Minestom/src/main/java/net/minestom/server/entity/ai/goal/RandomStrollGoal.java

package net.minestom.server.entity.ai.goal;

import net.minestom.server.entity.EntityCreature;
import net.minestom.server.entity.ai.GoalSelector;
import net.minestom.server.utils.coordinate.Vec;
import org.jetbrains.annotations.NotNull;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class RandomStrollGoal extends GoalSelector {

    private static final long DELAY = 2500;

    private final int radius;
    private final List<Vec> closePositions;

    private long lastStroll;

    public RandomStrollGoal(@NotNull EntityCreature entityCreature, int radius) {
        super(entityCreature);
        this.radius = radius;
        this.closePositions = getNearbyBlocks(radius);
    }

    @Override
    public boolean shouldStart() {
        return System.currentTimeMillis() - lastStroll >= DELAY;
    }

    @Override
    public void start() {
        Collections.shuffle(closePositions);
        for (var position : closePositions) {
            final var target = entityCreature.getPosition().add(position);
            final boolean result = entityCreature.getNavigator().setPathTo(target);
            if (result) {
                break;
            }
        }
    }

    @Override
    public void tick(long time) {
    }

    @Override
    public boolean shouldEnd() {
        return true;
    }

    @Override
    public void end() {
        this.lastStroll = System.currentTimeMillis();
    }

    public int getRadius() {
        return radius;
    }

    @NotNull
    private List<Vec> getNearbyBlocks(int radius) {
        List<Vec> blocks = new ArrayList<>();
        for (int x = -radius; x <= radius; x++) {
            for (int y = -radius; y <= radius; y++) {
                for (int z = -radius; z <= radius; z++) {
                    blocks.add(new Vec(x, y, z));
                }
            }
        }
        return blocks;
    }
}