package nova.monadic_sfx.ui.components.router

import scala.concurrent.duration._

import cats.kernel.Eq
import cats.syntax.eq._
import com.softwaremill.quicklens._
import io.circe.Codec
import io.circe.Decoder
import io.circe.Encoder
import io.circe.generic.JsonCodec
import io.circe.generic.semiauto._
import io.odin.Logger
import monix.bio.Task
import monix.eval.Coeval
import monix.reactive.Observable
import nova.monadic_sfx.util.History
import nova.monadic_sfx.util.IOUtils
import nova.monadic_sfx.util.controls.JFXSpinner
import nova.monadic_sfx.util.reactive.store.Middlewares
import nova.monadic_sfx.util.reactive.store.Reducer
import nova.monadic_sfx.util.reactive.store.Store
import scalafx.scene.Parent

object FXRouter {

  final case class State[P](page: P, history: History[P])
  object State {
    implicit def eqForAction[T] = Eq.fromUniversalEquals[State[T]]
  }

  sealed abstract class Action[+T]
  final case class Replace[T](page: T) extends Action[T]
  final case class HistoryEvent[T](page: T) extends Action[T]
  final case object Forward extends Action[Nothing]
  final case object Backward extends Action[Nothing]

  object Action {
    implicit def codec[T: Encoder: Decoder]: Codec[Action[T]] = deriveCodec
    implicit def eqForAction[T] = Eq.fromUniversalEquals[Action[T]]
  }

  type FXStore[P] = Store[Action[P], State[P]]

}

class FXRouter[P]()(implicit E: Encoder[P], D: Decoder[P]) {
  import FXRouter._

  def store(initialPage: P, logger: Logger[Task]): Task[FXStore[P]] =
    Task.deferAction(implicit s =>
      for {
        mw <- Middlewares.actionLoggerMiddleware[Action[P], State[P]](
          logger,
          "RouterStore"
        )
        store <- Store.createL[Action[P], State[P]](
          Replace(initialPage),
          State(initialPage, History(initialPage)),
          Reducer.withOptionalEffects[Task, Action[P], State[P]](reducer _),
          Seq(mw)
          // Seq(classOf[HistoryEvent[P]])
        )
      } yield store
    )

  def reducer(
      state: State[P],
      action: Action[P]
  ): (State[P], Option[Task[Action[P]]]) =
    action match {
      // case Init => (state, None)
      case Replace(p) =>
        (state.copy(page = p, history = state.history :+ p), None)
      case HistoryEvent(p) =>
        (state.copy(page = p), None)
      case Forward =>
        val s1 = state.modify(_.history).using(_.forward)
        val s2 = s1.modify(_.page).setTo(s1.history.current)
        s2 -> Some(Task.pure(HistoryEvent(s2.history.current)))
      case Backward =>
        val s1 = state.modify(_.history).using(_.backward)
        val s2 = s1.modify(_.page).setTo(s1.history.current)
        s2 -> Some(Task.pure(HistoryEvent(s2.history.current)))
    }

  def render(
      resolver: P => Parent,
      transitionDelay: FiniteDuration = 500.millis
  )(implicit store: FXStore[P]) =
    store
      .filter {
        case (a, _) => a =!= FXRouter.Forward
      }
      .filter {
        case (a, _) => a =!= FXRouter.Backward
      }
      .distinctUntilChanged
      .flatMap {
        case (_, FXRouter.State(p, _)) =>
          Observable.from(Coeval(new JFXSpinner)) ++ Observable.from(
            IOUtils.toTask(
              Task
                .racePair(
                  Task.sleep(transitionDelay),
                  Task.pure(resolver(p))
                )
                .flatMap {
                  case Left(_ -> fib)    => fib.join
                  case Right(fib -> res) => fib.join >> Task.pure(res)
                }
            )
          )
      }

  def link(
      page: P,
      store: FXStore[P]
  ) = {
    store.onNext(Replace(page))
  }
}

@JsonCodec
sealed trait Page
object Page {
  final case object Home extends Page
  final case object UserHome extends Page
  final case object Todo extends Page

  implicit val eqForPage = Eq.fromUniversalEquals[Page]
}

// case class State()
// object RouterStore {

//   sealed trait Action
//   case object Init extends Action

//   def reducer(state: State, action: Action) =
//     action match {
//       case Init => state

//     }
//   def apply() =
//     Store.createL[Action, State](Init, State(), Reducer(reducer _), Seq.empty)
// }