package net.minecraft.world.entity.npc.wanderingtrader;

import java.util.Optional;
import net.minecraft.core.BlockPos;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.tags.BiomeTags;
import net.minecraft.util.Mth;
import net.minecraft.util.RandomSource;
import net.minecraft.world.entity.EntitySpawnReason;
import net.minecraft.world.entity.EntityTypes;
import net.minecraft.world.entity.SpawnPlacementType;
import net.minecraft.world.entity.SpawnPlacements;
import net.minecraft.world.entity.ai.village.poi.PoiManager;
import net.minecraft.world.entity.ai.village.poi.PoiTypes;
import net.minecraft.world.entity.animal.equine.TraderLlama;
import net.minecraft.world.entity.player.Player;
import net.minecraft.world.level.BlockGetter;
import net.minecraft.world.level.CustomSpawner;
import net.minecraft.world.level.LevelReader;
import net.minecraft.world.level.gamerules.GameRules;
import net.minecraft.world.level.saveddata.WanderingTraderData;
import net.minecraft.world.level.storage.SavedDataStorage;
import org.jspecify.annotations.Nullable;

public class WanderingTraderSpawner implements CustomSpawner {
	private static final int DEFAULT_TICK_DELAY = 1200;
	public static final int DEFAULT_SPAWN_DELAY = 24000;
	public static final int MIN_SPAWN_CHANCE = 25;
	private static final int MAX_SPAWN_CHANCE = 75;
	private static final int SPAWN_CHANCE_INCREASE = 25;
	private static final int SPAWN_ONE_IN_X_CHANCE = 10;
	private static final int NUMBER_OF_SPAWN_ATTEMPTS = 10;
	private final RandomSource random = RandomSource.create();
	private final SavedDataStorage savedDataStorage;
	private int tickDelay;
	@Nullable
	private WanderingTraderData traderData;

	public WanderingTraderSpawner(final SavedDataStorage savedDataStorage) {
		this.savedDataStorage = savedDataStorage;
		this.tickDelay = 1200;
		this.traderData = null;
	}

	@Override
	public void tick(final ServerLevel level, final boolean spawnEnemies) {
		if (level.getGameRules().get(GameRules.SPAWN_WANDERING_TRADERS)) {
			if (--this.tickDelay <= 0) {
				this.tickDelay = 1200;
				WanderingTraderData data = this.getTraderData();
				int spawnDelay = data.spawnDelay() - 1200;
				data.setSpawnDelay(spawnDelay);
				if (spawnDelay <= 0) {
					data.setSpawnDelay(24000);
					int chanceToSpawn = data.spawnChance();
					int newSpawnChance = Mth.clamp(chanceToSpawn + 25, 25, 75);
					data.setSpawnChance(newSpawnChance);
					if (this.random.nextInt(100) <= chanceToSpawn) {
						if (this.spawn(level)) {
							data.setSpawnChance(25);
						}
					}
				}
			}
		}
	}

	private WanderingTraderData getTraderData() {
		if (this.traderData == null) {
			this.traderData = this.savedDataStorage.computeIfAbsent(WanderingTraderData.TYPE);
		}

		return this.traderData;
	}

	private boolean spawn(final ServerLevel level) {
		Player player = level.getRandomPlayer();
		if (player == null) {
			return true;
		} else if (this.random.nextInt(10) != 0) {
			return false;
		} else {
			BlockPos playerPos = player.blockPosition();
			int radius = 48;
			PoiManager poiManager = level.getPoiManager();
			Optional<BlockPos> poiPos = poiManager.find(p -> p.is(PoiTypes.MEETING), p -> true, playerPos, 48, PoiManager.Occupancy.ANY);
			BlockPos referencePos = (BlockPos)poiPos.orElse(playerPos);
			BlockPos spawnPosition = this.findSpawnPositionNear(level, referencePos, 48);
			if (spawnPosition != null && this.hasEnoughSpace(level, spawnPosition)) {
				if (level.getBiome(spawnPosition).is(BiomeTags.WITHOUT_WANDERING_TRADER_SPAWNS)) {
					return false;
				}

				WanderingTrader trader = EntityTypes.WANDERING_TRADER.spawn(level, spawnPosition, EntitySpawnReason.EVENT);
				if (trader != null) {
					for (int i = 0; i < 2; i++) {
						this.tryToSpawnLlamaFor(level, trader, 4);
					}

					trader.setDespawnDelay(48000);
					trader.setWanderTarget(referencePos);
					trader.setHomeTo(referencePos, 16);
					return true;
				}
			}

			return false;
		}
	}

	private void tryToSpawnLlamaFor(final ServerLevel level, final WanderingTrader trader, final int radius) {
		BlockPos spawnPosition = this.findSpawnPositionNear(level, trader.blockPosition(), radius);
		if (spawnPosition != null) {
			TraderLlama llama = EntityTypes.TRADER_LLAMA.spawn(level, spawnPosition, EntitySpawnReason.EVENT);
			if (llama != null) {
				llama.setLeashedTo(trader, true);
			}
		}
	}

	@Nullable
	private BlockPos findSpawnPositionNear(final LevelReader level, final BlockPos referencePosition, final int radius) {
		BlockPos spawnPosition = null;
		SpawnPlacementType wanderingTraderSpawnType = SpawnPlacements.getPlacementType(EntityTypes.WANDERING_TRADER);

		for (int i = 0; i < 10; i++) {
			int xPosition = referencePosition.getX() + this.random.nextInt(radius * 2) - radius;
			int zPosition = referencePosition.getZ() + this.random.nextInt(radius * 2) - radius;
			int yPosition = level.getHeight(SpawnPlacements.getHeightmapType(EntityTypes.WANDERING_TRADER), xPosition, zPosition);
			BlockPos spawnPos = new BlockPos(xPosition, yPosition, zPosition);
			if (wanderingTraderSpawnType.isSpawnPositionOk(level, spawnPos, EntityTypes.WANDERING_TRADER)) {
				spawnPosition = spawnPos;
				break;
			}
		}

		return spawnPosition;
	}

	private boolean hasEnoughSpace(final BlockGetter level, final BlockPos spawnPos) {
		for (BlockPos pos : BlockPos.betweenClosed(spawnPos, spawnPos.offset(1, 2, 1))) {
			if (!level.getBlockState(pos).getCollisionShape(level, pos).isEmpty()) {
				return false;
			}
		}

		return true;
	}
}