[in_app_purchase_storekit] Add support for purchase and transactions

packages/in_app_purchase/in_app_purchase_storekit/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.3.18+2
+
+* Adds support for StoreKit2's `purchase` and `transactions`
+
 ## 0.3.18+1
 
 * Adds support for StoreKit2's `canMakePayments` and `products` 

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

@@ -27,6 +27,21 @@ public class InAppPurchasePlugin: NSObject, FlutterPlugin, InAppPurchaseAPI {
   // This property is optional, as it requires self to exist to be initialized.
   public var paymentQueueHandler: FLTPaymentQueueHandlerProtocol?
 
+  // This should be an Task, but Task is on available >= iOS 13
+  private var _updateListenerTask: Any?
+
+  @available(iOS 13.0, *)
+  var updateListenerTask: Task<(), Never> {
+    return self._updateListenerTask as! Task<(), Never>
+  }
+
+  @available(iOS 13.0, *)
+  func setListenerTaskAsTask(task: Task<(), Never>) {
+    self._updateListenerTask = task
+  }
+
+  var transactionCallbackAPI: InAppPurchase2CallbackAPI? = nil
+
   public static func register(with registrar: FlutterPluginRegistrar) {
     #if os(iOS)
       let messenger = registrar.messenger()
@@ -93,6 +108,7 @@ public class InAppPurchasePlugin: NSObject, FlutterPlugin, InAppPurchaseAPI {
       let messenger = registrar.messenger
     #endif
     setupTransactionObserverChannelIfNeeded(withMessenger: messenger)
+    self.transactionCallbackAPI = InAppPurchase2CallbackAPI(binaryMessenger: messenger)
   }
 
   // MARK: - Pigeon Functions

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

@@ -4,16 +4,17 @@
 
 @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
+  /// 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
+  /// 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
   ) {
@@ -34,4 +35,146 @@ extension InAppPurchasePlugin: InAppPurchase2API {
       }
     }
   }
+
+  /// Gets the appropriate product, then calls purchase on it.
+  /// https://developer.apple.com/documentation/storekit/product/3791971-purchase
+  func purchase(
+    id: String, options: SK2ProductPurchaseOptionsMessage?,
+    completion: @escaping (Result<SK2ProductPurchaseResultMessage, Error>) -> Void
+  ) {
+    Task { @MainActor in
+      do {
+        guard let product = try await Product.products(for: [id]).first else {
+          let error = PigeonError(
+            code: "storekit2_failed_to_fetch_product",
+            message: "Storekit has failed to fetch this product.",
+            details: "Product ID : \(id)")
+          return completion(.failure(error))
+        }
+
+        let result = try await product.purchase(options: [])
+
+        switch result {
+        case .success(let verification):
+          switch verification {
+          case .verified(let transaction):
+            self.sendTransactionUpdate(transaction: transaction)
+            completion(.success(result.convertToPigeon()))
+          case .unverified(_, let error):
+            completion(.failure(error))
+          }
+        case .pending:
+          completion(
+            .failure(
+              PigeonError(
+                code: "storekit2_purchase_pending",
+                message:
+                  "This transaction is still pending and but may complete in the future. If it completes, it will be delivered via `purchaseStream`",
+                details: "Product ID : \(id)")))
+        case .userCancelled:
+          completion(
+            .failure(
+              PigeonError(
+                code: "storekit2_purchase_cancelled",
+                message: "This transaction has been cancelled by the user.",
+                details: "Product ID : \(id)")))
+        @unknown default:
+          fatalError("An unknown StoreKit PurchaseResult has been encountered.")
+        }
+      } catch {
+        completion(.failure(error))
+      }
+    }
+  }
+
+  /// Wrapper method around StoreKit2's transactions() method
+  /// https://developer.apple.com/documentation/storekit/product/3851116-products
+  func transactions(
+    completion: @escaping (Result<[SK2TransactionMessage], Error>) -> Void
+  ) {
+    Task {
+      @MainActor in
+      do {
+        let transactionsMsgs = await rawTransactions().map {
+          $0.convertToPigeon()
+        }
+        completion(.success(transactionsMsgs))
+      }
+    }
+  }
+
+  /// Wrapper method around StoreKit2's finish() method https://developer.apple.com/documentation/storekit/transaction/3749694-finish
+  func finish(id: Int64, completion: @escaping (Result<Void, Error>) -> Void) {
+    Task {
+      let transaction = try await fetchTransaction(by: UInt64(id))
+      if let transaction = transaction {
+        await transaction.finish()
+      }
+    }
+  }
+
+  /// This Task listens  to Transation.updates as shown here
+  /// https://developer.apple.com/documentation/storekit/transaction/3851206-updates
+  /// This function should be called as soon as the app starts to avoid missing any Transactions done outside of the app.
+  func startListeningToTransactions() throws {
+    self.setListenerTaskAsTask(
+      task: Task { [weak self] in
+        for await verificationResult in Transaction.updates {
+          switch verificationResult {
+          case .verified(let transaction):
+            self?.sendTransactionUpdate(transaction: transaction)
+          case .unverified:
+            break
+          }
+        }
+      })
+  }
+
+  /// Stop subscribing to Transaction.updates
+  func stopListeningToTransactions() throws {
+    updateListenerTask.cancel()
+  }
+
+  /// Sends an transaction back to Dart. Access these transactions with `purchaseStream`
+  func sendTransactionUpdate(transaction: Transaction) {
+    let transactionMessage = transaction.convertToPigeon()
+    transactionCallbackAPI?.onTransactionsUpdated(newTransaction: transactionMessage) { result in
+      switch result {
+      case .success: break
+      case .failure(let error):
+        print("Failed to send transaction updates: \(error)")
+      }
+    }
+  }
+
+  // MARK: - Convenience Functions
+
+  /// Helper function that fetches and unwraps all verified transactions
+  private func rawTransactions() async -> [Transaction] {
+    var transactions: [Transaction] = []
+    for await verificationResult in Transaction.all {
+      switch verificationResult {
+      case .verified(let transaction):
+        transactions.append(transaction)
+      case .unverified:
+        break
+      }
+    }
+    return transactions
+  }
+
+  /// Helper function to fetch specific transaction
+  private func fetchTransaction(by id: UInt64) async throws -> Transaction? {
+    for await result in Transaction.all {
+      switch result {
+      case .verified(let transaction):
+        if transaction.id == id {
+          return transaction
+        }
+      case .unverified:
+        continue
+      }
+    }
+    return nil
+  }
 }

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

@@ -167,3 +167,38 @@ extension SK2PriceLocaleMessage: Equatable {
     return lhs.currencyCode == rhs.currencyCode && lhs.currencySymbol == rhs.currencySymbol
   }
 }
+
+@available(iOS 15.0, macOS 12.0, *)
+extension Product.PurchaseResult {
+  func convertToPigeon() -> SK2ProductPurchaseResultMessage {
+    switch self {
+    case .success(_):
+      return SK2ProductPurchaseResultMessage.success
+    case .userCancelled:
+      return SK2ProductPurchaseResultMessage.userCancelled
+    case .pending:
+      return SK2ProductPurchaseResultMessage.pending
+    @unknown default:
+      fatalError()
+    }
+  }
+}
+
+@available(iOS 15.0, macOS 12.0, *)
+extension Transaction {
+  func convertToPigeon(restoring: Bool = false) -> SK2TransactionMessage {
+
+    let dateFromatter: DateFormatter = DateFormatter()
+    dateFromatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
+
+    return SK2TransactionMessage(
+      id: Int64(id),
+      originalId: Int64(originalID),
+      productId: productID,
+      purchaseDate: dateFromatter.string(from: purchaseDate),
+      purchasedQuantity: Int64(purchasedQuantity),
+      appAccountToken: appAccountToken?.uuidString,
+      restoring: restoring
+    )
+  }
+}