package net.minecraft.client.multiplayer;

import java.util.function.Function;
import net.fabricmc.api.EnvType;
import net.fabricmc.api.Environment;
import org.jetbrains.annotations.Nullable;

@Environment(EnvType.CLIENT)
public class CacheSlot<C extends CacheSlot.Cleaner<C>, D> {
	private final Function<C, D> operation;
	@Nullable
	private C context;
	@Nullable
	private D value;

	public CacheSlot(Function<C, D> operation) {
		this.operation = operation;
	}

	public D compute(C context) {
		if (context == this.context && this.value != null) {
			return this.value;
		} else {
			D object = (D)this.operation.apply(context);
			this.value = object;
			this.context = context;
			context.registerForCleaning(this);
			return object;
		}
	}

	public void clear() {
		this.value = null;
		this.context = null;
	}

	@FunctionalInterface
	@Environment(EnvType.CLIENT)
	public interface Cleaner<C extends CacheSlot.Cleaner<C>> {
		void registerForCleaning(CacheSlot<C, ?> cacheSlot);
	}
}