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

import java.util.function.Predicate;
import net.minecraft.world.Difficulty;
import net.minecraft.world.entity.LivingEntity;
import net.minecraft.world.entity.Mob;
import org.jetbrains.annotations.Nullable;

public class TargetingConditions {
	public static final TargetingConditions DEFAULT = forCombat();
	private static final double MIN_VISIBILITY_DISTANCE_FOR_INVISIBLE_TARGET = 2.0;
	private final boolean isCombat;
	private double range = -1.0;
	private boolean checkLineOfSight = true;
	private boolean testInvisible = true;
	@Nullable
	private Predicate<LivingEntity> selector;

	private TargetingConditions(boolean isCombat) {
		this.isCombat = isCombat;
	}

	public static TargetingConditions forCombat() {
		return new TargetingConditions(true);
	}

	public static TargetingConditions forNonCombat() {
		return new TargetingConditions(false);
	}

	public TargetingConditions copy() {
		TargetingConditions targetingConditions = this.isCombat ? forCombat() : forNonCombat();
		targetingConditions.range = this.range;
		targetingConditions.checkLineOfSight = this.checkLineOfSight;
		targetingConditions.testInvisible = this.testInvisible;
		targetingConditions.selector = this.selector;
		return targetingConditions;
	}

	public TargetingConditions range(double distance) {
		this.range = distance;
		return this;
	}

	public TargetingConditions ignoreLineOfSight() {
		this.checkLineOfSight = false;
		return this;
	}

	public TargetingConditions ignoreInvisibilityTesting() {
		this.testInvisible = false;
		return this;
	}

	public TargetingConditions selector(@Nullable Predicate<LivingEntity> customPredicate) {
		this.selector = customPredicate;
		return this;
	}

	public boolean test(@Nullable LivingEntity attacker, LivingEntity target) {
		if (attacker == target) {
			return false;
		} else if (!target.canBeSeenByAnyone()) {
			return false;
		} else if (this.selector != null && !this.selector.test(target)) {
			return false;
		} else {
			if (attacker == null) {
				if (this.isCombat && (!target.canBeSeenAsEnemy() || target.level().getDifficulty() == Difficulty.PEACEFUL)) {
					return false;
				}
			} else {
				if (this.isCombat && (!attacker.canAttack(target) || !attacker.canAttackType(target.getType()) || attacker.isAlliedTo(target))) {
					return false;
				}

				if (this.range > 0.0) {
					double d = this.testInvisible ? target.getVisibilityPercent(attacker) : 1.0;
					double e = Math.max(this.range * d, 2.0);
					double f = attacker.distanceToSqr(target.getX(), target.getY(), target.getZ());
					if (f > e * e) {
						return false;
					}
				}

				if (this.checkLineOfSight && attacker instanceof Mob mob && !mob.getSensing().hasLineOfSight(target)) {
					return false;
				}
			}

			return true;
		}
	}
}