import io.reactivex.Observable
import io.reactivex.rxkotlin.Observables
import io.reactivex.schedulers.Schedulers

val BAD_SESSION_ID = "BAD_SESSION_ID"
val GOOD_SESSION_ID = "GOOD_SESSION_ID"

fun main(args: Array<String>) {

    val fileList = listOf("file1", "file2", "file3", "file4")
    val filesObservables = Observable.fromIterable(fileList)
            .flatMap { prepareFile(it) }
            .toList()
            .toObservable()
            .publish()
            .autoConnect(2)

    val requestSingle = Observable.just(Request())

    val responseObservable = Observables.zip(filesObservables, requestSingle, { a, b -> Pair(a, b) })
            .flatMap { sendRequest(it.first, it.second, BAD_SESSION_ID) }
            .publish()
            .autoConnect(2)

    val requestFirstAttempt = responseObservable
            .filter { it == ErrorCode.OK }

    val sessionIdSingle = responseObservable
            .filter { it == ErrorCode.BAD_SESSION_ID }
            .flatMap { reLogin() }

    val requestSecondAttempt = Observables.zip(sessionIdSingle, filesObservables, requestSingle, { a, b, c -> Triple(a, b, c) })
            .flatMap { sendRequest(it.second, it.third, it.first) }

    Observable.merge(requestFirstAttempt, requestSecondAttempt)
            .subscribeOn(Schedulers.trampoline())
            .first(ErrorCode.UNKNOWN_ERROR)
            .subscribe({ value ->
                println("errorCode = $value")
            }, { error ->
                error.printStackTrace()
            })
}

fun prepareFile(file: String): Observable<String> {
    println("prepareFile")
    return Observable.just(file)
}

fun reLogin(): Observable<String> {
    println("reLogin")
    return Observable.just(GOOD_SESSION_ID)
}

fun sendRequest(files: MutableList<String>, request: Request, sessionId: String): Observable<ErrorCode> {
    return if (sessionId == BAD_SESSION_ID) {
        println("sendRequest BAD_SESSION_ID")
        Observable.just(ErrorCode.BAD_SESSION_ID)
    } else {
        println("sendRequest GOOD_SESSION_ID")
        Observable.just(ErrorCode.OK)
    }
}

class Request

enum class ErrorCode {
    OK,
    BAD_SESSION_ID,
    UNKNOWN_ERROR
}