import akka.actor._
import akka.pattern.{AskTimeoutException, ask}
import akka.util.Timeout
import com.ctilogic.cvd.common.aux.StackTraceHelper
import com.ctilogic.cvd.common.messaging.{ErrorResponse, InternalRequest}
import com.github.levkhomich.akka.tracing.{ActorTracing, TracingSupport}
import scala.concurrent.{Future, ExecutionContext}
import scala.util.control.ControlThrowable



/**
 * This trait provides inheritor ability to communicate with services in distributed by cluster using `askService`
 * and `tellService` methods.
 */
trait DistributedServicesSupport { this: Actor with ActorTracing ⇒
    val apiRouter = CommonActorSelections.apiRouterSelection(context)

    /**
     * This method sends the `request` using the ask pattern to the service on one of nodes with `role`.
     *
     * This method provides request tracing.
     *
     * @param role the role of the node that should process the request.
     * @param request the request message.
     * @param parentRequest parent request should be provided, if the `request` generated by other request, for example
     *                      by REST request.
     * @param t ask timeout
     * @param ec ask executionContext
     * @return future with response.
     */
    def askService(role: NodeRole.Value, request: InternalRequest, parentRequest: TracingSupport)
            (implicit t: Timeout, ec: ExecutionContext): Future[Any] = {
        val future = apiRouter ? request.asChildOf(parentRequest)
        future map {
            case msg =>
                trace.record(request, "Ask service response: " + msg)
                msg
        } recover {
            case e: ControlThrowable =>
                throw e

            case e: AskTimeoutException =>
                trace.record(request, StackTraceHelper.format(e))
                ErrorResponse.ServiceUnavailable

            case e: Throwable =>
                trace.record(request, StackTraceHelper.format(e))
                ErrorResponse.InternalServerError("error asking " + role + " for " + request)
        }
    }


    /**
     * This method sends the `request` using tell to the appropriate service on one of nodes with `role`.
     *
     * This method provides request tracing.
     *
     * @param role the role of the node that should process the request.
     * @param request the request message.
     * @param parentRequest parent request should be provided, if the `request` generated by other request, for example
     *                      by REST request.
     */
    def tellService(role: NodeRole.Value, request: InternalRequest, parentRequest: TracingSupport): Unit = {
        apiRouter ! request.asChildOf(parentRequest)
    }
}