[in_app_purchase] Add support to cross-grade a subscription on Android

AUTHORS

@@ -56,4 +56,5 @@ Giancarlo Rocha <giancarloiff@gmail.com>
 Ryo Miyake <ryo@miyake.id>
 Théo Champion <contact.theochampion@gmail.com>
 Kazuki Yamaguchi <y.kazuki0614n@gmail.com>
-Eitan Schwartz <eshvartz@gmail.com>
+Eitan Schwartz <eshvartz@gmail.com>
+Alessandro Agosto <agosto.alessandro@gmail.com>

packages/in_app_purchase/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.3.4
+
+* Android: Add support for subscription cross-grades
+
 ## 0.3.3
 
 * Introduce `SKPaymentQueueWrapper.transactions`.
@@ -9,7 +13,7 @@
 ## 0.3.2+1
 
 * iOS: Fix only transactions with SKPaymentTransactionStatePurchased and SKPaymentTransactionStateFailed can be finished.
-* iOS: Only one pending transaction of a given product is allowed.  
+* iOS: Only one pending transaction of a given product is allowed.
 
 ## 0.3.2
 

packages/in_app_purchase/android/src/main/java/io/flutter/plugins/inapppurchase/MethodCallHandlerImpl.java

@@ -120,7 +120,10 @@ public void onMethodCall(MethodCall call, MethodChannel.Result result) {
         break;
       case InAppPurchasePlugin.MethodNames.LAUNCH_BILLING_FLOW:
         launchBillingFlow(
-            (String) call.argument("sku"), (String) call.argument("accountId"), result);
+            (String) call.argument("sku"),
+            (String) call.argument("accountId"),
+            (String) call.argument("oldSku"),
+            result);
         break;
       case InAppPurchasePlugin.MethodNames.QUERY_PURCHASES:
         queryPurchases((String) call.argument("skuType"), result);
@@ -189,7 +192,10 @@ public void onSkuDetailsResponse(
   }
 
   private void launchBillingFlow(
-      String sku, @Nullable String accountId, MethodChannel.Result result) {
+      String sku,
+      @Nullable String accountId,
+      @Nullable String oldSku,
+      MethodChannel.Result result) {
     if (billingClientError(result)) {
       return;
     }
@@ -203,6 +209,19 @@ private void launchBillingFlow(
       return;
     }
 
+    SkuDetails oldSkuDetails = null;
+
+    if (oldSku != null) {
+      oldSkuDetails = cachedSkus.get(oldSku);
+      if (oldSkuDetails == null) {
+        result.error(
+            "NOT_FOUND",
+            "Details for sku " + oldSku + " are not available. Has this ID already been fetched?",
+            null);
+        return;
+      }
+    }
+
     if (activity == null) {
       result.error(
           "ACTIVITY_UNAVAILABLE",
@@ -213,8 +232,17 @@ private void launchBillingFlow(
       return;
     }
 
-    BillingFlowParams.Builder paramsBuilder =
-        BillingFlowParams.newBuilder().setSkuDetails(skuDetails);
+    BillingFlowParams.Builder paramsBuilder;
+
+    // Requested a subscription cross-grade.
+    if (oldSkuDetails != null) {
+      // NOTE: currently only the default proration mode is supported.
+      // https://developer.android.com/google/play/billing/billing_subscriptions#set-proration-mode
+      paramsBuilder = BillingFlowParams.newBuilder().setSkuDetails(skuDetails).setOldSku(oldSku);
+    } else {
+      paramsBuilder = BillingFlowParams.newBuilder().setSkuDetails(skuDetails);
+    }
+
     if (accountId != null && !accountId.isEmpty()) {
       paramsBuilder.setAccountId(accountId);
     }

packages/in_app_purchase/lib/src/billing_client_wrappers/billing_client_wrapper.dart

@@ -168,11 +168,12 @@ class BillingClient {
   /// and [the given
   /// accountId](https://developer.android.com/reference/com/android/billingclient/api/BillingFlowParams.Builder.html#setAccountId(java.lang.String)).
   Future<BillingResultWrapper> launchBillingFlow(
-      {@required String sku, String accountId}) async {
+      {@required String sku, String accountId, String oldSku}) async {
     assert(sku != null);
     final Map<String, dynamic> arguments = <String, dynamic>{
       'sku': sku,
       'accountId': accountId,
+      'oldSku': oldSku,
     };
     return BillingResultWrapper.fromJson(
         await channel.invokeMapMethod<String, dynamic>(

packages/in_app_purchase/lib/src/in_app_purchase/google_play_connection.dart

@@ -56,7 +56,8 @@ class GooglePlayConnection
     BillingResultWrapper billingResultWrapper =
         await billingClient.launchBillingFlow(
             sku: purchaseParam.productDetails.id,
-            accountId: purchaseParam.applicationUserName);
+            accountId: purchaseParam.applicationUserName,
+            oldSku: purchaseParam.oldProduct?.id);
     return billingResultWrapper.responseCode == BillingResponse.ok;
   }
 

packages/in_app_purchase/lib/src/in_app_purchase/purchase_details.dart

@@ -79,7 +79,8 @@ class PurchaseParam {
   PurchaseParam(
       {@required this.productDetails,
       this.applicationUserName,
-      this.sandboxTesting});
+      this.sandboxTesting,
+      this.oldProduct});
 
   /// The product to create payment for.
   ///
@@ -96,6 +97,10 @@ class PurchaseParam {
 
   /// The 'sandboxTesting' is only available on iOS, set it to `true` for testing in AppStore's sandbox environment. The default value is `false`.
   final bool sandboxTesting;
+
+  /// The 'oldProduct' is only available on Android for non-consumable resources and is meant to allow subscription cross-grades.
+  /// By setting this you will replace the subscription represented by `oldProduct`. On iOS this is ignored.
+  final ProductDetails oldProduct;
 }
 
 /// Represents the transaction details of a purchase.

packages/in_app_purchase/pubspec.yaml

@@ -1,7 +1,7 @@
 name: in_app_purchase
 description: A Flutter plugin for in-app purchases. Exposes APIs for making in-app purchases through the App Store and Google Play.
 homepage: https://github.com/flutter/plugins/tree/master/packages/in_app_purchase
-version: 0.3.3
+version: 0.3.4
 
 dependencies:
   async: ^2.0.8

packages/in_app_purchase/test/billing_client_wrappers/billing_client_wrapper_test.dart

@@ -159,6 +159,7 @@ void main() {
           stubPlatform.previousCallMatching(launchMethodName).arguments;
       expect(arguments['sku'], equals(skuDetails.sku));
       expect(arguments['accountId'], equals(accountId));
+      expect(arguments['oldSku'], isNull);
     });
 
     test('handles null accountId', () async {
@@ -178,6 +179,32 @@ void main() {
           stubPlatform.previousCallMatching(launchMethodName).arguments;
       expect(arguments['sku'], equals(skuDetails.sku));
       expect(arguments['accountId'], isNull);
+      expect(arguments['oldSku'], isNull);
+    });
+
+    test('handles oldSku', () async {
+      const String debugMessage = 'dummy message';
+      final BillingResponse responseCode = BillingResponse.ok;
+      final BillingResultWrapper expectedBillingResult = BillingResultWrapper(
+          responseCode: responseCode, debugMessage: debugMessage);
+      stubPlatform.addResponse(
+        name: launchMethodName,
+        value: buildBillingResultMap(expectedBillingResult),
+      );
+      final SkuDetailsWrapper skuDetails = dummySkuDetails;
+      final String accountId = "hashedAccountId";
+
+      expect(
+          await billingClient.launchBillingFlow(
+              sku: skuDetails.sku,
+              accountId: accountId,
+              oldSku: skuDetails.sku),
+          equals(expectedBillingResult));
+      Map<dynamic, dynamic> arguments =
+          stubPlatform.previousCallMatching(launchMethodName).arguments;
+      expect(arguments['sku'], equals(skuDetails.sku));
+      expect(arguments['accountId'], equals(accountId));
+      expect(arguments['oldSku'], equals(skuDetails.sku));
     });
   });