Add Lightweight modifier - movement speed boost

src/main/java/dev/marston/randomloot/loot/modifiers/ModifierRegistry.java

@@ -89,6 +89,7 @@ public static Modifier getModifier(String name) {
 	public static Modifier LIVING = register(new Healing());
 	public static Modifier HUNTER = register(new Hunter());
 	public static Modifier CHAOTIC = register(new Chaotic());
+	public static Modifier LIGHTWEIGHT = register(new Lightweight());
 
 	public static Modifier BUSTED = register(new Busted());
 	public static Modifier FIERCE = register(new Fierce());
@@ -105,7 +106,7 @@ public static Modifier getModifier(String name) {
 	public static final Set<Modifier> HURTERS = Set.of(CRITICAL, CHARGING, FLAMING, COMBO, DRAINING, POISONOUS,
 			WITHERING, BLINDING, BEZERK, NEMESIS, SOULBOUND, SCORCHED, FROZEN, OVERGROWN, FIERCE, FEASTING, EXECUTIONER, CROWD_PLEASER, PUMMELING, HAILEYS_WRATH, MUNCHIES, CHAOTIC, FRAGILE, CLUNKY, EARLY_BIRD);
 	public static final Set<Modifier> HOLDERS = Set.of(HASTY, ABSORBTION, FILLING, RAINY, ORE_FINDER, SPAWNER_FINDER,
-			LIVING, REGENERATING, RESISTANT, FIRE_RESISTANT, AQUATIC, HUNTER, FEASTING, NATURALIST, CLUNKY);
+			LIVING, REGENERATING, RESISTANT, FIRE_RESISTANT, AQUATIC, HUNTER, FEASTING, NATURALIST, CLUNKY, LIGHTWEIGHT);
 
 	public static final Set<Modifier> STATS = Set.of(BUSTED, FIERCE, MUNCHIES, CHAOTIC, FRAGILE);
 

src/main/java/dev/marston/randomloot/loot/modifiers/holders/Lightweight.java

@@ -0,0 +1,110 @@
+package dev.marston.randomloot.loot.modifiers.holders;
+
+import dev.marston.randomloot.loot.LootItem.ToolType;
+import dev.marston.randomloot.loot.LootUtils;
+import dev.marston.randomloot.loot.modifiers.HoldModifier;
+import dev.marston.randomloot.loot.modifiers.Modifier;
+import net.minecraft.ChatFormatting;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.network.chat.Component;
+import net.minecraft.network.chat.MutableComponent;
+import net.minecraft.world.effect.MobEffectInstance;
+import net.minecraft.world.effect.MobEffects;
+import net.minecraft.world.entity.Entity;
+import net.minecraft.world.entity.LivingEntity;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.level.Level;
+
+import java.util.List;
+
+public class Lightweight implements HoldModifier {
+
+	private String name;
+	private int power;
+	private final static String POWER = "power";
+	private final static String LEVEL = "trait_level";
+
+	private int level = 0;
+
+	public Lightweight(String name, int power, int level) {
+		this.name = name;
+		this.power = power;
+		this.level = level;
+	}
+
+	public Lightweight() {
+		this.name = "Lightweight";
+		this.power = 0;
+		this.level = 0;
+	}
+
+	public Modifier clone() {
+		return new Lightweight();
+	}
+
+	@Override
+	public CompoundTag toNBT() {
+		CompoundTag tag = new CompoundTag();
+		tag.putString(NAME, name);
+		tag.putInt(POWER, power);
+		tag.putInt(LEVEL, level);
+		return tag;
+	}
+
+	@Override
+	public Modifier fromNBT(CompoundTag tag) {
+		return new Lightweight(tag.getStringOr(NAME, "Lightweight"), tag.getIntOr(POWER, 0), tag.getIntOr(LEVEL, 0));
+	}
+
+	@Override
+	public String name() {
+		if (this.level == 0) {
+			return this.name;
+		}
+		return this.name + " " + LootUtils.roman(this.level + 1);
+	}
+
+	@Override
+	public String tagName() {
+		return "lightweight";
+	}
+
+	@Override
+	public String color() {
+		return ChatFormatting.AQUA.getName();
+	}
+
+	@Override
+	public String description() {
+		return "While holding the tool, gain Speed " + LootUtils.roman(this.level + 1) + " effect.";
+	}
+
+	@Override
+	public void writeToLore(List<Component> list, boolean shift) {
+		MutableComponent comp = Modifier.makeComp(this.name(), this.color());
+		list.add(comp);
+	}
+
+	@Override
+	public boolean forTool(ToolType type) {
+		return true;
+	}
+
+	@Override
+	public void hold(ItemStack stack, Level level, Entity holder) {
+		MobEffectInstance speed = new MobEffectInstance(MobEffects.SPEED, 2, power, true, false);
+
+		if (holder instanceof LivingEntity le) {
+			le.addEffect(speed);
+		}
+	}
+
+	public boolean canLevel() {
+		return level < 2;
+	}
+
+	public void levelUp() {
+		this.level++;
+		this.power++;
+	}
+}

src/main/resources/data/randomloot/recipe/trait_lightweight.json

@@ -0,0 +1,8 @@
+{
+  "type": "randomloot:trait_change",
+  "item": {
+    "count": 1,
+    "id": "minecraft:rabbit_hide"
+  },
+  "trait": "lightweight"
+}