fix MaterialSet issues

common/api/src/main/java/com/dfsek/terra/api/util/MaterialSet.java

@@ -1,12 +1,43 @@
 package com.dfsek.terra.api.util;
 
 import com.dfsek.terra.api.block.BlockType;
+import com.dfsek.terra.api.block.state.BlockState;
 
+import java.io.Serial;
+import java.util.AbstractSet;
+import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashSet;
+import java.util.Iterator;
 import java.util.Set;
 
-public interface MaterialSet extends Set<BlockType> {
-    static MaterialSet empty() {
-        return (MaterialSet) (Object) Collections.emptySet();
+public class MaterialSet extends HashSet<BlockType> {
+    @Serial
+    private static final long serialVersionUID = 3056512763631017301L;
+
+    public static MaterialSet singleton(BlockType material) {
+        MaterialSet set = new MaterialSet();
+        set.add(material);
+        return set;
+    }
+
+    public static MaterialSet get(BlockType... materials) {
+        MaterialSet set = new MaterialSet();
+        set.addAll(Arrays.asList(materials));
+        return set;
+    }
+
+    public static MaterialSet get(BlockState... materials) {
+        MaterialSet set = new MaterialSet();
+        Arrays.stream(materials).forEach(set::add);
+        return set;
+    }
+
+    public static MaterialSet empty() {
+        return new MaterialSet();
+    }
+
+    private void add(BlockState data) {
+        add(data.getBlockType());
     }
 }