// I have no expirience with Scalaz, but I believe that Scalaz's Kleisli and the one of Cats are quite similar
import cats.Id
import cats.data.Kleisli
import cats.implicits._

case class User(id: Int, name: String, active: Boolean)

trait UserService {
  type DeactivateConfigT

  def deactivate(id: Int): Kleisli[Id, DeactivateConfigT, User]
}

trait UserRepository {
  type GetConfigT
  type SaveConfigT

  def get(id: Int): Kleisli[Option, GetConfigT, Unit]
  def save(user: User): Kleisli[Id, SaveConfigT, Unit]
}

object DbUserRepository extends UserRepository {
  final case class DbConfig(host: String, user: String, password: String, db: String)
  type GetConfigT = DbConfig
  type SaveConfigT = DbConfig

  // Implementation of the following methods are straightforward (or at least I think so), because
  // they do not depend on something returning Kleisli itself
  def get(id: Int): Kleisli[Option, GetConfigT, Unit] = ???
  def save(user: User): Kleisli[Id, SaveConfigT, Unit] = ???
}

object DefaultUserService extends UserService {
  final case class DeactivateConfig(repo: UserRepository)
  type DeactivateConfigT = DeactivateConfig

  // And here I have no idea how we should use UserRepository here. Especially taking into account
  // that we want to keep things decoupled and we depend here on the UserRepository trait, not a
  // concrete implementation with a known configuration requirements
  def deactivate(id: Int): Kleisli[Id, DeactivateConfigT, User] = ???
}