[Feature] API to simplify generation of Creative-Tabs

src/main/java/org/betterx/bclib/complexmaterials/ComplexMaterial.java

@@ -10,6 +10,7 @@ import org.betterx.worlds.together.tag.v3.TagManager;
 
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.tags.TagKey;
+import net.minecraft.world.item.BlockItem;
 import net.minecraft.world.item.Item;
 import net.minecraft.world.level.block.Block;
 import net.minecraft.world.level.block.state.BlockBehaviour;
@@ -209,6 +210,31 @@ public abstract class ComplexMaterial {
         return blocks.get(key.suffix);
     }
 
+    /**
+     * Get initiated {@link Block} from this {@link ComplexMaterial}.
+     *
+     * @param key {@link MaterialSlot} The Block Entry
+     * @param <M> The {@link ComplexMaterial} this slot is usable for Type
+     * @return {@link Block} or {@code null} if nothing is stored.
+     */
+    @Nullable
+    public <M extends ComplexMaterial> BlockItem getBlockItem(MaterialSlot<M> key) {
+        return getBlockItem(key.suffix);
+    }
+
+    /**
+     * Get initiated {@link Block} from this {@link ComplexMaterial}.
+     *
+     * @param key {@link MaterialSlot} The Block Entry
+     * @param <M> The {@link ComplexMaterial} this slot is usable for Type
+     * @return {@link Block} or {@code null} if nothing is stored.
+     */
+    @Nullable
+    public BlockItem getBlockItem(String key) {
+        final Block bl = blocks.get(key);
+        return bl != null && bl.asItem() instanceof BlockItem bi ? bi : null;
+    }
+
     /**
      * Get initiated {@link Item} from this {@link ComplexMaterial}.
      *

src/main/java/org/betterx/bclib/creativetab/BCLCreativeTab.java

@@ -0,0 +1,97 @@
+package org.betterx.bclib.creativetab;
+
+import org.betterx.bclib.behaviours.interfaces.*;
+
+import net.minecraft.core.registries.Registries;
+import net.minecraft.network.chat.Component;
+import net.minecraft.resources.ResourceKey;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.world.item.BlockItem;
+import net.minecraft.world.item.CreativeModeTab;
+import net.minecraft.world.item.Item;
+import net.minecraft.world.level.ItemLike;
+
+import java.util.LinkedList;
+import java.util.List;
+import org.jetbrains.annotations.NotNull;
+
+public class BCLCreativeTab {
+    public static CreativeTabPredicate NATURE = item -> item instanceof BlockItem bi
+            && (bi.getBlock() instanceof BehaviourSapling
+            || bi.getBlock() instanceof BehaviourSeed
+            || bi.getBlock() instanceof BehaviourLeaves
+            || bi.getBlock() instanceof BehaviourPlant
+            || bi.getBlock() instanceof BehaviourWaterPlant
+            || bi.getBlock() instanceof BehaviourVine);
+
+    public static CreativeTabPredicate BLOCKS = item -> item instanceof BlockItem;
+
+    public interface CreativeTabPredicate {
+        boolean contains(Item item);
+    }
+
+    public final ResourceLocation id;
+    public final ItemLike icon;
+    public final Component title;
+    public final CreativeTabPredicate predicate;
+
+    public final ResourceKey<CreativeModeTab> key;
+
+    public BCLCreativeTab(ResourceLocation id, ItemLike icon, Component title, CreativeTabPredicate predicate) {
+        this.id = id;
+        this.icon = icon;
+        this.title = title;
+        this.predicate = predicate;
+        this.key = ResourceKey.create(
+                Registries.CREATIVE_MODE_TAB,
+                id
+        );
+        this.items = new LinkedList<>();
+    }
+
+    protected final List<Item> items;
+
+    void addItem(Item item) {
+        items.add(item);
+    }
+
+    public static class Builder {
+        private final String name;
+        private final ResourceLocation id;
+        private ItemLike icon;
+        private CreativeTabPredicate predicate = item -> true;
+        private Component title;
+        private final BCLCreativeTabManager manager;
+
+        public Builder(@NotNull BCLCreativeTabManager manager, @NotNull String name) {
+            this.name = name;
+            this.manager = manager;
+            this.id = new ResourceLocation(manager.modID, name + "_tab");
+            this.title = Component.translatable("itemGroup." + manager.modID + "." + name);
+        }
+
+        public Builder setIcon(ItemLike icon) {
+            this.icon = icon;
+            return this;
+        }
+
+        public Builder setPredicate(CreativeTabPredicate predicate) {
+            this.predicate = predicate;
+            return this;
+        }
+
+        public Builder setTitle(Component title) {
+            this.title = title;
+            return this;
+        }
+
+        public BCLCreativeTabManager build() {
+            if (icon == null)
+                throw new IllegalStateException("Icon must be set");
+            BCLCreativeTab res = new BCLCreativeTab(id, icon, title, predicate);
+            manager.tabs.add(res);
+
+            return manager;
+        }
+    }
+}

src/main/java/org/betterx/bclib/creativetab/BCLCreativeTabManager.java

@@ -0,0 +1,79 @@
+package org.betterx.bclib.creativetab;
+
+import org.betterx.bclib.registry.BaseRegistry;
+
+import net.minecraft.core.Registry;
+import net.minecraft.core.registries.BuiltInRegistries;
+import net.minecraft.world.item.Item;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.level.ItemLike;
+
+import net.fabricmc.fabric.api.itemgroup.v1.FabricItemGroup;
+
+import java.util.LinkedList;
+import java.util.List;
+
+public class BCLCreativeTabManager {
+    public final String modID;
+    protected final List<BCLCreativeTab> tabs = new LinkedList<>();
+
+    public static BCLCreativeTabManager create(String modID) {
+        return new BCLCreativeTabManager(modID);
+    }
+
+    protected BCLCreativeTabManager(String modID) {
+        this.modID = modID;
+    }
+
+    public BCLCreativeTab.Builder createTab(String name) {
+        return new BCLCreativeTab.Builder(this, name);
+    }
+
+    public BCLCreativeTab.Builder createBlockTab(ItemLike icon) {
+        return new BCLCreativeTab.Builder(this, "blocks").setIcon(icon).setPredicate(BCLCreativeTab.BLOCKS);
+    }
+
+    public BCLCreativeTab.Builder createItemsTab(ItemLike icon) {
+        return new BCLCreativeTab.Builder(this, "items").setIcon(icon);
+    }
+
+    public BCLCreativeTabManager processBCLRegistry() {
+        process(BaseRegistry.getModItems(modID));
+        process(BaseRegistry.getModBlockItems(modID));
+        return this;
+    }
+
+    public BCLCreativeTabManager process(List<Item> items) {
+        for (Item item : items) {
+            for (BCLCreativeTab tab : tabs) {
+                if (tab.predicate.contains(item)) {
+                    tab.addItem(item);
+                    break;
+                }
+            }
+        }
+
+        return this;
+    }
+
+    public void register() {
+        for (BCLCreativeTab tab : tabs) {
+            var tabItem = FabricItemGroup
+                    .builder()
+                    .icon(() -> new ItemStack(tab.icon))
+                    .title(tab.title)
+                    .displayItems((featureFlagSet, output) -> {
+                        output.acceptAll(tab.items.stream().map(ItemStack::new).toList());
+                        tab.items.clear();
+                    }).build();
+
+            Registry.register(
+                    BuiltInRegistries.CREATIVE_MODE_TAB,
+                    tab.key,
+                    tabItem
+            );
+        }
+
+        this.tabs.clear();
+    }
+}