My non-blocking scala recommender, searching through database for cheaper merchant, scala, slick

Recommender.scala

class Recommender(transactionModel: SasquatchTransactionModel)(implicit ec: ExecutionContext) extends StrictLogging {

  def findCheaperMerchant(transaction: SasquatchTransactionDTO): DBRead[Seq[SasquatchRecommendation]] = {
    val mId: String = transaction.merchantId
    logger.info(s"Computing cheaper merchant for transaction: ${transaction.extId} merchant: ${mId}")

    val top10NearestMerchants = transactionModel.nearestNeighbour(
      long = transaction.long,
      lat = transaction.lat,
      category = transaction.category
    )

    val isCheaper: (SasquatchTransaction) => Boolean = _.amount.abs < transaction.amount.abs
    val notSelf: (SasquatchTransaction) => Boolean = _.merchantId != mId

    top10NearestMerchants.flatMap(nearMerchants => {
      def getDistance(merchantId: String) = nearMerchants.filter(_.id == merchantId).map(_.distance).headOption
      logger.info(s"Found near Merchants: ${nearMerchants.filter(_.id != mId).map(_.id)}")
      transactionModel.findByMerchantDistanceInSet(nearMerchants)
        .map(_.filter(isCheaper)
          .filter(notSelf).flatMap(recommendedTransaction =>
            for {
              mmId <- recommendedTransaction.merchantId
              dist <- getDistance(mId)
            } yield SasquatchRecommendation(mId, mmId, dist)))
    })
  }
}

case class SasquatchTransactionDTO(extId: String, merchantId: String, category: String, long: Float, lat: Float, amount: BigDecimal)