//> using scala "3.3.5"
//> using dep "io.github.marcinzh::turbolift-core:0.112.0"
//> using dep "io.github.marcinzh::turbolift-bindless:0.112.0"

/************* HOW TO RUN ********************
1. Ensure you have Java 11 or newer
2. Install scala-cli
3. Execute `scala-cli <link-to-this-gist>`
**********************************************/

import turbolift.{!!, Signature, Effect, Handler}
import turbolift.effects.{Console, IO, Error, ErrorSignature}
import turbolift.Extensions._
import turbolift.bindless._


trait ChoiceSignature extends Signature:
  def fail(reason: String): Nothing !! ThisEffect
  def choose: Boolean !! ThisEffect


trait ChoiceEffect extends Effect[ChoiceSignature] with ChoiceSignature:
  final override def fail(reason: String): Nothing !! ThisEffect = perform(_.fail(reason))
  final override def choose: Boolean !! ThisEffect = perform(_.choose)


extension (fx: ChoiceEffect)
  def handler_NoThrowOnFail =
    new fx.impl.Stateless[Identity, Vector, Any] with fx.impl.Sequential with ChoiceSignature:
      override def onReturn(a: Unknown) = Vector(a).pure_!!
      override def fail(reason: String): Nothing !! ThisEffect = Control.abort(Vector())
      override def choose = Control.capture(k => k(false).zipWith(k(true))(_ ++ _))
    .toHandler

  // Takes an instance of `Error` effect as a dependency
  def handler_ThrowOnFail(errorFx: Error[String]): Handler[Identity, Vector, fx.type, errorFx.type] =
    new fx.impl.Stateless[Identity, Vector, errorFx.type] with fx.impl.Sequential with ChoiceSignature:
      override def onReturn(a: Unknown) = Vector(a).pure_!!
      override def fail(reason: String): Nothing !! ThisEffect = errorFx.raise(reason)
      override def choose = Control.capture(k => k(false).zipWith(k(true))(_ ++ _))
    .toHandler


extension (fx: Error[String])
  def hookLoggingToCatch[A, U <: Console & fx.type](comp: A !! U): A !! U =
    // Mostly a copy & paste of the original handler for `Error` effect
    new fx.impl.Stateless[Identity, [X] =>> Either[String, X], Console] with fx.impl.Sequential with ErrorSignature[String, String]:
      override def onReturn(a: Unknown) = Right(a).pure_!!
      override def raise(e: String) = Control.abort(Left(e))
      override def raises(e: String) = Control.abort(Left(e))
      override def toEither[A, U <: ThisEffect](comp: A !! U) = Control.delimit(comp)
      override def catchAllEff[A, U <: ThisEffect](body: A !! U)(f: String => A !! U): A !! U =
        toEither(
          Console.println("[LOG] Entering catch scope...") &&!
          body
        ).flatMap:
          case Right(a) => a.pure_!!
          case Left(e) =>
            Console.println(s"[LOG] Caught exception: $e") &&!
            f(e)
    .toHandler
    .handle(comp)
    .flatMap(fx.fromEither)


/***************************************************************
In Turbolift effects are not only types, but also values.
See `Labelled Effects` at https://marcinzh.github.io/turbolift/advanced/labelled.html
All code ABOVE is effect-instance-independent, taking them as parameters if required.
All code BELOW depends on concrete effect instances.
***************************************************************/
case object MyError extends Error[String]
case object MyChoice extends ChoiceEffect
type MyError = MyError.type
type MyChoice = MyChoice.type


def failWhenBothTrue: (Boolean, Boolean) !! (MyChoice & Console) =
  `do`:
    val x = MyChoice.choose.!
    val y = MyChoice.choose.!
    if x && y then MyChoice.fail("x = y = True").!
    Console.println(s"x=$x y=$y").!
    (x, y)


def catchFail: Option[(Boolean, Boolean)] !! (MyChoice & MyError & Console) =
  MyError.catchAllEff(failWhenBothTrue.map(Some(_))): reason =>
    Console.println(s"caught failure: $reason") &&!
    None.pure_!!


def program: Option[(Boolean, Boolean)] !! (MyChoice & MyError & Console) =
  MyError.hookLoggingToCatch(catchFail)


@main def main =
  `do`:
    Console.println("[NoThrowOnFail]").!
    val r1 = program.handleWith(MyChoice.handler_NoThrowOnFail).handleWith(MyError.handler).!
    Console.println(r1.toString).!
    Console.println("").!
    Console.println("[ThrowOnFail]").!
    val r2 = program.handleWith(MyChoice.handler_ThrowOnFail(MyError)).handleWith(MyError.handler).!
    Console.println(r2.toString).!
  .handleWith(Console.handler)
  .runIO