package net.minecraft.world.entity.ai.goal.target;

import java.util.EnumSet;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.server.level.ServerPlayer;
import net.minecraft.world.entity.LivingEntity;
import net.minecraft.world.entity.Mob;
import net.minecraft.world.entity.ai.goal.Goal.Flag;
import net.minecraft.world.entity.ai.targeting.TargetingConditions;
import net.minecraft.world.entity.player.Player;
import net.minecraft.world.phys.AABB;
import org.jetbrains.annotations.Nullable;

public class NearestAttackableTargetGoal<T extends LivingEntity> extends TargetGoal {
	private static final int DEFAULT_RANDOM_INTERVAL = 10;
	protected final Class<T> targetType;
	protected final int randomInterval;
	@Nullable
	protected LivingEntity target;
	/**
	 * This filter is applied to the Entity search. Only matching entities will be targeted.
	 */
	protected TargetingConditions targetConditions;

	public NearestAttackableTargetGoal(Mob mob, Class<T> targetType, boolean mustSee) {
		this(mob, targetType, 10, mustSee, false, null);
	}

	public NearestAttackableTargetGoal(Mob mob, Class<T> targetType, boolean mustSee, TargetingConditions.Selector selector) {
		this(mob, targetType, 10, mustSee, false, selector);
	}

	public NearestAttackableTargetGoal(Mob mob, Class<T> targetType, boolean mustSee, boolean mustReach) {
		this(mob, targetType, 10, mustSee, mustReach, null);
	}

	public NearestAttackableTargetGoal(
		Mob mob, Class<T> targetType, int interval, boolean mustSee, boolean mustReach, @Nullable TargetingConditions.Selector selector
	) {
		super(mob, mustSee, mustReach);
		this.targetType = targetType;
		this.randomInterval = reducedTickDelay(interval);
		this.setFlags(EnumSet.of(Flag.TARGET));
		this.targetConditions = TargetingConditions.forCombat().range(this.getFollowDistance()).selector(selector);
	}

	@Override
	public boolean canUse() {
		if (this.randomInterval > 0 && this.mob.getRandom().nextInt(this.randomInterval) != 0) {
			return false;
		} else {
			this.findTarget();
			return this.target != null;
		}
	}

	protected AABB getTargetSearchArea(double targetDistance) {
		return this.mob.getBoundingBox().inflate(targetDistance, targetDistance, targetDistance);
	}

	protected void findTarget() {
		ServerLevel serverLevel = getServerLevel(this.mob);
		if (this.targetType != Player.class && this.targetType != ServerPlayer.class) {
			this.target = serverLevel.getNearestEntity(
				this.mob.level().getEntitiesOfClass(this.targetType, this.getTargetSearchArea(this.getFollowDistance()), livingEntity -> true),
				this.getTargetConditions(),
				this.mob,
				this.mob.getX(),
				this.mob.getEyeY(),
				this.mob.getZ()
			);
		} else {
			this.target = serverLevel.getNearestPlayer(this.getTargetConditions(), this.mob, this.mob.getX(), this.mob.getEyeY(), this.mob.getZ());
		}
	}

	@Override
	public void start() {
		this.mob.setTarget(this.target);
		super.start();
	}

	public void setTarget(@Nullable LivingEntity target) {
		this.target = target;
	}

	private TargetingConditions getTargetConditions() {
		return this.targetConditions.range(this.getFollowDistance());
	}
}