package net.minecraft.world.level.block.entity.trialspawner;

import java.util.List;
import java.util.Objects;
import java.util.UUID;
import java.util.function.Predicate;
import net.minecraft.core.BlockPos;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.server.level.ServerPlayer;
import net.minecraft.world.entity.Entity;
import net.minecraft.world.entity.EntityTypes;
import net.minecraft.world.entity.LivingEntity;
import net.minecraft.world.entity.player.Player;
import net.minecraft.world.level.ClipContext;
import net.minecraft.world.level.Level;
import net.minecraft.world.level.entity.EntityTypeTest;
import net.minecraft.world.phys.AABB;
import net.minecraft.world.phys.BlockHitResult;
import net.minecraft.world.phys.HitResult;
import net.minecraft.world.phys.Vec3;
import net.minecraft.world.phys.shapes.CollisionContext;

public interface PlayerDetector {
	PlayerDetector NO_CREATIVE_PLAYERS = (level, selector, pos, requiredPlayerRange, requireLineOfSight) -> selector.getPlayers(
			level, p -> p.blockPosition().closerThan(pos, requiredPlayerRange) && !p.isCreative() && !p.isSpectator()
		)
		.stream()
		.filter(player -> !requireLineOfSight || inLineOfSight(level, Vec3.atCenterOf(pos), player.getEyePosition()))
		.map(Entity::getUUID)
		.toList();
	PlayerDetector INCLUDING_CREATIVE_PLAYERS = (level, selector, pos, requiredPlayerRange, requireLineOfSight) -> selector.getPlayers(
			level, p -> p.blockPosition().closerThan(pos, requiredPlayerRange) && !p.isSpectator()
		)
		.stream()
		.filter(player -> !requireLineOfSight || inLineOfSight(level, Vec3.atCenterOf(pos), player.getEyePosition()))
		.map(Entity::getUUID)
		.toList();
	PlayerDetector SHEEP = (level, selector, pos, requiredPlayerRange, requireLineOfSight) -> {
		AABB area = new AABB(pos).inflate(requiredPlayerRange);
		return selector.getEntities(level, EntityTypes.SHEEP, area, LivingEntity::isAlive)
			.stream()
			.filter(entity -> !requireLineOfSight || inLineOfSight(level, Vec3.atCenterOf(pos), entity.getEyePosition()))
			.map(Entity::getUUID)
			.toList();
	};

	List<UUID> detect(
		final ServerLevel level,
		final PlayerDetector.EntitySelector selector,
		final BlockPos spawnerPos,
		final double requiredPlayerRange,
		final boolean requireLineOfSight
	);

	private static boolean inLineOfSight(final Level level, final Vec3 origin, final Vec3 dest) {
		BlockHitResult hitResult = level.clip(new ClipContext(dest, origin, ClipContext.Block.VISUAL, ClipContext.Fluid.NONE, CollisionContext.empty()));
		return hitResult.getBlockPos().equals(BlockPos.containing(origin)) || hitResult.getType() == HitResult.Type.MISS;
	}

	public interface EntitySelector {
		PlayerDetector.EntitySelector SELECT_FROM_LEVEL = new PlayerDetector.EntitySelector() {
			@Override
			public List<ServerPlayer> getPlayers(final ServerLevel level, final Predicate<? super Player> selector) {
				return level.getPlayers(selector);
			}

			@Override
			public <T extends Entity> List<T> getEntities(
				final ServerLevel level, final EntityTypeTest<Entity, T> type, final AABB aabb, final Predicate<? super T> selector
			) {
				return level.getEntities(type, aabb, selector);
			}
		};

		List<? extends Player> getPlayers(final ServerLevel level, final Predicate<? super Player> selector);

		<T extends Entity> List<T> getEntities(final ServerLevel level, final EntityTypeTest<Entity, T> type, final AABB bb, final Predicate<? super T> selector);

		static PlayerDetector.EntitySelector onlySelectPlayer(final Player player) {
			return onlySelectPlayers(List.of(player));
		}

		static PlayerDetector.EntitySelector onlySelectPlayers(final List<Player> players) {
			return new PlayerDetector.EntitySelector() {
				@Override
				public List<Player> getPlayers(final ServerLevel level, final Predicate<? super Player> selector) {
					return players.stream().filter(selector).toList();
				}

				@Override
				public <T extends Entity> List<T> getEntities(
					final ServerLevel level, final EntityTypeTest<Entity, T> type, final AABB bb, final Predicate<? super T> selector
				) {
					return players.stream().map(type::tryCast).filter(Objects::nonNull).filter(selector).toList();
				}
			};
		}
	}
}