Allow use of Tags in block ID lists

src/main/java/com/dfsek/terra/util/TagUtil.java

@@ -0,0 +1,55 @@
+package com.dfsek.terra.util;
+
+import com.dfsek.terra.Debug;
+import org.bukkit.Material;
+import org.bukkit.Tag;
+import org.jetbrains.annotations.NotNull;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+@SuppressWarnings("unchecked")
+public class TagUtil {
+    private static final Map<String, Set<Material>> tagMap;
+
+    static {
+        Debug.info("Loading tags...");
+        tagMap = new HashMap<>();
+
+        Field[] tags = Tag.class.getFields(); // Add Bukkit tags
+        for(Field field : tags) {
+            if(Modifier.isStatic(field.getModifiers())) {
+                try {
+                    Tag<Material> tag = (Tag<Material>) field.get(new Object());
+                    tagMap.put(tag.getKey().toString(), tag.getValues());
+                    Debug.info("Loaded tag: #" + tag.getKey().toString());
+                } catch(IllegalAccessException e) {
+                    e.printStackTrace();
+                } catch(ClassCastException ignore) {
+                }
+            }
+        }
+        putCustomSet("minecraft:base_stone_nether", Material.NETHERRACK, Material.BASALT, Material.BLACKSTONE);
+        putCustomSet("minecraft:base_stone_overworld", Material.STONE, Material.GRANITE, Material.DIORITE, Material.ANDESITE);
+    }
+
+    private static Set<Material> getSet(Material... materials) {
+        return Stream.of(materials).collect(Collectors.toSet());
+    }
+
+    private static void putCustomSet(String key, Material... materials) {
+        tagMap.put(key, getSet(materials));
+        Debug.info("Loaded tag: #" + key);
+    }
+
+    @NotNull
+    public static Set<Material> getTag(String tag) {
+        return Objects.requireNonNull(tagMap.get(tag));
+    }
+}