public void launchBillingFlow()

in TrivialDriveJava/app/src/main/java/com/sample/android/trivialdrivesample/billing/BillingDataSource.java [706:773]
68 lines of code
15 McCabe index (conditional complexity)

    public void launchBillingFlow(Activity activity, @NonNull String sku,
            String... upgradeSkus) {
        LiveData<SkuDetails> skuDetailsLiveData = skuDetailsLiveDataMap.get(sku);
        assert skuDetailsLiveData != null;
        SkuDetails skuDetails = skuDetailsLiveData.getValue();
        if (null != skuDetails) {
            if (null != upgradeSkus && upgradeSkus.length > 0) {
                billingClient.queryPurchasesAsync(BillingClient.SkuType.SUBS,
                        (br, purchasesList) -> {
                            List<Purchase> heldSubscriptions = new LinkedList<>();
                            if (br.getResponseCode() != BillingClient.BillingResponseCode.OK) {
                                Log.e(TAG, "Problem getting purchases: " + br.getDebugMessage());
                            } else {
                                if (null != purchasesList) {
                                    for (Purchase purchase : purchasesList) {
                                        for (String upgradeSku : upgradeSkus) {
                                            for (String purchaseSku : purchase.getSkus()) {
                                                if (purchaseSku.equals(upgradeSku)) {
                                                    if ( !heldSubscriptions.contains(purchase) ) {
                                                        heldSubscriptions.add(purchase);
                                                    }
                                                }
                                            }
                                        }
                                    }
                                }
                            }
                            BillingFlowParams.Builder billingFlowParamsBuilder = BillingFlowParams.newBuilder();
                            billingFlowParamsBuilder.setSkuDetails(skuDetails);
                            switch (heldSubscriptions.size()) {
                                case 1:  // Upgrade flow!
                                    Purchase purchase = heldSubscriptions.get(0);
                                    billingFlowParamsBuilder.setSubscriptionUpdateParams(
                                            BillingFlowParams.SubscriptionUpdateParams.newBuilder()
                                                    .setOldSkuPurchaseToken(heldSubscriptions.get(0)
                                                            .getPurchaseToken())
                                                    .build()
                                    );
                                    br = billingClient.launchBillingFlow(activity,
                                            billingFlowParamsBuilder.build());
                                    if (br.getResponseCode() == BillingClient.BillingResponseCode.OK) {
                                        billingFlowInProcess.postValue(true);
                                    } else {
                                        Log.e(TAG, "Billing failed: + " + br.getDebugMessage());
                                    }
                                    break;
                                case 0:
                                    break;
                                default:
                                    Log.e(TAG, heldSubscriptions.size() +
                                            " subscriptions subscribed to. Upgrade not possible.");
                            }
                        });
            } else {
                BillingFlowParams.Builder billingFlowParamsBuilder = BillingFlowParams.newBuilder();
                billingFlowParamsBuilder.setSkuDetails(skuDetails);
                BillingResult br = billingClient.launchBillingFlow(activity,
                        billingFlowParamsBuilder.build());
                if (br.getResponseCode() == BillingClient.BillingResponseCode.OK) {
                    billingFlowInProcess.postValue(true);
                } else {
                    Log.e(TAG, "Billing failed: + " + br.getDebugMessage());
                }
            }
        } else {
            Log.e(TAG, "SkuDetails not found for: " + sku);
        }
    }