refactor: multiple unnamed creative item group is allowed

api/src/main/java/org/allaymc/api/item/creative/CreativeItemCategory.java

@@ -7,25 +7,25 @@
 import java.util.Map;
 
 /**
- * Represents a category of creative items. A category in a collection of groups and some ungrouped items.
+ * Represents a category of creative items. A category is a collection of named and unnamed groups.
  * Currently, there are only four visible categories in the creative inventory, and they are {@code Construction},
  * {@code Nature}, {@code Equipment}, and {@code Items}.
  *
  * @author daoge_cmd
  */
 public interface CreativeItemCategory {
     /**
-     * Get a specific group by name in this category.
+     * Get a specific group by index in this category.
      *
-     * @param name the name of the group. If an empty string is passed, the default group will be returned.
-     *             Translation key is supported here.
+     * @param index the index of the group.
      *
-     * @return the group with the specified name, or the default group if the name is empty. {@code null} will be returned if the group does not exist.
+     * @return the group with the specified index. {@code null} will be returned if the group does not exist.
      */
-    CreativeItemGroup getGroup(@MayContainTrKey String name);
+    CreativeItemGroup getGroup(int index);
 
     /**
-     * Register a new group in this category.
+     * Register a new named group in the category. See docs in {@link CreativeItemGroup} for more details
+     * about the difference between named and unnamed groups.
      *
      * @param name the name of the group, empty string is not allowed here. Translation key is supported.
      * @param icon the icon of the group.
@@ -35,21 +35,20 @@ public interface CreativeItemCategory {
     CreativeItemGroup registerGroup(@MayContainTrKey String name, ItemStack icon);
 
     /**
-     * Get the default group in this category.
+     * Register a new unnamed group in the category. See docs in {@link CreativeItemGroup} for more details
+     * about the difference between named and unnamed groups.
      *
-     * @return the default group.
+     * @return the registered group.
      */
-    default CreativeItemGroup getDefaultGroup() {
-        return getGroup("");
-    }
+    CreativeItemGroup registerUnnamedGroup();
 
     /**
      * Get all groups in this category.
      *
      * @return a map of all groups in this category.
      */
     @UnmodifiableView
-    Map<String, CreativeItemGroup> getGroups();
+    Map<Integer, CreativeItemGroup> getGroups();
 
     /**
      * Get the type of this category.

api/src/main/java/org/allaymc/api/item/creative/CreativeItemGroup.java

@@ -6,8 +6,15 @@
 import java.util.Map;
 
 /**
- * Represents a single creative item group, which can contain multiple items.
- * It is collapsed by default, but can be expanded by clicking.
+ * Represents a single creative item group, which can contain multiple items. There
+ * are two types of group: named and unnamed.
+ * <p>
+ * Named group's name is not empty. It is folded by default and can be expanded by
+ * clicking. When the group is folded, the icon will be shown above the group.
+ * <p>
+ * Unnamed group's name is empty. The items are flatten and cannot be folded. Multiple
+ * unnamed groups is allowed and can between two named groups to separate them. The icon
+ * of unnamed group can only be air since it will never be shown.
  *
  * @author daoge_cmd
  */
@@ -58,4 +65,13 @@ public interface CreativeItemGroup {
      * @return the category of this group.
      */
     CreativeItemCategory getCategory();
+
+    /**
+     * Check if this group is an unnamed group
+     *
+     * @return {@code true} if this group is an unnamed group, {@code false} otherwise.
+     */
+    default boolean isUnnamedGroup() {
+        return getName().isEmpty();
+    }
 }

server/src/main/java/org/allaymc/server/item/creative/AllayCreativeItemCategory.java

@@ -1,10 +1,12 @@
 package org.allaymc.server.item.creative;
 
-import it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap;
+import com.google.common.base.Preconditions;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 import lombok.Getter;
 import org.allaymc.api.item.ItemStack;
 import org.allaymc.api.item.creative.CreativeItemCategory;
 import org.allaymc.api.item.creative.CreativeItemGroup;
+import org.allaymc.api.item.interfaces.ItemAirStack;
 
 import java.util.Collections;
 import java.util.Map;
@@ -17,28 +19,37 @@ public class AllayCreativeItemCategory implements CreativeItemCategory {
     @Getter
     protected final org.cloudburstmc.protocol.bedrock.data.inventory.CreativeItemCategory type;
 
-    protected Map<String, CreativeItemGroup> groups;
+    protected Map<Integer, CreativeItemGroup> groups;
 
     public AllayCreativeItemCategory(AllayCreativeItemRegistry registry, org.cloudburstmc.protocol.bedrock.data.inventory.CreativeItemCategory type) {
         this.registry = registry;
         this.type = type;
-        this.groups = new Object2ObjectOpenHashMap<>();
+        this.groups = new Int2ObjectOpenHashMap<>();
     }
 
     @Override
-    public CreativeItemGroup getGroup(String name) {
-        return groups.get(name);
+    public CreativeItemGroup getGroup(int index) {
+        return groups.get(index);
     }
 
     @Override
     public CreativeItemGroup registerGroup(String name, ItemStack icon) {
+        Preconditions.checkNotNull(name);
+        Preconditions.checkNotNull(icon);
         var group = new AllayCreativeItemGroup(registry, this, name, icon);
-        groups.put(name, group);
+        groups.put(group.getIndex(), group);
         return group;
     }
 
     @Override
-    public Map<String, CreativeItemGroup> getGroups() {
+    public CreativeItemGroup registerUnnamedGroup() {
+        var group = new AllayCreativeItemGroup(registry, this, "", ItemAirStack.AIR_STACK);
+        groups.put(group.getIndex(), group);
+        return group;
+    }
+
+    @Override
+    public Map<Integer, CreativeItemGroup> getGroups() {
         return Collections.unmodifiableMap(groups);
     }
 }

server/src/main/java/org/allaymc/server/item/creative/AllayCreativeItemRegistry.java

@@ -11,7 +11,6 @@
 import org.allaymc.api.item.creative.CreativeItemGroup;
 import org.allaymc.api.item.creative.CreativeItemRegistry;
 import org.allaymc.api.item.initinfo.ItemStackInitInfo;
-import org.allaymc.api.item.type.ItemTypes;
 import org.allaymc.api.registry.Registries;
 import org.allaymc.api.utils.Identifier;
 import org.allaymc.api.utils.Utils;
@@ -59,18 +58,15 @@ protected void load() {
             JsonParser.parseReader(reader).getAsJsonArray().forEach(entry -> {
                 var group = entry.getAsJsonObject();
                 var category = getCategory(CreativeItemCategory.valueOf(group.get("category").getAsString().toUpperCase()));
-
-                ItemStack iconItemStack;
-                if (group.has("icon")) {
+                var name = group.get("name").getAsString();
+                if (name.isEmpty()) {
+                    category.registerUnnamedGroup();
+                } else {
                     var iconItemTypeName = new Identifier(group.get("icon").getAsString());
                     var iconItemType = Registries.ITEMS.get(iconItemTypeName);
                     Objects.requireNonNull(iconItemType, "Unknown icon item type: " + iconItemTypeName);
-                    iconItemStack = iconItemType.createItemStack();
-                } else {
-                    iconItemStack = ItemTypes.AIR.createItemStack();
+                    category.registerGroup(name, iconItemType.createItemStack());
                 }
-
-                category.registerGroup(group.get("name").getAsString(), iconItemStack);
             });
         }
 
@@ -89,12 +85,13 @@ protected void load() {
                                 .extraTag(item.getCompound("tag", NbtMap.builder().build()))
                                 .autoAssignStackNetworkId(false).build()
                 );
-                var groupName = item.getString("group");
-                var group = category.getGroup(groupName);
+                int groupIndex = (int) item.getLong("groupIndex");
+                var group = category.getGroup(groupIndex);
                 if (group == null) {
-                    log.warn("Unknown group {} for item {} in category {}!", groupName, itemTypeName, category.getType());
-                    group = category.getDefaultGroup();
+                    log.warn("Unknown group index {} for item {} in category {}!", groupIndex, itemTypeName, category.getType());
+                    continue;
                 }
+
                 group.registerItem(itemStack);
             }
         }