DialogQueue-4

dq.kt

class DialogHandlerImpl(
    private val queue: DialogQueue,
): DialogHandler {

    override fun <Req, Res> showDialog(
        builder: DialogBuilder<Req, Res>,
        req: Req,
        priority: DialogQueue.Priority
    ) {
        show(builder = builder, req = req, priority = priority)
    }

    override suspend fun <Req, Res> showDialogForResult(
        builder: DialogBuilder<Req, Res>,
        req: Req,
        priority: DialogQueue.Priority
    ): Result<Res> {
        return runCatching {
            show(builder = builder, req = req, priority = priority).await()
        }
    }

    override suspend fun <Res> showDialogForResult(
        builder: DialogBuilder<Unit, Res>,
        priority: DialogQueue.Priority
    ): Result<Res> {
        return showDialogForResult(builder, Unit)
    }

    private fun <Req, Res> show(
        builder: DialogBuilder<Req, Res>,
        req: Req,
        priority: DialogQueue.Priority
    ): CompletableDeferred<Res> {
        var deferred = CompletableDeferred<Res>()
        val tag = "DialogHandler::${builder::class.java.simpleName}::${req}"
        queue.add(
            DialogQueueElement(
                priority = priority,
                tag = tag,
                dialogBuilder =  { context, dismiss ->
                    // 다이얼로그를 onPause에서 닫고 다시 꺼내서 보여줄때는 
                    // CompletableDeferred가 이미 Completed된 상태라 닫기를 눌러도 먹통이 될 것이다. 
                    // 그래서 다이얼로그를 빌드할때 CompletableDeferred가 isCompleted 라면
                    // 새로운 deferred를 생성해서 넘겨준다.
                    if (deferred.isCompleted) {
                        deferred = CompletableDeferred()
                    }
                    deferred.invokeOnCompletion { dismiss() }
                    builder.build(
                        context = context,
                        req = req,
                        deferred = deferred,
                    )
                }
            )
        )
        return deferred
    }
}