * Unregister all listeners associated with the plugin.
      */
     void unregisterAllListeners();
+
+    /**
+     * Register a packet listener.
+     *
+     * @param listener The listener.
+     */
+    void registerPacketListener(@NotNull PacketListener listener);
 }

eco-api/src/main/java/com/willfp/eco/core/integrations/guidetection/GUIDetectionIntegration.java

@@ -0,0 +1,18 @@
+package com.willfp.eco.core.integrations.guidetection;
+
+import com.willfp.eco.core.integrations.Integration;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Wrapper class for GUI integrations.
+ */
+public interface GUIDetectionIntegration extends Integration {
+    /**
+     * Determine if a player is in a GUI.
+     *
+     * @param player The player.
+     * @return If the player is in a GUI.
+     */
+    boolean hasGUIOpen(@NotNull final Player player);
+}

eco-api/src/main/java/com/willfp/eco/core/integrations/guidetection/GUIDetectionManager.java

@@ -0,0 +1,52 @@
+package com.willfp.eco.core.integrations.guidetection;
+
+import com.willfp.eco.util.MenuUtils;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * Class to handle GUI detection.
+ */
+public final class GUIDetectionManager {
+    /**
+     * A set of all registered integrations.
+     */
+    private static final Set<GUIDetectionIntegration> REGISTERED = new HashSet<>();
+
+    /**
+     * Register a new integration.
+     *
+     * @param integration The integration to register.
+     */
+    public static void register(@NotNull final GUIDetectionIntegration integration) {
+        REGISTERED.removeIf(it -> it.getPluginName().equalsIgnoreCase(integration.getPluginName()));
+        REGISTERED.add(integration);
+    }
+
+    /**
+     * Get if a player is in a GUI.
+     *
+     * @param player The player.
+     * @return If the player has a GUI open.
+     */
+    public static boolean hasGUIOpen(@NotNull final Player player) {
+        if (MenuUtils.getOpenMenu(player) != null) {
+            return true;
+        }
+
+        for (GUIDetectionIntegration integration : REGISTERED) {
+            if (integration.hasGUIOpen(player)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    private GUIDetectionManager() {
+        throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/integrations/placeholder/PlaceholderManager.java

@@ -1,13 +1,16 @@
 package com.willfp.eco.core.integrations.placeholder;
 
+import com.github.benmanes.caffeine.cache.Cache;
 import com.github.benmanes.caffeine.cache.Caffeine;
 import com.github.benmanes.caffeine.cache.LoadingCache;
 import com.willfp.eco.core.Eco;
 import com.willfp.eco.core.EcoPlugin;
 import com.willfp.eco.core.placeholder.AdditionalPlayer;
+import com.willfp.eco.core.placeholder.DynamicPlaceholder;
 import com.willfp.eco.core.placeholder.InjectablePlaceholder;
 import com.willfp.eco.core.placeholder.Placeholder;
 import com.willfp.eco.core.placeholder.PlaceholderInjectable;
+import com.willfp.eco.core.placeholder.PlayerDynamicPlaceholder;
 import com.willfp.eco.core.placeholder.PlayerPlaceholder;
 import com.willfp.eco.core.placeholder.PlayerStaticPlaceholder;
 import com.willfp.eco.core.placeholder.PlayerlessPlaceholder;
@@ -24,6 +27,7 @@ import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.regex.Matcher;
@@ -37,13 +41,20 @@ public final class PlaceholderManager {
     /**
      * All registered placeholders.
      */
-    private static final Map<EcoPlugin, Map<String, Placeholder>> REGISTERED_PLACEHOLDERS = new HashMap<>();
+    private static final Map<EcoPlugin, Map<Pattern, Placeholder>> REGISTERED_PLACEHOLDERS = new HashMap<>();
 
     /**
      * All registered placeholder integrations.
      */
     private static final Set<PlaceholderIntegration> REGISTERED_INTEGRATIONS = new HashSet<>();
 
+    /**
+     * Placeholder Lookup Cache.
+     */
+    private static final Cache<PlaceholderLookup, Optional<Placeholder>> PLACEHOLDER_LOOKUP_CACHE = Caffeine.newBuilder()
+            .expireAfterWrite(1, TimeUnit.SECONDS)
+            .build();
+
     /**
      * Placeholder Cache.
      */
@@ -51,10 +62,17 @@ public final class PlaceholderManager {
             .expireAfterWrite(50, TimeUnit.MILLISECONDS)
             .build(key -> key.entry.getValue(key.player));
 
+    /**
+     * Dynamic Placeholder Cache.
+     */
+    private static final LoadingCache<DynamicEntryWithPlayer, String> DYNAMIC_PLACEHOLDER_CACHE = Caffeine.newBuilder()
+            .expireAfterWrite(50, TimeUnit.MILLISECONDS)
+            .build(key -> key.entry.getValue(key.args, key.player));
+
     /**
      * The default PlaceholderAPI pattern; brought in for compatibility.
      */
-    private static final Pattern PATTERN = Pattern.compile("[%]([^% ]+)[%]");
+    private static final Pattern PATTERN = Pattern.compile("%([^% ]+)%");
 
     /**
      * Empty injectable object.
@@ -88,14 +106,17 @@ public final class PlaceholderManager {
      * @param placeholder The placeholder to register.
      */
     public static void registerPlaceholder(@NotNull final Placeholder placeholder) {
-        if (placeholder instanceof StaticPlaceholder) {
+        if (placeholder instanceof StaticPlaceholder || placeholder instanceof PlayerStaticPlaceholder) {
             throw new IllegalArgumentException("Static placeholders cannot be registered!");
         }
 
         EcoPlugin plugin = placeholder.getPlugin() == null ? Eco.get().getEcoPlugin() : placeholder.getPlugin();
-        Map<String, Placeholder> pluginPlaceholders = REGISTERED_PLACEHOLDERS
+
+        Map<Pattern, Placeholder> pluginPlaceholders = REGISTERED_PLACEHOLDERS
                 .getOrDefault(plugin, new HashMap<>());
-        pluginPlaceholders.put(placeholder.getIdentifier(), placeholder);
+
+        pluginPlaceholders.put(placeholder.getPattern(), placeholder);
+
         REGISTERED_PLACEHOLDERS.put(plugin, pluginPlaceholders);
     }
 
@@ -136,21 +157,47 @@ public final class PlaceholderManager {
     public static String getResult(@Nullable final Player player,
                                    @NotNull final String identifier,
                                    @Nullable final EcoPlugin plugin) {
-        EcoPlugin owner = plugin == null ? Eco.get().getEcoPlugin() : plugin;
-        Placeholder placeholder = REGISTERED_PLACEHOLDERS.getOrDefault(owner, new HashMap<>()).get(identifier.toLowerCase());
+        // This is really janky, and it sucks, but it works so?
+        // Compensating for regex being slow so that's why we get it.
+        Placeholder placeholder = PLACEHOLDER_LOOKUP_CACHE.get(
+                new PlaceholderLookup(identifier, plugin),
+                (it) -> {
+                    EcoPlugin owner = plugin == null ? Eco.get().getEcoPlugin() : plugin;
 
-        if (placeholder == null && plugin != null) {
-            Placeholder alternate = REGISTERED_PLACEHOLDERS.getOrDefault(Eco.get().getEcoPlugin(), new HashMap<>())
-                    .get(identifier.toLowerCase());
-            if (alternate != null) {
-                placeholder = alternate;
-            }
-        }
+                    // I hate the streams API.
+                    Optional<Placeholder> found = REGISTERED_PLACEHOLDERS
+                            .getOrDefault(owner, new HashMap<>())
+                            .entrySet()
+                            .stream().filter(entry -> entry.getKey().matcher(identifier).matches())
+                            .map(Map.Entry::getValue)
+                            .findFirst();
+
+                    if (found.isEmpty() && plugin != null) {
+                        // Here we go again! Something about legacy support? I don't remember.
+                        // I won't touch it though, I'm scared of the placeholder system.
+                        found = REGISTERED_PLACEHOLDERS
+                                .getOrDefault(Eco.get().getEcoPlugin(), new HashMap<>())
+                                .entrySet()
+                                .stream().filter(entry -> entry.getKey().matcher(identifier).matches())
+                                .map(Map.Entry::getValue)
+                                .findFirst();
+                    }
+
+                    return found;
+                }
+        ).orElse(null);
 
         if (placeholder == null) {
             return "";
         }
 
+        /*
+        This code here is *really* not very good. It's mega externalized logic hacked
+        together and made worse by the addition of dynamic placeholders. But it works,
+        and it means I don't have to rewrite the whole placeholder system. So it's
+        good enough for me.
+         */
+
         if (placeholder instanceof PlayerPlaceholder playerPlaceholder) {
             if (player == null) {
                 return "";
@@ -159,6 +206,14 @@ public final class PlaceholderManager {
             }
         } else if (placeholder instanceof PlayerlessPlaceholder playerlessPlaceholder) {
             return playerlessPlaceholder.getValue();
+        } else if (placeholder instanceof PlayerDynamicPlaceholder playerDynamicPlaceholder) {
+            if (player == null) {
+                return "";
+            } else {
+                return DYNAMIC_PLACEHOLDER_CACHE.get(new DynamicEntryWithPlayer(playerDynamicPlaceholder, identifier, player));
+            }
+        } else if (placeholder instanceof DynamicPlaceholder dynamicPlaceholder) {
+            return dynamicPlaceholder.getValue(identifier);
         } else {
             return "";
         }
@@ -245,8 +300,10 @@ public final class PlaceholderManager {
         for (PlaceholderIntegration integration : REGISTERED_INTEGRATIONS) {
             processed = integration.translate(processed, player);
         }
+
         for (InjectablePlaceholder injection : context.getPlaceholderInjections()) {
             // Do I know this is a bad way of doing this? Yes.
+            // I know it's deprecated, but it's fast.
             if (injection instanceof StaticPlaceholder placeholder) {
                 processed = processed.replace("%" + placeholder.getIdentifier() + "%", placeholder.getValue());
             } else if (injection instanceof PlayerStaticPlaceholder placeholder && player != null) {
@@ -280,11 +337,22 @@ public final class PlaceholderManager {
         return new ArrayList<>(found);
     }
 
+    private record PlaceholderLookup(@NotNull String identifier,
+                                     @Nullable EcoPlugin plugin) {
+
+    }
+
     private record EntryWithPlayer(@NotNull PlayerPlaceholder entry,
                                    @NotNull Player player) {
 
     }
 
+    private record DynamicEntryWithPlayer(@NotNull PlayerDynamicPlaceholder entry,
+                                          @NotNull String args,
+                                          @NotNull Player player) {
+
+    }
+
     private PlaceholderManager() {
         throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
     }

eco-api/src/main/java/com/willfp/eco/core/packet/Packet.java

@@ -0,0 +1,21 @@
+package com.willfp.eco.core.packet;
+
+import com.willfp.eco.core.Eco;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Represents a packet.
+ *
+ * @param handle The NMS handle.
+ */
+public record Packet(@NotNull Object handle) {
+    /**
+     * Send to a player.
+     *
+     * @param player The player.
+     */
+    void send(@NotNull final Player player) {
+        Eco.get().sendPacket(player, this);
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/packet/PacketEvent.java

@@ -0,0 +1,67 @@
+package com.willfp.eco.core.packet;
+
+import org.bukkit.entity.Player;
+import org.bukkit.event.Cancellable;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Represents a packet being sent or received.
+ */
+public class PacketEvent implements Cancellable {
+    /**
+     * The packet.
+     */
+    private final Packet packet;
+
+    /**
+     * The player.
+     */
+    private final Player player;
+
+    /**
+     * If the event should be cancelled.
+     */
+    private boolean cancelled = false;
+
+    /**
+     * Create a new packet event.
+     *
+     * @param packet The packet.
+     * @param player The player.
+     */
+    public PacketEvent(@NotNull final Packet packet,
+                       @NotNull final Player player) {
+        this.packet = packet;
+        this.player = player;
+    }
+
+    /**
+     * Get the packet.
+     *
+     * @return The packet.
+     */
+    @NotNull
+    public Packet getPacket() {
+        return packet;
+    }
+
+    /**
+     * Get the player.
+     *
+     * @return The player.
+     */
+    @NotNull
+    public Player getPlayer() {
+        return player;
+    }
+
+    @Override
+    public boolean isCancelled() {
+        return cancelled;
+    }
+
+    @Override
+    public void setCancelled(final boolean cancelled) {
+        this.cancelled = cancelled;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/packet/PacketListener.java

@@ -0,0 +1,35 @@
+package com.willfp.eco.core.packet;
+
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Listens to packets.
+ */
+public interface PacketListener {
+    /**
+     * Called when a handle is sent.
+     *
+     * @param event The event.
+     */
+    default void onSend(@NotNull final PacketEvent event) {
+        // Override when needed.
+    }
+
+    /**
+     * Called when a handle is received.
+     *
+     * @param event The event.
+     */
+    default void onReceive(@NotNull final PacketEvent event) {
+        // Override when needed.
+    }
+
+    /**
+     * Get the priority of the listener.
+     *
+     * @return The priority.
+     */
+    default PacketPriority getPriority() {
+        return PacketPriority.NORMAL;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/packet/PacketPriority.java

@@ -0,0 +1,31 @@
+package com.willfp.eco.core.packet;
+
+/**
+ * The priority (order) of packet listeners.
+ */
+public enum PacketPriority {
+    /**
+     * Ran first.
+     */
+    LOWEST,
+
+    /**
+     * Ran second.
+     */
+    LOW,
+
+    /**
+     * Ran third.
+     */
+    NORMAL,
+
+    /**
+     * Ran fourth.
+     */
+    HIGH,
+
+    /**
+     * Ran last.
+     */
+    HIGHEST
+}

eco-api/src/main/java/com/willfp/eco/core/placeholder/DynamicPlaceholder.java

@@ -0,0 +1,102 @@
+package com.willfp.eco.core.placeholder;
+
+import com.willfp.eco.core.EcoPlugin;
+import com.willfp.eco.core.integrations.placeholder.PlaceholderManager;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Objects;
+import java.util.function.Function;
+import java.util.regex.Pattern;
+
+/**
+ * A placeholder that does not require a player and supports dynamic styles.
+ */
+public final class DynamicPlaceholder implements Placeholder {
+    /**
+     * The placeholder pattern.
+     */
+    private final Pattern pattern;
+
+    /**
+     * The function to retrieve the output of the placeholder.
+     */
+    private final Function<String, String> function;
+
+    /**
+     * The plugin for the placeholder.
+     */
+    private final EcoPlugin plugin;
+
+    /**
+     * Create a new dynamic placeholder.
+     *
+     * @param plugin   The plugin.
+     * @param pattern  The pattern.
+     * @param function The function to retrieve the value.
+     */
+    public DynamicPlaceholder(@NotNull final EcoPlugin plugin,
+                              @NotNull final Pattern pattern,
+                              @NotNull final Function<String, String> function) {
+        this.plugin = plugin;
+        this.pattern = pattern;
+        this.function = function;
+    }
+
+    /**
+     * Get the value of the placeholder.
+     *
+     * @param args The args.
+     * @return The value.
+     */
+    @NotNull
+    public String getValue(@NotNull final String args) {
+        return function.apply(args);
+    }
+
+    /**
+     * Register the placeholder.
+     *
+     * @return The placeholder.
+     */
+    public DynamicPlaceholder register() {
+        PlaceholderManager.registerPlaceholder(this);
+        return this;
+    }
+
+    @Override
+    public @NotNull EcoPlugin getPlugin() {
+        return this.plugin;
+    }
+
+    @Override
+    @Deprecated
+    public @NotNull String getIdentifier() {
+        return "dynamic";
+    }
+
+    @NotNull
+    @Override
+    public Pattern getPattern() {
+        return this.pattern;
+    }
+
+    @Override
+    public boolean equals(@Nullable final Object o) {
+        if (this == o) {
+            return true;
+        }
+
+        if (!(o instanceof DynamicPlaceholder that)) {
+            return false;
+        }
+
+        return Objects.equals(this.getPattern(), that.getPattern())
+                && Objects.equals(this.getPlugin(), that.getPlugin());
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(this.getIdentifier(), this.getPlugin());
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/placeholder/InjectablePlaceholder.java

@@ -2,13 +2,14 @@ package com.willfp.eco.core.placeholder;
 
 import com.willfp.eco.core.Eco;
 import com.willfp.eco.core.EcoPlugin;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * Placeholders that can be injected into {@link PlaceholderInjectable} objects.
  */
 public sealed interface InjectablePlaceholder extends Placeholder permits PlayerStaticPlaceholder, StaticPlaceholder {
     @Override
-    default EcoPlugin getPlugin() {
+    default @NotNull EcoPlugin getPlugin() {
         return Eco.get().getEcoPlugin();
     }
 }

eco-api/src/main/java/com/willfp/eco/core/placeholder/Placeholder.java

@@ -1,16 +1,22 @@
 package com.willfp.eco.core.placeholder;
 
 import com.willfp.eco.core.EcoPlugin;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.regex.Pattern;
 
 /**
  * A placeholder represents a string that can hold a value.
  */
-public sealed interface Placeholder permits PlayerPlaceholder, PlayerlessPlaceholder, InjectablePlaceholder {
+public sealed interface Placeholder permits PlayerPlaceholder, PlayerlessPlaceholder,
+        DynamicPlaceholder, PlayerDynamicPlaceholder, InjectablePlaceholder {
     /**
      * Get the plugin that holds the placeholder.
      *
      * @return The plugin.
      */
+    @Nullable
     EcoPlugin getPlugin();
 
     /**
@@ -18,5 +24,16 @@ public sealed interface Placeholder permits PlayerPlaceholder, PlayerlessPlaceho
      *
      * @return The identifier.
      */
+    @NotNull
     String getIdentifier();
+
+    /**
+     * Get the pattern for the placeholder.
+     *
+     * @return The pattern.
+     */
+    @NotNull
+    default Pattern getPattern() {
+        return Pattern.compile(this.getIdentifier());
+    }
 }

eco-api/src/main/java/com/willfp/eco/core/placeholder/PlayerDynamicPlaceholder.java

@@ -0,0 +1,105 @@
+package com.willfp.eco.core.placeholder;
+
+import com.willfp.eco.core.EcoPlugin;
+import com.willfp.eco.core.integrations.placeholder.PlaceholderManager;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Objects;
+import java.util.function.BiFunction;
+import java.util.regex.Pattern;
+
+/**
+ * A placeholder that does not require a player and supports dynamic styles.
+ */
+public final class PlayerDynamicPlaceholder implements Placeholder {
+    /**
+     * The placeholder pattern.
+     */
+    private final Pattern pattern;
+
+    /**
+     * The function to retrieve the output of the placeholder.
+     */
+    private final BiFunction<String, Player, String> function;
+
+    /**
+     * The plugin for the placeholder.
+     */
+    private final EcoPlugin plugin;
+
+    /**
+     * Create a new dynamic placeholder.
+     *
+     * @param plugin   The plugin.
+     * @param pattern  The pattern.
+     * @param function The function to retrieve the value.
+     */
+    public PlayerDynamicPlaceholder(@NotNull final EcoPlugin plugin,
+                                    @NotNull final Pattern pattern,
+                                    @NotNull final BiFunction<String, Player, String> function) {
+        this.plugin = plugin;
+        this.pattern = pattern;
+        this.function = function;
+    }
+
+    /**
+     * Get the value of the placeholder.
+     *
+     * @param args   The args.
+     * @param player The player.
+     * @return The value.
+     */
+    @NotNull
+    public String getValue(@NotNull final String args,
+                           @NotNull final Player player) {
+        return function.apply(args, player);
+    }
+
+    /**
+     * Register the placeholder.
+     *
+     * @return The placeholder.
+     */
+    public PlayerDynamicPlaceholder register() {
+        PlaceholderManager.registerPlaceholder(this);
+        return this;
+    }
+
+    @Override
+    public @NotNull EcoPlugin getPlugin() {
+        return this.plugin;
+    }
+
+    @Override
+    @Deprecated
+    public @NotNull String getIdentifier() {
+        return "dynamic";
+    }
+
+    @NotNull
+    @Override
+    public Pattern getPattern() {
+        return this.pattern;
+    }
+
+    @Override
+    public boolean equals(@Nullable final Object o) {
+        if (this == o) {
+            return true;
+        }
+
+        if (!(o instanceof PlayerDynamicPlaceholder that)) {
+            return false;
+        }
+
+        return Objects.equals(this.getPattern(), that.getPattern())
+                && Objects.equals(this.getPlugin(), that.getPlugin());
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(this.getIdentifier(), this.getPlugin());
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/placeholder/PlayerPlaceholder.java

@@ -8,6 +8,7 @@ import org.jetbrains.annotations.Nullable;
 
 import java.util.Objects;
 import java.util.function.Function;
+import java.util.regex.Pattern;
 
 /**
  * A placeholder that requires a player.
@@ -18,6 +19,11 @@ public final class PlayerPlaceholder implements Placeholder {
      */
     private final String identifier;
 
+    /**
+     * The placeholder pattern.
+     */
+    private final Pattern pattern;
+
     /**
      * The function to retrieve the output of the placeholder given a player.
      */
@@ -40,6 +46,7 @@ public final class PlayerPlaceholder implements Placeholder {
                              @NotNull final Function<Player, String> function) {
         this.plugin = plugin;
         this.identifier = identifier;
+        this.pattern = Pattern.compile(identifier);
         this.function = function;
     }
 
@@ -49,6 +56,7 @@ public final class PlayerPlaceholder implements Placeholder {
      * @param player The player.
      * @return The value.
      */
+    @NotNull
     public String getValue(@NotNull final Player player) {
         return function.apply(player);
     }
@@ -64,15 +72,21 @@ public final class PlayerPlaceholder implements Placeholder {
     }
 
     @Override
-    public EcoPlugin getPlugin() {
+    public @NotNull EcoPlugin getPlugin() {
         return this.plugin;
     }
 
     @Override
-    public String getIdentifier() {
+    public @NotNull String getIdentifier() {
         return this.identifier;
     }
 
+    @NotNull
+    @Override
+    public Pattern getPattern() {
+        return this.pattern;
+    }
+
     @Override
     public boolean equals(@Nullable final Object o) {
         if (this == o) {

eco-api/src/main/java/com/willfp/eco/core/placeholder/PlayerStaticPlaceholder.java

@@ -6,6 +6,7 @@ import org.jetbrains.annotations.Nullable;
 
 import java.util.Objects;
 import java.util.function.Function;
+import java.util.regex.Pattern;
 
 /**
  * A placeholder that cannot be registered, and exists purely in injection.
@@ -16,6 +17,11 @@ public final class PlayerStaticPlaceholder implements InjectablePlaceholder {
      */
     private final String identifier;
 
+    /**
+     * The placeholder pattern.
+     */
+    private final Pattern pattern;
+
     /**
      * The function to retrieve the output of the placeholder.
      */
@@ -30,6 +36,7 @@ public final class PlayerStaticPlaceholder implements InjectablePlaceholder {
     public PlayerStaticPlaceholder(@NotNull final String identifier,
                                    @NotNull final Function<Player, String> function) {
         this.identifier = identifier;
+        this.pattern = Pattern.compile(identifier);
         this.function = function;
     }
 
@@ -39,15 +46,22 @@ public final class PlayerStaticPlaceholder implements InjectablePlaceholder {
      * @param player The player.
      * @return The value.
      */
+    @NotNull
     public String getValue(@NotNull final Player player) {
         return function.apply(player);
     }
 
     @Override
-    public String getIdentifier() {
+    public @NotNull String getIdentifier() {
         return this.identifier;
     }
 
+    @NotNull
+    @Override
+    public Pattern getPattern() {
+        return this.pattern;
+    }
+
     @Override
     public boolean equals(@Nullable final Object o) {
         if (this == o) {

eco-api/src/main/java/com/willfp/eco/core/placeholder/PlayerlessPlaceholder.java

@@ -7,16 +7,22 @@ import org.jetbrains.annotations.Nullable;
 
 import java.util.Objects;
 import java.util.function.Supplier;
+import java.util.regex.Pattern;
 
 /**
  * A placeholder that does not require a player.
  */
 public final class PlayerlessPlaceholder implements Placeholder {
     /**
-     * The name of the placeholder.
+     * The placeholder identifier.
      */
     private final String identifier;
 
+    /**
+     * The placeholder pattern.
+     */
+    private final Pattern pattern;
+
     /**
      * The function to retrieve the output of the placeholder.
      */
@@ -39,6 +45,7 @@ public final class PlayerlessPlaceholder implements Placeholder {
                                  @NotNull final Supplier<String> function) {
         this.plugin = plugin;
         this.identifier = identifier;
+        this.pattern = Pattern.compile(identifier);
         this.function = function;
     }
 
@@ -62,15 +69,21 @@ public final class PlayerlessPlaceholder implements Placeholder {
     }
 
     @Override
-    public EcoPlugin getPlugin() {
+    public @NotNull EcoPlugin getPlugin() {
         return this.plugin;
     }
 
     @Override
-    public String getIdentifier() {
+    public @NotNull String getIdentifier() {
         return this.identifier;
     }
 
+    @NotNull
+    @Override
+    public Pattern getPattern() {
+        return this.pattern;
+    }
+
     @Override
     public boolean equals(@Nullable final Object o) {
         if (this == o) {

eco-api/src/main/java/com/willfp/eco/core/placeholder/StaticPlaceholder.java

@@ -5,6 +5,7 @@ import org.jetbrains.annotations.Nullable;
 
 import java.util.Objects;
 import java.util.function.Supplier;
+import java.util.regex.Pattern;
 
 /**
  * A placeholder that cannot be registered, and exists purely in injection.
@@ -15,6 +16,11 @@ public final class StaticPlaceholder implements InjectablePlaceholder {
      */
     private final String identifier;
 
+    /**
+     * The placeholder pattern.
+     */
+    private final Pattern pattern;
+
     /**
      * The function to retrieve the output of the placeholder.
      */
@@ -29,6 +35,7 @@ public final class StaticPlaceholder implements InjectablePlaceholder {
     public StaticPlaceholder(@NotNull final String identifier,
                              @NotNull final Supplier<String> function) {
         this.identifier = identifier;
+        this.pattern = Pattern.compile(identifier);
         this.function = function;
     }
 
@@ -37,15 +44,22 @@ public final class StaticPlaceholder implements InjectablePlaceholder {
      *
      * @return The value.
      */
+    @NotNull
     public String getValue() {
         return function.get();
     }
 
     @Override
-    public String getIdentifier() {
+    public @NotNull String getIdentifier() {
         return this.identifier;
     }
 
+    @NotNull
+    @Override
+    public Pattern getPattern() {
+        return this.pattern;
+    }
+
     @Override
     public boolean equals(@Nullable final Object o) {
         if (this == o) {

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

@@ -71,10 +71,6 @@ public final class Prices {
                 ctx
         );
 
-        if (function.apply(context) <= 0) {
-            return new PriceFree();
-        }
-
         // Default to economy
         if (priceName == null) {
             return new PriceEconomy(context, function);

eco-api/src/main/kotlin/com/willfp/eco/core/packet/Packet.kt

@@ -0,0 +1,9 @@
+@file:JvmName("PacketExtensions")
+
+package com.willfp.eco.core.packet
+
+import org.bukkit.entity.Player
+
+/** @see Packet.send */
+fun Player.sendPacket(packet: Packet) =
+    packet.send(this)

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

@@ -8,8 +8,11 @@ import org.bukkit.command.TabCompleter
 class DelegatedBukkitCommand(
     private val delegate: EcoPluginCommand
 ) : Command(delegate.name), TabCompleter, PluginIdentifiableCommand {
+    private var _aliases: List<String>? = null
+    private var _description: String? = null
+
     override fun execute(sender: CommandSender, label: String, args: Array<out String>?): Boolean {
-        return false
+        return delegate.onCommand(sender, this, label, args)
     }
 
     override fun onTabComplete(
@@ -18,11 +21,21 @@ class DelegatedBukkitCommand(
         label: String,
         args: Array<out String>?
     ): List<String> {
-        return mutableListOf() // Mutable in case bukkit requires this (I haven't checked.)
+        return delegate.onTabComplete(sender, this, label, args) ?: emptyList()
     }
 
     override fun getPlugin() = delegate.plugin
     override fun getPermission() = delegate.permission
-    override fun getDescription() = delegate.description ?: ""
-    override fun getAliases(): List<String> = delegate.aliases
+    override fun getDescription() = _description ?: delegate.description ?: ""
+    override fun getAliases(): List<String> = _aliases ?: delegate.aliases
+
+    override fun setDescription(description: String): Command {
+        this._description = description
+        return this
+    }
+
+    override fun setAliases(aliases: List<String>): Command {
+        this._aliases = aliases
+        return this
+    }
 }

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

@@ -17,27 +17,25 @@ class EcoPluginCommand(
     override fun register() {
         val command = Bukkit.getPluginCommand(name)
 
+        val knownDescription = command?.description ?: description ?: ""
+        val knownAliases = command?.aliases ?: aliases
+
         if (command == null) {
             unregister()
-
             commandMap.register(plugin.name.lowercase(), DelegatedBukkitCommand(this))
         } else {
             command.setExecutor(this)
-
-
-            description?.let {
-                command.setDescription(it)
-            }
-
-            if (aliases.isNotEmpty()) {
-                command.aliases = aliases
-            }
+            command.tabCompleter = this
+            command.description = knownDescription
+            command.aliases = knownAliases
         }
+
+        Eco.get().syncCommands()
     }
 
     override fun unregister() {
-        val found = commandMap.getCommand(name)
-        found?.unregister(commandMap)
+        commandMap.getCommand(name)?.unregister(commandMap)
+        Eco.get().unregisterCommand(this)
 
         Eco.get().syncCommands()
     }

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

@@ -50,8 +50,8 @@ abstract class HandledCommand(
         command: Command,
         label: String,
         args: Array<out String>?
-    ): MutableList<String>? {
-        return handleTabComplete(sender, args?.toList() ?: listOf()).toMutableList()
+    ): List<String>? {
+        return handleTabComplete(sender, args?.toList() ?: listOf())
     }
 
     override fun getPlugin() = this.plugin

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/events/EcoEventManager.kt

@@ -2,11 +2,38 @@ package com.willfp.eco.internal.events
 
 import com.willfp.eco.core.EcoPlugin
 import com.willfp.eco.core.events.EventManager
+import com.willfp.eco.core.packet.PacketEvent
+import com.willfp.eco.core.packet.PacketListener
+import com.willfp.eco.core.packet.PacketPriority
 import org.bukkit.Bukkit
 import org.bukkit.event.HandlerList
 import org.bukkit.event.Listener
 
-class EcoEventManager (private val plugin: EcoPlugin) : EventManager {
+
+private class RegisteredPacketListener(
+    val plugin: EcoPlugin,
+    val listener: PacketListener
+)
+
+private val listeners = mutableMapOf<PacketPriority, MutableList<RegisteredPacketListener>>()
+
+fun PacketEvent.handleSend() {
+    for (priority in PacketPriority.values()) {
+        for (listener in listeners[priority] ?: continue) {
+            listener.listener.onSend(this)
+        }
+    }
+}
+
+fun PacketEvent.handleReceive() {
+    for (priority in PacketPriority.values()) {
+        for (listener in listeners[priority] ?: continue) {
+            listener.listener.onReceive(this)
+        }
+    }
+}
+
+class EcoEventManager(private val plugin: EcoPlugin) : EventManager {
     override fun registerListener(listener: Listener) {
         Bukkit.getPluginManager().registerEvents(listener, plugin)
     }
@@ -17,5 +44,17 @@ class EcoEventManager (private val plugin: EcoPlugin) : EventManager {
 
     override fun unregisterAllListeners() {
         HandlerList.unregisterAll(plugin)
+        for (value in listeners.values) {
+            value.removeIf { it.plugin == plugin }
+        }
     }
-}
+
+    override fun registerPacketListener(listener: PacketListener) {
+        listeners.getOrPut(listener.priority) { mutableListOf() }.add(
+            RegisteredPacketListener(
+                plugin,
+                listener
+            )
+        )
+    }
+}

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

@@ -6,12 +6,14 @@ import com.willfp.eco.internal.spigot.proxy.common.ai.EntityGoalFactory
 import com.willfp.eco.internal.spigot.proxy.common.ai.TargetGoalFactory
 import net.minecraft.nbt.CompoundTag
 import net.minecraft.resources.ResourceLocation
+import net.minecraft.server.level.ServerPlayer
 import net.minecraft.world.entity.LivingEntity
 import net.minecraft.world.entity.PathfinderMob
 import net.minecraft.world.item.Item
 import org.bukkit.Material
 import org.bukkit.NamespacedKey
 import org.bukkit.entity.Mob
+import org.bukkit.entity.Player
 import org.bukkit.inventory.ItemStack
 import org.bukkit.persistence.PersistentDataContainer
 
@@ -63,6 +65,9 @@ fun CompoundTag.makePdc(base: Boolean = false): PersistentDataContainer =
 fun CompoundTag.setPdc(pdc: PersistentDataContainer?, item: net.minecraft.world.item.ItemStack? = null) =
     impl.setPdc(this, pdc, item)
 
+fun Player.toNMS(): ServerPlayer =
+    impl.toNMS(this)
+
 interface CommonsProvider {
     val nbtTagString: Int
 
@@ -94,6 +99,8 @@ interface CommonsProvider {
 
     fun itemToMaterial(item: Item): Material
 
+    fun toNMS(player: Player): ServerPlayer
+
     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/packet/EcoChannelDuplexHandler.kt

@@ -0,0 +1,48 @@
+package com.willfp.eco.internal.spigot.proxy.common.packet
+
+import com.willfp.eco.core.packet.Packet
+import com.willfp.eco.core.packet.PacketEvent
+import com.willfp.eco.internal.events.handleReceive
+import com.willfp.eco.internal.events.handleSend
+import io.netty.channel.ChannelDuplexHandler
+import io.netty.channel.ChannelHandlerContext
+import io.netty.channel.ChannelPromise
+import org.bukkit.Bukkit
+import java.util.UUID
+
+class EcoChannelDuplexHandler(
+    private val uuid: UUID
+) : ChannelDuplexHandler() {
+
+    override fun channelRead(ctx: ChannelHandlerContext, msg: Any) {
+        val player = Bukkit.getPlayer(uuid)
+
+        if (player != null) {
+            val event = PacketEvent(Packet(msg), player)
+
+            event.handleReceive()
+
+            if (!event.isCancelled) {
+                super.channelRead(ctx, msg)
+            }
+        } else {
+            super.channelRead(ctx, msg)
+        }
+    }
+
+    override fun write(ctx: ChannelHandlerContext, msg: Any, promise: ChannelPromise) {
+        val player = Bukkit.getPlayer(uuid)
+
+        if (player != null) {
+            val event = PacketEvent(Packet(msg), player)
+
+            event.handleSend()
+
+            if (!event.isCancelled) {
+                super.write(ctx, msg, promise)
+            }
+        } else {
+            super.write(ctx, msg, promise)
+        }
+    }
+}

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

@@ -0,0 +1,31 @@
+package com.willfp.eco.internal.spigot.proxy.common.packet
+
+import com.willfp.eco.internal.spigot.proxy.common.toNMS
+import org.bukkit.event.EventHandler
+import org.bukkit.event.Listener
+import org.bukkit.event.player.PlayerJoinEvent
+import org.bukkit.event.player.PlayerQuitEvent
+
+object PacketInjectorListener : Listener {
+    @EventHandler
+    fun onJoin(event: PlayerJoinEvent) {
+        val player = event.player
+
+        val channel = player.toNMS().connection.connection.channel
+
+        channel.pipeline().addBefore("packet_handler", "eco_packets", EcoChannelDuplexHandler(player.uniqueId))
+    }
+
+    @EventHandler
+    fun onLeave(event: PlayerQuitEvent) {
+        val player = event.player
+
+        val channel = player.toNMS().connection.connection.channel
+
+        channel.eventLoop().submit {
+            if (channel.pipeline().get("eco_packets") != null) {
+                channel.pipeline().remove("eco_packets")
+            }
+        }
+    }
+}

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

@@ -0,0 +1,32 @@
+package com.willfp.eco.internal.spigot.proxy.common.packet.display
+
+import com.willfp.eco.core.EcoPlugin
+import com.willfp.eco.core.packet.PacketEvent
+import com.willfp.eco.core.packet.PacketListener
+import net.minecraft.network.protocol.game.ClientboundPlaceGhostRecipePacket
+import net.minecraft.resources.ResourceLocation
+
+class PacketAutoRecipe(
+    private val plugin: EcoPlugin
+) : PacketListener {
+    override fun onSend(event: PacketEvent) {
+        val packet = event.packet.handle as? ClientboundPlaceGhostRecipePacket ?: return
+
+        if (!plugin.configYml.getBool("displayed-recipes")) {
+            return
+        }
+
+        if (!EcoPlugin.getPluginNames().contains(packet.recipe.namespace)) {
+            return
+        }
+
+        if (packet.recipe.path.contains("_displayed")) {
+            return
+        }
+
+        val fKey = packet.javaClass.getDeclaredField("b")
+        fKey.isAccessible = true
+        val key = fKey[packet] as ResourceLocation
+        fKey[packet] = ResourceLocation(key.namespace, key.path + "_displayed")
+    }
+}

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

@@ -0,0 +1,17 @@
+package com.willfp.eco.internal.spigot.proxy.common.packet.display
+
+import com.willfp.eco.core.packet.PacketEvent
+import com.willfp.eco.core.packet.PacketListener
+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.ServerboundSetCarriedItemPacket
+
+object PacketHeldItemSlot : PacketListener {
+    override fun onReceive(event: PacketEvent) {
+        if (event.packet.handle !is ServerboundSetCarriedItemPacket) {
+            return
+        }
+
+        event.player.lastDisplayFrame = DisplayFrame.EMPTY
+    }
+}

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

@@ -0,0 +1,39 @@
+package com.willfp.eco.internal.spigot.proxy.common.packet.display
+
+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.asNMSStack
+import net.minecraft.nbt.CompoundTag
+import net.minecraft.network.protocol.game.ClientboundMerchantOffersPacket
+import net.minecraft.world.item.ItemStack
+import net.minecraft.world.item.trading.MerchantOffer
+import net.minecraft.world.item.trading.MerchantOffers
+
+object PacketOpenWindowMerchant : 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 nbt = offer.createTag()
+            for (tag in arrayOf("buy", "buyB", "sell")) {
+                val nms = ItemStack.of(nbt.getCompound(tag))
+                val displayed = Display.display(nms.asBukkitStack(), event.player)
+                val itemNBT = displayed.asNMSStack().save(CompoundTag())
+                nbt.put(tag, itemNBT)
+            }
+
+            offers += MerchantOffer(nbt)
+        }
+
+        field.set(packet, offers)
+    }
+}

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

@@ -0,0 +1,19 @@
+package com.willfp.eco.internal.spigot.proxy.common.packet.display
+
+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 PacketSetCreativeSlot : PacketListener {
+    override fun onReceive(event: PacketEvent) {
+        val packet = event.packet.handle as? ServerboundSetCreativeModeSlotPacket ?: return
+
+        Display.revert(packet.item.asBukkitStack())
+
+        event.player.lastDisplayFrame = DisplayFrame.EMPTY
+    }
+}

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

@@ -0,0 +1,19 @@
+package com.willfp.eco.internal.spigot.proxy.common.packet.display
+
+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.ClientboundContainerSetSlotPacket
+
+object PacketSetSlot : PacketListener {
+    override fun onSend(event: PacketEvent) {
+        val packet = event.packet.handle as? ClientboundContainerSetSlotPacket ?: return
+
+        Display.display(packet.item.asBukkitStack(), event.player)
+
+        event.player.lastDisplayFrame = DisplayFrame.EMPTY
+    }
+}

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

@@ -1,39 +1,40 @@
-package com.willfp.eco.internal.spigot.display
+package com.willfp.eco.internal.spigot.proxy.common.packet.display
 
-import com.comphenix.protocol.PacketType
-import com.comphenix.protocol.events.PacketContainer
-import com.comphenix.protocol.events.PacketEvent
-import com.willfp.eco.core.AbstractPacketAdapter
 import com.willfp.eco.core.EcoPlugin
 import com.willfp.eco.core.display.Display
 import com.willfp.eco.core.items.HashedItem
-import com.willfp.eco.internal.spigot.display.frame.DisplayFrame
-import com.willfp.eco.internal.spigot.display.frame.lastDisplayFrame
+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.asNMSStack
+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.ClientboundContainerSetContentPacket
 import org.bukkit.entity.Player
 import org.bukkit.inventory.ItemStack
+import java.util.UUID
 import java.util.concurrent.ConcurrentHashMap
 
-class PacketWindowItems(plugin: EcoPlugin) : AbstractPacketAdapter(plugin, PacketType.Play.Server.WINDOW_ITEMS, false) {
-    private val lastKnownWindowIDs = ConcurrentHashMap<String, Int>()
+class PacketWindowItems(
+    private val plugin: EcoPlugin
+) : PacketListener {
+    private val lastKnownWindowIDs = ConcurrentHashMap<UUID, Int>()
 
-    override fun onSend(
-        packet: PacketContainer,
-        player: Player,
-        event: PacketEvent
-    ) {
-        packet.itemModifier.modify(0) {
-            Display.display(
-                it, player
-            )
-        }
+    private val field = ClientboundContainerSetContentPacket::class.java
+        .declaredFields
+        .first { it.type == List::class.java }
+        .apply { isAccessible = true }
 
-        val windowId = packet.integers.read(0)
+    override fun onSend(event: PacketEvent) {
+        val packet = event.packet.handle as? ClientboundContainerSetContentPacket ?: return
+        val player = event.player
 
-        // Using name because UUID is unreliable with ProtocolLib players.
-        val name = player.name
+        Display.display(packet.carriedItem.asBukkitStack(), player)
 
-        val lastKnownID = lastKnownWindowIDs[name]
-        lastKnownWindowIDs[name] = windowId
+        val windowId = packet.containerId
+
+        val lastKnownID = lastKnownWindowIDs[player.uniqueId]
+        lastKnownWindowIDs[player.uniqueId] = windowId
 
         // If there is any change in window ID at any point,
         // Remove the last display frame to prevent any potential conflicts.
@@ -43,17 +44,20 @@ class PacketWindowItems(plugin: EcoPlugin) : AbstractPacketAdapter(plugin, Packe
             player.lastDisplayFrame = DisplayFrame.EMPTY
         }
 
-        val itemStacks = packet.itemListModifier.read(0) ?: return
+        val itemStacks = packet.items.map { it.asBukkitStack() }
 
-        packet.itemListModifier.write(0, modifyWindowItems(itemStacks, windowId, player))
+        val newItems = modifyWindowItems(itemStacks.toMutableList(), windowId, player)
+
+        field.set(packet, newItems.map { it.asNMSStack() })
     }
 
+
     private fun modifyWindowItems(
         itemStacks: MutableList<ItemStack>,
         windowId: Int,
         player: Player
     ): MutableList<ItemStack> {
-        if (this.getPlugin().configYml.getBool("use-display-frame") && windowId == 0) {
+        if (plugin.configYml.getBool("use-display-frame") && windowId == 0) {
             val frameMap = mutableMapOf<Byte, HashedItem>()
 
             for (index in itemStacks.indices) {

eco-core/core-nms/nms-common/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/common/packet/display/frame/DisplayFrame.kt

@@ -1,6 +1,5 @@
-package com.willfp.eco.internal.spigot.display.frame
+package com.willfp.eco.internal.spigot.proxy.common.packet.display.frame
 
-import com.comphenix.protocol.injector.temporary.TemporaryPlayer
 import com.willfp.eco.core.items.HashedItem
 import org.bukkit.entity.Player
 import org.bukkit.inventory.ItemStack
@@ -33,22 +32,12 @@ private val frames = ConcurrentHashMap<UUID, DisplayFrame>()
 
 var Player.lastDisplayFrame: DisplayFrame
     get() {
-        // ProtocolLib fix
-        if (this is TemporaryPlayer) {
-            return DisplayFrame.EMPTY
-        }
-
         return frames[this.uniqueId] ?: DisplayFrame.EMPTY
     }
     set(value) {
-        // ProtocolLib fix
-        if (this is TemporaryPlayer) {
-            return
-        }
-
         frames[this.uniqueId] = value
     }
 
 fun clearFrames() {
     frames.clear()
-}
+}

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

@@ -1,15 +0,0 @@
-package com.willfp.eco.internal.spigot.proxy.v1_17_R1
-
-import com.willfp.eco.internal.spigot.proxy.AutoCraftProxy
-import net.minecraft.network.protocol.game.ClientboundPlaceGhostRecipePacket
-import net.minecraft.resources.ResourceLocation
-
-class AutoCraft : AutoCraftProxy {
-    override fun modifyPacket(packet: Any) {
-        val recipePacket = packet as ClientboundPlaceGhostRecipePacket
-        val fKey = recipePacket.javaClass.getDeclaredField("b")
-        fKey.isAccessible = true
-        val key = fKey[recipePacket] as ResourceLocation
-        fKey[recipePacket] = ResourceLocation(key.namespace, key.path + "_displayed")
-    }
-}

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

@@ -1,6 +1,6 @@
 package com.willfp.eco.internal.spigot.proxy.v1_17_R1
 
-import com.willfp.eco.core.command.impl.PluginCommand
+import com.willfp.eco.core.command.PluginCommandBase
 import com.willfp.eco.internal.spigot.proxy.BukkitCommandsProxy
 import org.bukkit.Bukkit
 import org.bukkit.command.Command
@@ -28,7 +28,7 @@ class BukkitCommands : BukkitCommandsProxy {
         (Bukkit.getServer() as CraftServer).syncCommands()
     }
 
-    override fun unregisterCommand(command: PluginCommand) {
+    override fun unregisterCommand(command: PluginCommandBase) {
         knownCommands.remove(command.name)
         knownCommands.remove("${command.plugin.name.lowercase()}:${command.name}")
     }

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

@@ -1,12 +1,15 @@
 package com.willfp.eco.internal.spigot.proxy.v1_17_R1
 
+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.minecraft.core.Registry
 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
@@ -15,6 +18,7 @@ import org.bukkit.NamespacedKey
 import org.bukkit.craftbukkit.v1_17_R1.CraftServer
 import org.bukkit.craftbukkit.v1_17_R1.entity.CraftEntity
 import org.bukkit.craftbukkit.v1_17_R1.entity.CraftMob
+import org.bukkit.craftbukkit.v1_17_R1.entity.CraftPlayer
 import org.bukkit.craftbukkit.v1_17_R1.inventory.CraftItemStack
 import org.bukkit.craftbukkit.v1_17_R1.persistence.CraftPersistentDataContainer
 import org.bukkit.craftbukkit.v1_17_R1.persistence.CraftPersistentDataTypeRegistry
@@ -22,13 +26,17 @@ import org.bukkit.craftbukkit.v1_17_R1.util.CraftMagicNumbers
 import org.bukkit.craftbukkit.v1_17_R1.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() {
+    override fun init(plugin: EcoPlugin) {
         CommonsProvider.setIfNeeded(CommonsProviderImpl)
+        plugin.onEnable {
+            plugin.eventManager.registerListener(PacketInjectorListener)
+        }
     }
 
     object CommonsProviderImpl : CommonsProvider {
@@ -60,7 +68,7 @@ class CommonsInitializer : CommonsInitializerProxy {
         }
 
         override fun asBukkitStack(itemStack: net.minecraft.world.item.ItemStack): ItemStack {
-            return CraftItemStack.asBukkitCopy(itemStack)
+            return CraftItemStack.asCraftMirror(itemStack)
         }
 
         override fun mergeIfNeeded(itemStack: ItemStack, nmsStack: net.minecraft.world.item.ItemStack) {
@@ -143,5 +151,9 @@ class CommonsInitializer : CommonsInitializerProxy {
         override fun itemToMaterial(item: Item) =
             Material.getMaterial(Registry.ITEM.getKey(item).path.uppercase())
                 ?: throw IllegalArgumentException("Invalid material!")
+
+        override fun toNMS(player: Player): ServerPlayer {
+            return (player as CraftPlayer).handle
+        }
     }
 }

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

@@ -0,0 +1,48 @@
+package com.willfp.eco.internal.spigot.proxy.v1_17_R1
+
+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 com.willfp.eco.internal.spigot.proxy.v1_17_R1.display.PacketChat
+import net.minecraft.network.protocol.Packet
+import org.bukkit.craftbukkit.v1_17_R1.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),
+            PacketChat
+        )
+    }
+}

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

@@ -1,41 +0,0 @@
-package com.willfp.eco.internal.spigot.proxy.v1_17_R1
-
-import com.willfp.eco.core.display.Display
-import com.willfp.eco.internal.spigot.proxy.VillagerTradeProxy
-import net.minecraft.nbt.CompoundTag
-import net.minecraft.world.item.ItemStack
-import net.minecraft.world.item.trading.MerchantOffer
-import org.bukkit.craftbukkit.v1_17_R1.inventory.CraftItemStack
-import org.bukkit.craftbukkit.v1_17_R1.inventory.CraftMerchantRecipe
-import org.bukkit.entity.Player
-import org.bukkit.inventory.MerchantRecipe
-import java.lang.reflect.Field
-
-class VillagerTrade : VillagerTradeProxy {
-    private val handle: Field = CraftMerchantRecipe::class.java.getDeclaredField("handle")
-
-    override fun displayTrade(
-        recipe: MerchantRecipe,
-        player: Player
-    ): MerchantRecipe {
-        recipe as CraftMerchantRecipe
-
-        val nbt = getHandle(recipe).createTag()
-        for (tag in arrayOf("buy", "buyB", "sell")) {
-            val nms = ItemStack.of(nbt.getCompound(tag))
-            val displayed = Display.display(CraftItemStack.asBukkitCopy(nms), player)
-            val itemNBT = CraftItemStack.asNMSCopy(displayed).save(CompoundTag())
-            nbt.put(tag, itemNBT)
-        }
-
-        return CraftMerchantRecipe(MerchantOffer(nbt))
-    }
-
-    private fun getHandle(recipe: CraftMerchantRecipe): MerchantOffer {
-        return handle[recipe] as MerchantOffer
-    }
-
-    init {
-        handle.isAccessible = true
-    }
-}

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

@@ -1,7 +1,8 @@
-package com.willfp.eco.internal.spigot.proxy.v1_17_R1
+package com.willfp.eco.internal.spigot.proxy.v1_17_R1.display
 
 import com.willfp.eco.core.display.Display
-import com.willfp.eco.internal.spigot.proxy.ChatComponentProxy
+import com.willfp.eco.core.packet.PacketEvent
+import com.willfp.eco.core.packet.PacketListener
 import net.kyori.adventure.nbt.api.BinaryTagHolder
 import net.kyori.adventure.text.BuildableComponent
 import net.kyori.adventure.text.Component
@@ -9,20 +10,28 @@ import net.kyori.adventure.text.TranslatableComponent
 import net.kyori.adventure.text.event.HoverEvent
 import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer
 import net.minecraft.nbt.TagParser
+import net.minecraft.network.protocol.game.ClientboundChatPacket
 import org.bukkit.Material
 import org.bukkit.craftbukkit.v1_17_R1.inventory.CraftItemStack
 import org.bukkit.entity.Player
 import org.bukkit.inventory.ItemStack
 
-@Suppress("UNCHECKED_CAST")
-class ChatComponent : ChatComponentProxy {
+object PacketChat : PacketListener {
     private val gsonComponentSerializer = GsonComponentSerializer.gson()
 
-    override fun modifyComponent(obj: Any, player: Player): Any {
-        if (obj !is net.minecraft.network.chat.Component) {
-            return obj
-        }
+    private val field = ClientboundChatPacket::class.java.declaredFields
+        .first { it.type == net.minecraft.network.chat.Component::class.java }
+        .apply { isAccessible = true }
 
+    override fun onSend(event: PacketEvent) {
+        val packet = event.packet.handle as? ClientboundChatPacket ?: return
+
+        val newMessage = modifyComponent(packet.message, event.player)
+
+        field.set(packet, newMessage)
+    }
+
+    private fun modifyComponent(obj: net.minecraft.network.chat.Component, player: Player): Any {
         val component = gsonComponentSerializer.deserialize(
             net.minecraft.network.chat.Component.Serializer.toJson(
                 obj
@@ -53,6 +62,7 @@ class ChatComponent : ChatComponentProxy {
         }
         component = component.children(children)
 
+        @Suppress("UNCHECKED_CAST")
         val hoverEvent: HoverEvent<Any> = component.style().hoverEvent() as HoverEvent<Any>? ?: return component
 
         val showItem = hoverEvent.value()
@@ -91,4 +101,4 @@ class ChatComponent : ChatComponentProxy {
         val style = component.style().hoverEvent(newHover)
         return component.style(style)
     }
-}
+}

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

@@ -1,15 +0,0 @@
-package com.willfp.eco.internal.spigot.proxy.v1_18_R1
-
-import com.willfp.eco.internal.spigot.proxy.AutoCraftProxy
-import net.minecraft.network.protocol.game.ClientboundPlaceGhostRecipePacket
-import net.minecraft.resources.ResourceLocation
-
-class AutoCraft : AutoCraftProxy {
-    override fun modifyPacket(packet: Any) {
-        val recipePacket = packet as ClientboundPlaceGhostRecipePacket
-        val fKey = recipePacket.javaClass.getDeclaredField("b")
-        fKey.isAccessible = true
-        val key = fKey[recipePacket] as ResourceLocation
-        fKey[recipePacket] = ResourceLocation(key.namespace, key.path + "_displayed")
-    }
-}

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

@@ -1,6 +1,6 @@
 package com.willfp.eco.internal.spigot.proxy.v1_18_R1
 
-import com.willfp.eco.core.command.impl.PluginCommand
+import com.willfp.eco.core.command.PluginCommandBase
 import com.willfp.eco.internal.spigot.proxy.BukkitCommandsProxy
 import org.bukkit.Bukkit
 import org.bukkit.command.Command
@@ -28,7 +28,7 @@ class BukkitCommands : BukkitCommandsProxy {
         (Bukkit.getServer() as CraftServer).syncCommands()
     }
 
-    override fun unregisterCommand(command: PluginCommand) {
+    override fun unregisterCommand(command: PluginCommandBase) {
         knownCommands.remove(command.name)
         knownCommands.remove("${command.plugin.name.lowercase()}:${command.name}")
     }

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

@@ -1,12 +1,15 @@
 package com.willfp.eco.internal.spigot.proxy.v1_18_R1
 
+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.minecraft.core.Registry
 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
@@ -15,6 +18,7 @@ import org.bukkit.NamespacedKey
 import org.bukkit.craftbukkit.v1_18_R1.CraftServer
 import org.bukkit.craftbukkit.v1_18_R1.entity.CraftEntity
 import org.bukkit.craftbukkit.v1_18_R1.entity.CraftMob
+import org.bukkit.craftbukkit.v1_18_R1.entity.CraftPlayer
 import org.bukkit.craftbukkit.v1_18_R1.inventory.CraftItemStack
 import org.bukkit.craftbukkit.v1_18_R1.persistence.CraftPersistentDataContainer
 import org.bukkit.craftbukkit.v1_18_R1.persistence.CraftPersistentDataTypeRegistry
@@ -22,13 +26,17 @@ import org.bukkit.craftbukkit.v1_18_R1.util.CraftMagicNumbers
 import org.bukkit.craftbukkit.v1_18_R1.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() {
+    override fun init(plugin: EcoPlugin) {
         CommonsProvider.setIfNeeded(CommonsProviderImpl)
+        plugin.onEnable {
+            plugin.eventManager.registerListener(PacketInjectorListener)
+        }
     }
 
     object CommonsProviderImpl : CommonsProvider {
@@ -60,7 +68,7 @@ class CommonsInitializer : CommonsInitializerProxy {
         }
 
         override fun asBukkitStack(itemStack: net.minecraft.world.item.ItemStack): ItemStack {
-            return CraftItemStack.asBukkitCopy(itemStack)
+            return CraftItemStack.asCraftMirror(itemStack)
         }
 
         override fun mergeIfNeeded(itemStack: ItemStack, nmsStack: net.minecraft.world.item.ItemStack) {
@@ -143,5 +151,9 @@ class CommonsInitializer : CommonsInitializerProxy {
         override fun itemToMaterial(item: Item) =
             Material.getMaterial(Registry.ITEM.getKey(item).path.uppercase())
                 ?: throw IllegalArgumentException("Invalid material!")
+
+        override fun toNMS(player: Player): ServerPlayer {
+            return (player as CraftPlayer).handle
+        }
     }
 }

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

@@ -0,0 +1,48 @@
+package com.willfp.eco.internal.spigot.proxy.v1_18_R1
+
+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 com.willfp.eco.internal.spigot.proxy.v1_18_R1.display.PacketChat
+import net.minecraft.network.protocol.Packet
+import org.bukkit.craftbukkit.v1_18_R1.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),
+            PacketChat
+        )
+    }
+}

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

@@ -1,41 +0,0 @@
-package com.willfp.eco.internal.spigot.proxy.v1_18_R1
-
-import com.willfp.eco.core.display.Display
-import com.willfp.eco.internal.spigot.proxy.VillagerTradeProxy
-import net.minecraft.nbt.CompoundTag
-import net.minecraft.world.item.ItemStack
-import net.minecraft.world.item.trading.MerchantOffer
-import org.bukkit.craftbukkit.v1_18_R1.inventory.CraftItemStack
-import org.bukkit.craftbukkit.v1_18_R1.inventory.CraftMerchantRecipe
-import org.bukkit.entity.Player
-import org.bukkit.inventory.MerchantRecipe
-import java.lang.reflect.Field
-
-class VillagerTrade : VillagerTradeProxy {
-    private val handle: Field = CraftMerchantRecipe::class.java.getDeclaredField("handle")
-
-    override fun displayTrade(
-        recipe: MerchantRecipe,
-        player: Player
-    ): MerchantRecipe {
-        recipe as CraftMerchantRecipe
-
-        val nbt = getHandle(recipe).createTag()
-        for (tag in arrayOf("buy", "buyB", "sell")) {
-            val nms = ItemStack.of(nbt.getCompound(tag))
-            val displayed = Display.display(CraftItemStack.asBukkitCopy(nms), player)
-            val itemNBT = CraftItemStack.asNMSCopy(displayed).save(CompoundTag())
-            nbt.put(tag, itemNBT)
-        }
-
-        return CraftMerchantRecipe(MerchantOffer(nbt))
-    }
-
-    private fun getHandle(recipe: CraftMerchantRecipe): MerchantOffer {
-        return handle[recipe] as MerchantOffer
-    }
-
-    init {
-        handle.isAccessible = true
-    }
-}

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

@@ -1,7 +1,8 @@
-package com.willfp.eco.internal.spigot.proxy.v1_18_R1
+package com.willfp.eco.internal.spigot.proxy.v1_18_R1.display
 
 import com.willfp.eco.core.display.Display
-import com.willfp.eco.internal.spigot.proxy.ChatComponentProxy
+import com.willfp.eco.core.packet.PacketEvent
+import com.willfp.eco.core.packet.PacketListener
 import net.kyori.adventure.nbt.api.BinaryTagHolder
 import net.kyori.adventure.text.BuildableComponent
 import net.kyori.adventure.text.Component
@@ -9,20 +10,28 @@ import net.kyori.adventure.text.TranslatableComponent
 import net.kyori.adventure.text.event.HoverEvent
 import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer
 import net.minecraft.nbt.TagParser
+import net.minecraft.network.protocol.game.ClientboundChatPacket
 import org.bukkit.Material
 import org.bukkit.craftbukkit.v1_18_R1.inventory.CraftItemStack
 import org.bukkit.entity.Player
 import org.bukkit.inventory.ItemStack
 
-@Suppress("UNCHECKED_CAST")
-class ChatComponent : ChatComponentProxy {
+object PacketChat : PacketListener {
     private val gsonComponentSerializer = GsonComponentSerializer.gson()
 
-    override fun modifyComponent(obj: Any, player: Player): Any {
-        if (obj !is net.minecraft.network.chat.Component) {
-            return obj
-        }
+    private val field = ClientboundChatPacket::class.java.declaredFields
+        .first { it.type == net.minecraft.network.chat.Component::class.java }
+        .apply { isAccessible = true }
 
+    override fun onSend(event: PacketEvent) {
+        val packet = event.packet.handle as? ClientboundChatPacket ?: return
+
+        val newMessage = modifyComponent(packet.message, event.player)
+
+        field.set(packet, newMessage)
+    }
+
+    private fun modifyComponent(obj: net.minecraft.network.chat.Component, player: Player): Any {
         val component = gsonComponentSerializer.deserialize(
             net.minecraft.network.chat.Component.Serializer.toJson(
                 obj
@@ -53,6 +62,7 @@ class ChatComponent : ChatComponentProxy {
         }
         component = component.children(children)
 
+        @Suppress("UNCHECKED_CAST")
         val hoverEvent: HoverEvent<Any> = component.style().hoverEvent() as HoverEvent<Any>? ?: return component
 
         val showItem = hoverEvent.value()
@@ -91,4 +101,4 @@ class ChatComponent : ChatComponentProxy {
         val style = component.style().hoverEvent(newHover)
         return component.style(style)
     }
-}
+}

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

@@ -1,15 +0,0 @@
-package com.willfp.eco.internal.spigot.proxy.v1_18_R2
-
-import com.willfp.eco.internal.spigot.proxy.AutoCraftProxy
-import net.minecraft.network.protocol.game.ClientboundPlaceGhostRecipePacket
-import net.minecraft.resources.ResourceLocation
-
-class AutoCraft : AutoCraftProxy {
-    override fun modifyPacket(packet: Any) {
-        val recipePacket = packet as ClientboundPlaceGhostRecipePacket
-        val fKey = recipePacket.javaClass.getDeclaredField("b")
-        fKey.isAccessible = true
-        val key = fKey[recipePacket] as ResourceLocation
-        fKey[recipePacket] = ResourceLocation(key.namespace, key.path + "_displayed")
-    }
-}

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

@@ -1,6 +1,6 @@
 package com.willfp.eco.internal.spigot.proxy.v1_18_R2
 
-import com.willfp.eco.core.command.impl.PluginCommand
+import com.willfp.eco.core.command.PluginCommandBase
 import com.willfp.eco.internal.spigot.proxy.BukkitCommandsProxy
 import org.bukkit.Bukkit
 import org.bukkit.command.Command
@@ -28,7 +28,7 @@ class BukkitCommands : BukkitCommandsProxy {
         (Bukkit.getServer() as CraftServer).syncCommands()
     }
 
-    override fun unregisterCommand(command: PluginCommand) {
+    override fun unregisterCommand(command: PluginCommandBase) {
         knownCommands.remove(command.name)
         knownCommands.remove("${command.plugin.name.lowercase()}:${command.name}")
     }

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

@@ -1,12 +1,15 @@
 package com.willfp.eco.internal.spigot.proxy.v1_18_R2
 
+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.minecraft.core.Registry
 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
@@ -15,6 +18,7 @@ import org.bukkit.NamespacedKey
 import org.bukkit.craftbukkit.v1_18_R2.CraftServer
 import org.bukkit.craftbukkit.v1_18_R2.entity.CraftEntity
 import org.bukkit.craftbukkit.v1_18_R2.entity.CraftMob
+import org.bukkit.craftbukkit.v1_18_R2.entity.CraftPlayer
 import org.bukkit.craftbukkit.v1_18_R2.inventory.CraftItemStack
 import org.bukkit.craftbukkit.v1_18_R2.persistence.CraftPersistentDataContainer
 import org.bukkit.craftbukkit.v1_18_R2.persistence.CraftPersistentDataTypeRegistry
@@ -22,13 +26,17 @@ import org.bukkit.craftbukkit.v1_18_R2.util.CraftMagicNumbers
 import org.bukkit.craftbukkit.v1_18_R2.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() {
+    override fun init(plugin: EcoPlugin) {
         CommonsProvider.setIfNeeded(CommonsProviderImpl)
+        plugin.onEnable {
+            plugin.eventManager.registerListener(PacketInjectorListener)
+        }
     }
 
     object CommonsProviderImpl : CommonsProvider {
@@ -60,7 +68,7 @@ class CommonsInitializer : CommonsInitializerProxy {
         }
 
         override fun asBukkitStack(itemStack: net.minecraft.world.item.ItemStack): ItemStack {
-            return CraftItemStack.asBukkitCopy(itemStack)
+            return CraftItemStack.asCraftMirror(itemStack)
         }
 
         override fun mergeIfNeeded(itemStack: ItemStack, nmsStack: net.minecraft.world.item.ItemStack) {
@@ -143,5 +151,9 @@ class CommonsInitializer : CommonsInitializerProxy {
         override fun itemToMaterial(item: Item) =
             Material.getMaterial(Registry.ITEM.getKey(item).path.uppercase())
                 ?: throw IllegalArgumentException("Invalid material!")
+
+        override fun toNMS(player: Player): ServerPlayer {
+            return (player as CraftPlayer).handle
+        }
     }
 }

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

@@ -0,0 +1,48 @@
+package com.willfp.eco.internal.spigot.proxy.v1_18_R2
+
+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 com.willfp.eco.internal.spigot.proxy.v1_18_R2.display.PacketChat
+import net.minecraft.network.protocol.Packet
+import org.bukkit.craftbukkit.v1_18_R2.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),
+            PacketChat
+        )
+    }
+}

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

@@ -1,41 +0,0 @@
-package com.willfp.eco.internal.spigot.proxy.v1_18_R2
-
-import com.willfp.eco.core.display.Display
-import com.willfp.eco.internal.spigot.proxy.VillagerTradeProxy
-import net.minecraft.nbt.CompoundTag
-import net.minecraft.world.item.ItemStack
-import net.minecraft.world.item.trading.MerchantOffer
-import org.bukkit.craftbukkit.v1_18_R2.inventory.CraftItemStack
-import org.bukkit.craftbukkit.v1_18_R2.inventory.CraftMerchantRecipe
-import org.bukkit.entity.Player
-import org.bukkit.inventory.MerchantRecipe
-import java.lang.reflect.Field
-
-class VillagerTrade : VillagerTradeProxy {
-    private val handle: Field = CraftMerchantRecipe::class.java.getDeclaredField("handle")
-
-    override fun displayTrade(
-        recipe: MerchantRecipe,
-        player: Player
-    ): MerchantRecipe {
-        recipe as CraftMerchantRecipe
-
-        val nbt = getHandle(recipe).createTag()
-        for (tag in arrayOf("buy", "buyB", "sell")) {
-            val nms = ItemStack.of(nbt.getCompound(tag))
-            val displayed = Display.display(CraftItemStack.asBukkitCopy(nms), player)
-            val itemNBT = CraftItemStack.asNMSCopy(displayed).save(CompoundTag())
-            nbt.put(tag, itemNBT)
-        }
-
-        return CraftMerchantRecipe(MerchantOffer(nbt))
-    }
-
-    private fun getHandle(recipe: CraftMerchantRecipe): MerchantOffer {
-        return handle[recipe] as MerchantOffer
-    }
-
-    init {
-        handle.isAccessible = true
-    }
-}

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

@@ -1,7 +1,8 @@
-package com.willfp.eco.internal.spigot.proxy.v1_18_R2
+package com.willfp.eco.internal.spigot.proxy.v1_18_R2.display
 
 import com.willfp.eco.core.display.Display
-import com.willfp.eco.internal.spigot.proxy.ChatComponentProxy
+import com.willfp.eco.core.packet.PacketEvent
+import com.willfp.eco.core.packet.PacketListener
 import net.kyori.adventure.nbt.api.BinaryTagHolder
 import net.kyori.adventure.text.BuildableComponent
 import net.kyori.adventure.text.Component
@@ -9,20 +10,28 @@ import net.kyori.adventure.text.TranslatableComponent
 import net.kyori.adventure.text.event.HoverEvent
 import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer
 import net.minecraft.nbt.TagParser
+import net.minecraft.network.protocol.game.ClientboundChatPacket
 import org.bukkit.Material
 import org.bukkit.craftbukkit.v1_18_R2.inventory.CraftItemStack
 import org.bukkit.entity.Player
 import org.bukkit.inventory.ItemStack
 
-@Suppress("UNCHECKED_CAST")
-class ChatComponent : ChatComponentProxy {
+object PacketChat : PacketListener {
     private val gsonComponentSerializer = GsonComponentSerializer.gson()
 
-    override fun modifyComponent(obj: Any, player: Player): Any {
-        if (obj !is net.minecraft.network.chat.Component) {
-            return obj
-        }
+    private val field = ClientboundChatPacket::class.java.declaredFields
+        .first { it.type == net.minecraft.network.chat.Component::class.java }
+        .apply { isAccessible = true }
 
+    override fun onSend(event: PacketEvent) {
+        val packet = event.packet.handle as? ClientboundChatPacket ?: return
+
+        val newMessage = modifyComponent(packet.message, event.player)
+
+        field.set(packet, newMessage)
+    }
+
+    private fun modifyComponent(obj: net.minecraft.network.chat.Component, player: Player): Any {
         val component = gsonComponentSerializer.deserialize(
             net.minecraft.network.chat.Component.Serializer.toJson(
                 obj
@@ -53,6 +62,7 @@ class ChatComponent : ChatComponentProxy {
         }
         component = component.children(children)
 
+        @Suppress("UNCHECKED_CAST")
         val hoverEvent: HoverEvent<Any> = component.style().hoverEvent() as HoverEvent<Any>? ?: return component
 
         val showItem = hoverEvent.value()
@@ -62,7 +72,8 @@ class ChatComponent : ChatComponentProxy {
         }
 
         val newShowItem = showItem.nbt(
-            BinaryTagHolder.binaryTagHolder(
+            @Suppress("UnstableApiUsage", "DEPRECATION")
+            BinaryTagHolder.of(
                 CraftItemStack.asNMSCopy(
                     Display.display(
                         CraftItemStack.asBukkitCopy(
@@ -90,4 +101,4 @@ class ChatComponent : ChatComponentProxy {
         val style = component.style().hoverEvent(newHover)
         return component.style(style)
     }
-}
+}

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

@@ -1,15 +0,0 @@
-package com.willfp.eco.internal.spigot.proxy.v1_19_R1
-
-import com.willfp.eco.internal.spigot.proxy.AutoCraftProxy
-import net.minecraft.network.protocol.game.ClientboundPlaceGhostRecipePacket
-import net.minecraft.resources.ResourceLocation
-
-class AutoCraft : AutoCraftProxy {
-    override fun modifyPacket(packet: Any) {
-        val recipePacket = packet as ClientboundPlaceGhostRecipePacket
-        val fKey = recipePacket.javaClass.getDeclaredField("b")
-        fKey.isAccessible = true
-        val key = fKey[recipePacket] as ResourceLocation
-        fKey[recipePacket] = ResourceLocation(key.namespace, key.path + "_displayed")
-    }
-}

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

@@ -1,6 +1,6 @@
 package com.willfp.eco.internal.spigot.proxy.v1_19_R1
 
-import com.willfp.eco.core.command.impl.PluginCommand
+import com.willfp.eco.core.command.PluginCommandBase
 import com.willfp.eco.internal.spigot.proxy.BukkitCommandsProxy
 import org.bukkit.Bukkit
 import org.bukkit.command.Command
@@ -28,7 +28,7 @@ class BukkitCommands : BukkitCommandsProxy {
         (Bukkit.getServer() as CraftServer).syncCommands()
     }
 
-    override fun unregisterCommand(command: PluginCommand) {
+    override fun unregisterCommand(command: PluginCommandBase) {
         knownCommands.remove(command.name)
         knownCommands.remove("${command.plugin.name.lowercase()}:${command.name}")
     }

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

@@ -1,93 +0,0 @@
-package com.willfp.eco.internal.spigot.proxy.v1_19_R1
-
-import com.willfp.eco.core.display.Display
-import com.willfp.eco.internal.spigot.proxy.ChatComponentProxy
-import net.kyori.adventure.nbt.api.BinaryTagHolder
-import net.kyori.adventure.text.BuildableComponent
-import net.kyori.adventure.text.Component
-import net.kyori.adventure.text.TranslatableComponent
-import net.kyori.adventure.text.event.HoverEvent
-import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer
-import net.minecraft.nbt.TagParser
-import org.bukkit.Material
-import org.bukkit.craftbukkit.v1_19_R1.inventory.CraftItemStack
-import org.bukkit.entity.Player
-import org.bukkit.inventory.ItemStack
-
-@Suppress("UNCHECKED_CAST")
-class ChatComponent : ChatComponentProxy {
-    private val gsonComponentSerializer = GsonComponentSerializer.gson()
-
-    override fun modifyComponent(obj: Any, player: Player): Any {
-        if (obj !is net.minecraft.network.chat.Component) {
-            return obj
-        }
-
-        val component = gsonComponentSerializer.deserialize(
-            net.minecraft.network.chat.Component.Serializer.toJson(
-                obj
-            )
-        ).asComponent() as BuildableComponent<*, *>
-
-        val newComponent = modifyBaseComponent(component, player)
-
-        return net.minecraft.network.chat.Component.Serializer.fromJson(
-            gsonComponentSerializer.serialize(newComponent.asComponent())
-        ) ?: obj
-    }
-
-    private fun modifyBaseComponent(baseComponent: Component, player: Player): Component {
-        var component = baseComponent
-
-        if (component is TranslatableComponent) {
-            val args = mutableListOf<Component>()
-            for (arg in component.args()) {
-                args.add(modifyBaseComponent(arg, player))
-            }
-            component = component.args(args)
-        }
-
-        val children = mutableListOf<Component>()
-        for (child in component.children()) {
-            children.add(modifyBaseComponent(child, player))
-        }
-        component = component.children(children)
-
-        val hoverEvent: HoverEvent<Any> = component.style().hoverEvent() as HoverEvent<Any>? ?: return component
-
-        val showItem = hoverEvent.value()
-
-        if (showItem !is HoverEvent.ShowItem) {
-            return component
-        }
-
-        val newShowItem = showItem.nbt(
-            BinaryTagHolder.binaryTagHolder(
-                CraftItemStack.asNMSCopy(
-                    Display.display(
-                        CraftItemStack.asBukkitCopy(
-                            CraftItemStack.asNMSCopy(
-                                ItemStack(
-                                    Material.matchMaterial(
-                                        showItem.item()
-                                            .toString()
-                                    ) ?: return component,
-                                    showItem.count()
-                                )
-                            ).apply {
-                                this.tag = TagParser.parseTag(
-                                    showItem.nbt()?.string() ?: return component
-                                ) ?: return component
-                            }
-                        ),
-                        player
-                    )
-                ).orCreateTag.toString()
-            )
-        )
-
-        val newHover = hoverEvent.value(newShowItem)
-        val style = component.style().hoverEvent(newHover)
-        return component.style(style)
-    }
-}

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

@@ -1,12 +1,15 @@
 package com.willfp.eco.internal.spigot.proxy.v1_19_R1
 
+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.minecraft.core.Registry
 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
@@ -15,6 +18,7 @@ import org.bukkit.NamespacedKey
 import org.bukkit.craftbukkit.v1_19_R1.CraftServer
 import org.bukkit.craftbukkit.v1_19_R1.entity.CraftEntity
 import org.bukkit.craftbukkit.v1_19_R1.entity.CraftMob
+import org.bukkit.craftbukkit.v1_19_R1.entity.CraftPlayer
 import org.bukkit.craftbukkit.v1_19_R1.inventory.CraftItemStack
 import org.bukkit.craftbukkit.v1_19_R1.persistence.CraftPersistentDataContainer
 import org.bukkit.craftbukkit.v1_19_R1.persistence.CraftPersistentDataTypeRegistry
@@ -22,13 +26,17 @@ import org.bukkit.craftbukkit.v1_19_R1.util.CraftMagicNumbers
 import org.bukkit.craftbukkit.v1_19_R1.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() {
+    override fun init(plugin: EcoPlugin) {
         CommonsProvider.setIfNeeded(CommonsProviderImpl)
+        plugin.onEnable {
+            plugin.eventManager.registerListener(PacketInjectorListener)
+        }
     }
 
     object CommonsProviderImpl : CommonsProvider {
@@ -60,7 +68,7 @@ class CommonsInitializer : CommonsInitializerProxy {
         }
 
         override fun asBukkitStack(itemStack: net.minecraft.world.item.ItemStack): ItemStack {
-            return CraftItemStack.asBukkitCopy(itemStack)
+            return CraftItemStack.asCraftMirror(itemStack)
         }
 
         override fun mergeIfNeeded(itemStack: ItemStack, nmsStack: net.minecraft.world.item.ItemStack) {
@@ -143,5 +151,9 @@ class CommonsInitializer : CommonsInitializerProxy {
         override fun itemToMaterial(item: Item) =
             Material.getMaterial(Registry.ITEM.getKey(item).path.uppercase())
                 ?: throw IllegalArgumentException("Invalid material!")
+
+        override fun toNMS(player: Player): ServerPlayer {
+            return (player as CraftPlayer).handle
+        }
     }
 }

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

@@ -0,0 +1,46 @@
+package com.willfp.eco.internal.spigot.proxy.v1_19_R1
+
+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_19_R1.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)
+        )
+    }
+}

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

@@ -1,41 +0,0 @@
-package com.willfp.eco.internal.spigot.proxy.v1_19_R1
-
-import com.willfp.eco.core.display.Display
-import com.willfp.eco.internal.spigot.proxy.VillagerTradeProxy
-import net.minecraft.nbt.CompoundTag
-import net.minecraft.world.item.ItemStack
-import net.minecraft.world.item.trading.MerchantOffer
-import org.bukkit.craftbukkit.v1_19_R1.inventory.CraftItemStack
-import org.bukkit.craftbukkit.v1_19_R1.inventory.CraftMerchantRecipe
-import org.bukkit.entity.Player
-import org.bukkit.inventory.MerchantRecipe
-import java.lang.reflect.Field
-
-class VillagerTrade : VillagerTradeProxy {
-    private val handle: Field = CraftMerchantRecipe::class.java.getDeclaredField("handle")
-
-    override fun displayTrade(
-        recipe: MerchantRecipe,
-        player: Player
-    ): MerchantRecipe {
-        recipe as CraftMerchantRecipe
-
-        val nbt = getHandle(recipe).createTag()
-        for (tag in arrayOf("buy", "buyB", "sell")) {
-            val nms = ItemStack.of(nbt.getCompound(tag))
-            val displayed = Display.display(CraftItemStack.asBukkitCopy(nms), player)
-            val itemNBT = CraftItemStack.asNMSCopy(displayed).save(CompoundTag())
-            nbt.put(tag, itemNBT)
-        }
-
-        return CraftMerchantRecipe(MerchantOffer(nbt))
-    }
-
-    private fun getHandle(recipe: CraftMerchantRecipe): MerchantOffer {
-        return handle[recipe] as MerchantOffer
-    }
-
-    init {
-        handle.isAccessible = true
-    }
-}

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

@@ -1,15 +0,0 @@
-package com.willfp.eco.internal.spigot.proxy.v1_19_R2
-
-import com.willfp.eco.internal.spigot.proxy.AutoCraftProxy
-import net.minecraft.network.protocol.game.ClientboundPlaceGhostRecipePacket
-import net.minecraft.resources.ResourceLocation
-
-class AutoCraft : AutoCraftProxy {
-    override fun modifyPacket(packet: Any) {
-        val recipePacket = packet as ClientboundPlaceGhostRecipePacket
-        val fKey = recipePacket.javaClass.getDeclaredField("b")
-        fKey.isAccessible = true
-        val key = fKey[recipePacket] as ResourceLocation
-        fKey[recipePacket] = ResourceLocation(key.namespace, key.path + "_displayed")
-    }
-}

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

@@ -1,6 +1,6 @@
 package com.willfp.eco.internal.spigot.proxy.v1_19_R2
 
-import com.willfp.eco.core.command.impl.PluginCommand
+import com.willfp.eco.core.command.PluginCommandBase
 import com.willfp.eco.internal.spigot.proxy.BukkitCommandsProxy
 import org.bukkit.Bukkit
 import org.bukkit.command.Command
@@ -28,7 +28,7 @@ class BukkitCommands : BukkitCommandsProxy {
         (Bukkit.getServer() as CraftServer).syncCommands()
     }
 
-    override fun unregisterCommand(command: PluginCommand) {
+    override fun unregisterCommand(command: PluginCommandBase) {
         knownCommands.remove(command.name)
         knownCommands.remove("${command.plugin.name.lowercase()}:${command.name}")
     }