jmonkey-test/src/main/scala/wow/doge/mygame/subsystems/scriptsystem/ScriptActor.scala

package wow.doge.mygame.state

import akka.actor.typed.scaladsl.Behaviors
import ammonite.Main
import akka.actor.typed.ActorRef
import ammonite.runtime.Storage.Folder
import ammonite.main.Defaults
import akka.actor.typed.Behavior
import akka.actor.typed.scaladsl.ActorContext
import ammonite.util.Res.Success
import javax.script.ScriptEngine
import javax.script.ScriptEngineManager
import groovy.util.GroovyScriptEngine
import cats.implicits._

object ScriptActor {
  type Kotlin
  type MyScriptEngine[T] = ScriptEngine
  type KotlinScriptEngine = MyScriptEngine[Kotlin]

  final case class Error(reason: String)

  sealed trait Command
  final case class CompileAny(
      path: os.Path,
      result: ActorRef[Either[Error, Any]]
  ) extends Command

  def defaultScalaRunner() =
    ammonite
      .Main(
        storageBackend = new Folder(
          // os.pwd / "target"
          Defaults.ammoniteHome,
          isRepl = false
        )
      )

  def defaultKotlinRunner(): KotlinScriptEngine = {
    val manager = new ScriptEngineManager()
    val engine = manager.getEngineByExtension("main.kts")
    engine
  }

  def defaultGroovyRunner(): GroovyScriptEngine =
    new GroovyScriptEngine(os.pwd.toString())

  def apply(
      scalaRunner: Main = defaultScalaRunner(),
      kotlinRunner: KotlinScriptEngine = defaultKotlinRunner(),
      groovyRunner: GroovyScriptEngine = defaultGroovyRunner()
      // parent: ActorRef[ScriptStoringActor.Command]
  ): Behavior[ScriptActor.Command] =
    Behaviors.setup(ctx =>
      new ScriptActor(
        scalaRunner,
        kotlinRunner,
        groovyRunner,
        ctx
      ).receiveMessage
    )

  sealed trait ScriptType
  case object ScalaType extends ScriptType
  case object KotlinType extends ScriptType
  case object GroovyType extends ScriptType

  def determineScriptType(path: os.Path): Either[Error, ScriptType] =
    path.toString match {
      case s if s.endsWith(".sc")       => Right(ScalaType)
      case s if s.endsWith(".main.kts") => Right(KotlinType)
      case s if s.endsWith(".groovy")   => Right(GroovyType)
      case _                            => Left(Error("Unknown script type"))
    }

  def runScala(path: os.Path, scalaRunner: ammonite.Main): Either[Error, Any] =
    scalaRunner
      .runScript(
        path,
        Seq.empty
      )
      ._1 match {
      case ammonite.util.Res.Exception(t, msg) => Left(Error(msg))

      case Success(obj) => Right(obj)

      case _ => Left(Error("Failed to run script"))
    }

  def runKotlin(
      path: os.Path,
      kotlinRunner: KotlinScriptEngine
  ): Either[Error, Any] =
    Either
      .catchNonFatal(kotlinRunner.eval(os.read(path)))
      .leftMap(t => Error(t.getMessage()))

  def runGroovy(
      path: os.Path,
      groovyRunner: GroovyScriptEngine
  ): Either[Error, Any] =
    Either
      .catchNonFatal(groovyRunner.run(path.relativeTo(os.pwd).toString(), ""))
      .leftMap(t => Error(t.getMessage()))

  def ensureReturnedObjectNotNull(scriptObject: Any): Either[Error, Any] =
    Either.fromOption(Option(scriptObject), Error("unknown object"))

}

class ScriptActor(
    val scalaRunner: ammonite.Main,
    val kotlinRunner: ScriptActor.KotlinScriptEngine,
    val groovyRunner: GroovyScriptEngine,
    context: ActorContext[ScriptActor.Command]
) {
  import ScriptActor._

  def receiveMessage: Behavior[Command] =
    Behaviors.receiveMessage { msg =>
      msg match {
        case CompileAny(path, requester) =>
          context.log.debug(s"Received $path")
          val res = getScript(path)
          context.log.debug(s"result = $res")
          requester ! res
          Behaviors.same
      }
    }

  def getScript(path: os.Path): Either[Error, Any] =
    determineScriptType(path) match {
      case Right(ScalaType) =>
        runScala(path, scalaRunner).flatMap(ensureReturnedObjectNotNull)
      case Right(KotlinType) =>
        runKotlin(path, kotlinRunner).flatMap(ensureReturnedObjectNotNull)
      case Right(GroovyType) =>
        runGroovy(path, groovyRunner).flatMap(ensureReturnedObjectNotNull)
      case l @ Left(err) => l
    }

}