app.kt

import arrow.continuations.SuspendApp
import arrow.continuations.SuspendAppScope
import arrow.continuations.exitApp
import arrow.fx.coroutines.resourceScope
import kotlin.time.Duration
import kotlin.time.Duration.Companion.milliseconds
import kotlin.time.Duration.Companion.seconds
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.awaitCancellation
import kotlinx.coroutines.awaitCancellation
import kotlinx.coroutines.async
import kotlinx.coroutines.delay
import kotlinx.coroutines.isActive
import kotlinx.coroutines.launch

fun interface Work {
  suspend fun SuspendAppScope.work()
}

sealed interface Mode : Work
data class Delay(val duration: Duration = 3.seconds) : Mode, Work by Work({ delay(duration) })
data object Wait : Mode, Work by Work({ awaitCancellation() })
data object Fail : Mode, Work by Work({ error("BOOM!") })
data object ChildFail : Mode, Work by Work({ launch { error("boom.") } })
data object ExitApp : Mode, Work by Work({ exitApp(42) })
data object ChildExitApp : Mode, Work by Work({ async { exitApp(2) }.await() })
data object ChildLaunchExitApp : Mode, Work by Work({
  launch { exitApp(24) }
  awaitCancellation()
})
data object ExitProcess : Mode, Work by Work({
  launch { exitProcess(42) }
  awaitCancellation()
})

data object Timeout : Mode, Work by Work({
  resourceScope {
    onRelease { delay(6.seconds) }
    awaitCancellation()
  }
})

fun app(mode: String?) = app(
  when (mode) {
    "delay" -> Delay()
    "wait" -> Wait
    "fail" -> Fail
    "childfail" -> ChildFail
    "exitapp" -> ExitApp
    "childexitapp" -> ChildExitApp
    "childlaunchexitapp" -> ChildLaunchExitApp
    "exit" -> ExitProcess
    "timeout" -> Timeout
    else -> Delay()
  }
)

fun app(work: Work) {
  println("pre-suspendapp")
  SuspendApp(timeout = 5.seconds) {
    println("Running $work")
    resourceScope {
      onRelease {
        println("resource cleaning... ($it)")
        delay(2.seconds)
        println("resource clean complete")
      }
      with(work) { work() }
    }
  }
  println("post-suspendapp")
}

expect fun exitProcess(code: Int): Nothing