[in_app_purchase_storekit] Add storekit 2 support for canMakePayments and products (#7473)

This PR contains support for StoreKit2's [canMakePayments](https://developer.apple.com/documentation/storekit/appstore/3822277-canmakepayments) and [products](https://developer.apple.com/documentation/storekit/product/3851116-products).

This also contains basic scaffolding for SK2 support, such as pigeon translators.

Part of flutter/flutter#116383

Author: LouiseHsu

packages/in_app_purchase/in_app_purchase_storekit/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.3.18+1
+
+* Adds support for StoreKit2's `canMakePayments` and `products` 
+
 ## 0.3.18
 
 * Updates minimum supported SDK version to Flutter 3.19/Dart 3.3.

packages/in_app_purchase/in_app_purchase_storekit/darwin/Classes/InAppPurchasePlugin.swift

@@ -41,6 +41,9 @@ public class InAppPurchasePlugin: NSObject, FlutterPlugin, InAppPurchaseAPI {
     registrar.addMethodCallDelegate(instance, channel: channel)
     registrar.addApplicationDelegate(instance)
     SetUpInAppPurchaseAPI(messenger, instance)
+    if #available(iOS 15.0, macOS 12.0, *) {
+      InAppPurchase2APISetup.setUp(binaryMessenger: messenger, api: instance)
+    }
   }
 
   // This init is used for tests

packages/in_app_purchase/in_app_purchase_storekit/darwin/Classes/StoreKit2/InAppPurchaseStoreKit2.swift

@@ -0,0 +1,37 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+@available(iOS 15.0, macOS 12.0, *)
+extension InAppPurchasePlugin: InAppPurchase2API {
+  // MARK: - Pigeon Functions
+
+  // Wrapper method around StoreKit2's canMakePayments() method
+  // https://developer.apple.com/documentation/storekit/appstore/3822277-canmakepayments
+  func canMakePayments() throws -> Bool {
+    return AppStore.canMakePayments
+  }
+
+  // Wrapper method around StoreKit2's products() method
+  // https://developer.apple.com/documentation/storekit/product/3851116-products
+  func products(
+    identifiers: [String], completion: @escaping (Result<[SK2ProductMessage], Error>) -> Void
+  ) {
+    Task {
+      do {
+        let products = try await Product.products(for: identifiers)
+        let productMessages = products.map {
+          $0.convertToPigeon
+        }
+        completion(.success(productMessages))
+      } catch {
+        completion(
+          .failure(
+            PigeonError(
+              code: "storekit2_products_error",
+              message: error.localizedDescription,
+              details: error.localizedDescription)))
+      }
+    }
+  }
+}

packages/in_app_purchase/in_app_purchase_storekit/darwin/Classes/StoreKit2/StoreKit2Translators.swift

@@ -0,0 +1,169 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import Foundation
+import StoreKit
+
+@available(iOS 15.0, macOS 12.0, *)
+extension Product {
+  var convertToPigeon: SK2ProductMessage {
+
+    return SK2ProductMessage(
+      id: id,
+      displayName: displayName,
+      description: description,
+      price: NSDecimalNumber(decimal: price).doubleValue,
+      displayPrice: displayPrice,
+      type: type.convertToPigeon,
+      subscription: subscription?.convertToPigeon,
+      priceLocale: priceFormatStyle.locale.convertToPigeon
+    )
+  }
+}
+
+extension SK2ProductMessage: Equatable {
+  static func == (lhs: SK2ProductMessage, rhs: SK2ProductMessage) -> Bool {
+    return lhs.id == rhs.id && lhs.displayName == rhs.displayName
+      && lhs.description == rhs.description && lhs.price == rhs.price
+      && lhs.displayPrice == rhs.displayPrice && lhs.type == rhs.type
+      && lhs.subscription == rhs.subscription && lhs.priceLocale == rhs.priceLocale
+  }
+}
+
+@available(iOS 15.0, macOS 12.0, *)
+extension Product.ProductType {
+  var convertToPigeon: SK2ProductTypeMessage {
+    switch self {
+    case Product.ProductType.autoRenewable:
+      return SK2ProductTypeMessage.autoRenewable
+    case Product.ProductType.consumable:
+      return SK2ProductTypeMessage.consumable
+    case Product.ProductType.nonConsumable:
+      return SK2ProductTypeMessage.nonConsumable
+    case Product.ProductType.nonRenewable:
+      return SK2ProductTypeMessage.nonRenewable
+    default:
+      fatalError("An unknown ProductType was passed in")
+    }
+  }
+}
+
+@available(iOS 15.0, macOS 12.0, *)
+extension Product.SubscriptionInfo {
+  var convertToPigeon: SK2SubscriptionInfoMessage {
+    return SK2SubscriptionInfoMessage(
+      promotionalOffers: promotionalOffers.map({ $0.convertToPigeon }),
+      subscriptionGroupID: subscriptionGroupID,
+      subscriptionPeriod: subscriptionPeriod.convertToPigeon)
+  }
+}
+
+extension SK2SubscriptionInfoMessage: Equatable {
+  static func == (lhs: SK2SubscriptionInfoMessage, rhs: SK2SubscriptionInfoMessage) -> Bool {
+    return lhs.promotionalOffers == rhs.promotionalOffers
+      && lhs.subscriptionGroupID == rhs.subscriptionGroupID
+      && lhs.subscriptionPeriod == rhs.subscriptionPeriod
+  }
+}
+
+@available(iOS 15.0, macOS 12.0, *)
+extension Product.SubscriptionOffer {
+  var convertToPigeon: SK2SubscriptionOfferMessage {
+    return SK2SubscriptionOfferMessage(
+      /// ID is always `nil` for introductory offers and never `nil` for other offer types.
+      id: id,
+      price: NSDecimalNumber(decimal: price).doubleValue,
+      type: type.convertToPigeon,
+      period: period.convertToPigeon,
+      periodCount: Int64(periodCount),
+      paymentMode: paymentMode.convertToPigeon
+    )
+  }
+}
+
+extension SK2SubscriptionOfferMessage: Equatable {
+  static func == (lhs: SK2SubscriptionOfferMessage, rhs: SK2SubscriptionOfferMessage) -> Bool {
+    return lhs.id == rhs.id && lhs.price == rhs.price && lhs.type == rhs.type
+      && lhs.period == rhs.period && lhs.periodCount == rhs.periodCount
+      && lhs.paymentMode == rhs.paymentMode
+  }
+}
+
+@available(iOS 15.0, macOS 12.0, *)
+extension Product.SubscriptionOffer.OfferType {
+  var convertToPigeon: SK2SubscriptionOfferTypeMessage {
+    switch self {
+    case .introductory:
+      return SK2SubscriptionOfferTypeMessage.introductory
+    case .promotional:
+      return SK2SubscriptionOfferTypeMessage.promotional
+    default:
+      fatalError("An unknown OfferType was passed in")
+    }
+  }
+}
+
+@available(iOS 15.0, macOS 12.0, *)
+extension Product.SubscriptionPeriod {
+  var convertToPigeon: SK2SubscriptionPeriodMessage {
+    return SK2SubscriptionPeriodMessage(
+      value: Int64(value),
+      unit: unit.convertToPigeon)
+  }
+}
+
+extension SK2SubscriptionPeriodMessage: Equatable {
+  static func == (lhs: SK2SubscriptionPeriodMessage, rhs: SK2SubscriptionPeriodMessage) -> Bool {
+    return lhs.value == rhs.value && lhs.unit == rhs.unit
+  }
+}
+
+@available(iOS 15.0, macOS 12.0, *)
+extension Product.SubscriptionPeriod.Unit {
+  var convertToPigeon: SK2SubscriptionPeriodUnitMessage {
+    switch self {
+    case .day:
+      return SK2SubscriptionPeriodUnitMessage.day
+    case .week:
+      return SK2SubscriptionPeriodUnitMessage.week
+    case .month:
+      return SK2SubscriptionPeriodUnitMessage.month
+    case .year:
+      return SK2SubscriptionPeriodUnitMessage.year
+    @unknown default:
+      fatalError("unknown SubscriptionPeriodUnit encountered")
+    }
+  }
+}
+
+@available(iOS 15.0, macOS 12.0, *)
+extension Product.SubscriptionOffer.PaymentMode {
+  var convertToPigeon: SK2SubscriptionOfferPaymentModeMessage {
+    switch self {
+    case .freeTrial:
+      return SK2SubscriptionOfferPaymentModeMessage.freeTrial
+    case .payUpFront:
+      return SK2SubscriptionOfferPaymentModeMessage.payUpFront
+    case .payAsYouGo:
+      return SK2SubscriptionOfferPaymentModeMessage.payAsYouGo
+    default:
+      fatalError("Encountered an unknown PaymentMode")
+    }
+  }
+}
+
+extension Locale {
+  var convertToPigeon: SK2PriceLocaleMessage {
+    return SK2PriceLocaleMessage(
+      currencyCode: currencyCode ?? "",
+      currencySymbol: currencySymbol ?? ""
+    )
+  }
+}
+
+extension SK2PriceLocaleMessage: Equatable {
+  static func == (lhs: SK2PriceLocaleMessage, rhs: SK2PriceLocaleMessage) -> Bool {
+    return lhs.currencyCode == rhs.currencyCode && lhs.currencySymbol == rhs.currencySymbol
+  }
+}