Server-side translations for items and inventory titles

inventoryaccess/inventory-access/src/main/java/xyz/xenondevs/inventoryaccess/component/AdventureComponentWrapper.java

@@ -3,6 +3,8 @@ package xyz.xenondevs.inventoryaccess.component;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer;
 import org.jetbrains.annotations.NotNull;
+import xyz.xenondevs.inventoryaccess.component.i18n.AdventureComponentLocalizer;
+import xyz.xenondevs.inventoryaccess.component.i18n.Languages;
 
 public class AdventureComponentWrapper implements ComponentWrapper {
     
@@ -18,9 +20,17 @@ public class AdventureComponentWrapper implements ComponentWrapper {
     }
     
     @Override
-    public @NotNull ComponentWrapper clone() {
+    public @NotNull AdventureComponentWrapper localized(@NotNull String lang) {
+        if (!Languages.getInstance().doesServerSideTranslations())
+            return this;
+        
+        return new AdventureComponentWrapper(AdventureComponentLocalizer.getInstance().localize(lang, component));
+    }
+    
+    @Override
+    public @NotNull AdventureComponentWrapper clone() {
         try {
-            return (ComponentWrapper) super.clone();
+            return (AdventureComponentWrapper) super.clone();
         } catch (CloneNotSupportedException e) {
             throw new AssertionError();
         }

inventoryaccess/inventory-access/src/main/java/xyz/xenondevs/inventoryaccess/component/BaseComponentWrapper.java

@@ -3,6 +3,8 @@ package xyz.xenondevs.inventoryaccess.component;
 import net.md_5.bungee.api.chat.BaseComponent;
 import net.md_5.bungee.chat.ComponentSerializer;
 import org.jetbrains.annotations.NotNull;
+import xyz.xenondevs.inventoryaccess.component.i18n.BaseComponentLocalizer;
+import xyz.xenondevs.inventoryaccess.component.i18n.Languages;
 
 public class BaseComponentWrapper implements ComponentWrapper {
     
@@ -12,6 +14,14 @@ public class BaseComponentWrapper implements ComponentWrapper {
         this.components = components;
     }
     
+    @Override
+    public @NotNull ComponentWrapper localized(@NotNull String lang) {
+        if (!Languages.getInstance().doesServerSideTranslations())
+            return this;
+        
+        return new BaseComponentWrapper(BaseComponentLocalizer.getInstance().localize(lang, components));
+    }
+    
     @Override
     public @NotNull String serializeToJson() {
         return ComponentSerializer.toString(components);

inventoryaccess/inventory-access/src/main/java/xyz/xenondevs/inventoryaccess/component/ComponentWrapper.java

@@ -1,11 +1,34 @@
 package xyz.xenondevs.inventoryaccess.component;
 
 import org.jetbrains.annotations.NotNull;
+import xyz.xenondevs.inventoryaccess.component.i18n.Languages;
 
 public interface ComponentWrapper extends Cloneable {
     
+    /**
+     * Serializes the component to a json string.
+     *
+     * @return The json representation of the component.
+     */
     @NotNull String serializeToJson();
     
+    /**
+     * Creates a localized version of the component by replacing all translatable components with text components
+     * of the specified language.
+     * <p>
+     * This method will return the same {@link ComponentWrapper} when {@link Languages} is disabled.
+     *
+     * @param lang The language to use.
+     * @return A new {@link ComponentWrapper} of the localized component or the same {@link ComponentWrapper}
+     * if {@link Languages} is disabled.
+     */
+    @NotNull ComponentWrapper localized(@NotNull String lang);
+    
+    /**
+     * Clones this {@link ComponentWrapper}.
+     *
+     * @return The cloned {@link ComponentWrapper}.
+     */
     @NotNull ComponentWrapper clone();
     
 }

inventoryaccess/inventory-access/src/main/java/xyz/xenondevs/inventoryaccess/component/i18n/AdventureComponentLocalizer.java

@@ -0,0 +1,57 @@
+package xyz.xenondevs.inventoryaccess.component.i18n;
+
+import net.kyori.adventure.text.*;
+
+public class AdventureComponentLocalizer extends ComponentLocalizer<Component> {
+    
+    public static final AdventureComponentLocalizer INSTANCE = new AdventureComponentLocalizer();
+    
+    private AdventureComponentLocalizer() {
+    }
+    
+    public static AdventureComponentLocalizer getInstance() {
+        return INSTANCE;
+    }
+    
+    @SuppressWarnings({"rawtypes", "unchecked"})
+    @Override
+    public Component localize(String lang, Component component) {
+        if (!(component instanceof BuildableComponent))
+            throw new IllegalStateException("Component is not a BuildableComponent");
+        
+        return localize(lang, (BuildableComponent) component);
+    }
+    
+    @SuppressWarnings("NonExtendableApiUsage")
+    private <C extends BuildableComponent<C, B>, B extends ComponentBuilder<C, B>> BuildableComponent<?, ?> localize(String lang, BuildableComponent<C, B> component) {
+        ComponentBuilder<?, ?> builder;
+        if (component instanceof TranslatableComponent) {
+            builder = localizeTranslatable(lang, (TranslatableComponent) component).toBuilder();
+        } else {
+            builder = component.toBuilder();
+        }
+        
+        builder.mapChildrenDeep(child -> {
+            if (child instanceof TranslatableComponent)
+                return localizeTranslatable(lang, (TranslatableComponent) child);
+            return child;
+        });
+        
+        return builder.build();
+    }
+    
+    private BuildableComponent<?, ?> localizeTranslatable(String lang, TranslatableComponent component) {
+        var formatString = Languages.getInstance().getFormatString(lang, component.key());
+        if (formatString == null)
+            return component;
+        
+        var children = decomposeFormatString(lang, formatString, component, component.args());
+        return Component.textOfChildren(children.toArray(ComponentLike[]::new)).style(component.style());
+    }
+    
+    @Override
+    protected Component createTextComponent(String text) {
+        return Component.text(text);
+    }
+    
+}

inventoryaccess/inventory-access/src/main/java/xyz/xenondevs/inventoryaccess/component/i18n/BaseComponentLocalizer.java

@@ -0,0 +1,71 @@
+package xyz.xenondevs.inventoryaccess.component.i18n;
+
+import net.md_5.bungee.api.chat.BaseComponent;
+import net.md_5.bungee.api.chat.TextComponent;
+import net.md_5.bungee.api.chat.TranslatableComponent;
+
+import java.util.stream.Collectors;
+
+public class BaseComponentLocalizer extends ComponentLocalizer<BaseComponent> {
+    
+    private static final BaseComponentLocalizer INSTANCE = new BaseComponentLocalizer();
+    
+    private BaseComponentLocalizer() {
+    }
+    
+    public static BaseComponentLocalizer getInstance() {
+        return INSTANCE;
+    }
+    
+    public BaseComponent[] localize(String lang, BaseComponent[] components) {
+        var localizedComponents = new BaseComponent[components.length];
+        for (int i = 0; i < components.length; i++) {
+            localizedComponents[i] = localize(lang, components[i]);
+        }
+        return localizedComponents;
+    }
+    
+    @Override
+    public BaseComponent localize(String lang, BaseComponent component) {
+        BaseComponent duplicate;
+        if (component instanceof TranslatableComponent) {
+            duplicate = localizeTranslatable(lang, (TranslatableComponent) component);
+        } else {
+            duplicate = component.duplicate();
+        }
+        
+        var extra = duplicate.getExtra();
+        if (extra != null) {
+            duplicate.setExtra(
+                extra.stream()
+                    .map(child -> localize(lang, child))
+                    .collect(Collectors.toList())
+            );
+        }
+        
+        return duplicate;
+    }
+    
+    private BaseComponent localizeTranslatable(String lang, TranslatableComponent component) {
+        var formatString = Languages.getInstance().getFormatString(lang, component.getTranslate());
+        if (formatString == null)
+            return component;
+        
+        var children = decomposeFormatString(lang, formatString, component, component.getWith());
+        var result = new TextComponent(children.toArray(BaseComponent[]::new));
+        
+        result.copyFormatting(component);
+        
+        var extra = component.getExtra();
+        if (extra != null)
+            result.setExtra(extra);
+        
+        return result;
+    }
+    
+    @Override
+    protected BaseComponent createTextComponent(String text) {
+        return new TextComponent(text);
+    }
+    
+}

inventoryaccess/inventory-access/src/main/java/xyz/xenondevs/inventoryaccess/component/i18n/ComponentLocalizer.java

@@ -0,0 +1,69 @@
+package xyz.xenondevs.inventoryaccess.component.i18n;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.regex.Pattern;
+
+abstract class ComponentLocalizer<C> {
+    
+    private static final Pattern FORMAT_PATTERN = Pattern.compile("%(?:(\\d+)\\$)?([A-Za-z%]|$)");
+    
+    public abstract C localize(String lang, C component);
+    
+    protected abstract C createTextComponent(String text);
+    
+    protected List<C> decomposeFormatString(String lang, String formatString, C component, List<C> args) {
+        var matcher = FORMAT_PATTERN.matcher(formatString);
+        
+        var components = new ArrayList<C>();
+        var sb = new StringBuilder();
+        var nextArgIdx = 0;
+        
+        var i = 0;
+        while (matcher.find(i)) {
+            var start = matcher.start();
+            var end = matcher.end();
+            
+            // check for escaped %
+            var matchedStr = formatString.substring(i, start);
+            if ("%%".equals(matchedStr)) {
+                sb.append('%');
+            } else {
+                // check for invalid format, only %s is supported
+                var argType = matcher.group(2);
+                if (!"s".equals(argType)) {
+                    throw new IllegalStateException("Unsupported format: '" + matchedStr + "'");
+                }
+                
+                // retrieve argument index
+                var argIdxStr = matcher.group(1);
+                var argIdx = argIdxStr == null ? nextArgIdx++ : Integer.parseInt(argIdxStr) - 1;
+                
+                // validate argument index
+                if (argIdx < 0)
+                    throw new IllegalStateException("Invalid argument index: " + argIdx);
+                
+                // append the text before the argument
+                sb.append(formatString, i, start);
+                // add text component
+                components.add(createTextComponent(sb.toString()));
+                // add argument component
+                components.add(args.size() <= argIdx ? createTextComponent("") : localize(lang, args.get(argIdx)));
+                // clear string builder
+                sb.setLength(0);
+            }
+            
+            // start next search after matcher end index
+            i = end;
+        }
+        
+        // append the text after the last argument
+        if (i < formatString.length()) {
+            sb.append(formatString, i, formatString.length());
+            components.add(createTextComponent(sb.toString()));
+        }
+        
+        return components;
+    }
+    
+}

inventoryaccess/inventory-access/src/main/java/xyz/xenondevs/inventoryaccess/component/i18n/Languages.java

@@ -0,0 +1,96 @@
+package xyz.xenondevs.inventoryaccess.component.i18n;
+
+import com.google.gson.stream.JsonReader;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import xyz.xenondevs.inventoryaccess.component.ComponentWrapper;
+
+import java.io.IOException;
+import java.io.Reader;
+import java.util.HashMap;
+import java.util.Map;
+
+public class Languages {
+    
+    private static final Languages INSTANCE = new Languages();
+    private final Map<String, Map<String, String>> translations = new HashMap<>();
+    private boolean serverSideTranslations = true;
+    
+    private Languages() {
+    }
+    
+    public static @NotNull Languages getInstance() {
+        return INSTANCE;
+    }
+    
+    /**
+     * Adds a language under the given lang code.
+     * <p>
+     * This method will replace any existing language with the same lang code.
+     *
+     * @param lang         The lang code of the language.
+     * @param translations The translations of the language.
+     */
+    public void addLanguage(@NotNull String lang, @NotNull Map<@NotNull String, @NotNull String> translations) {
+        this.translations.put(lang, translations);
+    }
+    
+    /**
+     * Adds a language under the given lang code after reading it from the given reader.
+     * <p>
+     * Note: The language is read as a json object with the translation keys as keys and the format strings as
+     * their string values. Any other json structure will result in an {@link IllegalStateException}.
+     * An example for such a structure are Minecraft's lang files.
+     *
+     * @param lang   The lang code of the language.
+     * @param reader The reader for a language json file.
+     * @throws IOException           If an error occurs while reading.
+     * @throws IllegalStateException If the json is not valid.
+     */
+    public void loadLanguage(@NotNull String lang, @NotNull Reader reader) throws IOException {
+        var translations = new HashMap<String, String>();
+        try (var jsonReader = new JsonReader(reader)) {
+            jsonReader.beginObject();
+            while (jsonReader.hasNext()) {
+                var key = jsonReader.nextName();
+                var value = jsonReader.nextString();
+                translations.put(key, value);
+            }
+            
+            addLanguage(lang, translations);
+        }
+    }
+    
+    /**
+     * Retrieves the format string for the given key under the given language.
+     *
+     * @param lang The language to use.
+     * @param key  The key of the format string.
+     * @return The format string or null if there is no such language or key.
+     */
+    public @Nullable String getFormatString(@NotNull String lang, @NotNull String key) {
+        var map = translations.get(lang);
+        if (map == null)
+            return null;
+        return map.get(key);
+    }
+    
+    /**
+     * Enables or disables server-side translations for {@link ComponentWrapper ComponentWrappers}.
+     *
+     * @param enable Whether server-side translations should be enabled.
+     */
+    public void enableServerSideTranslations(boolean enable) {
+        serverSideTranslations = enable;
+    }
+    
+    /**
+     * Checks whether server-side translations are enabled.
+     *
+     * @return Whether server-side translations are enabled.
+     */
+    public boolean doesServerSideTranslations() {
+        return serverSideTranslations;
+    }
+    
+}

invui/src/main/java/xyz/xenondevs/invui/gui/AbstractGui.java

@@ -124,13 +124,13 @@ public abstract class AbstractGui implements Gui, GuiParent {
     }
     
     private boolean didClickBackgroundItem(Player player, SlotElement.VISlotElement element, VirtualInventory inventory, int slot, ItemStack clicked) {
-        UUID uuid = player.getUniqueId();
+        String lang = player.getLocale();
         return inventory.getUnsafeItemStack(slot) == null
-            && (isBuilderSimilar(background, uuid, clicked) || isBuilderSimilar(element.getBackground(), uuid, clicked));
+            && (isBuilderSimilar(background, lang, clicked) || isBuilderSimilar(element.getBackground(), lang, clicked));
     }
     
-    private boolean isBuilderSimilar(ItemProvider builder, UUID uuid, ItemStack expected) {
+    private boolean isBuilderSimilar(ItemProvider builder, String lang, ItemStack expected) {
-        return builder != null && builder.getFor(uuid).isSimilar(expected);
+        return builder != null && builder.get(lang).isSimilar(expected);
     }
     
     @SuppressWarnings("deprecation")

invui/src/main/java/xyz/xenondevs/invui/gui/SlotElement.java

@@ -7,11 +7,10 @@ import xyz.xenondevs.invui.virtualinventory.VirtualInventory;
 
 import java.util.ArrayList;
 import java.util.List;
-import java.util.UUID;
 
 public interface SlotElement {
     
-    ItemStack getItemStack(UUID viewerUUID);
+    ItemStack getItemStack(String lang);
     
     SlotElement getHoldingElement();
     
@@ -31,8 +30,8 @@ public interface SlotElement {
         }
         
         @Override
-        public ItemStack getItemStack(UUID viewerUUID) {
+        public ItemStack getItemStack(String lang) {
-            return item.getItemProvider().getFor(viewerUUID);
+            return item.getItemProvider().get(lang);
         }
         
         @Override
@@ -76,9 +75,9 @@ public interface SlotElement {
         }
         
         @Override
-        public ItemStack getItemStack(UUID viewerUUID) {
+        public ItemStack getItemStack(String lang) {
             ItemStack itemStack = virtualInventory.getUnsafeItemStack(slot);
-            if (itemStack == null && background != null) itemStack = background.getFor(viewerUUID);
+            if (itemStack == null && background != null) itemStack = background.get(lang);
             return itemStack;
         }
         
@@ -139,9 +138,9 @@ public interface SlotElement {
         }
         
         @Override
-        public ItemStack getItemStack(UUID viewerUUID) {
+        public ItemStack getItemStack(String lang) {
             SlotElement holdingElement = getHoldingElement();
-            return holdingElement != null ? holdingElement.getItemStack(viewerUUID) : null;
+            return holdingElement != null ? holdingElement.getItemStack(lang) : null;
         }
         
     }

invui/src/main/java/xyz/xenondevs/invui/item/ItemProvider.java

@@ -1,35 +1,33 @@
 package xyz.xenondevs.invui.item;
 
 import org.bukkit.Material;
-import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
-import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
-import xyz.xenondevs.invui.window.AbstractWindow;
 
-import java.util.UUID;
 import java.util.function.Supplier;
 
 public interface ItemProvider extends Supplier<ItemStack>, Cloneable {
     
+    /**
+     * An {@link ItemProvider} for an {@link ItemStack}.
+     */
     ItemProvider EMPTY = new ItemWrapper(new ItemStack(Material.AIR));
     
     /**
-     * Builds the {@link ItemStack}
+     * Gets the {@link ItemStack} translated in the specified language.
      *
+     * @param lang The language to translate the item in.
      * @return The {@link ItemStack}
      */
-    ItemStack get();
+    ItemStack get(@Nullable String lang);
     
     /**
-     * Gets the {@link ItemStack} for a specific player.
+     * Gets the {@link ItemStack} without requesting a specific language.
-     * This is the method called by {@link AbstractWindow} which gives you
-     * the option to (for example) create a subclass of {@link ItemProvider} that automatically
-     * translates the item's name into the player's language.
      *
-     * @param playerUUID The {@link UUID} of the {@link Player}
-     *                   for whom this {@link ItemStack} should be made.
      * @return The {@link ItemStack}
      */
-    ItemStack getFor(@NotNull UUID playerUUID);
+    default ItemStack get() {
+        return get(null);
+    }
     
 }

invui/src/main/java/xyz/xenondevs/invui/item/ItemWrapper.java

@@ -1,7 +1,6 @@
 package xyz.xenondevs.invui.item;
 
 import org.bukkit.inventory.ItemStack;
-import org.jetbrains.annotations.NotNull;
 
 import java.util.UUID;
 
@@ -18,12 +17,7 @@ public class ItemWrapper implements ItemProvider {
     }
     
     @Override
-    public ItemStack get() {
+    public ItemStack get(String lang) {
-        return itemStack;
-    }
-    
-    @Override
-    public ItemStack getFor(@NotNull UUID playerUUID) {
         return itemStack;
     }
     

invui/src/main/java/xyz/xenondevs/invui/item/builder/AbstractItemBuilder.java

@@ -3,21 +3,23 @@ package xyz.xenondevs.invui.item.builder;
 import net.md_5.bungee.api.chat.BaseComponent;
 import org.bukkit.Material;
 import org.bukkit.enchantments.Enchantment;
-import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemFlag;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.meta.Damageable;
 import org.bukkit.inventory.meta.ItemMeta;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 import xyz.xenondevs.inventoryaccess.InventoryAccess;
 import xyz.xenondevs.inventoryaccess.component.BaseComponentWrapper;
 import xyz.xenondevs.inventoryaccess.component.ComponentWrapper;
 import xyz.xenondevs.invui.item.ItemProvider;
 import xyz.xenondevs.invui.util.ComponentUtils;
 import xyz.xenondevs.invui.util.Pair;
-import xyz.xenondevs.invui.window.AbstractWindow;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
@@ -71,7 +73,7 @@ public abstract class AbstractItemBuilder<T> implements ItemProvider {
      * @return The {@link ItemStack}
      */
     @Override
-    public ItemStack get() {
+    public ItemStack get(@Nullable String lang) {
         ItemStack itemStack;
         if (base != null) {
             itemStack = base;
@@ -83,12 +85,25 @@ public abstract class AbstractItemBuilder<T> implements ItemProvider {
         ItemMeta itemMeta = itemStack.getItemMeta();
         if (itemMeta != null) {
             // display name
-            if (displayName != null)
+            if (displayName != null) {
-                InventoryAccess.getItemUtils().setDisplayName(itemMeta, displayName);
+                InventoryAccess.getItemUtils().setDisplayName(
+                    itemMeta,
+                    (lang != null) ? displayName.localized(lang) : displayName
+                );
+            }
             
             // lore
-            if (lore != null)
+            if (lore != null) {
+                if (lang != null) {
+                    var translatedLore = lore.stream()
+                        .map(wrapper -> wrapper.localized(lang))
+                        .collect(Collectors.toList());
+                    
+                    InventoryAccess.getItemUtils().setLore(itemMeta, translatedLore);
+                } else {
                     InventoryAccess.getItemUtils().setLore(itemMeta, lore);
+                }
+            }
             
             // damage
             if (itemMeta instanceof Damageable)
@@ -127,21 +142,6 @@ public abstract class AbstractItemBuilder<T> implements ItemProvider {
         return itemStack;
     }
     
-    /**
-     * Builds the {@link ItemStack} for a specific player.
-     * This is the method called by {@link AbstractWindow} which gives you
-     * the option to (for example) create a subclass of {@link AbstractItemBuilder} that automatically
-     * translates the item's name into the player's language.
-     *
-     * @param playerUUID The {@link UUID} of the {@link Player}
-     *                   for whom this {@link ItemStack} should be built.
-     * @return The {@link ItemStack}
-     */
-    @Override
-    public ItemStack getFor(@NotNull UUID playerUUID) {
-        return get();
-    }
-    
     public T removeLoreLine(int index) {
         if (lore != null) lore.remove(index);
         return getThis();

invui/src/main/java/xyz/xenondevs/invui/window/AbstractWindow.java

@@ -66,9 +66,9 @@ public abstract class AbstractWindow implements Window, GuiParent {
     protected void redrawItem(int index, SlotElement element, boolean setItem) {
         // put ItemStack in inventory
         ItemStack itemStack;
-        if (element == null || (element instanceof SlotElement.VISlotElement && element.getItemStack(viewerUUID) == null)) {
+        if (element == null || (element instanceof SlotElement.VISlotElement && element.getItemStack(getLang()) == null)) {
             ItemProvider background = getGuiAt(index).getFirst().getBackground();
-            itemStack = background == null ? null : background.getFor(viewerUUID);
+            itemStack = background == null ? null : background.get(getLang());
         } else if (element instanceof SlotElement.LinkedSlotElement && element.getHoldingElement() == null) {
             ItemProvider background = null;
             
@@ -80,9 +80,9 @@ public abstract class AbstractWindow implements Window, GuiParent {
                 if (background != null) break;
             }
             
-            itemStack = background == null ? null : background.getFor(viewerUUID);
+            itemStack = background == null ? null : background.get(getLang());
         } else {
-            itemStack = element.getItemStack(viewerUUID);
+            itemStack = element.getItemStack(getLang());
             
             // This makes every item unique to prevent Shift-DoubleClick "clicking" multiple items at the same time.
             if (itemStack.hasItemMeta()) {
@@ -255,7 +255,11 @@ public abstract class AbstractWindow implements Window, GuiParent {
         
         Player viewer = getViewer();
         if (viewer == null) throw new IllegalStateException("The player is not online.");
-        InventoryAccess.getInventoryUtils().openCustomInventory(viewer, getInventories()[0], title);
+        InventoryAccess.getInventoryUtils().openCustomInventory(
+            viewer,
+            getInventories()[0],
+            title.localized(viewer.getLocale())
+        );
     }
     
     @Override
@@ -263,7 +267,10 @@ public abstract class AbstractWindow implements Window, GuiParent {
         this.title = title;
         Player currentViewer = getCurrentViewer();
         if (currentViewer != null) {
-            InventoryAccess.getInventoryUtils().updateOpenInventoryTitle(currentViewer, title);
+            InventoryAccess.getInventoryUtils().updateOpenInventoryTitle(
+                currentViewer,
+                title.localized(currentViewer.getLocale())
+            );
         }
     }
     
@@ -307,6 +314,15 @@ public abstract class AbstractWindow implements Window, GuiParent {
         return Bukkit.getPlayer(viewerUUID);
     }
     
+    // TODO: could also return null / "en_us"
+    public @NotNull String getLang() {
+        var player = getViewer();
+        if (player == null)
+            throw new IllegalStateException("Tried to receive the language from a viewer that is not online.");
+        
+        return player.getLocale();
+    }
+    
     @Override
     public @NotNull UUID getViewerUUID() {
         return viewerUUID;