import StoreKit
import RxSwift
import RxStoreKit

let disposeBag = DisposeBag()

let productRequest = SKProductsRequest(productIdentifiers: Set(["your app product id"]))
productRequest.rx.productsRequest
    .subscribe(onNext: { product in
        print(product)
    }).disposed(by: disposeBag)
productRequest.start()

SKPaymentQueue.default().rx.restoreCompletedTransactions()
    .subscribe(onNext: { queue in
        // paymentQueueRestoreCompletedTransactionsFinished
        print(queue)
    }, onError: { error in
        // restoreCompletedTransactionsFailedWithError
        print(queue)
    }).disposed(by: disposeBag)

let productRequest = SKProductsRequest(productIdentifiers: Set(["xxx.xxx.xxx"]))
productRequest.rx.productsRequest
    .flatMap { response -> Observable<SKProduct> in
        return Observable.from(response.products)
    }
    .flatMap { product -> Observable<SKPaymentTransaction> in
        return SKPaymentQueue.default().rx.add(product: product)
    }
    .subscribe(onNext: { transition in
        print(transition)
    }).disposed(by: disposeBag)
productRequest.start()

let productRequest = SKProductsRequest(productIdentifiers: Set(["xxx.xxx.xxx"]))
productRequest.rx.productsRequest
    .flatMap { response -> Observable<SKProduct> in
        return Observable.from(response.products)
    }
    .flatMap { product -> Observable<SKPaymentTransaction> in
        return SKPaymentQueue.default().rx.add(product: product)
    }
    .flatMap { transaction -> Observable<SKDownload> in
        return SKPaymentQueue.default().rx.start(downloads: transaction.downloads)
    }
    .subscribe(onNext: { download in
        print(download)
    }).disposed(by: disposeBag)
productRequest.start()