package me.illusion.utilities;

import net.minecraft.world.entity.EntityInsentient;
import net.minecraft.world.entity.EntityLiving;
import net.minecraft.world.entity.ai.goal.PathfinderGoal;
import net.minecraft.world.entity.ai.goal.PathfinderGoalWrapped;
import org.bukkit.Bukkit;
import org.bukkit.craftbukkit.v1_18_R1.entity.CraftLivingEntity;
import org.bukkit.entity.Entity;
import org.bukkit.entity.EntityType;
import org.bukkit.entity.LivingEntity;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.entity.CreatureSpawnEvent;
import org.bukkit.event.world.EntitiesLoadEvent;
import org.bukkit.plugin.java.JavaPlugin;

import java.util.EnumSet;
import java.util.HashMap;
import java.util.Map;
import java.util.function.Consumer;
import java.util.function.Function;

/**
 * This class is used to modify the Pathfinders of any monster that may spawn,
 * remove or add new pathfinders, and overall provides a cleaner solution.
 *
 * For future maintainers: There are 2 PathfinderGoalSelectors present in the
 * EntityInsentient class, one for the pathfinding and one for the target.
 *
 * A PathfinderGoalSelector contains a List<WrappedPathfinderGoal> which stores
 * both the pathfinder goal and its priority on the list. If a PathfinderGoal
 * is triggered, further elements on the list won't be triggered.
 *
 * @author Illusion
 */
public class PathfinderInjector implements Listener {

    private static boolean initialized = false;

    private static final EnumSet<EntityType> wipableEntityTypes = EnumSet.noneOf(EntityType.class);

    private static final Map<Class<? extends EntityInsentient>, Consumer<EntityInsentient>> onSpawn = new HashMap<>();

    public static void init(JavaPlugin plugin) {
        if (initialized) {
            return;
        }

        initialized = true;
        Bukkit.getPluginManager().registerEvents(new PathfinderInjector(), plugin);
    }

    public static <T extends EntityInsentient> void inject(Class<T> entityClass, Function<EntityInsentient, PathfinderGoal> injector) {
        onSpawn.put(
                entityClass,
                onSpawn.getOrDefault(entityClass, (e) -> {})
                        .andThen((entityInsentient) ->
                                entityInsentient
                                        .bR // Attack goal selector
                                        .c() // List of WrappedPathfinderGoal
                                        .add(new PathfinderGoalWrapped(entityInsentient.bR.c().size() + 1 /* Last priority, preserves order */,
                                                injector.apply(entityInsentient)))
                        )
        );
    }

    public static void onSpawn(Class<? extends EntityInsentient> entityClass, Consumer<EntityInsentient> onSpawn) {
        PathfinderInjector.onSpawn.put(entityClass, onSpawn);
    }
    public static void wipeOnSpawn(EntityType type) {
        wipableEntityTypes.add(type);
    }

    @EventHandler
    private void onSpawn(CreatureSpawnEvent event) {
        LivingEntity entity = event.getEntity();

        EntityLiving nmsEntity = ((CraftLivingEntity) entity).getHandle();

        EntityInsentient entityInsentient = (EntityInsentient) nmsEntity;

        if (wipableEntityTypes.contains(entity.getType())) {
            entityInsentient.bR.c().clear(); // attack pathfinder selector
            entityInsentient.bS.c().clear(); // movement pathfinder selector
        }

        onSpawn.getOrDefault(entityInsentient.getClass(), (e) -> {}).accept(entityInsentient);

    }

    @EventHandler
    private void onLoad(EntitiesLoadEvent event) {
        for (Entity entity : event.getEntities()) {
            if(!(entity instanceof LivingEntity)) {
                continue;
            }

            EntityLiving nmsEntity = ((CraftLivingEntity) entity).getHandle();

            EntityInsentient entityInsentient = (EntityInsentient) nmsEntity;

            if (wipableEntityTypes.contains(entity.getType())) {
                entityInsentient.bR.c().clear(); // attack pathfinder selector
                entityInsentient.bS.c().clear(); // movement pathfinder selector
            }

            onSpawn.getOrDefault(entityInsentient.getClass(), (e) -> {}).accept(entityInsentient);
        }
    }
}