package org.mineacademy.boss.hook;

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.TimeUnit;

import javax.annotation.Nullable;

import org.bukkit.GameMode;
import org.bukkit.Location;
import org.bukkit.entity.Entity;
import org.bukkit.entity.EntityType;
import org.bukkit.entity.LivingEntity;
import org.bukkit.entity.Player;
import org.bukkit.inventory.ItemStack;
import org.mineacademy.boss.model.Boss;
import org.mineacademy.boss.model.BossCitizensSettings;
import org.mineacademy.boss.model.BossRegion;
import org.mineacademy.boss.model.SpawnedBoss;
import org.mineacademy.fo.Common;
import org.mineacademy.fo.MinecraftVersion;
import org.mineacademy.fo.MinecraftVersion.V;
import org.mineacademy.fo.PlayerUtil;
import org.mineacademy.fo.collection.expiringmap.ExpiringMap;
import org.mineacademy.fo.jsonsimple.JSONObject;
import org.mineacademy.fo.jsonsimple.JSONParser;
import org.mineacademy.fo.remain.CompEquipmentSlot;
import org.mineacademy.fo.remain.Remain;

import net.citizensnpcs.api.CitizensAPI;
import net.citizensnpcs.api.ai.EntityTarget;
import net.citizensnpcs.api.ai.Goal;
import net.citizensnpcs.api.ai.Navigator;
import net.citizensnpcs.api.ai.goals.WanderGoal;
import net.citizensnpcs.api.npc.MetadataStore;
import net.citizensnpcs.api.npc.NPC;
import net.citizensnpcs.api.trait.trait.Equipment;
import net.citizensnpcs.api.trait.trait.Equipment.EquipmentSlot;
import net.citizensnpcs.trait.SkinTrait;

/**
 * Connector to Citizens for integration.
 */
public final class CitizensHook {

	/*
	 * Skin cache
	 */
	private static final Map<String, JSONObject> cache = ExpiringMap.builder().expiration(30, TimeUnit.MINUTES).build();

	/**
	 * Register our custom traits
	 */
	public static void registerTraits() {
		if (MinecraftVersion.atLeast(V.v1_9))
			try {
				net.citizensnpcs.api.CitizensAPI.getTraitFactory().registerTrait(net.citizensnpcs.api.trait.TraitInfo.create(MaxHealthTrait.class));
			} catch (final Throwable t) {
				// Ignore, no implementation for the current MC version
			}
	}

	/**
	 * Spawns the given Boss at the location with help of Citizens
	 *
	 * @param boss
	 * @param location
	 * @return
	 */
	public static Entity spawn(Boss boss, Location location) {
		final String alias = boss.getAlias();
		final NPC npc = CitizensAPI.getNPCRegistry().createNPC(boss.getType(), alias.length() > 16 ? alias.substring(0, 16) : alias);

		// Apply attributes
		update(boss, npc);

		// Spawn
		if (!npc.spawn(location)) {
			npc.destroy();

			return null;
		}

		// Set initial health to max and save
		((LivingEntity) npc.getEntity()).setHealth(boss.getMaxHealth());
		final MaxHealthTrait trait = npc.getOrAddTrait(MaxHealthTrait.class);

		if (trait != null)
			trait.health = ((LivingEntity) npc.getEntity()).getHealth();

		return npc.getEntity();
	}

	/**
	 * Updates Boss behavior for the spawned Boss entity
	 *
	 * @param boss
	 * @param entity
	 */
	public static void update(Boss boss, Entity entity) {
		final NPC npc = CitizensAPI.getNPCRegistry().getNPC(entity);

		if (npc == null)
			return;

		if (!npc.isSpawned())
			npc.destroy();

		update(boss, npc);
	}

	/**
	 * Updates Boss behavior for the spawned Boss entity
	 *
	 * @param boss
	 * @param npc
	 */
	public static void update(Boss boss, NPC npc) {

		final BossCitizensSettings citizens = boss.getCitizensSettings();
		final MetadataStore data = npc.data();

		npc.setProtected(false);

		npc.getOrAddTrait(MaxHealthTrait.class);

		final Equipment equipment = npc.getOrAddTrait(Equipment.class);

		for (final CompEquipmentSlot slot : CompEquipmentSlot.values()) {
			final ItemStack item = boss.getEquipmentItem(slot);

			equipment.set(EquipmentSlot.valueOf(slot.getBukkitName()), item);
		}

		data.setPersistent("BossName", boss.getName());

		if (citizens.getDeathSound() != null)
			data.setPersistent(NPC.Metadata.DEATH_SOUND, citizens.getDeathSound());

		if (citizens.getHurtSound() != null)
			data.setPersistent(NPC.Metadata.HURT_SOUND, citizens.getHurtSound());

		if (citizens.getAmbientSound() != null)
			data.setPersistent(NPC.Metadata.AMBIENT_SOUND, citizens.getAmbientSound());

		data.setPersistent(NPC.Metadata.DROPS_ITEMS, true);
		data.setPersistent(NPC.Metadata.COLLIDABLE, true);
		data.setPersistent(NPC.Metadata.DAMAGE_OTHERS, true);

		if (citizens.isTargetGoalEnabled()) {
			final Goal goal = BossTargetNearbyEntityGoal.builder(npc)
					.aggressive(citizens.isTargetGoalAggressive())
					.radius(citizens.getTargetGoalRadius())
					.targets(citizens.getTargetGoalEntities())
					.build();

			npc.getDefaultGoalController().addGoal(goal, 1);
		}

		if (citizens.isWanderGoalEnabled())
			npc.getDefaultGoalController().addGoal(WanderGoal.builder(npc).xrange(citizens.getWanderGoalRadius()).yrange(citizens.getWanderGoalRadius()).build(), citizens.getWanderGoalRadius());
		else
			npc.getDefaultGoalController().cancelCurrentExecution();

		final Navigator gps = npc.getNavigator();

		// Fix weird slow motion issue
		if (boss.getType() == EntityType.PLAYER) {
			gps.getLocalParameters().speedModifier(1F);
			gps.getLocalParameters().speed(1F);
			gps.getLocalParameters().baseSpeed(4F);
		}

		// https://github.com/kangarko/Boss/issues/1195#issuecomment-1692729888
		gps.getLocalParameters().distanceMargin(0.5).pathDistanceMargin(0.5);

		// Fallback to MC AI
		if (!citizens.isTargetGoalEnabled() && !citizens.isWanderGoalEnabled())
			npc.setUseMinecraftAI(true);

		// Remove teleporting to players when far away
		npc.getNavigator().getDefaultParameters().stuckAction(null);

		// Set skin and finalize
		setSkinUrl(boss, npc);
	}

	/*
	 * Helper to set Skin URL
	 */
	private static void setSkinUrl(Boss boss, NPC npc) {
		final String skin = boss.getCitizensSettings().getSkinOrAlias();
		final SkinTrait trait = npc.getOrAddTrait(SkinTrait.class);

		if (skin.startsWith("http://") || skin.startsWith("https://")) {

			Common.runAsync(() -> {
				final JSONObject output = cache.get(skin);

				if (output != null) {
					setSkin0(npc, trait, cache.get(skin));

					return;
				}

				try {
					final URL target = new URL("https://api.mineskin.org/generate/url");
					final HttpURLConnection connection = (HttpURLConnection) target.openConnection();

					connection.setRequestMethod("POST");
					connection.setDoOutput(true);
					connection.setConnectTimeout(2_000);
					connection.setReadTimeout(5_000);

					try (DataOutputStream out = new DataOutputStream(connection.getOutputStream())) {
						out.writeBytes("url=" + URLEncoder.encode(skin, "UTF-8"));
						out.close();

						try (BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()))) {
							final JSONObject newOutput = (JSONObject) JSONParser.deserialize(reader);
							connection.disconnect();

							Common.runLater(() -> {
								setSkin0(npc, trait, newOutput);

								cache.put(skin, newOutput);
							});
						}
					}

				} catch (final Throwable t) {
					Common.error(t, "Failed fetching NPC's " + npc.getName() + " skin from URL, check if it is valid.", "URL:" + skin);
				}
			});

		} else
			trait.setSkinName(skin, true);
	}

	/*
	 * Helper method to set the persistent skin trait
	 */
	private static void setSkin0(NPC npc, SkinTrait trait, JSONObject output) {
		final JSONObject data = (JSONObject) output.get("data");
		final String uuid = (String) data.get("uuid");

		final JSONObject texture = (JSONObject) data.get("texture");
		final String textureEncoded = (String) texture.get("value");
		final String signature = (String) texture.get("signature");

		trait.setSkinPersistent(uuid, signature, textureEncoded);
	}

	/**
	 * Attempts to destroy NPC associated with the given NPC
	 *
	 * @param entity
	 */
	public static void destroy(Entity entity) {
		final NPC npc = CitizensAPI.getNPCRegistry().getNPC(entity);

		if (npc != null)
			npc.destroy();
	}

	/**
	 * Retargets the closest entity for the given boss
	 *
	 * @param spawnedBoss the boss
	 */
	public static void retarget(SpawnedBoss spawnedBoss) {
		final Entity entity = spawnedBoss.getEntity();
		final Boss boss = spawnedBoss.getBoss();

		final BossRegion spawnRegion = boss.isKeptInSpawnRegion() ? spawnedBoss.getSpawnRegion() : null;

		final NPC npc = CitizensAPI.getNPCRegistry().getNPC(entity);
		final BossCitizensSettings citizens = boss.getCitizensSettings();

		if (npc != null && citizens.isTargetGoalEnabled()) {

			final List<Entity> potentialTargets = new ArrayList<>();
			final EntityTarget oldTarget = npc.getNavigator().getEntityTarget();

			for (final Entity nearby : Remain.getNearbyEntities(entity.getLocation(), citizens.getTargetGoalRadius())) {

				// Ignore same type entities
				if (entity.getType() == nearby.getType())
					continue;

				// Do not target self
				if (entity.getUniqueId().equals(nearby.getUniqueId()))
					continue;

				// Only retarget to someone else
				if (oldTarget != null && oldTarget.getTarget().getUniqueId().equals(nearby.getUniqueId()))
					continue;

				// Ignore entities out of reach
				if (spawnRegion != null && !spawnRegion.isWithin(nearby.getLocation()))
					continue;

				if (nearby instanceof Player) {
					final Player player = (Player) nearby;

					if (player.getGameMode() != GameMode.SURVIVAL || PlayerUtil.isVanished(player))
						continue;
				}

				final SpawnedBoss nearbyBoss = Boss.findBoss(nearby);

				if (nearbyBoss != null && nearbyBoss.getBoss().equals(boss))
					continue;

				if (citizens.getTargetGoalEntities().contains(nearby.getType()))
					potentialTargets.add(nearby);
			}

			if (!potentialTargets.isEmpty()) {
				Collections.shuffle(potentialTargets);

				npc.getNavigator().setTarget(potentialTargets.get(0), citizens.isTargetGoalAggressive());
			}
		}

		// Remove teleporting to players when far away
		if (npc != null)
			npc.getNavigator().getDefaultParameters().stuckAction(null);
	}

	/**
	 * Sends the given Boss to the given location
	 *
	 * @param boss
	 * @param target
	 */
	public static void sendToLocation(SpawnedBoss boss, Location target) {
		final NPC npc = CitizensAPI.getNPCRegistry().getNPC(boss.getEntity());

		if (npc != null)
			npc.getNavigator().setTarget(target);
	}

	/**
	 * Attempts to find a boss from the given NPC.
	 *
	 * @param entity
	 * @return
	 */
	@Nullable
	public static SpawnedBoss findNPC(Entity entity) {
		final NPC npc = CitizensAPI.getNPCRegistry().getNPC(entity);

		if (npc != null) {
			final String bossName = npc.data().get("BossName");

			if (bossName != null) {
				final Boss boss = Boss.findBoss(bossName);

				if (boss != null)
					return new SpawnedBoss(boss, (LivingEntity) entity);
			}
		}

		return null;
	}
}