Use Item only at night

I am trying to make it so that upon right click "IF" it is night time "THEN" item applies potion effects,  "ELSE" Message player "Not Night Time Yet" 

I just cannot figure out how to set up if statement right please help

public class Artefact5RightclickedProcedure {

    public static void execute(Entity entity) {

        if (entity == null)

            return;

        if (true) {

            if (entity instanceof LivingEntity _entity)

                _entity.addEffect(new MobEffectInstance(MobEffects.NIGHT_VISION, 500, 4));

            if (entity instanceof LivingEntity _entity)

                _entity.addEffect(new MobEffectInstance(MobEffects.INVISIBILITY, 500, 4));

            if (entity instanceof Player _player)

                _player.getCooldowns().addCooldown(DungeonsRpgMcModItems.ARTEFACT_5.get(), 600);

        } else {

            if (entity instanceof Player _player && !_player.level.isClientSide())

                _player.displayClientMessage(new TextComponent("It not dark yet"), (true));

        }

    }

}