feat: support external purchase api with listener (#18)

Align apis with openiap-gql@1.0.12 which supports external billing.
- hyodotdev/openiap-gql#15

Author: hyochan

Example/OpenIapExample/Screens/AllProductsView.swift

@@ -226,7 +226,7 @@ struct AllProductsView: View {
             }
 
             HStack {
-                Text(product.displayPrice ?? "--")
+                Text(product.displayPrice)
                     .font(.title2)
                     .fontWeight(.bold)
                     .foregroundColor(.blue)

Example/OpenIapExample/Screens/AlternativeBillingScreen.swift

@@ -131,7 +131,7 @@ struct AlternativeBillingScreen: View {
                 .autocapitalization(.none)
                 .keyboardType(.URL)
 
-            Text("This URL will be opened when a user taps Purchase. Make sure the URL is valid and accessible.")
+            Text("Tap Purchase on any product below. The ExternalPurchase API (iOS 18.2+) will show Apple's notice sheet before opening this URL.")
                 .font(.caption)
                 .foregroundColor(.secondary)
         }
@@ -221,14 +221,18 @@ struct AlternativeBillingScreen: View {
                 )
                 InstructionRow(
                     number: "2",
-                    text: "Tap Purchase on any product"
+                    text: "Tap Purchase on any product below"
                 )
                 InstructionRow(
                     number: "3",
-                    text: "User will be redirected to the external URL"
+                    text: "Apple's notice sheet appears (iOS 18.2+)"
                 )
                 InstructionRow(
                     number: "4",
+                    text: "User taps Continue → Opens external URL"
+                )
+                InstructionRow(
+                    number: "5",
                     text: "Complete purchase on your website"
                 )
             }
@@ -239,7 +243,7 @@ struct AlternativeBillingScreen: View {
                     .fontWeight(.semibold)
                     .foregroundColor(AppColors.warning)
 
-                Text("• iOS 16.0 or later required\n• Valid external URL needed\n• useAlternativeBilling: true is set\n• onPurchaseUpdated will NOT fire\n• Implement deep link to return to app")
+                Text("• iOS 18.2+ required for ExternalPurchase API\n• Apple's official alternative billing compliance\n• Notice sheet shows App Store warning\n• Purchase completes on external website\n• Deep link needed to return to app")
                     .font(.caption)
                     .foregroundColor(.secondary)
             }
@@ -315,66 +319,75 @@ struct AlternativeBillingScreen: View {
         }
     }
 
-    // MARK: - Purchase Flow with Alternative Billing
+    // MARK: - Purchase Flow with Alternative Billing (iOS 18.2+)
 
     private func purchaseProduct(_ product: OpenIapProduct) {
         print("🛒 [AlternativeBilling] Starting alternative billing purchase for: \(product.id)")
         print("🌐 [AlternativeBilling] External URL: \(externalUrl)")
 
-        Task {
-            do {
-                let requestType: ProductQueryType = product.type == .subs ? .subs : .inApp
-
-                // Create request based on product type
-                let request: RequestPurchaseProps.Request
-                if requestType == .subs {
-                    let subscriptionProps = RequestSubscriptionIosProps(
-                        externalPurchaseUrl: externalUrl,
-                        sku: product.id
-                    )
-
-                    request = .subscription(RequestSubscriptionPropsByPlatforms(
-                        ios: subscriptionProps
-                    ))
-                } else {
-                    let iosProps = RequestPurchaseIosProps(
-                        externalPurchaseUrl: externalUrl,
-                        sku: product.id
-                    )
-
-                    request = .purchase(RequestPurchasePropsByPlatforms(
-                        ios: iosProps
-                    ))
+        if #available(iOS 18.2, *) {
+            Task { await testExternalPurchaseFlow() }
+        } else {
+            errorMessage = "Alternative billing with ExternalPurchase API requires iOS 18.2 or later"
+            showError = true
+        }
+    }
+
+    // MARK: - External Purchase Flow (iOS 18.2+)
+
+    @available(iOS 18.2, *)
+    private func testExternalPurchaseFlow() async {
+        print("🔷 [AlternativeBilling] Testing external purchase flow...")
+
+        do {
+            // Step 1: Check if notice sheet can be presented
+            let canPresent = try await OpenIapModule.shared.canPresentExternalPurchaseNoticeIOS()
+            print("✅ [AlternativeBilling] Can present notice sheet: \(canPresent)")
+
+            guard canPresent else {
+                await MainActor.run {
+                    errorMessage = "External purchase notice sheet is not available on this device"
+                    showError = true
                 }
+                return
+            }
 
-                let params = RequestPurchaseProps(
-                    request: request,
-                    type: requestType,
-                    useAlternativeBilling: true
-                )
+            // Step 2: Present notice sheet
+            let noticeResult = try await OpenIapModule.shared.presentExternalPurchaseNoticeSheetIOS()
+            print("✅ [AlternativeBilling] Notice sheet result: \(noticeResult.result)")
 
-                _ = try await OpenIapModule.shared.requestPurchase(params)
+            if noticeResult.result == .continue {
+                // Step 3: Present external purchase link
+                let linkResult = try await OpenIapModule.shared.presentExternalPurchaseLinkIOS(externalUrl)
+                print("✅ [AlternativeBilling] Link result: \(linkResult.success)")
 
-                // When using external URL, the purchase is handled externally
                 await MainActor.run {
-                    purchaseResultMessage = """
-                    🌐 Redirected to external URL
-                    Product: \(product.id)
-                    URL: \(externalUrl)
-
-                    Complete the purchase on the external website.
-                    Note: onPurchaseUpdated will NOT be called.
-                    """
+                    if linkResult.success {
+                        purchaseResultMessage = """
+                        🌐 External purchase flow completed
+                        User was redirected to: \(externalUrl)
+                        """
+                    } else {
+                        purchaseResultMessage = """
+                        ❌ External purchase link failed
+                        Error: \(linkResult.error ?? "Unknown error")
+                        """
+                    }
                     showPurchaseResult = true
                 }
-
-            } catch {
-                print("❌ [AlternativeBilling] Purchase failed: \(error.localizedDescription)")
+            } else {
                 await MainActor.run {
-                    errorMessage = "Alternative billing error: \(error.localizedDescription)"
-                    showError = true
+                    purchaseResultMessage = "User dismissed the notice sheet"
+                    showPurchaseResult = true
                 }
             }
+
+        } catch {
+            print("❌ [AlternativeBilling] External purchase flow error: \(error)")
+            await MainActor.run {
+                errorMessage = "External purchase flow error: \(error.localizedDescription)"
+                showError = true
+            }
         }
     }
 

Sources/Models/Types.swift

@@ -57,10 +57,19 @@ public enum ErrorCode: String, Codable, CaseIterable {
     case emptySkuList = "empty-sku-list"
 }
 
+/// User actions on external purchase notice sheet (iOS 18.2+)
+public enum ExternalPurchaseNoticeAction: String, Codable, CaseIterable {
+    /// User chose to continue to external purchase
+    case `continue` = "continue"
+    /// User dismissed the notice sheet
+    case dismissed = "dismissed"
+}
+
 public enum IapEvent: String, Codable, CaseIterable {
     case purchaseUpdated = "purchase-updated"
     case purchaseError = "purchase-error"
     case promotedProductIos = "promoted-product-ios"
+    case userChoiceBillingAndroid = "user-choice-billing-android"
 }
 
 public enum IapPlatform: String, Codable, CaseIterable {
@@ -217,6 +226,22 @@ public struct EntitlementIOS: Codable {
     public var transactionId: String
 }
 
+/// Result of presenting an external purchase link (iOS 18.2+)
+public struct ExternalPurchaseLinkResultIOS: Codable {
+    /// Optional error message if the presentation failed
+    public var error: String?
+    /// Whether the user completed the external purchase flow
+    public var success: Bool
+}
+
+/// Result of presenting external purchase notice sheet (iOS 18.2+)
+public struct ExternalPurchaseNoticeResultIOS: Codable {
+    /// Optional error message if the presentation failed
+    public var error: String?
+    /// Notice result indicating user action
+    public var result: ExternalPurchaseNoticeAction
+}
+
 public enum FetchProductsResult {
     case products([Product]?)
     case subscriptions([ProductSubscription]?)
@@ -469,6 +494,15 @@ public struct SubscriptionStatusIOS: Codable {
     public var state: String
 }
 
+/// User Choice Billing event details (Android)
+/// Fired when a user selects alternative billing in the User Choice Billing dialog
+public struct UserChoiceBillingDetails: Codable {
+    /// Token that must be reported to Google Play within 24 hours
+    public var externalTransactionToken: String
+    /// List of product IDs selected by the user
+    public var products: [String]
+}
+
 public typealias VoidResult = Void
 
 // MARK: - Input Objects
@@ -635,8 +669,6 @@ public struct RequestPurchaseIosProps: Codable {
     public var andDangerouslyFinishTransactionAutomatically: Bool?
     /// App account token for user tracking
     public var appAccountToken: String?
-    /// External purchase URL for alternative billing (iOS)
-    public var externalPurchaseUrl: String?
     /// Purchase quantity
     public var quantity: Int?
     /// Product SKU
@@ -647,14 +679,12 @@ public struct RequestPurchaseIosProps: Codable {
     public init(
         andDangerouslyFinishTransactionAutomatically: Bool? = nil,
         appAccountToken: String? = nil,
-        externalPurchaseUrl: String? = nil,
         quantity: Int? = nil,
         sku: String,
         withOffer: DiscountOfferInputIOS? = nil
     ) {
         self.andDangerouslyFinishTransactionAutomatically = andDangerouslyFinishTransactionAutomatically
         self.appAccountToken = appAccountToken
-        self.externalPurchaseUrl = externalPurchaseUrl
         self.quantity = quantity
         self.sku = sku
         self.withOffer = withOffer
@@ -784,23 +814,19 @@ public struct RequestSubscriptionAndroidProps: Codable {
 public struct RequestSubscriptionIosProps: Codable {
     public var andDangerouslyFinishTransactionAutomatically: Bool?
     public var appAccountToken: String?
-    /// External purchase URL for alternative billing (iOS)
-    public var externalPurchaseUrl: String?
     public var quantity: Int?
     public var sku: String
     public var withOffer: DiscountOfferInputIOS?
 
     public init(
         andDangerouslyFinishTransactionAutomatically: Bool? = nil,
         appAccountToken: String? = nil,
-        externalPurchaseUrl: String? = nil,
         quantity: Int? = nil,
         sku: String,
         withOffer: DiscountOfferInputIOS? = nil
     ) {
         self.andDangerouslyFinishTransactionAutomatically = andDangerouslyFinishTransactionAutomatically
         self.appAccountToken = appAccountToken
-        self.externalPurchaseUrl = externalPurchaseUrl
         self.quantity = quantity
         self.sku = sku
         self.withOffer = withOffer
@@ -1155,6 +1181,10 @@ public protocol MutationResolver {
     func initConnection(_ config: InitConnectionConfig?) async throws -> Bool
     /// Present the App Store code redemption sheet
     func presentCodeRedemptionSheetIOS() async throws -> Bool
+    /// Present external purchase custom link with StoreKit UI (iOS 18.2+)
+    func presentExternalPurchaseLinkIOS(_ url: String) async throws -> ExternalPurchaseLinkResultIOS
+    /// Present external purchase notice sheet (iOS 18.2+)
+    func presentExternalPurchaseNoticeSheetIOS() async throws -> ExternalPurchaseNoticeResultIOS
     /// Initiate a purchase flow; rely on events for final state
     func requestPurchase(_ params: RequestPurchaseProps) async throws -> RequestPurchaseResult?
     /// Purchase the promoted product surfaced by the App Store
@@ -1178,6 +1208,8 @@ public protocol MutationResolver {
 
 /// GraphQL root query operations.
 public protocol QueryResolver {
+    /// Check if external purchase notice sheet can be presented (iOS 18.2+)
+    func canPresentExternalPurchaseNoticeIOS() async throws -> Bool
     /// Get current StoreKit 2 entitlements (iOS 15+)
     func currentEntitlementIOS(_ sku: String) async throws -> PurchaseIOS?
     /// Retrieve products or subscriptions from the store
@@ -1222,6 +1254,9 @@ public protocol SubscriptionResolver {
     func purchaseError() async throws -> PurchaseError
     /// Fires when a purchase completes successfully or a pending purchase resolves
     func purchaseUpdated() async throws -> Purchase
+    /// Fires when a user selects alternative billing in the User Choice Billing dialog (Android only)
+    /// Only triggered when the user selects alternative billing instead of Google Play billing
+    func userChoiceBillingAndroid() async throws -> UserChoiceBillingDetails
 }
 
 // MARK: - Root Operation Helpers
@@ -1239,6 +1274,8 @@ public typealias MutationEndConnectionHandler = () async throws -> Bool
 public typealias MutationFinishTransactionHandler = (_ purchase: PurchaseInput, _ isConsumable: Bool?) async throws -> Void
 public typealias MutationInitConnectionHandler = (_ config: InitConnectionConfig?) async throws -> Bool
 public typealias MutationPresentCodeRedemptionSheetIOSHandler = () async throws -> Bool
+public typealias MutationPresentExternalPurchaseLinkIOSHandler = (_ url: String) async throws -> ExternalPurchaseLinkResultIOS
+public typealias MutationPresentExternalPurchaseNoticeSheetIOSHandler = () async throws -> ExternalPurchaseNoticeResultIOS
 public typealias MutationRequestPurchaseHandler = (_ params: RequestPurchaseProps) async throws -> RequestPurchaseResult?
 public typealias MutationRequestPurchaseOnPromotedProductIOSHandler = () async throws -> Bool
 public typealias MutationRestorePurchasesHandler = () async throws -> Void
@@ -1259,6 +1296,8 @@ public struct MutationHandlers {
     public var finishTransaction: MutationFinishTransactionHandler?
     public var initConnection: MutationInitConnectionHandler?
     public var presentCodeRedemptionSheetIOS: MutationPresentCodeRedemptionSheetIOSHandler?
+    public var presentExternalPurchaseLinkIOS: MutationPresentExternalPurchaseLinkIOSHandler?
+    public var presentExternalPurchaseNoticeSheetIOS: MutationPresentExternalPurchaseNoticeSheetIOSHandler?
     public var requestPurchase: MutationRequestPurchaseHandler?
     public var requestPurchaseOnPromotedProductIOS: MutationRequestPurchaseOnPromotedProductIOSHandler?
     public var restorePurchases: MutationRestorePurchasesHandler?
@@ -1279,6 +1318,8 @@ public struct MutationHandlers {
         finishTransaction: MutationFinishTransactionHandler? = nil,
         initConnection: MutationInitConnectionHandler? = nil,
         presentCodeRedemptionSheetIOS: MutationPresentCodeRedemptionSheetIOSHandler? = nil,
+        presentExternalPurchaseLinkIOS: MutationPresentExternalPurchaseLinkIOSHandler? = nil,
+        presentExternalPurchaseNoticeSheetIOS: MutationPresentExternalPurchaseNoticeSheetIOSHandler? = nil,
         requestPurchase: MutationRequestPurchaseHandler? = nil,
         requestPurchaseOnPromotedProductIOS: MutationRequestPurchaseOnPromotedProductIOSHandler? = nil,
         restorePurchases: MutationRestorePurchasesHandler? = nil,
@@ -1298,6 +1339,8 @@ public struct MutationHandlers {
         self.finishTransaction = finishTransaction
         self.initConnection = initConnection
         self.presentCodeRedemptionSheetIOS = presentCodeRedemptionSheetIOS
+        self.presentExternalPurchaseLinkIOS = presentExternalPurchaseLinkIOS
+        self.presentExternalPurchaseNoticeSheetIOS = presentExternalPurchaseNoticeSheetIOS
         self.requestPurchase = requestPurchase
         self.requestPurchaseOnPromotedProductIOS = requestPurchaseOnPromotedProductIOS
         self.restorePurchases = restorePurchases
@@ -1310,6 +1353,7 @@ public struct MutationHandlers {
 
 // MARK: - Query Helpers
 
+public typealias QueryCanPresentExternalPurchaseNoticeIOSHandler = () async throws -> Bool
 public typealias QueryCurrentEntitlementIOSHandler = (_ sku: String) async throws -> PurchaseIOS?
 public typealias QueryFetchProductsHandler = (_ params: ProductRequest) async throws -> FetchProductsResult
 public typealias QueryGetActiveSubscriptionsHandler = (_ subscriptionIds: [String]?) async throws -> [ActiveSubscription]
@@ -1329,6 +1373,7 @@ public typealias QuerySubscriptionStatusIOSHandler = (_ sku: String) async throw
 public typealias QueryValidateReceiptIOSHandler = (_ options: ReceiptValidationProps) async throws -> ReceiptValidationResultIOS
 
 public struct QueryHandlers {
+    public var canPresentExternalPurchaseNoticeIOS: QueryCanPresentExternalPurchaseNoticeIOSHandler?
     public var currentEntitlementIOS: QueryCurrentEntitlementIOSHandler?
     public var fetchProducts: QueryFetchProductsHandler?
     public var getActiveSubscriptions: QueryGetActiveSubscriptionsHandler?
@@ -1348,6 +1393,7 @@ public struct QueryHandlers {
     public var validateReceiptIOS: QueryValidateReceiptIOSHandler?
 
     public init(
+        canPresentExternalPurchaseNoticeIOS: QueryCanPresentExternalPurchaseNoticeIOSHandler? = nil,
         currentEntitlementIOS: QueryCurrentEntitlementIOSHandler? = nil,
         fetchProducts: QueryFetchProductsHandler? = nil,
         getActiveSubscriptions: QueryGetActiveSubscriptionsHandler? = nil,
@@ -1366,6 +1412,7 @@ public struct QueryHandlers {
         subscriptionStatusIOS: QuerySubscriptionStatusIOSHandler? = nil,
         validateReceiptIOS: QueryValidateReceiptIOSHandler? = nil
     ) {
+        self.canPresentExternalPurchaseNoticeIOS = canPresentExternalPurchaseNoticeIOS
         self.currentEntitlementIOS = currentEntitlementIOS
         self.fetchProducts = fetchProducts
         self.getActiveSubscriptions = getActiveSubscriptions
@@ -1391,19 +1438,23 @@ public struct QueryHandlers {
 public typealias SubscriptionPromotedProductIOSHandler = () async throws -> String
 public typealias SubscriptionPurchaseErrorHandler = () async throws -> PurchaseError
 public typealias SubscriptionPurchaseUpdatedHandler = () async throws -> Purchase
+public typealias SubscriptionUserChoiceBillingAndroidHandler = () async throws -> UserChoiceBillingDetails
 
 public struct SubscriptionHandlers {
     public var promotedProductIOS: SubscriptionPromotedProductIOSHandler?
     public var purchaseError: SubscriptionPurchaseErrorHandler?
     public var purchaseUpdated: SubscriptionPurchaseUpdatedHandler?
+    public var userChoiceBillingAndroid: SubscriptionUserChoiceBillingAndroidHandler?
 
     public init(
         promotedProductIOS: SubscriptionPromotedProductIOSHandler? = nil,
         purchaseError: SubscriptionPurchaseErrorHandler? = nil,
-        purchaseUpdated: SubscriptionPurchaseUpdatedHandler? = nil
+        purchaseUpdated: SubscriptionPurchaseUpdatedHandler? = nil,
+        userChoiceBillingAndroid: SubscriptionUserChoiceBillingAndroidHandler? = nil
     ) {
         self.promotedProductIOS = promotedProductIOS
         self.purchaseError = purchaseError
         self.purchaseUpdated = purchaseUpdated
+        self.userChoiceBillingAndroid = userChoiceBillingAndroid
     }
 }