GoalRoute.java

import com.destroystokyo.paper.entity.ai.Goal;
import com.destroystokyo.paper.entity.ai.GoalKey;
import com.destroystokyo.paper.entity.ai.GoalType;
import lombok.NonNull;
import org.bukkit.Location;
import org.bukkit.entity.Mob;

import java.util.Arrays;
import java.util.EnumSet;
import java.util.List;

// Author: Dymeth.Ru
public class GoalRoute implements Goal<Mob> {
    private static final GoalKey<Mob> KEY = AiHelper.key(GoalRoute.class, Mob.class);

    private final Mob mob;
    private final List<Location> route;
    private final double movingSpeed;
    private final StuckPolicy stuckPolicy;
    private int currentPointIndex;
    private ExactNavigator navigator;
    private boolean failed;

    public GoalRoute(@NonNull Mob mob, double movingSpeed, @NonNull StuckPolicy stuckPolicy, @NonNull Location... route) {
        this(mob, movingSpeed, stuckPolicy, Arrays.asList(route));
    }

    public GoalRoute(@NonNull Mob mob, double movingSpeed, @NonNull StuckPolicy stuckPolicy, @NonNull List<Location> route) {
        this.mob = mob;
        this.route = route;
        this.movingSpeed = movingSpeed;
        this.stuckPolicy = stuckPolicy;
        this.currentPointIndex = 0;
        this.failed = false;
        this.startPointNavigation();
    }

    @Override
    public boolean shouldActivate() {
        return !this.failed;
    }

    @Override
    public void stop() {
        this.mob.getPathfinder().stopPathfinding();
        this.mob.setTarget(null);
    }

    @Override
    public void tick() {
        if (!this.navigator.isPathCompleteOrFailed()) return;
        this.startPointNavigation();
        this.currentPointIndex++;
        if (this.currentPointIndex == this.route.size()) this.currentPointIndex = 0;
    }

    @Override
    @NonNull
    public GoalKey<Mob> getKey() {
        return KEY;
    }

    @Override
    @NonNull
    public EnumSet<GoalType> getTypes() {
        return EnumSet.of(GoalType.MOVE, GoalType.LOOK, GoalType.JUMP);
    }

    private void startPointNavigation() {
        this.navigator = new ExactNavigator(this.mob, this.route.get(this.currentPointIndex), this.movingSpeed, exactNavigator -> {
            switch (this.stuckPolicy) {
                case SKIP_POINT:
                    return false;
                case STOP_PATHFINDING:
                    this.failed = true;
                    return false;
                case WAIT_FOR_PATH:
                    return true;
            }
            throw new IllegalStateException();
        });
    }

    public enum StuckPolicy {
        SKIP_POINT,
        STOP_PATHFINDING,
        WAIT_FOR_PATH
    }
}