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

import net.minecraft.world.entity.ai.Brain;
import org.jspecify.annotations.Nullable;

public class MemorySlot<T> {
	private static final long NEVER_EXPIRE = Long.MAX_VALUE;
	@Nullable
	private T value;
	private long timeToLive;

	private MemorySlot(@Nullable final T value, final long timeToLive) {
		this.value = value;
		this.timeToLive = timeToLive;
	}

	public void tick() {
		if (this.hasValue() && this.canExpire()) {
			if (this.hasExpired()) {
				this.clear();
			} else {
				this.timeToLive--;
			}
		}
	}

	public static <T> MemorySlot<T> create() {
		return new MemorySlot<>(null, Long.MAX_VALUE);
	}

	public void set(final T value, final long timeToLive) {
		this.value = value;
		this.timeToLive = timeToLive;
	}

	public void set(final T value) {
		this.set(value, Long.MAX_VALUE);
	}

	public void clear() {
		this.value = null;
		this.timeToLive = Long.MAX_VALUE;
	}

	public boolean hasValue() {
		return this.value != null;
	}

	@Nullable
	public T value() {
		return this.value;
	}

	public boolean canExpire() {
		return this.timeToLive != Long.MAX_VALUE;
	}

	public boolean hasExpired() {
		return this.timeToLive <= 0L;
	}

	public long timeToLive() {
		return this.timeToLive;
	}

	public String toString() {
		return this.value == null ? "<empty>" : this.value + (this.canExpire() ? " (ttl: " + this.timeToLive + ")" : "");
	}

	public void visit(final MemoryModuleType<T> type, final Brain.Visitor visitor) {
		if (this.value != null) {
			if (this.canExpire()) {
				visitor.accept(type, this.value, this.timeToLive);
			} else {
				visitor.accept(type, this.value);
			}
		} else {
			visitor.acceptEmpty(type);
		}
	}
}