package net.minecraft.world.entity.ai.sensing;

import com.google.common.collect.ImmutableSet;
import java.util.Comparator;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.world.entity.EntitySelector;
import net.minecraft.world.entity.LivingEntity;
import net.minecraft.world.entity.ai.Brain;
import net.minecraft.world.entity.ai.attributes.Attributes;
import net.minecraft.world.entity.ai.memory.MemoryModuleType;
import net.minecraft.world.entity.player.Player;

public class PlayerSensor extends Sensor<LivingEntity> {
	@Override
	public Set<MemoryModuleType<?>> requires() {
		return ImmutableSet.of(
			MemoryModuleType.NEAREST_PLAYERS,
			MemoryModuleType.NEAREST_VISIBLE_PLAYER,
			MemoryModuleType.NEAREST_VISIBLE_ATTACKABLE_PLAYER,
			MemoryModuleType.NEAREST_VISIBLE_ATTACKABLE_PLAYERS
		);
	}

	@Override
	protected void doTick(final ServerLevel level, final LivingEntity body) {
		List<Player> players = (List<Player>)level.players()
			.stream()
			.filter(EntitySelector.NO_SPECTATORS)
			.filter(player -> body.closerThan(player, this.getFollowDistance(body)))
			.sorted(Comparator.comparingDouble(body::distanceToSqr))
			.collect(Collectors.toList());
		Brain<?> brain = body.getBrain();
		brain.setMemory(MemoryModuleType.NEAREST_PLAYERS, players);
		List<Player> visiblePlayers = (List<Player>)players.stream()
			.filter(livingEntity -> isEntityTargetable(level, body, livingEntity))
			.collect(Collectors.toList());
		brain.setMemory(MemoryModuleType.NEAREST_VISIBLE_PLAYER, visiblePlayers.isEmpty() ? null : (Player)visiblePlayers.get(0));
		List<Player> visibleAttackablePlayers = visiblePlayers.stream().filter(livingEntity -> isEntityAttackable(level, body, livingEntity)).toList();
		brain.setMemory(MemoryModuleType.NEAREST_VISIBLE_ATTACKABLE_PLAYERS, visibleAttackablePlayers);
		brain.setMemory(MemoryModuleType.NEAREST_VISIBLE_ATTACKABLE_PLAYER, visibleAttackablePlayers.isEmpty() ? null : (Player)visibleAttackablePlayers.get(0));
	}

	protected double getFollowDistance(final LivingEntity body) {
		return body.getAttributeValue(Attributes.FOLLOW_RANGE);
	}
}