Monadic-ScalaFX-Demo/src/main/scala/nova/monadic_sfx/pages/LoginPage.scala

package nova.monadic_sfx.pages
import nova.monadic_sfx.AppTypes
import scalafx.scene.control.TextField
import scalafx.scene.control._
import scalafx.scene.layout.VBox
import scalafx.scene.Node
import scalafx.Includes._
import scalafx.scene.Parent
import scalafx.application.JFXApp.PrimaryStage
import nova.monadic_sfx.http.requests.DummyRequest
import monix.eval.Task
import monix.execution.Scheduler
// import io.odin.syntax._
// import _root_.monix.eval.Task
// import io.odin.monix._
// import javafx.beans.property.ObjectProperty
// import javafx.event.{ActionEvent, EventHandler}
class LoginPage(
    appStage: PrimaryStage,
    backend: AppTypes.HttpBackend,
    system: akka.actor.ActorSystem
) {

  val dummyRequester = new DummyRequest(backend)

  //pure function callbacks, but with side effects still
  private def onLogout(stage: PrimaryStage) =
    for {
      _ <- Task { println("logging out") }
      root <- render
      _ <- Task(stage.scene().setRoot(root))
    } yield ()

  private def onLogin(stage: PrimaryStage) =
    Task.deferAction { implicit Scheduler =>
      for {
        _ <- Task(println("logging in"))
        root <- Task {
          stage
            .scene()
            .setRoot(
              HomePage(
                backend,
                system,
                () => runFxTask(onLogout(appStage))
              )
            )
        }
      } yield ()
    }

  private lazy val root = Task.deferAction(implicit scheduler =>
    Task {
      new VBox {
        children = Seq(
          new Label {
            text = "username"
          },
          new TextField(),
          new Label {
            text = "password"
          },
          new TextField(),
          new Button {
            text = "Login"
            onAction = () =>
              runFxTask {
                Task
                  .parZip2(
                    dummyRequester
                      .send(),
                    // .executeOn(Scheduler.global)
                    onLogin(appStage)
                  )
              }
          }
        )
      }
    }
  )
  def render: Task[Parent] = root

  /**
    * Implicitly runs monix task as fire and forget. \
    * For use in ScalaFX callbacks.
    *
    * @param task
    * @param s
    */
  def runFxTask[T](task: => Task[T])(implicit s: Scheduler) = {
    task.runAsyncAndForget
  }

}

object LoginPage {
  def apply(
      appStage: PrimaryStage,
      backend: AppTypes.HttpBackend,
      system: akka.actor.ActorSystem
  ) = new LoginPage(appStage, backend, system).render
}