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

import it.unimi.dsi.fastutil.ints.IntOpenHashSet;
import it.unimi.dsi.fastutil.ints.IntSet;
import net.minecraft.util.profiling.Profiler;
import net.minecraft.util.profiling.ProfilerFiller;
import net.minecraft.world.entity.Entity;
import net.minecraft.world.entity.Mob;

public class Sensing {
	private final Mob mob;
	private final IntSet seen = new IntOpenHashSet();
	private final IntSet unseen = new IntOpenHashSet();

	public Sensing(final Mob mob) {
		this.mob = mob;
	}

	public void tick() {
		this.seen.clear();
		this.unseen.clear();
	}

	public boolean hasLineOfSight(final Entity target) {
		int targetId = target.getId();
		if (this.seen.contains(targetId)) {
			return true;
		} else if (this.unseen.contains(targetId)) {
			return false;
		} else {
			ProfilerFiller profiler = Profiler.get();
			profiler.push("hasLineOfSight");
			boolean hasLineOfSight = this.mob.hasLineOfSight(target);
			profiler.pop();
			if (hasLineOfSight) {
				this.seen.add(targetId);
			} else {
				this.unseen.add(targetId);
			}

			return hasLineOfSight;
		}
	}
}