ReaderComposabilityPOC.scala

package ru.itclover.streammachine.http.routes

import akka.actor.ActorSystem
import akka.http.scaladsl.server.Directives.{complete, path}
import akka.http.scaladsl.server.Route
import akka.http.scaladsl.server.Directives._
import cats.data.Reader
import org.apache.flink.streaming.api.scala.StreamExecutionEnvironment
import ru.itclover.streammachine.http.domain.output.SuccessfulResponse
import ru.itclover.streammachine.http.protocols.JsonProtocols
import scala.concurrent.ExecutionContextExecutor


trait App {
  implicit val as: ActorSystem
  implicit val executionContext: ExecutionContextExecutor
  implicit def streamEnvironment: StreamExecutionEnvironment

  val composeRoutes: Reader[ExecutionContextExecutor, Route] = for {
    streams <- FindStreamPatterns.fromExecutionContext
    batches <- FindBatchPatterns.fromExecutionContext
  } yield streams ~ batches

  val route: Route = composeRoutes.run(executionContext)

  // ...
}


trait FindStreamPatterns extends JsonProtocols {

  implicit val streamEnv: StreamExecutionEnvironment
  implicit val executionContext: ExecutionContextExecutor

  val route: Route = {
    path("find" / "stream") {
      complete(SuccessfulResponse(1))
    }
  }
}

object FindStreamPatterns {
  def fromExecutionContext(implicit env: StreamExecutionEnvironment): Reader[ExecutionContextExecutor, Route] = Reader { executor =>
    new FindStreamPatterns {
      implicit val streamEnv: StreamExecutionEnvironment = env
      implicit val executionContext: ExecutionContextExecutor = executor
    }.route
  }
}


trait FindBatchPatterns extends JsonProtocols {

  implicit val as: ActorSystem
  implicit val executionContext: ExecutionContextExecutor

  val route: Route = {
    path("find" / "batch") {
      complete(SuccessfulResponse(1))
    }
  }
}

object FindBatchPatterns {
  def fromExecutionContext: Reader[ExecutionContextExecutor, Route] = Reader { env =>
    new FindBatchPatterns {
      implicit val as: ActorSystem = as
      implicit val executionContext: ExecutionContextExecutor = env
    }.route
  }
}