minecraft-src/net/minecraft/world/entity/ai/attributes/AttributeInstance.java

package net.minecraft.world.entity.ai.attributes;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Maps;
import com.mojang.serialization.Codec;
import it.unimi.dsi.fastutil.objects.Object2ObjectArrayMap;
import it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.function.Consumer;
import net.minecraft.core.Holder;
import net.minecraft.core.registries.BuiltInRegistries;
import net.minecraft.nbt.CompoundTag;
import net.minecraft.resources.ResourceLocation;
import org.jetbrains.annotations.Nullable;

public class AttributeInstance {
	private static final String BASE_FIELD = "base";
	private static final String MODIFIERS_FIELD = "modifiers";
	public static final String ID_FIELD = "id";
	public static final Codec<Holder<Attribute>> TYPE_CODEC = BuiltInRegistries.ATTRIBUTE.holderByNameCodec();
	/**
	 * The Attribute this is an instance of
	 */
	private final Holder<Attribute> attribute;
	private final Map<AttributeModifier.Operation, Map<ResourceLocation, AttributeModifier>> modifiersByOperation = Maps.newEnumMap(
		AttributeModifier.Operation.class
	);
	private final Map<ResourceLocation, AttributeModifier> modifierById = new Object2ObjectArrayMap<>();
	private final Map<ResourceLocation, AttributeModifier> permanentModifiers = new Object2ObjectArrayMap<>();
	private double baseValue;
	private boolean dirty = true;
	private double cachedValue;
	private final Consumer<AttributeInstance> onDirty;

	public AttributeInstance(Holder<Attribute> attribute, Consumer<AttributeInstance> onDirty) {
		this.attribute = attribute;
		this.onDirty = onDirty;
		this.baseValue = attribute.value().getDefaultValue();
	}

	public Holder<Attribute> getAttribute() {
		return this.attribute;
	}

	public double getBaseValue() {
		return this.baseValue;
	}

	public void setBaseValue(double baseValue) {
		if (baseValue != this.baseValue) {
			this.baseValue = baseValue;
			this.setDirty();
		}
	}

	@VisibleForTesting
	Map<ResourceLocation, AttributeModifier> getModifiers(AttributeModifier.Operation operation) {
		return (Map<ResourceLocation, AttributeModifier>)this.modifiersByOperation.computeIfAbsent(operation, operationx -> new Object2ObjectOpenHashMap());
	}

	public Set<AttributeModifier> getModifiers() {
		return ImmutableSet.copyOf(this.modifierById.values());
	}

	public Set<AttributeModifier> getPermanentModifiers() {
		return ImmutableSet.copyOf(this.permanentModifiers.values());
	}

	@Nullable
	public AttributeModifier getModifier(ResourceLocation id) {
		return (AttributeModifier)this.modifierById.get(id);
	}

	public boolean hasModifier(ResourceLocation id) {
		return this.modifierById.get(id) != null;
	}

	private void addModifier(AttributeModifier modifier) {
		AttributeModifier attributeModifier = (AttributeModifier)this.modifierById.putIfAbsent(modifier.id(), modifier);
		if (attributeModifier != null) {
			throw new IllegalArgumentException("Modifier is already applied on this attribute!");
		} else {
			this.getModifiers(modifier.operation()).put(modifier.id(), modifier);
			this.setDirty();
		}
	}

	public void addOrUpdateTransientModifier(AttributeModifier modifier) {
		AttributeModifier attributeModifier = (AttributeModifier)this.modifierById.put(modifier.id(), modifier);
		if (modifier != attributeModifier) {
			this.getModifiers(modifier.operation()).put(modifier.id(), modifier);
			this.setDirty();
		}
	}

	public void addTransientModifier(AttributeModifier modifier) {
		this.addModifier(modifier);
	}

	public void addOrReplacePermanentModifier(AttributeModifier modifier) {
		this.removeModifier(modifier.id());
		this.addModifier(modifier);
		this.permanentModifiers.put(modifier.id(), modifier);
	}

	public void addPermanentModifier(AttributeModifier modifier) {
		this.addModifier(modifier);
		this.permanentModifiers.put(modifier.id(), modifier);
	}

	public void addPermanentModifiers(Collection<AttributeModifier> modifiers) {
		for (AttributeModifier attributeModifier : modifiers) {
			this.addPermanentModifier(attributeModifier);
		}
	}

	protected void setDirty() {
		this.dirty = true;
		this.onDirty.accept(this);
	}

	public void removeModifier(AttributeModifier modifier) {
		this.removeModifier(modifier.id());
	}

	public boolean removeModifier(ResourceLocation id) {
		AttributeModifier attributeModifier = (AttributeModifier)this.modifierById.remove(id);
		if (attributeModifier == null) {
			return false;
		} else {
			this.getModifiers(attributeModifier.operation()).remove(id);
			this.permanentModifiers.remove(id);
			this.setDirty();
			return true;
		}
	}

	public void removeModifiers() {
		for (AttributeModifier attributeModifier : this.getModifiers()) {
			this.removeModifier(attributeModifier);
		}
	}

	public double getValue() {
		if (this.dirty) {
			this.cachedValue = this.calculateValue();
			this.dirty = false;
		}

		return this.cachedValue;
	}

	private double calculateValue() {
		double d = this.getBaseValue();

		for (AttributeModifier attributeModifier : this.getModifiersOrEmpty(AttributeModifier.Operation.ADD_VALUE)) {
			d += attributeModifier.amount();
		}

		double e = d;

		for (AttributeModifier attributeModifier2 : this.getModifiersOrEmpty(AttributeModifier.Operation.ADD_MULTIPLIED_BASE)) {
			e += d * attributeModifier2.amount();
		}

		for (AttributeModifier attributeModifier2 : this.getModifiersOrEmpty(AttributeModifier.Operation.ADD_MULTIPLIED_TOTAL)) {
			e *= 1.0 + attributeModifier2.amount();
		}

		return this.attribute.value().sanitizeValue(e);
	}

	private Collection<AttributeModifier> getModifiersOrEmpty(AttributeModifier.Operation operation) {
		return ((Map)this.modifiersByOperation.getOrDefault(operation, Map.of())).values();
	}

	public void replaceFrom(AttributeInstance instance) {
		this.baseValue = instance.baseValue;
		this.modifierById.clear();
		this.modifierById.putAll(instance.modifierById);
		this.permanentModifiers.clear();
		this.permanentModifiers.putAll(instance.permanentModifiers);
		this.modifiersByOperation.clear();
		instance.modifiersByOperation.forEach((operation, map) -> this.getModifiers(operation).putAll(map));
		this.setDirty();
	}

	public CompoundTag save() {
		CompoundTag compoundTag = new CompoundTag();
		compoundTag.store("id", TYPE_CODEC, this.attribute);
		compoundTag.putDouble("base", this.baseValue);
		if (!this.permanentModifiers.isEmpty()) {
			compoundTag.store("modifiers", AttributeModifier.CODEC.listOf(), List.copyOf(this.permanentModifiers.values()));
		}

		return compoundTag;
	}

	public void load(CompoundTag nbt) {
		this.baseValue = nbt.getDoubleOr("base", 0.0);

		for (AttributeModifier attributeModifier : (List)nbt.read("modifiers", AttributeModifier.CODEC.listOf()).orElse(List.of())) {
			this.modifierById.put(attributeModifier.id(), attributeModifier);
			this.getModifiers(attributeModifier.operation()).put(attributeModifier.id(), attributeModifier);
			this.permanentModifiers.put(attributeModifier.id(), attributeModifier);
		}

		this.setDirty();
	}
}