Cleaned up Menu API

This reverts commit a9c32000d8.

README.md

@@ -39,7 +39,7 @@ and many more.
 # For developers
 
 ## Javadoc
-The 6.38.2 Javadoc can be found [here](https://javadoc.jitpack.io/com/willfp/eco/6.38.2/javadoc/)
+The 6.45.0 Javadoc can be found [here](https://javadoc.jitpack.io/com/willfp/eco/6.45.0/javadoc/)
 
 ## Plugin Information
 
@@ -68,7 +68,7 @@ dependencies {
 }
 ```
 
-Replace `Tag` with a release tag for eco, eg `6.27.2`.
+Replace `Tag` with a release tag for eco, eg `6.45.0`.
 
 Maven:
 
@@ -88,7 +88,7 @@ Maven:
 </dependency>
 ```
 
-Replace `Tag` with a release tag for eco, eg `6.27.2`.
+Replace `Tag` with a release tag for eco, eg `6.45.0`.
 
 ## Build locally:
 

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

@@ -21,10 +21,8 @@ import com.willfp.eco.core.gui.menu.MenuBuilder;
 import com.willfp.eco.core.gui.menu.MenuType;
 import com.willfp.eco.core.gui.slot.SlotBuilder;
 import com.willfp.eco.core.gui.slot.functional.SlotProvider;
-import com.willfp.eco.core.integrations.placeholder.PlaceholderIntegration;
 import com.willfp.eco.core.items.TestableItem;
-import com.willfp.eco.core.placeholder.AdditionalPlayer;
-import com.willfp.eco.core.placeholder.PlaceholderInjectable;
+import com.willfp.eco.core.math.MathContext;
 import com.willfp.eco.core.proxy.ProxyFactory;
 import com.willfp.eco.core.scheduling.Scheduler;
 import net.kyori.adventure.platform.bukkit.BukkitAudiences;
@@ -42,7 +40,6 @@ import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import java.util.Collection;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -138,10 +135,8 @@ public interface Eco {
      * Create a PAPI integration.
      *
      * @param plugin The plugin.
-     * @return The integration.
      */
-    @NotNull
-    PlaceholderIntegration createPAPIIntegration(@NotNull EcoPlugin plugin);
+    void createPAPIIntegration(@NotNull EcoPlugin plugin);
 
     /**
      * Create a proxy factory.
@@ -173,6 +168,7 @@ public interface Eco {
      * @param requiresChangesToSave If the config must be changed in order to save the config.
      * @return The config implementation.
      */
+    @NotNull
     LoadableConfig createUpdatableConfig(@NotNull String configName,
                                          @NotNull PluginLike plugin,
                                          @NotNull String subDirectoryPath,
@@ -193,6 +189,7 @@ public interface Eco {
      * @param requiresChangesToSave If the config must be changed in order to save the config.
      * @return The config implementation.
      */
+    @NotNull
     LoadableConfig createLoadableConfig(@NotNull String configName,
                                         @NotNull PluginLike plugin,
                                         @NotNull String subDirectoryPath,
@@ -206,6 +203,7 @@ public interface Eco {
      * @param config The handle.
      * @return The config implementation.
      */
+    @NotNull
     Config wrapConfigurationSection(@NotNull ConfigurationSection config);
 
     /**
@@ -215,6 +213,7 @@ public interface Eco {
      * @param type   The config type.
      * @return The config implementation.
      */
+    @NotNull
     Config createConfig(@NotNull Map<String, Object> values,
                         @NotNull ConfigType type);
 
@@ -225,6 +224,7 @@ public interface Eco {
      * @param type     The type.
      * @return The config implementation.
      */
+    @NotNull
     Config createConfig(@NotNull String contents,
                         @NotNull ConfigType type);
 
@@ -335,23 +335,16 @@ public interface Eco {
      *
      * @return The keys.
      */
+    @NotNull
     Set<PersistentDataKey<?>> getRegisteredPersistentDataKeys();
 
-    /**
-     * Get persistent data key from namespaced key.
-     *
-     * @param namespacedKey The key.
-     * @return The key, or null if not found.
-     */
-    @Nullable
-    PersistentDataKey<?> getPersistentDataKeyFrom(@NotNull NamespacedKey namespacedKey);
-
     /**
      * Load a player profile.
      *
      * @param uuid The UUID.
      * @return The profile.
      */
+    @NotNull
     PlayerProfile loadPlayerProfile(@NotNull UUID uuid);
 
     /**
@@ -359,6 +352,7 @@ public interface Eco {
      *
      * @return The profile.
      */
+    @NotNull
     ServerProfile getServerProfile();
 
     /**
@@ -370,24 +364,6 @@ public interface Eco {
      */
     void unloadPlayerProfile(@NotNull UUID uuid);
 
-    /**
-     * Save keys for a player.
-     * <p>
-     * Can run async if using MySQL.
-     *
-     * @param uuid The uuid.
-     * @param keys The keys.
-     */
-    void savePersistentDataKeysFor(@NotNull UUID uuid,
-                                   @NotNull Set<PersistentDataKey<?>> keys);
-
-    /**
-     * Commit all changes to the file.
-     * <p>
-     * Does nothing if using MySQL.
-     */
-    void saveAllProfiles();
-
     /**
      * Create dummy entity - never spawned, exists purely in code.
      *
@@ -513,16 +489,12 @@ public interface Eco {
     /**
      * Evaluate an expression.
      *
-     * @param expression        The expression.
-     * @param player            The player.
-     * @param injectable        The injectable placeholders.
-     * @param additionalPlayers The additional players.
+     * @param expression The expression.
+     * @param context    The context.
      * @return The value of the expression, or zero if invalid.
      */
     double evaluate(@NotNull String expression,
-                    @Nullable Player player,
-                    @NotNull PlaceholderInjectable injectable,
-                    @NotNull Collection<AdditionalPlayer> additionalPlayers);
+                    @NotNull MathContext context);
 
     /**
      * Get the menu a player currently has open.
@@ -533,6 +505,11 @@ public interface Eco {
     @Nullable
     Menu getOpenMenu(@NotNull Player player);
 
+    /**
+     * Sync commands.
+     */
+    void syncCommands();
+
     /**
      * 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

@@ -13,7 +13,6 @@ 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.integrations.placeholder.PlaceholderManager;
 import com.willfp.eco.core.proxy.ProxyFactory;
 import com.willfp.eco.core.scheduling.Scheduler;
 import com.willfp.eco.core.web.UpdateChecker;
@@ -153,6 +152,31 @@ public abstract class EcoPlugin extends JavaPlugin implements PluginLike {
     @Nullable
     private final ProxyFactory proxyFactory;
 
+    /**
+     * The tasks to run on enable.
+     */
+    private final List<Runnable> onEnable = new ArrayList<>();
+
+    /**
+     * The tasks to run on disable.
+     */
+    private final List<Runnable> onDisable = new ArrayList<>();
+
+    /**
+     * The tasks to run on reload.
+     */
+    private final List<Runnable> onReload = new ArrayList<>();
+
+    /**
+     * The tasks to run on load.
+     */
+    private final List<Runnable> onLoad = new ArrayList<>();
+
+    /**
+     * The tasks to run after load.
+     */
+    private final List<Runnable> afterLoad = new ArrayList<>();
+
     /**
      * Create a new plugin.
      * <p>
@@ -375,8 +399,7 @@ public abstract class EcoPlugin extends JavaPlugin implements PluginLike {
                 .collect(Collectors.toSet());
 
         if (enabledPlugins.contains("PlaceholderAPI".toLowerCase())) {
-            this.loadedIntegrations.add("PlaceholderAPI");
-            PlaceholderManager.addIntegration(Eco.get().createPAPIIntegration(this));
+            Eco.get().createPAPIIntegration(this);
         }
 
         this.loadIntegrationLoaders().forEach(integrationLoader -> {
@@ -386,6 +409,8 @@ public abstract class EcoPlugin extends JavaPlugin implements PluginLike {
             }
         });
 
+        this.loadedIntegrations.removeIf(pl -> pl.equalsIgnoreCase(this.getName()));
+
         this.getLogger().info("Loaded integrations: " + String.join(", ", this.getLoadedIntegrations()));
 
         Prerequisite.update();
@@ -414,10 +439,20 @@ public abstract class EcoPlugin extends JavaPlugin implements PluginLike {
         }
 
         this.handleEnable();
+        this.onEnable.forEach(Runnable::run);
 
         this.getLogger().info("");
     }
 
+    /**
+     * Add new task to run on enable.
+     *
+     * @param task The task.
+     */
+    public final void onEnable(@NotNull final Runnable task) {
+        this.onEnable.add(task);
+    }
+
     /**
      * Default code to be executed on plugin disable.
      */
@@ -429,6 +464,7 @@ public abstract class EcoPlugin extends JavaPlugin implements PluginLike {
         this.getScheduler().cancelAll();
 
         this.handleDisable();
+        this.onDisable.forEach(Runnable::run);
 
         if (this.isSupportingExtensions()) {
             this.getExtensionLoader().unloadExtensions();
@@ -438,6 +474,15 @@ public abstract class EcoPlugin extends JavaPlugin implements PluginLike {
         Eco.get().clean(this);
     }
 
+    /**
+     * Add new task to run on disable.
+     *
+     * @param task The task.
+     */
+    public final void onDisable(@NotNull final Runnable task) {
+        this.onDisable.add(task);
+    }
+
     /**
      * Default code to be executed on plugin load.
      */
@@ -446,6 +491,16 @@ public abstract class EcoPlugin extends JavaPlugin implements PluginLike {
         super.onLoad();
 
         this.handleLoad();
+        this.onLoad.forEach(Runnable::run);
+    }
+
+    /**
+     * Add new task to run on load.
+     *
+     * @param task The task.
+     */
+    public final void onLoad(@NotNull final Runnable task) {
+        this.onLoad.add(task);
     }
 
     /**
@@ -478,6 +533,7 @@ public abstract class EcoPlugin extends JavaPlugin implements PluginLike {
         }
 
         this.handleAfterLoad();
+        this.afterLoad.forEach(Runnable::run);
 
         this.reload();
 
@@ -488,6 +544,15 @@ public abstract class EcoPlugin extends JavaPlugin implements PluginLike {
         this.getLogger().info("Loaded " + this.color + this.getName());
     }
 
+    /**
+     * Add new task to run after load.
+     *
+     * @param task The task.
+     */
+    public final void afterLoad(@NotNull final Runnable task) {
+        this.afterLoad.add(task);
+    }
+
     /**
      * Reload the plugin.
      */
@@ -499,12 +564,22 @@ public abstract class EcoPlugin extends JavaPlugin implements PluginLike {
         this.getConfigHandler().callUpdate(); // Call twice to fix issues
 
         this.handleReload();
+        this.onReload.forEach(Runnable::run);
 
         for (Extension extension : this.extensionLoader.getLoadedExtensions()) {
             extension.handleReload();
         }
     }
 
+    /**
+     * Add new task to run on enable.
+     *
+     * @param task The task.
+     */
+    public final void onReload(@NotNull final Runnable task) {
+        this.onReload.add(task);
+    }
+
     /**
      * Reload the plugin and return the time taken to reload.
      *

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

@@ -1,7 +1,9 @@
 package com.willfp.eco.core.command;
 
+import com.google.common.collect.ImmutableList;
 import com.willfp.eco.core.EcoPlugin;
 import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.ArrayList;
@@ -43,8 +45,6 @@ public interface CommandBase {
 
     /**
      * Handle command execution.
-     * <p>
-     * Marked as default void with no implementation for backwards compatibility.
      *
      * @param sender The sender.
      * @param args   The args.
@@ -54,20 +54,43 @@ public interface CommandBase {
         // Do nothing.
     }
 
+    /**
+     * Handle command execution from players.
+     *
+     * @param sender The sender.
+     * @param args   The args.
+     */
+    default void onExecute(@NotNull Player sender,
+                           @NotNull List<String> args) {
+        // Do nothing.
+    }
+
     /**
      * Handle tab completion.
-     * <p>
-     * Marked as default void with no implementation for backwards compatibility.
      *
      * @param sender The sender.
      * @param args   The args.
      * @return The results.
      */
+    @NotNull
     default List<String> tabComplete(@NotNull CommandSender sender,
                                      @NotNull List<String> args) {
         return new ArrayList<>();
     }
 
+    /**
+     * Handle tab completion.
+     *
+     * @param sender The sender.
+     * @param args   The args.
+     * @return The results.
+     */
+    @NotNull
+    default List<String> tabComplete(@NotNull Player sender,
+                                     @NotNull List<String> args) {
+        return new ArrayList<>();
+    }
+
     /**
      * Get the plugin.
      *
@@ -83,7 +106,11 @@ public interface CommandBase {
      * @deprecated Use {@link CommandBase#onExecute(CommandSender, List)} instead.
      */
     @Deprecated(forRemoval = true)
-    CommandHandler getHandler();
+    default CommandHandler getHandler() {
+        return (a, b) -> {
+
+        };
+    }
 
     /**
      * Set the handler.
@@ -93,7 +120,9 @@ public interface CommandBase {
      * @deprecated Handlers have been deprecated.
      */
     @Deprecated(forRemoval = true)
-    void setHandler(@NotNull CommandHandler handler);
+    default void setHandler(@NotNull final CommandHandler handler) {
+        // Do nothing.
+    }
 
     /**
      * Get the tab completer.
@@ -103,7 +132,9 @@ public interface CommandBase {
      * @deprecated Use {@link CommandBase#tabComplete(CommandSender, List)} instead.
      */
     @Deprecated(forRemoval = true)
-    TabCompleteHandler getTabCompleter();
+    default TabCompleteHandler getTabCompleter() {
+        return (a, b) -> ImmutableList.of();
+    }
 
     /**
      * Set the tab completer.
@@ -113,5 +144,7 @@ public interface CommandBase {
      * @deprecated Handlers have been deprecated.
      */
     @Deprecated(forRemoval = true)
-    void setTabCompleter(@NotNull TabCompleteHandler handler);
+    default void setTabCompleter(@NotNull final TabCompleteHandler handler) {
+        // Do nothing.
+    }
 }

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

@@ -0,0 +1,71 @@
+package com.willfp.eco.core.command.impl;
+
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.PluginIdentifiableCommand;
+import org.bukkit.command.TabCompleter;
+import org.bukkit.plugin.Plugin;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.List;
+
+/**
+ * Delegates a bukkit command to an eco command (for registrations).
+ */
+public final class DelegatedBukkitCommand extends Command implements TabCompleter, PluginIdentifiableCommand {
+    /**
+     * The delegate command.
+     */
+    private final PluginCommand delegate;
+
+    /**
+     * Create a new delegated command.
+     *
+     * @param delegate The delegate.
+     */
+    public DelegatedBukkitCommand(@NotNull final PluginCommand delegate) {
+        super(delegate.getName());
+
+        this.delegate = delegate;
+    }
+
+    @Override
+    public boolean execute(@NotNull final CommandSender commandSender,
+                           @NotNull final String label,
+                           @NotNull final String[] args) {
+        return delegate.onCommand(commandSender, this, label, args);
+    }
+
+    @Override
+    public List<String> onTabComplete(@NotNull final CommandSender commandSender,
+                                      @NotNull final Command command,
+                                      @NotNull final String label,
+                                      @NotNull final String[] args) {
+        return delegate.onTabComplete(commandSender, command, label, args);
+    }
+
+    @NotNull
+    @Override
+    public Plugin getPlugin() {
+        return this.delegate.getPlugin();
+    }
+
+    @Nullable
+    @Override
+    public String getPermission() {
+        return this.delegate.getPermission();
+    }
+
+    @NotNull
+    @Override
+    public String getDescription() {
+        return this.delegate.getDescription() == null ? "" : this.delegate.getDescription();
+    }
+
+    @NotNull
+    @Override
+    public List<String> getAliases() {
+        return this.delegate.getAliases();
+    }
+}

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

@@ -145,6 +145,9 @@ abstract class HandledCommand implements CommandBase {
             this.getHandler().onExecute(sender, Arrays.asList(args));
         } else {
             this.onExecute(sender, Arrays.asList(args));
+            if (sender instanceof Player player) {
+                this.onExecute(player, Arrays.asList(args));
+            }
         }
     }
 
@@ -202,7 +205,11 @@ abstract class HandledCommand implements CommandBase {
         if (this.getTabCompleter() != null) {
             return this.getTabCompleter().tabComplete(sender, Arrays.asList(args));
         } else {
-            return this.tabComplete(sender, Arrays.asList(args));
+            List<String> completions = this.tabComplete(sender, Arrays.asList(args));
+            if (sender instanceof Player player) {
+                completions.addAll(this.tabComplete(player, Arrays.asList(args)));
+            }
+            return completions;
         }
     }
 

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

@@ -1,14 +1,18 @@
 package com.willfp.eco.core.command.impl;
 
+import com.willfp.eco.core.Eco;
 import com.willfp.eco.core.EcoPlugin;
 import org.bukkit.Bukkit;
 import org.bukkit.command.Command;
 import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandMap;
 import org.bukkit.command.CommandSender;
 import org.bukkit.command.TabCompleter;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+import java.lang.reflect.Field;
+import java.util.ArrayList;
 import java.util.List;
 
 /**
@@ -38,14 +42,63 @@ public abstract class PluginCommand extends HandledCommand implements CommandExe
 
     /**
      * Registers the command with the server,
-     * <p>
-     * Requires the command name to exist, defined in plugin.yml.
      */
     public final void register() {
         org.bukkit.command.PluginCommand command = Bukkit.getPluginCommand(this.getName());
-        assert command != null;
-        command.setExecutor(this);
-        command.setTabCompleter(this);
+        if (command != null) {
+            command.setExecutor(this);
+            command.setTabCompleter(this);
+
+            if (this.getDescription() != null) {
+                command.setDescription(this.getDescription());
+            }
+
+            List<String> aliases = new ArrayList<>(command.getAliases());
+            aliases.addAll(this.getAliases());
+            command.setAliases(aliases);
+        } else {
+            this.unregister();
+
+            CommandMap commandMap = getCommandMap();
+
+            commandMap.register(this.getPlugin().getName().toLowerCase(), new DelegatedBukkitCommand(this));
+        }
+
+        Eco.get().syncCommands();
+    }
+
+    /**
+     * Unregisters the command from the server.
+     */
+    public final void unregister() {
+        CommandMap commandMap = getCommandMap();
+
+        Command found = commandMap.getCommand(this.getName());
+        if (found != null) {
+            found.unregister(commandMap);
+        }
+
+        Eco.get().syncCommands();
+    }
+
+    /**
+     * Get aliases. Leave null if this command is from plugin.yml.
+     *
+     * @return The aliases.
+     */
+    @NotNull
+    public List<String> getAliases() {
+        return new ArrayList<>();
+    }
+
+    /**
+     * Get description.
+     *
+     * @return The description.
+     */
+    @Nullable
+    public String getDescription() {
+        return null;
     }
 
     /**
@@ -93,4 +146,19 @@ public abstract class PluginCommand extends HandledCommand implements CommandExe
 
         return this.handleTabCompletion(sender, args);
     }
+
+    /**
+     * Get the internal server CommandMap.
+     *
+     * @return The CommandMap.
+     */
+    public static CommandMap getCommandMap() {
+        try {
+            Field field = Bukkit.getServer().getClass().getDeclaredField("commandMap");
+            field.setAccessible(true);
+            return (CommandMap) field.get(Bukkit.getServer());
+        } catch (NoSuchFieldException | IllegalAccessException e) {
+            throw new NullPointerException("Command map wasn't found!");
+        }
+    }
 }

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

@@ -6,12 +6,12 @@ import org.jetbrains.annotations.Nullable;
 /**
  * Builder for configs to create them programmatically.
  */
-public class BuildableConfig extends TransientConfig {
+public class BuildableConfig extends GenericConfig {
     /**
      * Create a new empty config builder.
      */
     public BuildableConfig() {
-        super();
+
     }
 
     /**

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

@@ -0,0 +1,157 @@
+package com.willfp.eco.core.config;
+
+import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.config.interfaces.Config;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.nio.file.Files;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Utilities / API methods for configs.
+ */
+public final class Configs {
+    /**
+     * Load a Config from a bukkit {@link ConfigurationSection}.
+     *
+     * @param config The ConfigurationSection.
+     * @return The config.
+     */
+    @NotNull
+    public static Config fromBukkit(@Nullable final ConfigurationSection config) {
+        return config == null ? empty() : Eco.get().wrapConfigurationSection(config);
+    }
+
+    /**
+     * Load a config from an {@link InputStream}.
+     * <p>
+     * Only for yaml configs.
+     *
+     * @param stream The InputStream.
+     * @return The config.
+     */
+    @NotNull
+    public static Config fromStream(@Nullable final InputStream stream) {
+        return stream != null ? fromBukkit(YamlConfiguration.loadConfiguration(
+                new InputStreamReader(stream)
+        )) : empty();
+    }
+
+    /**
+     * Load a config from a file.
+     *
+     * @param file The file.
+     * @return The config.
+     */
+    @NotNull
+    public static Config fromFile(@Nullable final File file) {
+        if (file == null) {
+            return empty();
+        }
+
+        int lastIndex = file.getName().lastIndexOf(".");
+
+        if (lastIndex < 0) {
+            return empty();
+        }
+
+        for (ConfigType type : ConfigType.values()) {
+            if (file.getName().substring(lastIndex + 1).equalsIgnoreCase(type.getExtension())) {
+                return fromFile(file, type);
+            }
+        }
+
+        return empty();
+    }
+
+    /**
+     * Load a config from a file.
+     *
+     * @param file The file.
+     * @param type The type.
+     * @return The config.
+     */
+    @NotNull
+    public static Config fromFile(@Nullable final File file,
+                                  @NotNull final ConfigType type) {
+        if (file == null) {
+            return empty();
+        }
+
+        try {
+            return Eco.get().createConfig(Files.readString(file.toPath()), type);
+        } catch (IOException e) {
+            return empty();
+        }
+    }
+
+    /**
+     * Load config from map (uses {@link ConfigType#JSON}).
+     *
+     * @param values The values.
+     * @return The config.
+     */
+    @NotNull
+    public static Config fromMap(@NotNull final Map<String, Object> values) {
+        return fromMap(values, ConfigType.JSON);
+    }
+
+    /**
+     * Load config from map.
+     *
+     * @param values The values.
+     * @param type   The type.
+     * @return The config.
+     */
+    @NotNull
+    public static Config fromMap(@NotNull final Map<String, Object> values,
+                                 @NotNull final ConfigType type) {
+        return Eco.get().createConfig(values, type);
+    }
+
+    /**
+     * Create empty config (uses {@link ConfigType#JSON}).
+     *
+     * @return An empty config.
+     */
+    @NotNull
+    public static Config empty() {
+        return fromMap(new HashMap<>(), ConfigType.JSON);
+    }
+
+    /**
+     * Create empty config.
+     *
+     * @param type The type.
+     * @return An empty config.
+     */
+    @NotNull
+    public static Config empty(@NotNull final ConfigType type) {
+        return fromMap(new HashMap<>(), type);
+    }
+
+    /**
+     * Load config from string.
+     *
+     * @param contents The contents of the config.
+     * @param type     The config type.
+     * @return The config.
+     */
+    @NotNull
+    public static Config fromString(@NotNull final String contents,
+                                    @NotNull final ConfigType type) {
+        return Eco.get().createConfig(contents, type);
+    }
+
+    private Configs() {
+        throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
+    }
+}

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

@@ -0,0 +1,27 @@
+package com.willfp.eco.core.config;
+
+import com.willfp.eco.core.config.interfaces.Config;
+import com.willfp.eco.core.config.wrapper.ConfigWrapper;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Generic config to simplify creating custom configs without having
+ * to meddle with delegation.
+ */
+public abstract class GenericConfig extends ConfigWrapper<Config> {
+    /**
+     * Create a new generic config.
+     */
+    protected GenericConfig() {
+        super(Configs.empty());
+    }
+
+    /**
+     * Create a new generic config.
+     *
+     * @param type The config type.
+     */
+    protected GenericConfig(@NotNull final ConfigType type) {
+        super(Configs.empty(type));
+    }
+}

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

@@ -20,7 +20,10 @@ import java.util.Map;
  * Config that exists purely in the code, not linked to any file.
  * <p>
  * Use for inline configs to move data around or to add subsections to other configs.
+ *
+ * @deprecated Poorly named class, makes the config system seem needlessly complicated.
  */
+@Deprecated(since = "6.44.0", forRemoval = true)
 public class TransientConfig extends ConfigWrapper<Config> {
     /**
      * @param config The ConfigurationSection handle.

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

@@ -2,7 +2,7 @@ package com.willfp.eco.core.config.interfaces;
 
 import com.willfp.eco.core.config.BuildableConfig;
 import com.willfp.eco.core.config.ConfigType;
-import com.willfp.eco.core.config.TransientConfig;
+import com.willfp.eco.core.config.Configs;
 import com.willfp.eco.core.placeholder.AdditionalPlayer;
 import com.willfp.eco.core.placeholder.InjectablePlaceholder;
 import com.willfp.eco.core.placeholder.PlaceholderInjectable;
@@ -103,7 +103,7 @@ public interface Config extends Cloneable, PlaceholderInjectable {
      */
     @NotNull
     default Config getSubsection(@NotNull String path) {
-        return Objects.requireNonNullElse(getSubsectionOrNull(path), new TransientConfig());
+        return Objects.requireNonNullElse(getSubsectionOrNull(path), Configs.empty());
     }
 
     /**

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

@@ -7,7 +7,6 @@ import org.bukkit.entity.Player;
 import org.bukkit.inventory.Inventory;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.persistence.PersistentDataType;
-import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 

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

@@ -63,11 +63,29 @@ public interface Menu {
      * @param player The player
      * @param menu   The menu.
      * @return The slot.
+     * @deprecated Menu shouldn't be a parameter.
      */
-    default Slot getSlot(int row,
-                         int column,
-                         @NotNull Player player,
-                         @NotNull Menu menu) {
+    @Deprecated(since = "6.46.0", forRemoval = true)
+    default Slot getSlot(final int row,
+                         final int column,
+                         @NotNull final Player player,
+                         @NotNull final Menu menu) {
+        return this.getSlot(row, column, player);
+    }
+
+    /**
+     * Get a slot at a given row and column.
+     * <p>
+     * Defaults to static slot if no reactive slot exists.
+     *
+     * @param row    The row.
+     * @param column The column.
+     * @param player The player
+     * @return The slot.
+     */
+    default Slot getSlot(final int row,
+                         final int column,
+                         @NotNull final Player player) {
         return this.getSlot(row, column);
     }
 
@@ -110,15 +128,32 @@ public interface Menu {
     }
 
     /**
-     * Add state for a player.
+     * Set state for a player.
      *
      * @param player The player.
      * @param key    The key.
      * @param value  The state.
      */
-    void addState(@NotNull Player player,
-                  @NotNull String key,
-                  @Nullable Object value);
+    default void setState(@NotNull Player player,
+                          @NotNull String key,
+                          @Nullable Object value) {
+        // Blank method for backwards compatibility.
+    }
+
+    /**
+     * Add state for a player.
+     *
+     * @param player The player.
+     * @param key    The key.
+     * @param value  The state.
+     * @deprecated Poorly named, use setState instead.
+     */
+    @Deprecated(since = "6.44.0", forRemoval = true)
+    default void addState(@NotNull Player player,
+                          @NotNull String key,
+                          @Nullable Object value) {
+        this.setState(player, key, value);
+    }
 
     /**
      * Remove state for a player.
@@ -221,7 +256,7 @@ public interface Menu {
                                   @NotNull final NamespacedKey key,
                                   @NotNull final PersistentDataType<T, Z> type,
                                   @NotNull final Z value) {
-        this.addState(player, key.toString(), value);
+        this.setState(player, key.toString(), value);
     }
 
     /**

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

@@ -139,7 +139,7 @@ public interface MenuBuilder extends PageBuilder {
      * @return The builder.
      */
     default MenuBuilder maxPages(@NotNull final Function<Player, Integer> pages) {
-        return onOpen((player, menu) -> menu.addState(player, Page.MAX_PAGE_KEY, pages.apply(player)));
+        return onRender((player, menu) -> menu.setState(player, Page.MAX_PAGE_KEY, pages.apply(player)));
     }
 
     /**
@@ -195,6 +195,16 @@ public interface MenuBuilder extends PageBuilder {
         return this;
     }
 
+    /**
+     * Add an action to run on build.
+     *
+     * @param action The action.
+     * @return The builder.
+     */
+    default MenuBuilder onBuild(@NotNull Consumer<Menu> action) {
+        return this;
+    }
+
     /**
      * Build the menu.
      *

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

@@ -0,0 +1,22 @@
+package com.willfp.eco.core.gui.menu.events;
+
+import com.willfp.eco.core.gui.menu.MenuEvent;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Represents a captive item change.
+ *
+ * @param row    The row.
+ * @param column The column.
+ * @param before The previous item in the slot.
+ * @param after  The new item in the slot.
+ */
+public record CaptiveItemChangeEvent(
+        int row,
+        int column,
+        @Nullable ItemStack before,
+        @Nullable ItemStack after
+) implements MenuEvent {
+
+}

eco-api/src/main/java/com/willfp/eco/core/gui/page/Page.java

@@ -9,8 +9,6 @@ import org.bukkit.entity.Player;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import java.util.Objects;
-
 /**
  * A page is a component representing another menu.
  * This allows full component support in pagination.
@@ -85,7 +83,7 @@ public final class Page implements GUIComponent {
             delegate = Eco.get().blendMenuState(page, menu);
         }
 
-        return page.getSlot(row, column, player, delegate);
+        return page.getSlot(row, column, player);
     }
 
     @Override

eco-api/src/main/java/com/willfp/eco/core/gui/page/PageChanger.java

@@ -48,7 +48,7 @@ public final class PageChanger implements GUIComponent {
                         return;
                     }
 
-                    menu.addState(player, Page.PAGE_KEY, newPage);
+                    menu.setState(player, Page.PAGE_KEY, newPage);
                     menu.callEvent(player, new PageChangeEvent(
                             newPage,
                             page

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

@@ -31,7 +31,7 @@ public abstract class CustomSlot implements Slot {
     }
 
     @Override
-    public ItemStack getItemStack(@NotNull final Player player) {
+    public @NotNull ItemStack getItemStack(@NotNull final Player player) {
         if (delegate == null) {
             throw new IllegalStateException("Custom Slot was not initialized!");
         }

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

@@ -29,8 +29,8 @@ public abstract class ReactiveSlot implements Slot {
                                  @NotNull final Menu menu);
 
     @Override
-    public ItemStack getItemStack(@NotNull final Player player) {
-        return new ItemStack(Material.STONE);
+    public @NotNull ItemStack getItemStack(@NotNull final Player player) {
+        return new ItemStack(Material.AIR);
     }
 
     @Override
@@ -40,8 +40,8 @@ public abstract class ReactiveSlot implements Slot {
     }
 
     @Override
-    public final Slot getActionableSlot(@NotNull final Player player,
-                                        @NotNull final Menu menu) {
+    public final @NotNull Slot getActionableSlot(@NotNull final Player player,
+                                                 @NotNull final Menu menu) {
         return getSlot(player, menu);
     }
 

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

@@ -30,6 +30,7 @@ public interface Slot extends GUIComponent {
      * @param player The player.
      * @return The ItemStack.
      */
+    @NotNull
     ItemStack getItemStack(@NotNull Player player);
 
     /**
@@ -60,6 +61,7 @@ public interface Slot extends GUIComponent {
      * @param menu   The menu.
      * @return The slot.
      */
+    @NotNull
     default Slot getActionableSlot(@NotNull final Player player,
                                    @NotNull final Menu menu) {
         return this;
@@ -125,7 +127,9 @@ public interface Slot extends GUIComponent {
      *
      * @param provider The provider.
      * @return The builder.
+     * @deprecated This method was written incorrectly, should have been a Player + Menu function.
      */
+    @Deprecated(since = "6.45.0", forRemoval = true)
     static SlotBuilder builder(@NotNull final Function<Player, ItemStack> provider) {
         return Eco.get().createSlotBuilder((player, menu) -> provider.apply(player));
     }

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

@@ -51,10 +51,15 @@ public final class PlaceholderManager {
             .expireAfterWrite(50, TimeUnit.MILLISECONDS)
             .build(key -> key.entry.getValue(key.player));
 
+    /**
+     * The default PlaceholderAPI pattern; brought in for compatibility.
+     */
+    private static final Pattern PATTERN = Pattern.compile("[%]([^% ]+)[%]");
+
     /**
      * Empty injectable object.
      */
-    private static final PlaceholderInjectable EMPTY_INJECTABLE = new PlaceholderInjectable() {
+    public static final PlaceholderInjectable EMPTY_INJECTABLE = new PlaceholderInjectable() {
         @Override
         public void clearInjectedPlaceholders() {
             // Do nothing.
@@ -67,11 +72,6 @@ public final class PlaceholderManager {
         }
     };
 
-    /**
-     * The default PlaceholderAPI pattern; brought in for compatibility.
-     */
-    private static final Pattern PATTERN = Pattern.compile("[%]([^%]+)[%]");
-
     /**
      * Register a new placeholder integration.
      *

eco-api/src/main/java/com/willfp/eco/core/integrations/shop/ShopManager.java

@@ -1,10 +1,7 @@
 package com.willfp.eco.core.integrations.shop;
 
-import com.willfp.eco.core.EcoPlugin;
 import org.bukkit.entity.Player;
-import org.bukkit.event.Listener;
 import org.bukkit.inventory.ItemStack;
-import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 

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

@@ -25,6 +25,7 @@ import org.jetbrains.annotations.Nullable;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
@@ -86,6 +87,11 @@ public final class Items {
      */
     private static final TestableItem EMPTY_TESTABLE_ITEM = new EmptyTestableItem();
 
+    /**
+     * Friendly material names (without underscores, etc.)
+     */
+    private static final Map<String, Material> FRIENDLY_MATERIAL_NAMES = new HashMap<>();
+
     /**
      * Register a new custom item.
      *
@@ -216,7 +222,7 @@ public final class Items {
             if (isWildcard) {
                 itemType = itemType.substring(1);
             }
-            Material material = Material.getMaterial(itemType.toUpperCase());
+            Material material = FRIENDLY_MATERIAL_NAMES.get(itemType.toLowerCase());
             if (material == null || material == Material.AIR) {
                 return new EmptyTestableItem();
             }
@@ -565,4 +571,25 @@ public final class Items {
     private Items() {
         throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
     }
+
+    static {
+        for (Material material : Material.values()) {
+            FRIENDLY_MATERIAL_NAMES.put(material.name().toLowerCase(), material);
+
+            String oneWord = material.name().toLowerCase().replace("_", "");
+            if (!FRIENDLY_MATERIAL_NAMES.containsKey(oneWord)) {
+                FRIENDLY_MATERIAL_NAMES.put(oneWord, material);
+            }
+
+            String plural = material.name().toLowerCase() + "s";
+            if (!FRIENDLY_MATERIAL_NAMES.containsKey(plural)) {
+                FRIENDLY_MATERIAL_NAMES.put(plural, material);
+            }
+
+            String oneWordPlural = oneWord + "s";
+            if (!FRIENDLY_MATERIAL_NAMES.containsKey(oneWordPlural)) {
+                FRIENDLY_MATERIAL_NAMES.put(oneWordPlural, material);
+            }
+        }
+    }
 }

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

@@ -14,7 +14,6 @@ import org.bukkit.persistence.PersistentDataType;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import java.util.ArrayList;
 import java.util.List;
 import java.util.function.Supplier;
 

eco-api/src/main/java/com/willfp/eco/core/math/MathContext.java

@@ -0,0 +1,63 @@
+package com.willfp.eco.core.math;
+
+import com.willfp.eco.core.integrations.placeholder.PlaceholderManager;
+import com.willfp.eco.core.placeholder.AdditionalPlayer;
+import com.willfp.eco.core.placeholder.PlaceholderInjectable;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Collection;
+import java.util.Collections;
+
+/**
+ * Represents a context to do math in.
+ *
+ * @param injectableContext The PlaceholderInjectable context.
+ * @param player            The player.
+ * @param additionalPlayers The additional players.
+ */
+public record MathContext(
+        @NotNull PlaceholderInjectable injectableContext,
+        @Nullable Player player,
+        @NotNull Collection<AdditionalPlayer> additionalPlayers
+) {
+    /**
+     * Empty math context.
+     */
+    public static final MathContext EMPTY = new MathContext(
+            PlaceholderManager.EMPTY_INJECTABLE,
+            null,
+            Collections.emptyList()
+    );
+
+    /**
+     * Create MathContext of a PlaceholderInjectable context.
+     *
+     * @param injectableContext The PlaceholderInjectable context.
+     * @return The MathContext.
+     */
+    public static MathContext of(@NotNull final PlaceholderInjectable injectableContext) {
+        return new MathContext(
+                injectableContext,
+                null,
+                Collections.emptyList()
+        );
+    }
+
+    /**
+     * Copy a MathContext with a player.
+     *
+     * @param context The context.
+     * @param player  The player.
+     * @return The new MathContext.
+     */
+    public static MathContext copyWithPlayer(@NotNull final MathContext context,
+                                             @Nullable final Player player) {
+        return new MathContext(
+                context.injectableContext(),
+                player,
+                context.additionalPlayers()
+        );
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/particle/ParticleFactory.java

@@ -0,0 +1,28 @@
+package com.willfp.eco.core.particle;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.List;
+
+/**
+ * Create particles.
+ */
+public interface ParticleFactory {
+    /**
+     * Get the names (how the particle looks in lookup strings).
+     * <p>
+     * For example, for RGB particles this would be 'rgb', 'color', etc.
+     *
+     * @return The allowed names.
+     */
+    @NotNull List<String> getNames();
+
+    /**
+     * Create the particle
+     *
+     * @param key The key.
+     * @return The particle.
+     */
+    @Nullable SpawnableParticle create(@NotNull String key);
+}

eco-api/src/main/java/com/willfp/eco/core/particle/Particles.java

@@ -0,0 +1,83 @@
+package com.willfp.eco.core.particle;
+
+import com.willfp.eco.core.particle.impl.EmptyParticle;
+import com.willfp.eco.core.particle.impl.SimpleParticle;
+import com.willfp.eco.util.StringUtils;
+import org.bukkit.Particle;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * Class to manage particles.
+ */
+public final class Particles {
+    /**
+     * All factories.
+     */
+    private static final Map<String, ParticleFactory> FACTORIES = new ConcurrentHashMap<>();
+
+    /**
+     * Register a new particle factory.
+     *
+     * @param factory The factory.
+     */
+    public static void registerParticleFactory(@NotNull final ParticleFactory factory) {
+        for (String name : factory.getNames()) {
+            FACTORIES.put(name.toLowerCase(), factory);
+        }
+    }
+
+    /**
+     * Lookup a particle from a string.
+     * <p>
+     * A particle string should look like {@code magic}, {@code rgb:00ff00}
+     *
+     * @param key The key.
+     * @return The particle, or an {@link EmptyParticle} if invalid.
+     */
+    @NotNull
+    public static SpawnableParticle lookup(@NotNull final String key) {
+        String[] args = StringUtils.parseTokens(key.toLowerCase());
+
+        if (args.length == 0) {
+            return new EmptyParticle();
+        }
+
+        SpawnableParticle spawnableParticle;
+
+        String[] split = args[0].split(":");
+
+        if (split.length == 1) {
+            try {
+                Particle particle = Particle.valueOf(args[0].toUpperCase());
+                spawnableParticle = new SimpleParticle(particle);
+            } catch (IllegalArgumentException e) {
+                spawnableParticle = new EmptyParticle();
+            }
+        } else if (split.length == 2) {
+            String name = split[0];
+            String factoryKey = split[1];
+
+            ParticleFactory factory = FACTORIES.get(name);
+            if (factory == null) {
+                spawnableParticle = new EmptyParticle();
+            } else {
+                spawnableParticle = factory.create(factoryKey);
+            }
+        } else {
+            return new EmptyParticle();
+        }
+
+        if (spawnableParticle == null || spawnableParticle instanceof EmptyParticle) {
+            return new EmptyParticle();
+        }
+
+        return spawnableParticle;
+    }
+
+    private Particles() {
+        throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/particle/SpawnableParticle.java

@@ -0,0 +1,27 @@
+package com.willfp.eco.core.particle;
+
+import org.bukkit.Location;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * A particle that can be spawned.
+ */
+public interface SpawnableParticle {
+    /**
+     * Spawn the particle at a location.
+     *
+     * @param location The location.
+     * @param amount   The amount to spawn.
+     */
+    void spawn(@NotNull Location location,
+               int amount);
+
+    /**
+     * Spawn the particle at a location.
+     *
+     * @param location The location.
+     */
+    default void spawn(@NotNull Location location) {
+        spawn(location, 1);
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/particle/impl/EmptyParticle.java

@@ -0,0 +1,16 @@
+package com.willfp.eco.core.particle.impl;
+
+import com.willfp.eco.core.particle.SpawnableParticle;
+import org.bukkit.Location;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Empty (invalid) particle that is spawned when an invalid key is provided.
+ */
+public final class EmptyParticle implements SpawnableParticle {
+    @Override
+    public void spawn(@NotNull final Location location,
+                      final int amount) {
+        // Do nothing.
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/particle/impl/SimpleParticle.java

@@ -0,0 +1,38 @@
+package com.willfp.eco.core.particle.impl;
+
+import com.willfp.eco.core.particle.SpawnableParticle;
+import org.bukkit.Location;
+import org.bukkit.Particle;
+import org.bukkit.World;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Empty (invalid) particle that is spawned when an invalid key is provided.
+ */
+public final class SimpleParticle implements SpawnableParticle {
+    /**
+     * The particle to be spawned.
+     */
+    private final Particle particle;
+
+    /**
+     * Create a new spawnable particle.
+     *
+     * @param particle The particle.
+     */
+    public SimpleParticle(@NotNull final Particle particle) {
+        this.particle = particle;
+    }
+
+    @Override
+    public void spawn(@NotNull final Location location,
+                      final int amount) {
+        World world = location.getWorld();
+
+        if (world == null) {
+            return;
+        }
+
+        world.spawnParticle(particle, location, amount, 0, 0, 0, 0, null);
+    }
+}

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

@@ -0,0 +1,156 @@
+package com.willfp.eco.core.price;
+
+import com.willfp.eco.core.config.interfaces.Config;
+import com.willfp.eco.core.math.MathContext;
+import com.willfp.eco.core.price.impl.PriceFree;
+import com.willfp.eco.core.serialization.ConfigDeserializer;
+import com.willfp.eco.util.NumberUtils;
+import com.willfp.eco.util.StringUtils;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Objects;
+
+/**
+ * A price that can be shown to a player.
+ */
+public final class ConfiguredPrice implements Price {
+    /**
+     * The deserializer.
+     */
+    private static final ConfigDeserializer<ConfiguredPrice> DESERIALIZER = new Deserializer();
+
+    /**
+     * Free.
+     */
+    private static final ConfiguredPrice FREE = new ConfiguredPrice(
+            new PriceFree(),
+            "Free"
+    );
+
+    /**
+     * The price.
+     */
+    private final Price price;
+
+    /**
+     * The format string.
+     */
+    private final String formatString;
+
+    /**
+     * Create a new Configured Price.
+     *
+     * @param price        The price.
+     * @param formatString The format string.
+     */
+    public ConfiguredPrice(@NotNull final Price price,
+                           @NotNull final String formatString) {
+        this.price = price;
+        this.formatString = formatString;
+    }
+
+    @Override
+    public boolean canAfford(@NotNull final Player player) {
+        return this.price.canAfford(player);
+    }
+
+    @Override
+    public void pay(@NotNull final Player player) {
+        this.price.pay(player);
+    }
+
+    @Override
+    public void giveTo(@NotNull final Player player) {
+        this.price.giveTo(player);
+    }
+
+    @Override
+    public double getValue(@NotNull final Player player) {
+        return this.price.getValue(player);
+    }
+
+    @Override
+    public double getMultiplier(@NotNull final Player player) {
+        return this.price.getMultiplier(player);
+    }
+
+    @Override
+    public void setMultiplier(@NotNull final Player player,
+                              final double multiplier) {
+        this.price.setMultiplier(player, multiplier);
+    }
+
+    /**
+     * Get the price that this delegates to.
+     *
+     * @return The price.
+     */
+    public Price getPrice() {
+        return price;
+    }
+
+    /**
+     * Get the display string for a player.
+     *
+     * @param player The player.
+     * @return The display string.
+     */
+    public String getDisplay(@NotNull final Player player) {
+        return StringUtils.format(
+                formatString.replace("%value%", NumberUtils.format(this.getPrice().getValue(player))),
+                player,
+                StringUtils.FormatOption.WITH_PLACEHOLDERS
+        );
+    }
+
+    /**
+     * Parse a configured price from config.
+     *
+     * @param config The config.
+     * @return The price, or null if it's invalid.
+     */
+    @Nullable
+    public static ConfiguredPrice create(@NotNull final Config config) {
+        return DESERIALIZER.deserialize(config);
+    }
+
+    /**
+     * Parse a configured price from config.
+     *
+     * @param config The config.
+     * @return The price, or free if invalid.
+     */
+    @NotNull
+    public static ConfiguredPrice createOrFree(@NotNull final Config config) {
+        return Objects.requireNonNullElse(create(config), FREE);
+    }
+
+    /**
+     * The deserializer for {@link ConfiguredPrice}.
+     */
+    private static final class Deserializer implements ConfigDeserializer<ConfiguredPrice> {
+        @Override
+        @Nullable
+        public ConfiguredPrice deserialize(@NotNull final Config config) {
+            if (!(
+                    config.has("value")
+                            && config.has("type")
+                            && config.has("display")
+            )) {
+                return null;
+            }
+
+            String formatString = config.getString("display");
+
+            Price price = Prices.create(
+                    config.getString("value"),
+                    config.getString("type"),
+                    MathContext.of(config)
+            );
+
+            return new ConfiguredPrice(price, formatString);
+        }
+    }
+}

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

@@ -0,0 +1,91 @@
+package com.willfp.eco.core.price;
+
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * A price that a player should pay.
+ */
+public interface Price {
+    /**
+     * Get if the player can afford the price.
+     *
+     * @param player The player.
+     * @return If the player can afford.
+     */
+    boolean canAfford(@NotNull Player player);
+
+    /**
+     * Make the player pay the price.
+     * <p>
+     * Only run this if the player can afford the price.
+     *
+     * @param player The player.
+     */
+    void pay(@NotNull Player player);
+
+    /**
+     * Give the value of the price to the player.
+     * <p>
+     * You should override this method, it's only marked as default for
+     * backwards compatibility purposes.
+     *
+     * @param player The player.
+     */
+    default void giveTo(@NotNull Player player) {
+        // Override when needed.
+    }
+
+    /**
+     * If the price is backed by a value, get it here.
+     *
+     * @param player The player.
+     * @return The value.
+     */
+    default double getValue(@NotNull final Player player) {
+        return 0;
+    }
+
+    /**
+     * If the price is backed by a value, get it here.
+     *
+     * @return The value.
+     * @deprecated Use getValue(Player) instead.
+     */
+    @Deprecated(since = "6.45.0", forRemoval = true)
+    default double getValue() {
+        return 0;
+    }
+
+    /**
+     * If the price is backed by a value, set it here.
+     *
+     * @param value The value.
+     * @deprecated Values shouldn't be fixed.
+     */
+    @Deprecated(since = "6.45.0", forRemoval = true)
+    default void setValue(final double value) {
+        // Override when needed.
+    }
+
+    /**
+     * Get the price multiplier for a player.
+     *
+     * @param player The player.
+     * @return The value.
+     */
+    default double getMultiplier(@NotNull final Player player) {
+        return 1;
+    }
+
+    /**
+     * Set the price multiplier for a player.
+     *
+     * @param player     The        player.
+     * @param multiplier The multiplier.
+     */
+    default void setMultiplier(@NotNull final Player player,
+                               final double multiplier) {
+        // Override when needed.
+    }
+}

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

@@ -0,0 +1,46 @@
+package com.willfp.eco.core.price;
+
+import com.willfp.eco.core.math.MathContext;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.List;
+import java.util.function.Function;
+
+/**
+ * Create prices.
+ * <p>
+ * You must override one of the create methods.
+ */
+public interface PriceFactory {
+    /**
+     * Get the names (how the price looks in lookup strings).
+     * <p>
+     * For example, for XP Levels this would be 'l', 'xpl', 'levels', etc.
+     *
+     * @return The allowed names.
+     */
+    @NotNull List<String> getNames();
+
+    /**
+     * Create the price.
+     *
+     * @param value The value.
+     * @return The price.
+     */
+    default @NotNull Price create(final double value) {
+        return create(MathContext.EMPTY, (ctx) -> value);
+    }
+
+    /**
+     * Create the price.
+     *
+     * @param baseContext The base MathContext.
+     * @param function    The function to use. Should use {@link MathContext#copyWithPlayer(MathContext, Player)} on calls.
+     * @return The price.
+     */
+    default @NotNull Price create(@NotNull final MathContext baseContext,
+                                  @NotNull final Function<MathContext, Double> function) {
+        return create(function.apply(baseContext));
+    }
+}

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

@@ -0,0 +1,103 @@
+package com.willfp.eco.core.price;
+
+import com.willfp.eco.core.items.Items;
+import com.willfp.eco.core.items.TestableItem;
+import com.willfp.eco.core.math.MathContext;
+import com.willfp.eco.core.price.impl.PriceEconomy;
+import com.willfp.eco.core.price.impl.PriceFree;
+import com.willfp.eco.core.price.impl.PriceItem;
+import com.willfp.eco.core.recipe.parts.EmptyTestableItem;
+import com.willfp.eco.util.NumberUtils;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Function;
+
+/**
+ * Class to manage prices.
+ */
+public final class Prices {
+    /**
+     * All factories.
+     */
+    private static final Map<String, PriceFactory> FACTORIES = new ConcurrentHashMap<>();
+
+    /**
+     * Register a new price factory.
+     *
+     * @param factory The factory.
+     */
+    public static void registerPriceFactory(@NotNull final PriceFactory factory) {
+        for (String name : factory.getNames()) {
+            FACTORIES.put(name.toLowerCase(), factory);
+        }
+    }
+
+    /**
+     * Create price from an expression (representing the value),
+     * and a price name.
+     * <p>
+     * Supports items as price names.
+     *
+     * @param expression The expression for the value.
+     * @param priceName  The price name.
+     * @return The price, or free if invalid.
+     */
+    @NotNull
+    public static Price create(@NotNull final String expression,
+                               @Nullable final String priceName) {
+        return create(expression, priceName, MathContext.EMPTY);
+    }
+
+    /**
+     * Create price from an expression (representing the value),
+     * and a price name. Uses a context to parse the expression.
+     * <p>
+     * Supports items as price names.
+     *
+     * @param expression The expression for the value.
+     * @param priceName  The price name.
+     * @param context    The math context to parse the expression.
+     * @return The price, or free if invalid.
+     */
+    @NotNull
+    public static Price create(@NotNull final String expression,
+                               @Nullable final String priceName,
+                               @NotNull final MathContext context) {
+        Function<MathContext, Double> function = (ctx) -> NumberUtils.evaluateExpression(
+                expression,
+                ctx
+        );
+
+        if (function.apply(context) <= 0) {
+            return new PriceFree();
+        }
+
+        // Default to economy
+        if (priceName == null) {
+            return new PriceEconomy(context, function);
+        }
+
+        // Find price factory
+        PriceFactory factory = FACTORIES.get(priceName);
+
+        // If no price factory, default to item price
+        if (factory == null) {
+            TestableItem item = Items.lookup(priceName);
+
+            if (item instanceof EmptyTestableItem) {
+                return new PriceFree();
+            }
+
+            return new PriceItem(context, function, item);
+        } else {
+            return factory.create(context, function);
+        }
+    }
+
+    private Prices() {
+        throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
+    }
+}

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

@@ -0,0 +1,84 @@
+package com.willfp.eco.core.price.impl;
+
+import com.willfp.eco.core.integrations.economy.EconomyManager;
+import com.willfp.eco.core.math.MathContext;
+import com.willfp.eco.core.price.Price;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.UUID;
+import java.util.function.Function;
+
+/**
+ * Economy-based price (for Vault, Treasury, etc.)
+ */
+public final class PriceEconomy implements Price {
+    /**
+     * The value of the price.
+     */
+    private final Function<MathContext, Double> function;
+
+    /**
+     * The base math context.
+     */
+    private final MathContext baseContext;
+
+    /**
+     * The multipliers.
+     */
+    private final Map<UUID, Double> multipliers = new HashMap<>();
+
+    /**
+     * Create a new economy-based price.
+     *
+     * @param value The value.
+     */
+    public PriceEconomy(final double value) {
+        this(MathContext.EMPTY, ctx -> value);
+    }
+
+    /**
+     * Create a new economy-based price.
+     *
+     * @param baseContext The base context.
+     * @param function    The function.
+     */
+    public PriceEconomy(@NotNull final MathContext baseContext,
+                        @NotNull final Function<MathContext, Double> function) {
+        this.baseContext = baseContext;
+        this.function = function;
+    }
+
+    @Override
+    public boolean canAfford(@NotNull final Player player) {
+        return EconomyManager.getBalance(player) >= getValue(player);
+    }
+
+    @Override
+    public void pay(@NotNull final Player player) {
+        EconomyManager.removeMoney(player, getValue(player));
+    }
+
+    @Override
+    public void giveTo(@NotNull final Player player) {
+        EconomyManager.giveMoney(player, getValue(player));
+    }
+
+    @Override
+    public double getValue(@NotNull final Player player) {
+        return this.function.apply(MathContext.copyWithPlayer(baseContext, player)) * getMultiplier(player);
+    }
+
+    @Override
+    public double getMultiplier(@NotNull final Player player) {
+        return this.multipliers.getOrDefault(player.getUniqueId(), 1.0);
+    }
+
+    @Override
+    public void setMultiplier(@NotNull final Player player,
+                              final double multiplier) {
+        this.multipliers.put(player.getUniqueId(), multiplier);
+    }
+}

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

@@ -0,0 +1,27 @@
+package com.willfp.eco.core.price.impl;
+
+import com.willfp.eco.core.price.Price;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Free (default) price.
+ */
+public final class PriceFree implements Price {
+    /**
+     * Create a new free price.
+     */
+    public PriceFree() {
+
+    }
+
+    @Override
+    public boolean canAfford(@NotNull final Player player) {
+        return true;
+    }
+
+    @Override
+    public void pay(@NotNull final Player player) {
+        // Do nothing.
+    }
+}

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

@@ -0,0 +1,149 @@
+package com.willfp.eco.core.price.impl;
+
+import com.willfp.eco.core.drops.DropQueue;
+import com.willfp.eco.core.items.TestableItem;
+import com.willfp.eco.core.math.MathContext;
+import com.willfp.eco.core.price.Price;
+import org.bukkit.Material;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.UUID;
+import java.util.function.Function;
+
+/**
+ * Item-based price.
+ */
+public final class PriceItem implements Price {
+    /**
+     * The base MathContext.
+     */
+    private final MathContext baseContext;
+
+    /**
+     * The amount of items.
+     */
+    private final Function<MathContext, Double> function;
+
+    /**
+     * The item.
+     */
+    private final TestableItem item;
+
+    /**
+     * The multipliers.
+     */
+    private final Map<UUID, Double> multipliers = new HashMap<>();
+
+    /**
+     * Create a new item-based price.
+     *
+     * @param amount The amount.
+     * @param item   The item.
+     */
+    public PriceItem(final int amount,
+                     @NotNull final TestableItem item) {
+        this(MathContext.EMPTY, ctx -> (double) amount, item);
+    }
+
+    /**
+     * Create a new item-based price.
+     *
+     * @param baseContext The base MathContext.
+     * @param function    The function to get the amount of items to remove.
+     * @param item        The item.
+     */
+    public PriceItem(@NotNull final MathContext baseContext,
+                     @NotNull final Function<MathContext, Double> function,
+                     @NotNull final TestableItem item) {
+        this.baseContext = baseContext;
+        this.function = function;
+        this.item = item;
+    }
+
+    /**
+     * Get the item.
+     *
+     * @return The item.
+     */
+    public TestableItem getItem() {
+        return item;
+    }
+
+    @Override
+    public boolean canAfford(@NotNull final Player player) {
+        int toRemove = (int) getValue(player);
+        if (toRemove <= 0) {
+            return true;
+        }
+
+        int count = 0;
+
+        for (ItemStack itemStack : player.getInventory().getContents()) {
+            if (item.matches(itemStack)) {
+                count += itemStack.getAmount();
+            }
+        }
+
+        return count >= toRemove;
+    }
+
+    @Override
+    public void pay(@NotNull final Player player) {
+        int toRemove = (int) getValue(player);
+        int count = 0;
+
+        for (ItemStack itemStack : player.getInventory().getContents()) {
+            if (count >= toRemove) {
+                break;
+            }
+
+            if (item.matches(itemStack)) {
+                int itemAmount = itemStack.getAmount();
+
+                if (itemAmount > toRemove) {
+                    itemStack.setAmount(itemAmount - toRemove);
+                }
+
+                if (itemAmount <= toRemove) {
+                    itemStack.setAmount(0);
+                    itemStack.setType(Material.AIR);
+                }
+
+                count += itemAmount;
+            }
+        }
+    }
+
+    @Override
+    public void giveTo(@NotNull final Player player) {
+        ItemStack itemStack = item.getItem().clone();
+        itemStack.setAmount((int) getValue(player));
+
+        new DropQueue(player)
+                .addItem(itemStack)
+                .forceTelekinesis()
+                .push();
+    }
+
+    @Override
+    public double getValue(@NotNull final Player player) {
+        return Math.toIntExact(Math.round(
+                this.function.apply(MathContext.copyWithPlayer(baseContext, player)) * getMultiplier(player)
+        ));
+    }
+
+    @Override
+    public double getMultiplier(@NotNull final Player player) {
+        return this.multipliers.getOrDefault(player.getUniqueId(), 1.0);
+    }
+
+    @Override
+    public void setMultiplier(@NotNull final Player player,
+                              final double multiplier) {
+        this.multipliers.put(player.getUniqueId(), multiplier);
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/sound/PlayableSound.java

@@ -0,0 +1,101 @@
+package com.willfp.eco.core.sound;
+
+import com.willfp.eco.core.config.interfaces.Config;
+import com.willfp.eco.core.serialization.ConfigDeserializer;
+import org.bukkit.Location;
+import org.bukkit.Sound;
+import org.bukkit.World;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Objects;
+
+/**
+ * A sound that can be played at a location.
+ *
+ * @param sound  The sound.
+ * @param pitch  The pitch.
+ * @param volume The volume.
+ */
+public record PlayableSound(@NotNull Sound sound,
+                            double pitch,
+                            double volume) {
+    /**
+     * The deserializer.
+     */
+    private static final ConfigDeserializer<PlayableSound> DESERIALIZER = new Deserializer();
+
+    /**
+     * Create a sound with a default volume.
+     *
+     * @param sound The sound.
+     * @param pitch The pitch.
+     */
+    public PlayableSound(@NotNull final Sound sound,
+                         final double pitch) {
+        this(sound, pitch, 1.0);
+    }
+
+    /**
+     * Play the sound to a player.
+     *
+     * @param player The player.
+     */
+    public void playTo(@NotNull final Player player) {
+        player.playSound(player.getLocation(), sound, (float) volume, (float) pitch);
+    }
+
+    /**
+     * Play the sound at a location.
+     *
+     * @param location The location.
+     */
+    public void playAt(@NotNull final Location location) {
+        World world = location.getWorld();
+
+        if (world == null) {
+            return;
+        }
+
+        world.playSound(location, sound, (float) volume, (float) pitch);
+    }
+
+    /**
+     * Parse a playable sound from config.
+     *
+     * @param config The config.
+     * @return The sound, or null if it's invalid.
+     */
+    @Nullable
+    public static PlayableSound create(@NotNull final Config config) {
+        return DESERIALIZER.deserialize(config);
+    }
+
+    /**
+     * The deserializer for {@link PlayableSound}.
+     */
+    private static final class Deserializer implements ConfigDeserializer<PlayableSound> {
+        @Override
+        public @Nullable PlayableSound deserialize(@NotNull final Config config) {
+            if (!config.has("sound")) {
+                return null;
+            }
+
+            try {
+                Sound sound = Sound.valueOf(config.getString("sound").toUpperCase());
+
+                double pitch = Objects.requireNonNullElse(config.getDouble("pitch"), 1.0);
+                double volume = Objects.requireNonNullElse(config.getDouble("volume"), 1.0);
+
+                return new PlayableSound(
+                        sound,
+                        pitch,
+                        volume
+                );
+            } catch (IllegalArgumentException e) {
+                return null;
+            }
+        }
+    }
+}

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

@@ -1,8 +1,10 @@
 package com.willfp.eco.util;
 
 import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.integrations.placeholder.PlaceholderManager;
 import com.willfp.eco.core.placeholder.AdditionalPlayer;
 import com.willfp.eco.core.placeholder.InjectablePlaceholder;
+import com.willfp.eco.core.math.MathContext;
 import com.willfp.eco.core.placeholder.PlaceholderInjectable;
 import com.willfp.eco.core.placeholder.StaticPlaceholder;
 import org.bukkit.entity.Player;
@@ -12,7 +14,6 @@ import org.jetbrains.annotations.Nullable;
 import java.text.DecimalFormat;
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.TreeMap;
@@ -240,7 +241,7 @@ public final class NumberUtils {
      * @return The value of the expression, or zero if invalid.
      */
     public static double evaluateExpression(@NotNull final String expression) {
-        return evaluateExpression(expression, null);
+        return evaluateExpression(expression, MathContext.EMPTY);
     }
 
     /**
@@ -252,18 +253,7 @@ public final class NumberUtils {
      */
     public static double evaluateExpression(@NotNull final String expression,
                                             @Nullable final Player player) {
-        return evaluateExpression(expression, player, new PlaceholderInjectable() {
-            @Override
-            public void clearInjectedPlaceholders() {
-                // Nothing.
-            }
-
-            @Override
-            public @NotNull
-            List<InjectablePlaceholder> getPlaceholderInjections() {
-                return Collections.emptyList();
-            }
-        });
+        return evaluateExpression(expression, player, PlaceholderManager.EMPTY_INJECTABLE);
     }
 
     /**
@@ -323,7 +313,23 @@ public final class NumberUtils {
                                             @Nullable final Player player,
                                             @NotNull final PlaceholderInjectable context,
                                             @NotNull final Collection<AdditionalPlayer> additionalPlayers) {
-        return Eco.get().evaluate(expression, player, context, additionalPlayers);
+        return Eco.get().evaluate(expression, new MathContext(
+                context,
+                player,
+                additionalPlayers
+        ));
+    }
+
+    /**
+     * Evaluate an expression with respect to a player (for placeholders).
+     *
+     * @param expression The expression.
+     * @param context    The math context.
+     * @return The value of the expression, or zero if invalid.
+     */
+    public static double evaluateExpression(@NotNull final String expression,
+                                            @NotNull final MathContext context) {
+        return Eco.get().evaluate(expression, context);
     }
 
     private NumberUtils() {

eco-api/src/main/kotlin/com/willfp/eco/core/config/ConfigHelpers.kt

@@ -3,9 +3,12 @@
 package com.willfp.eco.core.config
 
 import com.willfp.eco.core.config.interfaces.Config
+import org.bukkit.configuration.ConfigurationSection
+import java.io.File
+import java.io.InputStream
 
 /** Helper class to create configs with a kotlin DSL. */
-class DSLConfig internal constructor(type: ConfigType) : TransientConfig(emptyMap(), type) {
+class DSLConfig internal constructor(type: ConfigType) : GenericConfig(type) {
     /**
      * Map a key to a value.
      *
@@ -34,3 +37,30 @@ class DSLConfig internal constructor(type: ConfigType) : TransientConfig(emptyMa
  */
 fun config(type: ConfigType = ConfigType.YAML, builder: DSLConfig.() -> Unit): Config =
     DSLConfig(type).apply(builder)
+
+/** @see Configs.empty */
+fun emptyConfig() = Configs.empty()
+
+/** @see Configs.empty */
+fun emptyConfig(type: ConfigType) = Configs.empty(type)
+
+/** @see Configs.fromBukkit */
+fun ConfigurationSection?.toConfig() = Configs.fromBukkit(this)
+
+/** @see Configs.fromStream */
+fun InputStream?.readConfig() = Configs.fromStream(this)
+
+/** @see Configs.fromFile */
+fun File?.readConfig() = Configs.fromFile(this)
+
+/** @see Configs.fromFile */
+fun File?.readConfig(type: ConfigType) = Configs.fromFile(this, type)
+
+/** @see Configs.fromMap */
+fun Map<String?, Any?>.toConfig() = Configs.fromMap(this)
+
+/** @see Configs.fromMap */
+fun Map<String?, Any?>.toConfig(type: ConfigType) = Configs.fromMap(this, type)
+
+/** @see Configs.fromString */
+fun readConfig(contents: String, type: ConfigType) = Configs.fromString(contents, type)

eco-api/src/main/kotlin/com/willfp/eco/core/gui/GUIHelpers.kt

@@ -4,9 +4,9 @@ package com.willfp.eco.core.gui
 
 import com.willfp.eco.core.gui.menu.Menu
 import com.willfp.eco.core.gui.menu.MenuBuilder
-import com.willfp.eco.core.gui.menu.MenuType
 import com.willfp.eco.core.gui.menu.MenuEvent
 import com.willfp.eco.core.gui.menu.MenuEventHandler
+import com.willfp.eco.core.gui.menu.MenuType
 import com.willfp.eco.core.gui.page.Page
 import com.willfp.eco.core.gui.page.PageBuilder
 import com.willfp.eco.core.gui.slot.Slot
@@ -184,6 +184,10 @@ inline fun <reified T : MenuEvent> MenuBuilder.onEvent(crossinline handler: (Pla
     })
 }
 
+/** @see MenuBuilder.onBuild */
+fun MenuBuilder.onBuild(action: (Menu) -> Unit): MenuBuilder =
+    this.onBuild { action(it) }
+
 /** Kotlin builder for menus. */
 fun menu(
     rows: Int,

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

@@ -0,0 +1,14 @@
+@file:JvmName("ItemBuilderExtensions")
+
+package com.willfp.eco.core.items.builder
+
+import com.willfp.eco.core.items.TestableItem
+import org.bukkit.inventory.ItemStack
+
+/** Modify an item with a builder. */
+fun TestableItem.modify(builder: ItemBuilder.() -> Unit): ItemStack =
+    this.item.modify(builder)
+
+/** Modify an item with a builder. */
+fun ItemStack.modify(builder: ItemBuilder.() -> Unit): ItemStack =
+    ItemStackBuilder(this).apply(builder).build()

eco-api/src/main/kotlin/com/willfp/eco/core/lookup/Testable.kt

@@ -0,0 +1,7 @@
+@file:JvmName("TestableExtensions")
+
+package com.willfp.eco.core.lookup
+
+/** @see Testable.matches */
+fun <T> T?.matches(test: Testable<T>) =
+    test.matches(this)

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

@@ -2,8 +2,8 @@ package com.willfp.eco.internal
 
 import com.willfp.eco.core.EcoPlugin
 import com.willfp.eco.core.PluginProps
-import com.willfp.eco.core.config.TransientConfig
 import com.willfp.eco.core.config.interfaces.Config
+import com.willfp.eco.core.config.readConfig
 
 object EcoPropsParser : PluginProps.PropsParser<Config> {
     override fun parseFrom(config: Config): PluginProps {
@@ -28,7 +28,7 @@ object EcoPropsParser : PluginProps.PropsParser<Config> {
         }
 
         return PluginProps.parse(
-            TransientConfig(plugin.getResourceAsStream("/eco.yml")),
+            plugin.getResourceAsStream("/eco.yml").readConfig(),
             Config::class.java
         )
     }

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

@@ -108,7 +108,7 @@ open class EcoConfig(
     }
 
     override fun getSubsectionsOrNull(path: String): List<Config>? {
-        return (get(path) as? Iterable<Config>)
+        return getList<Config>(path)
             ?.map { it.apply { this.addInjectablePlaceholder(injections) } }
             ?.toList()
     }
@@ -122,7 +122,7 @@ open class EcoConfig(
     }
 
     override fun getIntsOrNull(path: String): List<Int>? {
-        return (get(path) as? Iterable<Number>)?.map { it.toInt() }
+        return getList<Number>(path)?.map { it.toInt() }
     }
 
     override fun getBoolOrNull(path: String): Boolean? {
@@ -130,7 +130,7 @@ open class EcoConfig(
     }
 
     override fun getBoolsOrNull(path: String): List<Boolean>? {
-        return (get(path) as? Iterable<Boolean>)?.toList()
+        return getList<Boolean>(path)?.toList()
     }
 
     override fun getStringOrNull(
@@ -154,7 +154,7 @@ open class EcoConfig(
         format: Boolean,
         option: StringUtils.FormatOption
     ): List<String>? {
-        val strings = (get(path) as? Iterable<*>)
+        val strings = getList<Any?>(path)
             ?.map { it?.toString() ?: "" }
             ?.toMutableList() ?: return null
         if (placeholderInjections.isNotEmpty() && format && option == StringUtils.FormatOption.WITH_PLACEHOLDERS) {
@@ -176,7 +176,7 @@ open class EcoConfig(
     }
 
     override fun getDoublesOrNull(path: String): List<Double>? {
-        return (get(path) as? Iterable<Number>)?.map { it.toDouble() }
+        return getList<Number>(path)?.map { it.toDouble() }
     }
 
     override fun addInjectablePlaceholder(placeholders: Iterable<InjectablePlaceholder>) {
@@ -215,4 +215,15 @@ open class EcoConfig(
     override fun toString(): String {
         return this.toPlaintext()
     }
+
+    private inline fun <reified T> getList(path: String): List<T>? {
+        val asIterable = get(path) as? Iterable<*> ?: return null
+        val asList = asIterable.toList()
+
+        if (asList.firstOrNull() !is T?) {
+            return emptyList()
+        }
+
+        return asList as List<T>
+    }
 }

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

@@ -3,7 +3,7 @@ package com.willfp.eco.internal.extensions
 import com.google.common.collect.ImmutableSet
 import com.willfp.eco.core.Eco
 import com.willfp.eco.core.EcoPlugin
-import com.willfp.eco.core.config.TransientConfig
+import com.willfp.eco.core.config.toConfig
 import com.willfp.eco.core.extensions.Extension
 import com.willfp.eco.core.extensions.ExtensionLoader
 import com.willfp.eco.core.extensions.ExtensionMetadata
@@ -48,7 +48,7 @@ class EcoExtensionLoader(
         val ymlIn = classLoader.getResourceAsStream("extension.yml")
             ?: throw MalformedExtensionException("No extension.yml found in " + extensionJar.name)
 
-        val extensionYml = TransientConfig(YamlConfiguration.loadConfiguration(InputStreamReader(ymlIn)))
+        val extensionYml = YamlConfiguration.loadConfiguration(InputStreamReader(ymlIn)).toConfig()
 
         val mainClass = extensionYml.getStringOrNull("main")
         var name = extensionYml.getStringOrNull("name")

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

@@ -11,8 +11,8 @@ class MergedStateMenu(
         return base.getState(player) + additional.getState(player)
     }
 
-    override fun addState(player: Player, key: String, value: Any?) {
-        base.addState(player, key, value)
+    override fun setState(player: Player, key: String, value: Any?) {
+        base.setState(player, key, value)
     }
 
     override fun clearState(player: Player) {

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

@@ -39,7 +39,7 @@ class EcoMenu(
     override fun getSlot(row: Int, column: Int): Slot =
         getPossiblyReactiveSlot(row, column, null)
 
-    override fun getSlot(row: Int, column: Int, player: Player, menu: Menu): Slot =
+    override fun getSlot(row: Int, column: Int, player: Player): Slot =
         getPossiblyReactiveSlot(row, column, player)
 
     override fun open(player: Player): Inventory {
@@ -110,7 +110,7 @@ class EcoMenu(
         this.handle(player, this@EcoMenu, event as T)
     }
 
-    override fun addState(player: Player, key: String, value: Any?) {
+    override fun setState(player: Player, key: String, value: Any?) {
         val inventory = player.renderedInventory ?: return
         inventory.state[key] = value
     }

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

@@ -22,6 +22,7 @@ class EcoMenuBuilder(
     private val onOpen = mutableListOf<OpenHandler>()
     private val onRender = mutableListOf<(Player, Menu) -> Unit>()
     private val menuEventHandlers = mutableListOf<MenuEventHandler<*>>()
+    private val onBuild = mutableListOf<(Menu) -> Unit>()
     private var allowsChangingHeldItem = false
 
     override fun getRows() = rows
@@ -80,6 +81,11 @@ class EcoMenuBuilder(
         return this
     }
 
+    override fun onBuild(action: Consumer<Menu>): MenuBuilder {
+        onBuild += { action.accept(it) }
+        return this
+    }
+
     override fun allowChangingHeldItem(): MenuBuilder {
         allowsChangingHeldItem = true
         return this
@@ -122,7 +128,7 @@ class EcoMenuBuilder(
             }
         }
 
-        return EcoMenu(
+        val menu = EcoMenu(
             rows,
             columns,
             layeredComponents,
@@ -133,5 +139,9 @@ class EcoMenuBuilder(
             menuEventHandlers,
             allowsChangingHeldItem
         )
+
+        onBuild.forEach { it(menu) } // Run on build functions.
+
+        return menu
     }
 }

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

@@ -1,5 +1,6 @@
 package com.willfp.eco.internal.gui.menu
 
+import com.willfp.eco.core.gui.menu.events.CaptiveItemChangeEvent
 import com.willfp.eco.core.items.isEmpty
 import com.willfp.eco.core.recipe.parts.EmptyTestableItem
 import com.willfp.eco.util.MenuUtils
@@ -31,14 +32,14 @@ class RenderedInventory(
     val state = mutableMapOf<String, Any?>()
 
     fun render() {
-        captiveItems.clear()
+        val newCaptive = mutableMapOf<GUIPosition, ItemStack>()
 
         for (row in (1..menu.rows)) {
             for (column in (1..menu.columns)) {
                 val position = GUIPosition(row, column)
                 val bukkit = MenuUtils.rowColumnToSlot(row, column, menu.columns)
 
-                val slot = menu.getSlot(row, column, player, menu)
+                val slot = menu.getSlot(row, column, player)
                 val renderedItem = slot.getItemStack(player)
 
                 if (slot.isCaptive(player, menu)) {
@@ -46,11 +47,11 @@ class RenderedInventory(
 
                     if (slot.isCaptiveFromEmpty) {
                         if (!actualItem.isEmpty) {
-                            captiveItems[position] = actualItem
+                            newCaptive[position] = actualItem
                         }
                     } else {
                         if (actualItem != renderedItem && !EmptyTestableItem().matches(actualItem)) {
-                            captiveItems[position] = actualItem
+                            newCaptive[position] = actualItem
                         }
                     }
                 } else {
@@ -59,15 +60,51 @@ class RenderedInventory(
             }
         }
 
+        val previousCaptive = captiveItems.toMap()
+        captiveItems.clear()
+        captiveItems.putAll(newCaptive)
+
+        // Call captive item change event
+        for (position in previousCaptive.keys union newCaptive.keys) {
+            if (previousCaptive[position] != newCaptive[position]) {
+                menu.callEvent(
+                    player, CaptiveItemChangeEvent(
+                        position.row,
+                        position.column,
+                        previousCaptive[position],
+                        newCaptive[position]
+                    )
+                )
+            }
+        }
+
         menu.runOnRender(player)
+
+        // Run second render if captive items changed
+        if (captiveItems != previousCaptive) {
+            for (row in (1..menu.rows)) {
+                for (column in (1..menu.columns)) {
+                    val bukkit = MenuUtils.rowColumnToSlot(row, column, menu.columns)
+
+                    val slot = menu.getSlot(row, column, player)
+                    val renderedItem = slot.getItemStack(player)
+
+                    if (!slot.isCaptive(player, menu)) {
+                        inventory.setItem(bukkit, renderedItem)
+                    }
+                }
+            }
+        }
     }
 
     fun renderDefaultCaptiveItems() {
+        menu.runOnRender(player)
+
         for (row in (1..menu.rows)) {
             for (column in (1..menu.columns)) {
                 val bukkit = MenuUtils.rowColumnToSlot(row, column, menu.columns)
 
-                val slot = menu.getSlot(row, column, player, menu)
+                val slot = menu.getSlot(row, column, player)
 
                 if (slot.isCaptive(player, menu)) {
                     inventory.setItem(bukkit, slot.getItemStack(player))

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

@@ -1,13 +1,15 @@
 package com.willfp.eco.internal.integrations
 
 import com.willfp.eco.core.EcoPlugin
-import com.willfp.eco.core.integrations.placeholder.PlaceholderIntegration
 import com.willfp.eco.core.integrations.placeholder.PlaceholderManager
-import me.clip.placeholderapi.PlaceholderAPI
 import me.clip.placeholderapi.expansion.PlaceholderExpansion
 import org.bukkit.entity.Player
 
-class PlaceholderIntegrationPAPI(private val plugin: EcoPlugin) : PlaceholderExpansion(), PlaceholderIntegration {
+class PAPIExpansion(private val plugin: EcoPlugin) : PlaceholderExpansion() {
+    init {
+        register()
+    }
+
     override fun persist(): Boolean {
         return true
     }
@@ -34,29 +36,4 @@ class PlaceholderIntegrationPAPI(private val plugin: EcoPlugin) : PlaceholderExp
     ): String {
         return PlaceholderManager.getResult(player, identifier, plugin)
     }
-
-    override fun registerIntegration() {
-        register()
-    }
-
-    override fun getPluginName(): String {
-        return "PlaceholderAPI"
-    }
-
-    override fun translate(
-        text: String,
-        player: Player?
-    ): String {
-        return PlaceholderAPI.setPlaceholders(player, text)
-    }
-
-    override fun findPlaceholdersIn(text: String): MutableList<String> {
-        val placeholders = mutableListOf<String>()
-        val matcher = PlaceholderAPI.getPlaceholderPattern().matcher(text)
-        while (matcher.find()) {
-            placeholders.add(matcher.group())
-        }
-
-        return placeholders
-    }
-}
+}

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

@@ -27,6 +27,10 @@ object ArgParserCustomModelData : LookupArgParser {
         return Predicate {
             val testMeta = it.itemMeta ?: return@Predicate false
 
+            if (!testMeta.hasCustomModelData()) {
+                return@Predicate false
+            }
+
             testMeta.customModelData == modelData
         }
     }

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/particle/ParticleFactoryRGB.kt

@@ -0,0 +1,36 @@
+package com.willfp.eco.internal.particle
+
+import com.willfp.eco.core.particle.ParticleFactory
+import com.willfp.eco.core.particle.SpawnableParticle
+import org.bukkit.Color
+import org.bukkit.Location
+import org.bukkit.Particle
+
+object ParticleFactoryRGB : ParticleFactory {
+    override fun getNames() = listOf(
+        "color",
+        "rgb",
+        "hex"
+    )
+
+    override fun create(key: String): SpawnableParticle? {
+        val hex = key.toIntOrNull(16) ?: return null
+        val color = try {
+            Color.fromRGB(hex)
+        } catch (e: IllegalArgumentException) {
+            return null
+        }
+
+        return SpawnableParticleRGB(Particle.DustOptions(color, 1.0f))
+    }
+
+    private class SpawnableParticleRGB(
+        private val options: Particle.DustOptions
+    ) : SpawnableParticle {
+        override fun spawn(location: Location, amount: Int) {
+            val world = location.world ?: return
+
+            world.spawnParticle(Particle.REDSTONE, location, amount, 0.0, 0.0, 0.0, 0.0, options)
+        }
+    }
+}

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/price/PriceFactoryEconomy.kt

@@ -0,0 +1,18 @@
+package com.willfp.eco.internal.price
+
+import com.willfp.eco.core.math.MathContext
+import com.willfp.eco.core.price.Price
+import com.willfp.eco.core.price.PriceFactory
+import com.willfp.eco.core.price.impl.PriceEconomy
+import java.util.function.Function
+
+object PriceFactoryEconomy : PriceFactory {
+    override fun getNames() = listOf(
+        "coins",
+        "$"
+    )
+
+    override fun create(baseContext: MathContext, function: Function<MathContext, Double>): Price {
+        return PriceEconomy(baseContext, function)
+    }
+}

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/price/PriceFactoryXP.kt

@@ -0,0 +1,50 @@
+package com.willfp.eco.internal.price
+
+import com.willfp.eco.core.math.MathContext
+import com.willfp.eco.core.price.Price
+import com.willfp.eco.core.price.PriceFactory
+import org.bukkit.entity.Player
+import java.util.UUID
+import java.util.function.Function
+import kotlin.math.roundToInt
+
+object PriceFactoryXP : PriceFactory {
+    override fun getNames() = listOf(
+        "xp",
+        "exp",
+        "experience"
+    )
+
+    override fun create(baseContext: MathContext, function: Function<MathContext, Double>): Price {
+        return PriceXP(baseContext) { function.apply(it).roundToInt() }
+    }
+
+    private class PriceXP(
+        private val baseContext: MathContext,
+        private val xp: (MathContext) -> Int
+    ) : Price {
+        private val multipliers = mutableMapOf<UUID, Double>()
+
+        override fun canAfford(player: Player) = player.totalExperience >= getValue(player)
+
+        override fun pay(player: Player) {
+            player.totalExperience -= getValue(player).roundToInt()
+        }
+
+        override fun giveTo(player: Player) {
+            player.totalExperience += getValue(player).roundToInt()
+        }
+
+        override fun getValue(player: Player): Double {
+            return xp(MathContext.copyWithPlayer(baseContext, player)) * getMultiplier(player)
+        }
+
+        override fun getMultiplier(player: Player): Double {
+            return multipliers[player.uniqueId] ?: 1.0
+        }
+
+        override fun setMultiplier(player: Player, multiplier: Double) {
+            multipliers[player.uniqueId] = multiplier.roundToInt().toDouble()
+        }
+    }
+}

eco-core/core-backend/src/main/kotlin/com/willfp/eco/internal/price/PriceFactoryXPLevels.kt

@@ -0,0 +1,51 @@
+package com.willfp.eco.internal.price
+
+import com.willfp.eco.core.math.MathContext
+import com.willfp.eco.core.price.Price
+import com.willfp.eco.core.price.PriceFactory
+import org.bukkit.entity.Player
+import java.util.UUID
+import java.util.function.Function
+import kotlin.math.roundToInt
+
+object PriceFactoryXPLevels : PriceFactory {
+    override fun getNames() = listOf(
+        "l",
+        "levels",
+        "xplevels",
+        "explevels",
+    )
+
+    override fun create(baseContext: MathContext, function: Function<MathContext, Double>): Price {
+        return PriceXPLevel(baseContext) { function.apply(it).roundToInt() }
+    }
+
+    private class PriceXPLevel(
+        private val baseContext: MathContext,
+        private val level: (MathContext) -> Int
+    ) : Price {
+        private val multipliers = mutableMapOf<UUID, Double>()
+
+        override fun canAfford(player: Player) = player.level >= getValue(player)
+
+        override fun pay(player: Player) {
+            player.level -= getValue(player).roundToInt()
+        }
+
+        override fun giveTo(player: Player) {
+            player.level += getValue(player).roundToInt()
+        }
+
+        override fun getValue(player: Player): Double {
+            return level(MathContext.copyWithPlayer(baseContext, player)) * getMultiplier(player)
+        }
+
+        override fun getMultiplier(player: Player): Double {
+            return multipliers[player.uniqueId] ?: 1.0
+        }
+
+        override fun setMultiplier(player: Player, multiplier: Double) {
+            multipliers[player.uniqueId] = multiplier.roundToInt().toDouble()
+        }
+    }
+}

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

@@ -29,7 +29,27 @@ var SkullMeta.texture: String?
             setProfile.isAccessible = true
         }
 
-        if (base64 == null) {
+        /* This length check below was lost in the conversion. For some reason the base64
+        * string is length 8 when this is called pretty frequently, causing an
+        * out of bounds exception.
+        *
+        * Could not pass event EntityPotionEffectEvent to Talismans v5.116.0
+        * java.lang.StringIndexOutOfBoundsException: begin -12, end 8, length 8
+        * at java.lang.String.checkBoundsBeginEnd(String.java:4604) ~[?:?]
+        * at java.lang.String.substring(String.java:2707) ~[?:?]
+        * at java.lang.String.substring(String.java:2680) ~[?:?]
+        * at com.willfp.eco.internal.spigot.proxy.v1_19_R1.common.SkullKt.setTexture(Skull.kt:36)
+        *
+        if (base64.length < 20) {
+            return
+        }
+        *
+        * ^ Update to this comment: a length 8 string ("textures") was being sent
+        * because the get() method wasn't working right. This has been fixed, but the
+        * check needs to remain implemented.
+        */
+
+        if (base64 == null || base64.length < 20) {
             setProfile.invoke(this, null)
         } else {
             val uuid = UUID(

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

@@ -1,21 +1,23 @@
 package com.willfp.eco.internal.spigot.proxy.common.ai.entity
 
-import com.willfp.eco.core.entities.ai.entity.EntityGoalLeapAtTarget
+import com.willfp.eco.core.entities.ai.entity.EntityGoalIllusionerBlindnessSpell
 import com.willfp.eco.internal.spigot.proxy.common.ai.EntityGoalFactory
-import com.willfp.eco.internal.spigot.proxy.common.ai.opengoals.IllusionerBlindnessSpellGoal
 import net.minecraft.world.entity.PathfinderMob
 import net.minecraft.world.entity.ai.goal.Goal
 import net.minecraft.world.entity.monster.Illusioner
 
-object IllusionerBlindnessSpellGoalFactory : EntityGoalFactory<EntityGoalLeapAtTarget> {
-    override fun create(apiGoal: EntityGoalLeapAtTarget, entity: PathfinderMob): Goal? {
+object IllusionerBlindnessSpellGoalFactory : EntityGoalFactory<EntityGoalIllusionerBlindnessSpell> {
+    override fun create(apiGoal: EntityGoalIllusionerBlindnessSpell, entity: PathfinderMob): Goal? {
         if (entity !is Illusioner) return null
 
-        return IllusionerBlindnessSpellGoal(
-            entity
-        )
+        // Have to use reflection for it to work
+        return Illusioner::class.java.declaredClasses[1]
+            .getDeclaredConstructor(Illusioner::class.java)
+            .apply { isAccessible = true }
+            .newInstance(entity) as Goal
     }
 
-    override fun isGoalOfType(goal: Goal) = goal is IllusionerBlindnessSpellGoal
-            || goal::class.java.name.contains("IllusionerBlindnessSpellGoal")
+    override fun isGoalOfType(goal: Goal): Boolean {
+        return Illusioner::class.java.declaredClasses[1].isInstance(goal)
+    }
 }

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

@@ -1,21 +1,23 @@
 package com.willfp.eco.internal.spigot.proxy.common.ai.entity
 
-import com.willfp.eco.core.entities.ai.entity.EntityGoalLeapAtTarget
+import com.willfp.eco.core.entities.ai.entity.EntityGoalIllusionerMirrorSpell
 import com.willfp.eco.internal.spigot.proxy.common.ai.EntityGoalFactory
-import com.willfp.eco.internal.spigot.proxy.common.ai.opengoals.IllusionerMirrorSpellGoal
 import net.minecraft.world.entity.PathfinderMob
 import net.minecraft.world.entity.ai.goal.Goal
 import net.minecraft.world.entity.monster.Illusioner
 
-object IllusionerMirrorSpellGoalFactory : EntityGoalFactory<EntityGoalLeapAtTarget> {
-    override fun create(apiGoal: EntityGoalLeapAtTarget, entity: PathfinderMob): Goal? {
+object IllusionerMirrorSpellGoalFactory : EntityGoalFactory<EntityGoalIllusionerMirrorSpell> {
+    override fun create(apiGoal: EntityGoalIllusionerMirrorSpell, entity: PathfinderMob): Goal? {
         if (entity !is Illusioner) return null
 
-        return IllusionerMirrorSpellGoal(
-            entity
-        )
+        // Have to use reflection for it to work
+        return Illusioner::class.java.declaredClasses[0]
+            .getDeclaredConstructor(Illusioner::class.java)
+            .apply { isAccessible = true }
+            .newInstance(entity) as Goal
     }
 
-    override fun isGoalOfType(goal: Goal) = goal is IllusionerMirrorSpellGoal
-            || goal::class.java.name.contains("IllusionerMirrorSpellGoal")
+    override fun isGoalOfType(goal: Goal): Boolean {
+        return Illusioner::class.java.declaredClasses[0].isInstance(goal)
+    }
 }

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

@@ -1,50 +0,0 @@
-package com.willfp.eco.internal.spigot.proxy.common.ai.opengoals
-
-import net.minecraft.sounds.SoundEvent
-import net.minecraft.sounds.SoundEvents
-import net.minecraft.world.Difficulty
-import net.minecraft.world.effect.MobEffectInstance
-import net.minecraft.world.effect.MobEffects
-import net.minecraft.world.entity.monster.Illusioner
-import net.minecraft.world.entity.monster.SpellcasterIllager
-import org.bukkit.event.entity.EntityPotionEffectEvent
-
-class IllusionerBlindnessSpellGoal(
-    private val illusioner: Illusioner
-) : OpenUseSpellGoal(illusioner) {
-    override val castingInterval = 180
-    override val castingTime = 20
-    override val spellPrepareSound: SoundEvent = SoundEvents.ILLUSIONER_PREPARE_BLINDNESS
-    override val spell: SpellcasterIllager.IllagerSpell = SpellcasterIllager.IllagerSpell.BLINDNESS
-
-    private var lastTargetId = 0
-
-    override fun canUse(): Boolean {
-        return if (super.canUse()) {
-            false
-        } else if (illusioner.target == null) {
-            false
-        } else if (illusioner.target!!.id == lastTargetId) {
-            false
-        } else {
-            illusioner.level.getCurrentDifficultyAt(illusioner.blockPosition()).isHarderThan(
-                Difficulty.NORMAL.ordinal.toFloat()
-            )
-        }
-    }
-
-    override fun start() {
-        super.start()
-        if (illusioner.target != null) {
-            lastTargetId = illusioner.target!!.id
-        }
-    }
-
-    override fun performSpellCasting() {
-        illusioner.target?.addEffect(
-            MobEffectInstance(MobEffects.BLINDNESS, 400),
-            illusioner,
-            EntityPotionEffectEvent.Cause.ATTACK
-        ) // CraftBukkit
-    }
-}

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

@@ -1,29 +0,0 @@
-package com.willfp.eco.internal.spigot.proxy.common.ai.opengoals
-
-import net.minecraft.sounds.SoundEvent
-import net.minecraft.sounds.SoundEvents
-import net.minecraft.world.effect.MobEffectInstance
-import net.minecraft.world.effect.MobEffects
-import net.minecraft.world.entity.monster.Illusioner
-import net.minecraft.world.entity.monster.SpellcasterIllager
-import org.bukkit.event.entity.EntityPotionEffectEvent
-
-class IllusionerMirrorSpellGoal(
-    private val illusioner: Illusioner
-) : OpenUseSpellGoal(illusioner) {
-    override val castingInterval = 340
-    override val castingTime = 20
-    override val spellPrepareSound: SoundEvent = SoundEvents.ILLUSIONER_PREPARE_MIRROR
-    override val spell: SpellcasterIllager.IllagerSpell = SpellcasterIllager.IllagerSpell.DISAPPEAR
-
-    override fun canUse(): Boolean {
-        return if (!super.canUse()) false else !illusioner.hasEffect(MobEffects.INVISIBILITY)
-    }
-
-    override fun performSpellCasting() {
-        illusioner.addEffect(
-            MobEffectInstance(MobEffects.INVISIBILITY, 1200),
-            EntityPotionEffectEvent.Cause.ILLUSION
-        )
-    }
-}

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

@@ -1,79 +0,0 @@
-package com.willfp.eco.internal.spigot.proxy.common.ai.opengoals
-
-import net.minecraft.sounds.SoundEvent
-import net.minecraft.world.entity.EntityType
-import net.minecraft.world.entity.LivingEntity
-import net.minecraft.world.entity.ai.goal.Goal
-import net.minecraft.world.entity.monster.SpellcasterIllager
-
-@Suppress("UNCHECKED_CAST")
-class DelegatedSpellcaster(private val handle: SpellcasterIllager) : SpellcasterIllager(
-    handle.type as EntityType<out SpellcasterIllager>,
-    handle.level
-) {
-    var openSpellCastingTickCount
-        get() = this.spellCastingTickCount
-        set(value) {
-            this.spellCastingTickCount = value
-        }
-
-    val openCastingSoundEvent = this.castingSoundEvent
-
-    override fun applyRaidBuffs(wave: Int, unused: Boolean) {
-        handle.applyRaidBuffs(wave, unused)
-    }
-
-    override fun getCelebrateSound(): SoundEvent {
-        return handle.celebrateSound
-    }
-
-    override fun getCastingSoundEvent(): SoundEvent {
-        return this.openCastingSoundEvent
-    }
-}
-
-@Suppress("NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS")
-abstract class OpenUseSpellGoal(
-    private val handle: SpellcasterIllager
-) : Goal() {
-    private var attackWarmupDelay = 0
-    private var nextAttackTickCount = 0
-
-    private val openHandle = DelegatedSpellcaster(handle)
-
-    override fun canUse(): Boolean {
-        val entityliving: LivingEntity = handle.target ?: return false
-        return if (entityliving.isAlive) if (handle.isCastingSpell) false else handle.tickCount >= nextAttackTickCount else false
-    }
-
-    override fun canContinueToUse(): Boolean {
-        val entityliving: LivingEntity = handle.target ?: return false
-        return entityliving.isAlive && attackWarmupDelay > 0
-    }
-
-    override fun start() {
-        attackWarmupDelay = castWarmupTime
-        openHandle.openSpellCastingTickCount = castingTime
-        nextAttackTickCount = handle.tickCount + castingInterval
-        val soundeffect = spellPrepareSound
-        if (soundeffect != null) {
-            handle.playSound(soundeffect, 1.0f, 1.0f)
-        }
-        handle.setIsCastingSpell(spell)
-    }
-
-    override fun tick() {
-        --attackWarmupDelay
-        if (attackWarmupDelay == 0) {
-            performSpellCasting()
-            handle.playSound(openHandle.openCastingSoundEvent, 1.0f, 1.0f)
-        }
-    }
-
-    protected abstract fun performSpellCasting()
-    protected abstract val castingTime: Int
-    protected abstract val castingInterval: Int
-    protected abstract val spellPrepareSound: SoundEvent?
-    protected abstract val spell: SpellcasterIllager.IllagerSpell?
-    protected open val castWarmupTime: Int = 60
-}

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

@@ -3,16 +3,28 @@ package com.willfp.eco.internal.spigot.proxy.v1_17_R1
 import com.willfp.eco.core.data.ExtendedPersistentDataContainer
 import com.willfp.eco.internal.spigot.proxy.ExtendedPersistentDataContainerFactoryProxy
 import net.minecraft.nbt.Tag
+import org.bukkit.Material
+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
+import org.bukkit.inventory.ItemStack
 import org.bukkit.persistence.PersistentDataContainer
 import org.bukkit.persistence.PersistentDataType
 
-class ExtendedPersistentDataContainerFactory: ExtendedPersistentDataContainerFactoryProxy {
+class ExtendedPersistentDataContainerFactory : ExtendedPersistentDataContainerFactoryProxy {
     @Suppress("UNCHECKED_CAST")
-    private val registry: CraftPersistentDataTypeRegistry =
-        CraftPersistentDataContainer::class.java.getDeclaredField("registry")
-            .apply { isAccessible = true }.get(null) as CraftPersistentDataTypeRegistry
+    private val registry: CraftPersistentDataTypeRegistry
+
+    init {
+        /*
+         Can't grab actual instance since it's in CraftMetaItem (which is package-private)
+         And getting it would mean more janky reflection
+         */
+        val item = CraftItemStack.asCraftCopy(ItemStack(Material.STONE))
+        val pdc = item.itemMeta!!.persistentDataContainer
+        this.registry = CraftPersistentDataContainer::class.java.getDeclaredField("registry")
+            .apply { isAccessible = true }.get(pdc) as CraftPersistentDataTypeRegistry
+    }
 
     override fun adapt(pdc: PersistentDataContainer): ExtendedPersistentDataContainer {
         return when (pdc) {
@@ -34,7 +46,8 @@ class ExtendedPersistentDataContainerFactory: ExtendedPersistentDataContainerFac
                 .apply { isAccessible = true }.get(handle) as MutableMap<String, Tag>
 
         override fun <T : Any, Z : Any> set(key: String, dataType: PersistentDataType<T, Z>, value: Z) {
-            customDataTags[key] = registry.wrap(dataType.primitiveType, dataType.toPrimitive(value, handle.adapterContext))
+            customDataTags[key] =
+                registry.wrap(dataType.primitiveType, dataType.toPrimitive(value, handle.adapterContext))
         }
 
         override fun <T : Any, Z : Any> has(key: String, dataType: PersistentDataType<T, Z>): Boolean {

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

@@ -0,0 +1,11 @@
+package com.willfp.eco.internal.spigot.proxy.v1_17_R1
+
+import com.willfp.eco.internal.spigot.proxy.SyncCommandsProxy
+import org.bukkit.Bukkit
+import org.bukkit.craftbukkit.v1_17_R1.CraftServer
+
+class SyncCommands : SyncCommandsProxy {
+    override fun syncCommands() {
+        (Bukkit.getServer() as CraftServer).syncCommands()
+    }
+}

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

@@ -3,16 +3,28 @@ package com.willfp.eco.internal.spigot.proxy.v1_18_R1
 import com.willfp.eco.core.data.ExtendedPersistentDataContainer
 import com.willfp.eco.internal.spigot.proxy.ExtendedPersistentDataContainerFactoryProxy
 import net.minecraft.nbt.Tag
+import org.bukkit.Material
+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
+import org.bukkit.inventory.ItemStack
 import org.bukkit.persistence.PersistentDataContainer
 import org.bukkit.persistence.PersistentDataType
 
 class ExtendedPersistentDataContainerFactory : ExtendedPersistentDataContainerFactoryProxy {
     @Suppress("UNCHECKED_CAST")
-    private val registry: CraftPersistentDataTypeRegistry =
-        CraftPersistentDataContainer::class.java.getDeclaredField("registry")
-            .apply { isAccessible = true }.get(null) as CraftPersistentDataTypeRegistry
+    private val registry: CraftPersistentDataTypeRegistry
+
+    init {
+        /*
+         Can't grab actual instance since it's in CraftMetaItem (which is package-private)
+         And getting it would mean more janky reflection
+         */
+        val item = CraftItemStack.asCraftCopy(ItemStack(Material.STONE))
+        val pdc = item.itemMeta!!.persistentDataContainer
+        this.registry = CraftPersistentDataContainer::class.java.getDeclaredField("registry")
+            .apply { isAccessible = true }.get(pdc) as CraftPersistentDataTypeRegistry
+    }
 
     override fun adapt(pdc: PersistentDataContainer): ExtendedPersistentDataContainer {
         return when (pdc) {

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

@@ -0,0 +1,11 @@
+package com.willfp.eco.internal.spigot.proxy.v1_18_R1
+
+import com.willfp.eco.internal.spigot.proxy.SyncCommandsProxy
+import org.bukkit.Bukkit
+import org.bukkit.craftbukkit.v1_18_R1.CraftServer
+
+class SyncCommands : SyncCommandsProxy {
+    override fun syncCommands() {
+        (Bukkit.getServer() as CraftServer).syncCommands()
+    }
+}

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

@@ -3,16 +3,28 @@ package com.willfp.eco.internal.spigot.proxy.v1_18_R2
 import com.willfp.eco.core.data.ExtendedPersistentDataContainer
 import com.willfp.eco.internal.spigot.proxy.ExtendedPersistentDataContainerFactoryProxy
 import net.minecraft.nbt.Tag
+import org.bukkit.Material
+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
+import org.bukkit.inventory.ItemStack
 import org.bukkit.persistence.PersistentDataContainer
 import org.bukkit.persistence.PersistentDataType
 
-class ExtendedPersistentDataContainerFactory: ExtendedPersistentDataContainerFactoryProxy {
+class ExtendedPersistentDataContainerFactory : ExtendedPersistentDataContainerFactoryProxy {
     @Suppress("UNCHECKED_CAST")
-    private val registry: CraftPersistentDataTypeRegistry =
-        CraftPersistentDataContainer::class.java.getDeclaredField("registry")
-            .apply { isAccessible = true }.get(null) as CraftPersistentDataTypeRegistry
+    private val registry: CraftPersistentDataTypeRegistry
+
+    init {
+        /*
+         Can't grab actual instance since it's in CraftMetaItem (which is package-private)
+         And getting it would mean more janky reflection
+         */
+        val item = CraftItemStack.asCraftCopy(ItemStack(Material.STONE))
+        val pdc = item.itemMeta!!.persistentDataContainer
+        this.registry = CraftPersistentDataContainer::class.java.getDeclaredField("registry")
+            .apply { isAccessible = true }.get(pdc) as CraftPersistentDataTypeRegistry
+    }
 
     override fun adapt(pdc: PersistentDataContainer): ExtendedPersistentDataContainer {
         return when (pdc) {
@@ -34,7 +46,8 @@ class ExtendedPersistentDataContainerFactory: ExtendedPersistentDataContainerFac
                 .apply { isAccessible = true }.get(handle) as MutableMap<String, Tag>
 
         override fun <T : Any, Z : Any> set(key: String, dataType: PersistentDataType<T, Z>, value: Z) {
-            customDataTags[key] = registry.wrap(dataType.primitiveType, dataType.toPrimitive(value, handle.adapterContext))
+            customDataTags[key] =
+                registry.wrap(dataType.primitiveType, dataType.toPrimitive(value, handle.adapterContext))
         }
 
         override fun <T : Any, Z : Any> has(key: String, dataType: PersistentDataType<T, Z>): Boolean {

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

@@ -0,0 +1,11 @@
+package com.willfp.eco.internal.spigot.proxy.v1_18_R2
+
+import com.willfp.eco.internal.spigot.proxy.SyncCommandsProxy
+import org.bukkit.Bukkit
+import org.bukkit.craftbukkit.v1_18_R2.CraftServer
+
+class SyncCommands : SyncCommandsProxy {
+    override fun syncCommands() {
+        (Bukkit.getServer() as CraftServer).syncCommands()
+    }
+}

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

@@ -3,21 +3,33 @@ package com.willfp.eco.internal.spigot.proxy.v1_19_R1
 import com.willfp.eco.core.data.ExtendedPersistentDataContainer
 import com.willfp.eco.internal.spigot.proxy.ExtendedPersistentDataContainerFactoryProxy
 import net.minecraft.nbt.Tag
+import org.bukkit.Material
+import org.bukkit.craftbukkit.v1_19_R1.inventory.CraftItemStack
 import org.bukkit.craftbukkit.v1_19_R1.persistence.CraftPersistentDataContainer
 import org.bukkit.craftbukkit.v1_19_R1.persistence.CraftPersistentDataTypeRegistry
+import org.bukkit.inventory.ItemStack
 import org.bukkit.persistence.PersistentDataContainer
 import org.bukkit.persistence.PersistentDataType
 
-class ExtendedPersistentDataContainerFactory: ExtendedPersistentDataContainerFactoryProxy {
+class ExtendedPersistentDataContainerFactory : ExtendedPersistentDataContainerFactoryProxy {
     @Suppress("UNCHECKED_CAST")
-    private val registry: CraftPersistentDataTypeRegistry =
-        CraftPersistentDataContainer::class.java.getDeclaredField("registry")
-            .apply { isAccessible = true }.get(null) as CraftPersistentDataTypeRegistry
+    private val registry: CraftPersistentDataTypeRegistry
+
+    init {
+        /*
+         Can't grab actual instance since it's in CraftMetaItem (which is package-private)
+         And getting it would mean more janky reflection
+         */
+        val item = CraftItemStack.asCraftCopy(ItemStack(Material.STONE))
+        val pdc = item.itemMeta!!.persistentDataContainer
+        this.registry = CraftPersistentDataContainer::class.java.getDeclaredField("registry")
+            .apply { isAccessible = true }.get(pdc) as CraftPersistentDataTypeRegistry
+    }
 
     override fun adapt(pdc: PersistentDataContainer): ExtendedPersistentDataContainer {
         return when (pdc) {
             is CraftPersistentDataContainer -> EcoPersistentDataContainer(pdc)
-            else -> throw IllegalArgumentException("Custom PDC instance is not supported!")
+            else -> throw IllegalArgumentException("Custom PDC instance ims not supported!")
         }
     }
 
@@ -34,7 +46,8 @@ class ExtendedPersistentDataContainerFactory: ExtendedPersistentDataContainerFac
                 .apply { isAccessible = true }.get(handle) as MutableMap<String, Tag>
 
         override fun <T : Any, Z : Any> set(key: String, dataType: PersistentDataType<T, Z>, value: Z) {
-            customDataTags[key] = registry.wrap(dataType.primitiveType, dataType.toPrimitive(value, handle.adapterContext))
+            customDataTags[key] =
+                registry.wrap(dataType.primitiveType, dataType.toPrimitive(value, handle.adapterContext))
         }
 
         override fun <T : Any, Z : Any> has(key: String, dataType: PersistentDataType<T, Z>): Boolean {

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

@@ -0,0 +1,11 @@
+package com.willfp.eco.internal.spigot.proxy.v1_19_R1
+
+import com.willfp.eco.internal.spigot.proxy.SyncCommandsProxy
+import org.bukkit.Bukkit
+import org.bukkit.craftbukkit.v1_19_R1.CraftServer
+
+class SyncCommands : SyncCommandsProxy {
+    override fun syncCommands() {
+        (Bukkit.getServer() as CraftServer).syncCommands()
+    }
+}

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/EcoImpl.kt

@@ -4,7 +4,6 @@ import com.willfp.eco.core.Eco
 import com.willfp.eco.core.EcoPlugin
 import com.willfp.eco.core.PluginLike
 import com.willfp.eco.core.PluginProps
-import com.willfp.eco.core.Prerequisite
 import com.willfp.eco.core.config.ConfigType
 import com.willfp.eco.core.config.interfaces.Config
 import com.willfp.eco.core.data.keys.PersistentDataKey
@@ -12,8 +11,7 @@ import com.willfp.eco.core.gui.menu.Menu
 import com.willfp.eco.core.gui.menu.MenuType
 import com.willfp.eco.core.gui.slot.functional.SlotProvider
 import com.willfp.eco.core.items.Items
-import com.willfp.eco.core.placeholder.AdditionalPlayer
-import com.willfp.eco.core.placeholder.PlaceholderInjectable
+import com.willfp.eco.core.math.MathContext
 import com.willfp.eco.internal.EcoPropsParser
 import com.willfp.eco.internal.config.EcoConfigHandler
 import com.willfp.eco.internal.config.EcoConfigSection
@@ -34,13 +32,13 @@ import com.willfp.eco.internal.gui.MergedStateMenu
 import com.willfp.eco.internal.gui.menu.EcoMenuBuilder
 import com.willfp.eco.internal.gui.menu.renderedInventory
 import com.willfp.eco.internal.gui.slot.EcoSlotBuilder
-import com.willfp.eco.internal.integrations.PlaceholderIntegrationPAPI
+import com.willfp.eco.internal.integrations.PAPIExpansion
 import com.willfp.eco.internal.logging.EcoLogger
 import com.willfp.eco.internal.proxy.EcoProxyFactory
 import com.willfp.eco.internal.scheduling.EcoScheduler
 import com.willfp.eco.internal.spigot.data.DataYml
-import com.willfp.eco.internal.spigot.data.EcoProfileHandler
 import com.willfp.eco.internal.spigot.data.KeyRegistry
+import com.willfp.eco.internal.spigot.data.ProfileHandler
 import com.willfp.eco.internal.spigot.data.storage.HandlerType
 import com.willfp.eco.internal.spigot.integrations.bstats.MetricHandler
 import com.willfp.eco.internal.spigot.math.evaluateExpression
@@ -52,8 +50,8 @@ import com.willfp.eco.internal.spigot.proxy.FastItemStackFactoryProxy
 import com.willfp.eco.internal.spigot.proxy.MiniMessageTranslatorProxy
 import com.willfp.eco.internal.spigot.proxy.SNBTConverterProxy
 import com.willfp.eco.internal.spigot.proxy.SkullProxy
+import com.willfp.eco.internal.spigot.proxy.SyncCommandsProxy
 import com.willfp.eco.internal.spigot.proxy.TPSProxy
-import net.kyori.adventure.platform.bukkit.BukkitAudiences
 import org.bukkit.Location
 import org.bukkit.NamespacedKey
 import org.bukkit.configuration.ConfigurationSection
@@ -72,7 +70,7 @@ private val loadedEcoPlugins = mutableMapOf<String, EcoPlugin>()
 class EcoImpl : EcoSpigotPlugin(), Eco {
     override val dataYml = DataYml(this)
 
-    override val profileHandler = EcoProfileHandler(
+    override val profileHandler = ProfileHandler(
         HandlerType.valueOf(this.configYml.getString("data-handler").uppercase()),
         this
     )
@@ -81,10 +79,6 @@ class EcoImpl : EcoSpigotPlugin(), Eco {
         getProxy(CommonsInitializerProxy::class.java).init()
     }
 
-    private var adventure: BukkitAudiences? = if (!Prerequisite.HAS_PAPER.isMet) {
-        BukkitAudiences.create(this)
-    } else null
-
     @Suppress("RedundantNullableReturnType")
     private val keyFactory: InternalNamespacedKeyFactory? =
         if (this.configYml.getBool("use-safer-namespacedkey-creation"))
@@ -114,8 +108,9 @@ class EcoImpl : EcoSpigotPlugin(), Eco {
     override fun createLogger(plugin: EcoPlugin) =
         EcoLogger(plugin)
 
-    override fun createPAPIIntegration(plugin: EcoPlugin) =
-        PlaceholderIntegrationPAPI(plugin)
+    override fun createPAPIIntegration(plugin: EcoPlugin) {
+        PAPIExpansion(plugin)
+    }
 
     override fun getEcoPlugin(): EcoPlugin =
         this
@@ -174,9 +169,6 @@ class EcoImpl : EcoSpigotPlugin(), Eco {
     override fun createDropQueue(player: Player) = if (this.configYml.getBool("use-fast-collated-drops"))
         EcoFastCollatedDropQueue(player) else EcoDropQueue(player)
 
-    override fun getPersistentDataKeyFrom(namespacedKey: NamespacedKey) =
-        KeyRegistry.getKeyFrom(namespacedKey)
-
     override fun getRegisteredPersistentDataKeys() =
         KeyRegistry.getRegisteredKeys()
 
@@ -235,7 +227,7 @@ class EcoImpl : EcoSpigotPlugin(), Eco {
         MetricHandler.createMetrics(plugin)
 
     override fun getAdventure() =
-        adventure
+        bukkitAudiences
 
     override fun getServerProfile() =
         profileHandler.loadServerProfile()
@@ -243,12 +235,6 @@ class EcoImpl : EcoSpigotPlugin(), Eco {
     override fun loadPlayerProfile(uuid: UUID) =
         profileHandler.load(uuid)
 
-    override fun saveAllProfiles() =
-        profileHandler.save()
-
-    override fun savePersistentDataKeysFor(uuid: UUID, keys: Set<PersistentDataKey<*>>) =
-        profileHandler.saveKeysFor(uuid, keys)
-
     override fun unloadPlayerProfile(uuid: UUID) =
         profileHandler.unloadPlayer(uuid)
 
@@ -292,13 +278,12 @@ class EcoImpl : EcoSpigotPlugin(), Eco {
     override fun getTPS() =
         getProxy(TPSProxy::class.java).getTPS()
 
-    override fun evaluate(
-        expression: String,
-        player: Player?,
-        injectable: PlaceholderInjectable,
-        additionalPlayers: MutableCollection<AdditionalPlayer>
-    ) = evaluateExpression(expression, player, injectable, additionalPlayers)
+    override fun evaluate(expression: String, context: MathContext) =
+        evaluateExpression(expression, context)
 
     override fun getOpenMenu(player: Player) =
         player.renderedInventory?.menu
+
+    override fun syncCommands() =
+        this.getProxy(SyncCommandsProxy::class.java).syncCommands()
 }

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/EcoSpigotPlugin.kt

@@ -14,8 +14,11 @@ import com.willfp.eco.core.integrations.customitems.CustomItemsManager
 import com.willfp.eco.core.integrations.economy.EconomyManager
 import com.willfp.eco.core.integrations.hologram.HologramManager
 import com.willfp.eco.core.integrations.mcmmo.McmmoManager
+import com.willfp.eco.core.integrations.placeholder.PlaceholderManager
 import com.willfp.eco.core.integrations.shop.ShopManager
 import com.willfp.eco.core.items.Items
+import com.willfp.eco.core.particle.Particles
+import com.willfp.eco.core.price.Prices
 import com.willfp.eco.internal.entities.EntityArgParserAdult
 import com.willfp.eco.internal.entities.EntityArgParserAttackDamage
 import com.willfp.eco.internal.entities.EntityArgParserAttackSpeed
@@ -44,11 +47,15 @@ import com.willfp.eco.internal.items.ArgParserTexture
 import com.willfp.eco.internal.items.ArgParserUnbreakable
 import com.willfp.eco.internal.lookup.SegmentParserGroup
 import com.willfp.eco.internal.lookup.SegmentParserUseIfPresent
+import com.willfp.eco.internal.particle.ParticleFactoryRGB
+import com.willfp.eco.internal.price.PriceFactoryEconomy
+import com.willfp.eco.internal.price.PriceFactoryXP
+import com.willfp.eco.internal.price.PriceFactoryXPLevels
 import com.willfp.eco.internal.spigot.arrows.ArrowDataListener
 import com.willfp.eco.internal.spigot.data.DataListener
 import com.willfp.eco.internal.spigot.data.DataYml
-import com.willfp.eco.internal.spigot.data.EcoProfileHandler
 import com.willfp.eco.internal.spigot.data.PlayerBlockListener
+import com.willfp.eco.internal.spigot.data.ProfileHandler
 import com.willfp.eco.internal.spigot.data.storage.ProfileSaver
 import com.willfp.eco.internal.spigot.display.PacketAutoRecipe
 import com.willfp.eco.internal.spigot.display.PacketChat
@@ -86,6 +93,7 @@ import com.willfp.eco.internal.spigot.integrations.antigrief.AntigriefGriefPreve
 import com.willfp.eco.internal.spigot.integrations.antigrief.AntigriefIridiumSkyblock
 import com.willfp.eco.internal.spigot.integrations.antigrief.AntigriefKingdoms
 import com.willfp.eco.internal.spigot.integrations.antigrief.AntigriefLands
+import com.willfp.eco.internal.spigot.integrations.antigrief.AntigriefPvPManager
 import com.willfp.eco.internal.spigot.integrations.antigrief.AntigriefRPGHorses
 import com.willfp.eco.internal.spigot.integrations.antigrief.AntigriefSuperiorSkyblock2
 import com.willfp.eco.internal.spigot.integrations.antigrief.AntigriefTowny
@@ -106,11 +114,11 @@ import com.willfp.eco.internal.spigot.integrations.hologram.HologramDecentHologr
 import com.willfp.eco.internal.spigot.integrations.hologram.HologramHolographicDisplays
 import com.willfp.eco.internal.spigot.integrations.mcmmo.McmmoIntegrationImpl
 import com.willfp.eco.internal.spigot.integrations.multiverseinventories.MultiverseInventoriesIntegration
+import com.willfp.eco.internal.spigot.integrations.placeholder.PlaceholderIntegrationPAPI
 import com.willfp.eco.internal.spigot.integrations.shop.ShopDeluxeSellwands
 import com.willfp.eco.internal.spigot.integrations.shop.ShopEconomyShopGUI
 import com.willfp.eco.internal.spigot.integrations.shop.ShopShopGuiPlus
 import com.willfp.eco.internal.spigot.integrations.shop.ShopZShop
-import com.willfp.eco.internal.spigot.player.PlayerHealthFixer
 import com.willfp.eco.internal.spigot.proxy.FastItemStackFactoryProxy
 import com.willfp.eco.internal.spigot.recipes.CraftingRecipeListener
 import com.willfp.eco.internal.spigot.recipes.StackedRecipeListener
@@ -118,6 +126,7 @@ import com.willfp.eco.internal.spigot.recipes.listeners.ComplexInComplex
 import com.willfp.eco.internal.spigot.recipes.listeners.ComplexInVanilla
 import com.willfp.eco.internal.spigot.recipes.stackhandlers.ShapedCraftingRecipeStackHandler
 import com.willfp.eco.internal.spigot.recipes.stackhandlers.ShapelessCraftingRecipeStackHandler
+import net.kyori.adventure.platform.bukkit.BukkitAudiences
 import net.milkbowl.vault.economy.Economy
 import org.bukkit.Bukkit
 import org.bukkit.Material
@@ -126,7 +135,8 @@ import org.bukkit.inventory.ItemStack
 
 abstract class EcoSpigotPlugin : EcoPlugin() {
     abstract val dataYml: DataYml
-    protected abstract val profileHandler: EcoProfileHandler
+    protected abstract val profileHandler: ProfileHandler
+    protected var bukkitAudiences: BukkitAudiences? = null
 
     init {
         Items.registerArgParser(ArgParserEnchantment)
@@ -157,6 +167,12 @@ abstract class EcoSpigotPlugin : EcoPlugin() {
         Entities.registerArgParser(EntityArgParserSilent)
         Entities.registerArgParser(EntityArgParserEquipment)
 
+        Prices.registerPriceFactory(PriceFactoryEconomy)
+        Prices.registerPriceFactory(PriceFactoryXPLevels)
+        Prices.registerPriceFactory(PriceFactoryXP)
+
+        Particles.registerParticleFactory(ParticleFactoryRGB)
+
         CraftingRecipeListener.registerListener(ComplexInComplex)
         CraftingRecipeListener.registerListener(ComplexInVanilla)
 
@@ -205,6 +221,11 @@ abstract class EcoSpigotPlugin : EcoPlugin() {
 
         // Preload categorized persistent data keys
         profileHandler.initialize()
+
+        // Init adventure
+        if (!Prerequisite.HAS_PAPER.isMet) {
+            bukkitAudiences = BukkitAudiences.create(this)
+        }
     }
 
     override fun handleDisable() {
@@ -263,6 +284,7 @@ abstract class EcoSpigotPlugin : EcoPlugin() {
                     AntigriefManager.register(AntigriefCombatLogXV11())
                 }
             },
+            IntegrationLoader("PvPManager") { AntigriefManager.register(AntigriefPvPManager()) },
 
             // Anticheat
             IntegrationLoader("AAC5") { AnticheatManager.register(AnticheatAAC()) },
@@ -311,6 +333,9 @@ abstract class EcoSpigotPlugin : EcoPlugin() {
                 }
             },
 
+            // Placeholder
+            IntegrationLoader("PlaceholderAPI") { PlaceholderManager.addIntegration(PlaceholderIntegrationPAPI()) },
+
             // Misc
             IntegrationLoader("mcMMO") { McmmoManager.register(McmmoIntegrationImpl()) },
             IntegrationLoader("Multiverse-Inventories") {
@@ -345,7 +370,6 @@ abstract class EcoSpigotPlugin : EcoPlugin() {
             ArmorChangeEventListeners(this),
             DataListener(this),
             PlayerBlockListener(this),
-            PlayerHealthFixer(this),
             ServerLocking
         )
 

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/KeyRegistry.kt

@@ -48,8 +48,4 @@ object KeyRegistry {
             else -> throw NullPointerException("Null value found!")
         }
     }
-
-    fun getKeyFrom(namespacedKey: NamespacedKey): PersistentDataKey<*>? {
-        return registry[namespacedKey]
-    }
 }

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/ProfileHandler.kt

@@ -18,7 +18,7 @@ import java.util.UUID
 
 val serverProfileUUID = UUID(0, 0)
 
-class EcoProfileHandler(
+class ProfileHandler(
     private val type: HandlerType,
     private val plugin: EcoSpigotPlugin
 ) {

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/storage/LegacyMySQLDataHandler.kt

@@ -7,7 +7,7 @@ import com.willfp.eco.core.EcoPlugin
 import com.willfp.eco.core.data.keys.PersistentDataKey
 import com.willfp.eco.core.data.keys.PersistentDataKeyType
 import com.willfp.eco.internal.spigot.EcoSpigotPlugin
-import com.willfp.eco.internal.spigot.data.EcoProfileHandler
+import com.willfp.eco.internal.spigot.data.ProfileHandler
 import com.willfp.eco.internal.spigot.data.serverProfileUUID
 import com.zaxxer.hikari.HikariConfig
 import com.zaxxer.hikari.HikariDataSource
@@ -49,8 +49,9 @@ the worst bodge I've shipped in production.
 @Suppress("UNCHECKED_CAST")
 class LegacyMySQLDataHandler(
     plugin: EcoSpigotPlugin,
-    handler: EcoProfileHandler
+    handler: ProfileHandler
 ) : DataHandler(HandlerType.LEGACY_MYSQL) {
+    private val database: Database
     private val playerHandler: ImplementedMySQLHandler
     private val serverHandler: ImplementedMySQLHandler
 
@@ -65,7 +66,7 @@ class LegacyMySQLDataHandler(
                 plugin.configYml.getString("mysql.database")
         config.maximumPoolSize = plugin.configYml.getInt("mysql.connections")
 
-        Database.connect(HikariDataSource(config))
+        database = Database.connect(HikariDataSource(config))
 
         playerHandler = ImplementedMySQLHandler(
             handler,
@@ -110,180 +111,180 @@ class LegacyMySQLDataHandler(
         playerHandler.initialize()
         serverHandler.initialize()
     }
-}
 
-@Suppress("UNCHECKED_CAST")
-private class ImplementedMySQLHandler(
-    private val handler: EcoProfileHandler,
-    private val table: UUIDTable,
-    private val plugin: EcoPlugin
-) {
-    private val rows = Caffeine.newBuilder()
-        .expireAfterWrite(3, TimeUnit.SECONDS)
-        .build<UUID, ResultRow>()
+    @Suppress("UNCHECKED_CAST")
+    private inner class ImplementedMySQLHandler(
+        private val handler: ProfileHandler,
+        private val table: UUIDTable,
+        private val plugin: EcoPlugin
+    ) {
+        private val rows = Caffeine.newBuilder()
+            .expireAfterWrite(3, TimeUnit.SECONDS)
+            .build<UUID, ResultRow>()
 
-    private val threadFactory = ThreadFactoryBuilder().setNameFormat("eco-mysql-thread-%d").build()
-    private val executor = Executors.newFixedThreadPool(plugin.configYml.getInt("mysql.threads"), threadFactory)
-    val registeredKeys = mutableSetOf<PersistentDataKey<*>>()
+        private val threadFactory = ThreadFactoryBuilder().setNameFormat("eco-legacy-mysql-thread-%d").build()
+        private val executor = Executors.newFixedThreadPool(plugin.configYml.getInt("mysql.threads"), threadFactory)
+        val registeredKeys = mutableSetOf<PersistentDataKey<*>>()
 
-    init {
-        transaction {
-            SchemaUtils.create(table)
+        init {
+            transaction(database) {
+                SchemaUtils.create(table)
+            }
         }
-    }
 
-    fun initialize() {
-        transaction {
-            SchemaUtils.createMissingTablesAndColumns(table, withLogs = false)
+        fun initialize() {
+            transaction(database) {
+                SchemaUtils.createMissingTablesAndColumns(table, withLogs = false)
+            }
         }
-    }
 
-    fun ensureKeyRegistration(key: PersistentDataKey<*>) {
-        if (table.columns.any { it.name == key.key.toString() }) {
+        fun ensureKeyRegistration(key: PersistentDataKey<*>) {
+            if (table.columns.any { it.name == key.key.toString() }) {
+                registeredKeys.add(key)
+                return
+            }
+
+            registerColumn(key)
             registeredKeys.add(key)
-            return
         }
 
-        registerColumn(key)
-        registeredKeys.add(key)
-    }
-
-    fun <T : Any> write(uuid: UUID, key: PersistentDataKey<T>, value: Any) {
-        getRow(uuid)
-        doWrite(uuid, key, key.type.constrainSQLTypes(value))
-    }
-
-    private fun doWrite(uuid: UUID, key: PersistentDataKey<*>, constrainedValue: Any) {
-        val column: Column<Any> = getColumn(key) as Column<Any>
-
-        executor.submit {
-            transaction {
-                table.update({ table.id eq uuid }) {
-                    it[column] = constrainedValue
-                }
-            }
-        }
-    }
-
-    fun saveKeysForRow(uuid: UUID, keys: Set<PersistentDataKey<*>>) {
-        saveRow(uuid, keys)
-    }
-
-    private fun saveRow(uuid: UUID, keys: Set<PersistentDataKey<*>>) {
-        val profile = handler.loadGenericProfile(uuid)
-
-        executor.submit {
-            transaction {
-                getRow(uuid)
-
-                for (key in keys) {
-                    doWrite(uuid, key, key.type.constrainSQLTypes(profile.read(key)))
-                }
-            }
-        }
-    }
-
-    fun <T> read(uuid: UUID, key: PersistentDataKey<T>): T? {
-        val doRead = Callable<T?> {
-            transaction {
-                val row = getRow(uuid)
-                val column = getColumn(key)
-                val raw = row[column]
-                key.type.fromConstrained(raw)
-            }
+        fun <T : Any> write(uuid: UUID, key: PersistentDataKey<T>, value: Any) {
+            getRow(uuid)
+            doWrite(uuid, key, key.type.constrainSQLTypes(value))
         }
 
-        ensureKeyRegistration(key) // DON'T DELETE THIS LINE! I know it's covered in getColumn, but I need to do it here as well.
+        private fun doWrite(uuid: UUID, key: PersistentDataKey<*>, constrainedValue: Any) {
+            val column: Column<Any> = getColumn(key) as Column<Any>
 
-        doRead.call()
-
-        return if (Eco.get().ecoPlugin.configYml.getBool("mysql.async-reads")) {
-            executor.submit(doRead).get()
-        } else {
-            doRead.call()
-        }
-    }
-
-    private fun <T> registerColumn(key: PersistentDataKey<T>) {
-        try {
-            transaction {
-                try {
-                    table.apply {
-                        if (table.columns.any { it.name == key.key.toString() }) {
-                            return@apply
-                        }
-
-                        when (key.type) {
-                            PersistentDataKeyType.INT -> registerColumn<Int>(key.key.toString(), IntegerColumnType())
-                                .default(key.defaultValue as Int)
-
-                            PersistentDataKeyType.DOUBLE -> registerColumn<Double>(
-                                key.key.toString(),
-                                DoubleColumnType()
-                            ).default(key.defaultValue as Double)
-
-                            PersistentDataKeyType.BOOLEAN -> registerColumn<Boolean>(
-                                key.key.toString(),
-                                BooleanColumnType()
-                            ).default(key.defaultValue as Boolean)
-
-                            PersistentDataKeyType.STRING -> registerColumn<String>(
-                                key.key.toString(),
-                                VarCharColumnType(512)
-                            ).default(key.defaultValue as String)
-
-                            PersistentDataKeyType.STRING_LIST -> registerColumn<String>(
-                                key.key.toString(),
-                                VarCharColumnType(8192)
-                            ).default(PersistentDataKeyType.STRING_LIST.constrainSQLTypes(key.defaultValue as List<String>) as String)
-
-                            PersistentDataKeyType.CONFIG -> throw IllegalArgumentException(
-                                "Config Persistent Data Keys are not supported by the legacy MySQL handler!"
-                            )
-
-                            else -> throw NullPointerException("Null value found!")
-                        }
+            executor.submit {
+                transaction(database) {
+                    table.update({ table.id eq uuid }) {
+                        it[column] = constrainedValue
                     }
-
-                    SchemaUtils.createMissingTablesAndColumns(table, withLogs = false)
-                } catch (e: Exception) {
-                    plugin.logger.info("MySQL Error 1!")
-                    e.printStackTrace()
-                    // What's that? Two enormous exception catches? That's right! This code sucks.
                 }
             }
-        } catch (e: Exception) {
-            plugin.logger.info("MySQL Error 2!")
-            e.printStackTrace()
-            // It might fail. Who cares? This is legacy.
         }
-    }
 
-    private fun getColumn(key: PersistentDataKey<*>): Column<*> {
-        ensureKeyRegistration(key)
+        fun saveKeysForRow(uuid: UUID, keys: Set<PersistentDataKey<*>>) {
+            saveRow(uuid, keys)
+        }
 
-        val name = key.key.toString()
+        private fun saveRow(uuid: UUID, keys: Set<PersistentDataKey<*>>) {
+            val profile = handler.loadGenericProfile(uuid)
 
-        return table.columns.first { it.name == name }
-    }
+            executor.submit {
+                transaction(database) {
+                    getRow(uuid)
 
-    private fun getRow(uuid: UUID): ResultRow {
-        fun select(uuid: UUID): ResultRow? {
-            return transaction {
-                table.select { table.id eq uuid }.limit(1).singleOrNull()
+                    for (key in keys) {
+                        doWrite(uuid, key, key.type.constrainSQLTypes(profile.read(key)))
+                    }
+                }
             }
         }
 
-        return rows.get(uuid) {
-            val row = select(uuid)
+        fun <T> read(uuid: UUID, key: PersistentDataKey<T>): T? {
+            val doRead = Callable<T?> {
+                transaction(database) {
+                    val row = getRow(uuid)
+                    val column = getColumn(key)
+                    val raw = row[column]
+                    key.type.fromConstrained(raw)
+                }
+            }
 
-            return@get if (row != null) {
-                row
+            ensureKeyRegistration(key) // DON'T DELETE THIS LINE! I know it's covered in getColumn, but I need to do it here as well.
+
+            doRead.call()
+
+            return if (Eco.get().ecoPlugin.configYml.getBool("mysql.async-reads")) {
+                executor.submit(doRead).get()
             } else {
-                transaction {
-                    table.insert { it[id] = uuid }
+                doRead.call()
+            }
+        }
+
+        private fun <T> registerColumn(key: PersistentDataKey<T>) {
+            try {
+                transaction(database) {
+                    try {
+                        table.apply {
+                            if (table.columns.any { it.name == key.key.toString() }) {
+                                return@apply
+                            }
+
+                            when (key.type) {
+                                PersistentDataKeyType.INT -> registerColumn<Int>(key.key.toString(), IntegerColumnType())
+                                    .default(key.defaultValue as Int)
+
+                                PersistentDataKeyType.DOUBLE -> registerColumn<Double>(
+                                    key.key.toString(),
+                                    DoubleColumnType()
+                                ).default(key.defaultValue as Double)
+
+                                PersistentDataKeyType.BOOLEAN -> registerColumn<Boolean>(
+                                    key.key.toString(),
+                                    BooleanColumnType()
+                                ).default(key.defaultValue as Boolean)
+
+                                PersistentDataKeyType.STRING -> registerColumn<String>(
+                                    key.key.toString(),
+                                    VarCharColumnType(512)
+                                ).default(key.defaultValue as String)
+
+                                PersistentDataKeyType.STRING_LIST -> registerColumn<String>(
+                                    key.key.toString(),
+                                    VarCharColumnType(8192)
+                                ).default(PersistentDataKeyType.STRING_LIST.constrainSQLTypes(key.defaultValue as List<String>) as String)
+
+                                PersistentDataKeyType.CONFIG -> throw IllegalArgumentException(
+                                    "Config Persistent Data Keys are not supported by the legacy MySQL handler!"
+                                )
+
+                                else -> throw NullPointerException("Null value found!")
+                            }
+                        }
+
+                        SchemaUtils.createMissingTablesAndColumns(table, withLogs = false)
+                    } catch (e: Exception) {
+                        plugin.logger.info("MySQL Error 1!")
+                        e.printStackTrace()
+                        // What's that? Two enormous exception catches? That's right! This code sucks.
+                    }
+                }
+            } catch (e: Exception) {
+                plugin.logger.info("MySQL Error 2!")
+                e.printStackTrace()
+                // It might fail. Who cares? This is legacy.
+            }
+        }
+
+        private fun getColumn(key: PersistentDataKey<*>): Column<*> {
+            ensureKeyRegistration(key)
+
+            val name = key.key.toString()
+
+            return table.columns.first { it.name == name }
+        }
+
+        private fun getRow(uuid: UUID): ResultRow {
+            fun select(uuid: UUID): ResultRow? {
+                return transaction(database) {
+                    table.select { table.id eq uuid }.limit(1).singleOrNull()
+                }
+            }
+
+            return rows.get(uuid) {
+                val row = select(uuid)
+
+                return@get if (row != null) {
+                    row
+                } else {
+                    transaction(database) {
+                        table.insert { it[id] = uuid }
+                    }
+                    select(uuid)
                 }
-                select(uuid)
             }
         }
     }

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/storage/MongoDataHandler.kt

@@ -3,7 +3,7 @@ package com.willfp.eco.internal.spigot.data.storage
 import com.willfp.eco.core.data.Profile
 import com.willfp.eco.core.data.keys.PersistentDataKey
 import com.willfp.eco.internal.spigot.EcoSpigotPlugin
-import com.willfp.eco.internal.spigot.data.EcoProfileHandler
+import com.willfp.eco.internal.spigot.data.ProfileHandler
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
@@ -20,7 +20,7 @@ import java.util.UUID
 @Suppress("UNCHECKED_CAST")
 class MongoDataHandler(
     plugin: EcoSpigotPlugin,
-    private val handler: EcoProfileHandler
+    private val handler: ProfileHandler
 ) : DataHandler(HandlerType.MONGO) {
     private val client: CoroutineClient
     private val collection: CoroutineCollection<UUIDProfile>

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/storage/MySQLDataHandler.kt

@@ -3,12 +3,12 @@ package com.willfp.eco.internal.spigot.data.storage
 import com.github.benmanes.caffeine.cache.Caffeine
 import com.google.common.util.concurrent.ThreadFactoryBuilder
 import com.willfp.eco.core.config.ConfigType
-import com.willfp.eco.core.config.TransientConfig
 import com.willfp.eco.core.config.interfaces.Config
+import com.willfp.eco.core.config.readConfig
 import com.willfp.eco.core.data.keys.PersistentDataKey
 import com.willfp.eco.core.data.keys.PersistentDataKeyType
 import com.willfp.eco.internal.spigot.EcoSpigotPlugin
-import com.willfp.eco.internal.spigot.data.EcoProfileHandler
+import com.willfp.eco.internal.spigot.data.ProfileHandler
 import com.zaxxer.hikari.HikariConfig
 import com.zaxxer.hikari.HikariDataSource
 import org.jetbrains.exposed.dao.id.UUIDTable
@@ -35,8 +35,9 @@ Whatever. At least it works.
 @Suppress("UNCHECKED_CAST")
 class MySQLDataHandler(
     private val plugin: EcoSpigotPlugin,
-    private val handler: EcoProfileHandler
+    private val handler: ProfileHandler
 ) : DataHandler(HandlerType.MYSQL) {
+    private val database: Database
     private val table = UUIDTable("eco_data")
 
     private val rows = Caffeine.newBuilder()
@@ -60,9 +61,9 @@ class MySQLDataHandler(
                 plugin.configYml.getString("mysql.database")
         config.maximumPoolSize = plugin.configYml.getInt("mysql.connections")
 
-        Database.connect(HikariDataSource(config))
+        database = Database.connect(HikariDataSource(config))
 
-        transaction {
+        transaction(database) {
             SchemaUtils.create(table)
 
             table.apply {
@@ -110,14 +111,14 @@ class MySQLDataHandler(
     }
 
     private fun getData(uuid: UUID): Config {
-        val plaintext = transaction {
+        val plaintext = transaction(database) {
             val row = rows.get(uuid) {
                 val row = table.select { table.id eq uuid }.limit(1).singleOrNull()
 
                 if (row != null) {
                     row
                 } else {
-                    transaction {
+                    transaction(database) {
                         table.insert {
                             it[id] = uuid
                             it[dataColumn] = "{}"
@@ -130,13 +131,12 @@ class MySQLDataHandler(
             row.getOrNull(dataColumn) ?: "{}"
         }
 
-
-        return TransientConfig(plaintext, ConfigType.JSON)
+        return readConfig(plaintext, ConfigType.JSON)
     }
 
     private fun setData(uuid: UUID, config: Config) {
         executor.submit {
-            transaction {
+            transaction(database) {
                 table.update({ table.id eq uuid }) {
                     it[dataColumn] = config.toPlaintext()
                 }
@@ -145,7 +145,7 @@ class MySQLDataHandler(
     }
 
     override fun initialize() {
-        transaction {
+        transaction(database) {
             SchemaUtils.createMissingTablesAndColumns(table, withLogs = false)
         }
     }

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/storage/ProfileSaver.kt

@@ -2,14 +2,16 @@ package com.willfp.eco.internal.spigot.data.storage
 
 import com.willfp.eco.core.EcoPlugin
 import com.willfp.eco.internal.spigot.data.EcoProfile
-import com.willfp.eco.internal.spigot.data.EcoProfileHandler
+import com.willfp.eco.internal.spigot.data.ProfileHandler
 
 class ProfileSaver(
     plugin: EcoPlugin,
-    handler: EcoProfileHandler
+    handler: ProfileHandler
 ) {
     init {
-        plugin.scheduler.runTimer(1, 1) {
+        val interval = plugin.configYml.getInt("save-interval").toLong()
+
+        plugin.scheduler.runTimer(20, interval) {
             for ((uuid, set) in EcoProfile.CHANGE_MAP) {
                 handler.saveKeysFor(uuid, set)
             }

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/data/storage/YamlDataHandler.kt

@@ -3,14 +3,14 @@ package com.willfp.eco.internal.spigot.data.storage
 import com.willfp.eco.core.data.keys.PersistentDataKey
 import com.willfp.eco.core.data.keys.PersistentDataKeyType
 import com.willfp.eco.internal.spigot.EcoSpigotPlugin
-import com.willfp.eco.internal.spigot.data.EcoProfileHandler
+import com.willfp.eco.internal.spigot.data.ProfileHandler
 import org.bukkit.NamespacedKey
 import java.util.UUID
 
 @Suppress("UNCHECKED_CAST")
 class YamlDataHandler(
     plugin: EcoSpigotPlugin,
-    private val handler: EcoProfileHandler
+    private val handler: ProfileHandler
 ) : DataHandler(HandlerType.YAML) {
     private val dataYml = plugin.dataYml
 

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/display/frame/DisplayFrame.kt

@@ -1,5 +1,6 @@
 package com.willfp.eco.internal.spigot.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
@@ -32,9 +33,19 @@ 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
     }
 

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/gui/GUIListener.kt

@@ -50,6 +50,14 @@ class GUIListener(private val plugin: EcoPlugin) : Listener {
         }
     }
 
+    @EventHandler(
+        priority = EventPriority.HIGHEST
+    )
+    fun handleRender(event: InventoryClickEvent) {
+        val player = event.whoClicked as? Player ?: return
+        player.renderActiveMenu()
+    }
+
     @EventHandler(
         priority = EventPriority.HIGH
     )
@@ -62,9 +70,7 @@ class GUIListener(private val plugin: EcoPlugin) : Listener {
 
         val (row, column) = MenuUtils.convertSlotToRowColumn(event.slot, menu.columns)
 
-        menu.getSlot(row, column, player, menu).handle(player, event, menu)
-
-        plugin.scheduler.run { rendered.render() }
+        menu.getSlot(row, column, player).handle(player, event, menu)
     }
 
     @EventHandler(
@@ -87,7 +93,7 @@ class GUIListener(private val plugin: EcoPlugin) : Listener {
 
         val (row, column) = MenuUtils.convertSlotToRowColumn(inv.firstEmpty(), menu.columns)
 
-        val slot = menu.getSlot(row, column, player, menu)
+        val slot = menu.getSlot(row, column, player)
 
         if (!slot.isCaptive(player, menu)) {
             event.isCancelled = true
@@ -172,7 +178,6 @@ class GUIListener(private val plugin: EcoPlugin) : Listener {
         val rendered = player.renderedInventory ?: return
 
         if (rendered.menu.allowsChangingHeldItem()) {
-            player.renderActiveMenu()
             return
         }
 

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/integrations/antigrief/AntigriefPvPManager.kt

@@ -0,0 +1,38 @@
+package com.willfp.eco.internal.spigot.integrations.antigrief
+
+import com.willfp.eco.core.integrations.antigrief.AntigriefIntegration
+import org.bukkit.Location
+import org.bukkit.block.Block
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Player
+import me.NoChance.PvPManager.PvPlayer
+
+class AntigriefPvPManager: AntigriefIntegration {
+    override fun getPluginName(): String {
+        return "PvPManager"
+    }
+
+    override fun canBreakBlock(player: Player, block: Block): Boolean {
+        return true
+    }
+
+    override fun canCreateExplosion(player: Player, location: Location): Boolean {
+        return true
+    }
+
+    override fun canPlaceBlock(player: Player, block: Block): Boolean {
+        return true
+    }
+
+    override fun canInjure(player: Player, victim: LivingEntity): Boolean {
+        return when(victim) {
+            is Player -> {
+                (PvPlayer.get(victim).isInCombat())}
+            else -> true
+        }
+    }
+
+    override fun canPickupItem(player: Player, location: Location): Boolean {
+        return true
+    }
+}

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/integrations/antigrief/AntigriefWorldGuard.kt

@@ -11,7 +11,11 @@ import com.willfp.eco.core.integrations.antigrief.AntigriefIntegration
 import org.apache.commons.lang.Validate
 import org.bukkit.Location
 import org.bukkit.block.Block
-import org.bukkit.entity.*
+import org.bukkit.entity.Animals
+import org.bukkit.entity.ArmorStand
+import org.bukkit.entity.LivingEntity
+import org.bukkit.entity.Monster
+import org.bukkit.entity.Player
 
 class AntigriefWorldGuard : AntigriefIntegration {
     override fun canBreakBlock(

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/integrations/customitems/CustomItemsScyther.kt

@@ -45,4 +45,4 @@ class CustomItemsScyther : CustomItemsIntegration {
             )
         }
     }
-}
+}

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/integrations/placeholder/PlaceholderIntegrationPAPI.kt

@@ -0,0 +1,35 @@
+package com.willfp.eco.internal.spigot.integrations.placeholder
+
+import com.willfp.eco.core.integrations.placeholder.PlaceholderIntegration
+import me.clip.placeholderapi.PlaceholderAPI
+import org.bukkit.entity.Player
+import java.util.regex.Pattern
+
+class PlaceholderIntegrationPAPI : PlaceholderIntegration {
+    private val pattern = Pattern.compile("[%]([^% ]+)[%]")
+
+    override fun registerIntegration() {
+        // Do nothing.
+    }
+
+    override fun getPluginName(): String {
+        return "PlaceholderAPI"
+    }
+
+    override fun translate(
+        text: String,
+        player: Player?
+    ): String {
+        return PlaceholderAPI.setPlaceholders(player, text)
+    }
+
+    override fun findPlaceholdersIn(text: String): MutableList<String> {
+        val placeholders = mutableListOf<String>()
+        val matcher = pattern.matcher(text)
+        while (matcher.find()) {
+            placeholders.add(matcher.group())
+        }
+
+        return placeholders
+    }
+}

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/math/CrunchHandler.kt

@@ -4,6 +4,7 @@ import com.github.benmanes.caffeine.cache.Cache
 import com.github.benmanes.caffeine.cache.Caffeine
 import com.willfp.eco.core.integrations.placeholder.PlaceholderManager
 import com.willfp.eco.core.placeholder.AdditionalPlayer
+import com.willfp.eco.core.math.MathContext
 import com.willfp.eco.core.placeholder.PlaceholderInjectable
 import org.bukkit.entity.Player
 import redempt.crunch.CompiledExpression
@@ -25,7 +26,15 @@ private val max = Function("max", 2) {
     max(it[0], it[1])
 }
 
-fun evaluateExpression(expression: String, player: Player?, context: PlaceholderInjectable, additional: Collection<AdditionalPlayer>): Double {
+fun evaluateExpression(expression: String, context: MathContext) =
+    evaluateExpression(expression, context.player, context.injectableContext, context.additionalPlayers)
+
+private fun evaluateExpression(
+    expression: String,
+    player: Player?,
+    context: PlaceholderInjectable,
+    additional: Collection<AdditionalPlayer>
+): Double {
     val placeholderValues = PlaceholderManager.findPlaceholdersIn(expression)
         .map { PlaceholderManager.translatePlaceholders(it, player, context, additional) }
         .map { runCatching { FastNumberParsing.parseDouble(it) }.getOrDefault(0.0) }

eco-core/core-plugin/src/main/kotlin/com/willfp/eco/internal/spigot/player/PlayerHealthFixer.kt

@@ -1,42 +0,0 @@
-package com.willfp.eco.internal.spigot.player
-
-import com.willfp.eco.core.EcoPlugin
-import com.willfp.eco.core.data.keys.PersistentDataKey
-import com.willfp.eco.core.data.keys.PersistentDataKeyType
-import com.willfp.eco.core.data.profile
-import org.bukkit.event.EventHandler
-import org.bukkit.event.Listener
-import org.bukkit.event.player.PlayerJoinEvent
-import org.bukkit.event.player.PlayerQuitEvent
-
-class PlayerHealthFixer(
-    private val plugin: EcoPlugin
-): Listener {
-    private val lastHealthKey = PersistentDataKey(
-        plugin.createNamespacedKey("last_health"),
-        PersistentDataKeyType.DOUBLE,
-        0.0
-    )
-
-    @EventHandler
-    fun onLeave(event: PlayerQuitEvent) {
-        if (!plugin.configYml.getBool("health-fixer")) {
-            return
-        }
-
-        val player = event.player
-        player.profile.write(lastHealthKey, player.health)
-    }
-
-    @EventHandler
-    fun onJoin(event: PlayerJoinEvent) {
-        if (!plugin.configYml.getBool("health-fixer")) {
-            return
-        }
-
-        val player = event.player
-        plugin.scheduler.runLater(2) {
-            player.health = player.profile.read(lastHealthKey)
-        }
-    }
-}

eco-core/core-plugin/src/main/resources/config.yml

@@ -30,6 +30,12 @@ mysql:
   user: username
   password: passy
 
+# How many ticks to wait between committing data to a database. This doesn't
+# affect yaml storage, only MySQL and MongoDB. By default, data is committed
+# every tick, but you can increase this to be every x ticks, for example 20
+# would be committing once a second.
+save-interval: 1
+
 # Options to manage the conflict finder
 conflicts:
   whitelist: # Plugins that should never be marked as conflicts
@@ -73,9 +79,6 @@ log-full-extension-errors: false
 # a custom crafting table, though, this won't affect anything, and you should disable the option.
 displayed-recipes: true
 
-# Save health on leave and set it back on join - works around attribute modifiers.
-health-fixer: false
-
 # If eco plugins should not check for updates; only enable this if you know what you're doing
 # as there can be urgent hotfixes that you are then not notified about. If you're confident
 # that you can manage updates on your own, turn this on.

eco-core/core-plugin/src/main/resources/plugin.yml

@@ -48,4 +48,5 @@ softdepend:
   - zShop
   - DeluxeSellwands
   - Scyther
-  - ModelEngine
+  - ModelEngine
+  - PvPManager

eco-core/core-proxy/src/main/kotlin/com/willfp/eco/internal/spigot/proxy/SyncCommandsProxy.kt

@@ -0,0 +1,5 @@
+package com.willfp.eco.internal.spigot.proxy
+
+interface SyncCommandsProxy {
+    fun syncCommands()
+}

gradle.properties

@@ -1,3 +1,3 @@
-version = 6.43.2
+version = 6.46.0
 plugin-name = eco
 kotlin.code.style = official