Implement PromotionalOffer model

Sources/Flare/Classes/Flare.swift

@@ -44,13 +44,17 @@ extension Flare: IFlare {
         try await iapProvider.fetch(productIDs: productIDs)
     }
 
-    public func purchase(product: StoreProduct, completion: @escaping Closure<Result<StoreTransaction, IAPError>>) {
+    public func purchase(
+        product: StoreProduct,
+        promotionalOffer: PromotionalOffer?,
+        completion: @escaping Closure<Result<StoreTransaction, IAPError>>
+    ) {
         guard iapProvider.canMakePayments else {
             completion(.failure(.paymentNotAllowed))
             return
         }
 
-        iapProvider.purchase(product: product) { result in
+        iapProvider.purchase(product: product, promotionalOffer: promotionalOffer) { result in
             switch result {
             case let .success(transaction):
                 completion(.success(transaction))
@@ -60,31 +64,33 @@ extension Flare: IFlare {
         }
     }
 
-    public func purchase(product: StoreProduct) async throws -> StoreTransaction {
+    public func purchase(product: StoreProduct, promotionalOffer: PromotionalOffer?) async throws -> StoreTransaction {
         guard iapProvider.canMakePayments else { throw IAPError.paymentNotAllowed }
-        return try await iapProvider.purchase(product: product)
+        return try await iapProvider.purchase(product: product, promotionalOffer: promotionalOffer)
     }
 
     @available(iOS 15.0, tvOS 15.0, watchOS 8.0, macOS 12.0, *)
     public func purchase(
         product: StoreProduct,
         options: Set<StoreKit.Product.PurchaseOption>,
+        promotionalOffer: PromotionalOffer?,
         completion: @escaping SendableClosure<Result<StoreTransaction, IAPError>>
     ) {
         guard iapProvider.canMakePayments else {
             completion(.failure(.paymentNotAllowed))
             return
         }
-        iapProvider.purchase(product: product, options: options, completion: completion)
+        iapProvider.purchase(product: product, options: options, promotionalOffer: promotionalOffer, completion: completion)
     }
 
     @available(iOS 15.0, tvOS 15.0, watchOS 8.0, macOS 12.0, *)
     public func purchase(
         product: StoreProduct,
-        options: Set<StoreKit.Product.PurchaseOption>
+        options: Set<StoreKit.Product.PurchaseOption>,
+        promotionalOffer: PromotionalOffer?
     ) async throws -> StoreTransaction {
         guard iapProvider.canMakePayments else { throw IAPError.paymentNotAllowed }
-        return try await iapProvider.purchase(product: product, options: options)
+        return try await iapProvider.purchase(product: product, options: options, promotionalOffer: promotionalOffer)
     }
 
     public func receipt(completion: @escaping Closure<Result<String, IAPError>>) {

Sources/Flare/Classes/IFlare.swift

@@ -6,6 +6,8 @@
 import Foundation
 import StoreKit
 
+// MARK: - IFlare
+
 /// `Flare` creates and manages in-app purchases.
 public protocol IFlare {
     /// Retrieves localized information from the App Store about a specified list of products.
@@ -32,21 +34,28 @@ public protocol IFlare {
     ///
     /// - Parameters:
     ///   - product: The product to be purchased.
+    ///   - promotionalOffer: The promotional offer.
     ///   - completion: The closure to be executed once the purchase is complete.
-    func purchase(product: StoreProduct, completion: @escaping Closure<Result<StoreTransaction, IAPError>>)
+    func purchase(
+        product: StoreProduct,
+        promotionalOffer: PromotionalOffer?,
+        completion: @escaping Closure<Result<StoreTransaction, IAPError>>
+    )
 
     /// Purchases a product.
     ///
     /// - Note: The method automatically checks if the user can purchase a product.
     ///         If the user can't make a payment, the method returns an error
     ///         with the type `IAPError.paymentNotAllowed`.
     ///
-    /// - Parameter product: The product to be purchased.
+    /// - Parameters:
+    ///   - product: The product to be purchased.
+    ///   - promotionalOffer: The promotional offer.
     ///
     /// - Throws: `IAPError.paymentNotAllowed` if user can't make payment.
     ///
     /// - Returns: A payment transaction.
-    func purchase(product: StoreProduct) async throws -> StoreTransaction
+    func purchase(product: StoreProduct, promotionalOffer: PromotionalOffer?) async throws -> StoreTransaction
 
     /// Purchases a product.
     ///
@@ -57,6 +66,7 @@ public protocol IFlare {
     /// - Parameters:
     ///   - product: The product to be purchased.
     ///   - options: The optional settings for a product purchase.
+    ///   - promotionalOffer: The promotional offer.
     ///   - completion: The closure to be executed once the purchase is complete.
     ///
     /// - Throws: `IAPError.paymentNotAllowed` if user can't make payment.
@@ -66,6 +76,7 @@ public protocol IFlare {
     func purchase(
         product: StoreProduct,
         options: Set<StoreKit.Product.PurchaseOption>,
+        promotionalOffer: PromotionalOffer?,
         completion: @escaping SendableClosure<Result<StoreTransaction, IAPError>>
     )
 
@@ -78,12 +89,17 @@ public protocol IFlare {
     /// - Parameters:
     ///   - product: The product to be purchased.
     ///   - options: The optional settings for a product purchase.
+    ///   - promotionalOffer: The promotional offer.
     ///
     /// - Throws: `IAPError.paymentNotAllowed` if user can't make payment.
     ///
     /// - Returns: A payment transaction.
     @available(iOS 15.0, tvOS 15.0, watchOS 8.0, macOS 12.0, *)
-    func purchase(product: StoreProduct, options: Set<StoreKit.Product.PurchaseOption>) async throws -> StoreTransaction
+    func purchase(
+        product: StoreProduct,
+        options: Set<StoreKit.Product.PurchaseOption>,
+        promotionalOffer: PromotionalOffer?
+    ) async throws -> StoreTransaction
 
     /// Refreshes the receipt, representing the user's transactions with your app.
     ///
@@ -129,3 +145,80 @@ public protocol IFlare {
         func beginRefundRequest(productID: String) async throws -> RefundRequestStatus
     #endif
 }
+
+public extension IFlare {
+    /// Performs a purchase of a product.
+    ///
+    /// - Note: The method automatically checks if the user can purchase a product.
+    ///         If the user can't make a payment, the method returns an error
+    ///         with the type `IAPError.paymentNotAllowed`.
+    ///
+    /// - Parameters:
+    ///   - product: The product to be purchased.
+    ///   - completion: The closure to be executed once the purchase is complete.
+    func purchase(
+        product: StoreProduct,
+        completion: @escaping Closure<Result<StoreTransaction, IAPError>>
+    ) {
+        purchase(product: product, promotionalOffer: nil, completion: completion)
+    }
+
+    /// Purchases a product.
+    ///
+    /// - Note: The method automatically checks if the user can purchase a product.
+    ///         If the user can't make a payment, the method returns an error
+    ///         with the type `IAPError.paymentNotAllowed`.
+    ///
+    /// - Parameter product: The product to be purchased.
+    ///
+    /// - Throws: `IAPError.paymentNotAllowed` if user can't make payment.
+    ///
+    /// - Returns: A payment transaction.
+    func purchase(product: StoreProduct) async throws -> StoreTransaction {
+        try await purchase(product: product, promotionalOffer: nil)
+    }
+
+    /// Purchases a product.
+    ///
+    /// - Note: The method automatically checks if the user can purchase a product.
+    ///         If the user can't make a payment, the method returns an error
+    ///         with the type `IAPError.paymentNotAllowed`.
+    ///
+    /// - Parameters:
+    ///   - product: The product to be purchased.
+    ///   - options: The optional settings for a product purchase.
+    ///   - completion: The closure to be executed once the purchase is complete.
+    ///
+    /// - Throws: `IAPError.paymentNotAllowed` if user can't make payment.
+    ///
+    /// - Returns: A payment transaction.
+    @available(iOS 15.0, tvOS 15.0, watchOS 8.0, macOS 12.0, *)
+    func purchase(
+        product: StoreProduct,
+        options: Set<StoreKit.Product.PurchaseOption>,
+        completion: @escaping SendableClosure<Result<StoreTransaction, IAPError>>
+    ) {
+        purchase(product: product, options: options, promotionalOffer: nil, completion: completion)
+    }
+
+    /// Purchases a product.
+    ///
+    /// - Note: The method automatically checks if the user can purchase a product.
+    ///         If the user can't make a payment, the method returns an error
+    ///         with the type `IAPError.paymentNotAllowed`.
+    ///
+    /// - Parameters:
+    ///   - product: The product to be purchased.
+    ///   - options: The optional settings for a product purchase.
+    ///
+    /// - Throws: `IAPError.paymentNotAllowed` if user can't make payment.
+    ///
+    /// - Returns: A payment transaction.
+    @available(iOS 15.0, tvOS 15.0, watchOS 8.0, macOS 12.0, *)
+    func purchase(
+        product: StoreProduct,
+        options: Set<StoreKit.Product.PurchaseOption>
+    ) async throws -> StoreTransaction {
+        try await purchase(product: product, options: options, promotionalOffer: nil)
+    }
+}

Sources/Flare/Classes/Models/IAPError.swift

@@ -38,6 +38,10 @@ public enum IAPError: Swift.Error {
     ///
     /// - Note: This is only available for StoreKit 2 transactions.
     case paymentDefferred
+    /// The decoding signature is failed.
+    ///
+    /// - Note: This is only available for StoreKit 2 transactions.
+    case failedToDecodeSignature(signature: String)
     /// The unknown error occurred.
     case unknown
 }

Sources/Flare/Classes/Models/Internal/Protocols/ISKProduct.swift

@@ -39,4 +39,6 @@ protocol ISKProduct {
 
     /// <#Description#>
     var discounts: [StoreProductDiscount] { get }
+
+    var subscriptionGroupIdentifier: String? { get }
 }

Sources/Flare/Classes/Models/Internal/SK1StoreProduct.swift

@@ -56,13 +56,9 @@ extension SK1StoreProduct: ISKProduct {
     }
 
     var productCategory: ProductCategory? {
-        guard #available(iOS 11.2, macOS 10.13.2, tvOS 11.2, watchOS 6.2, *) else {
-            return .nonSubscription
-        }
-        return subscriptionPeriod == nil ? .nonSubscription : .subscription
+        subscriptionPeriod == nil ? .nonSubscription : .subscription
     }
 
-    @available(iOS 11.2, macOS 10.13.2, tvOS 11.2, watchOS 6.2, *)
     var subscriptionPeriod: SubscriptionPeriod? {
         guard let subscriptionPeriod = product.subscriptionPeriod, subscriptionPeriod.numberOfUnits > 0 else {
             return nil
@@ -77,4 +73,8 @@ extension SK1StoreProduct: ISKProduct {
     var discounts: [StoreProductDiscount] {
         product.discounts.compactMap { StoreProductDiscount(skProductDiscount: $0) }
     }
+
+    var subscriptionGroupIdentifier: String? {
+        product.subscriptionGroupIdentifier
+    }
 }

Sources/Flare/Classes/Models/Internal/SK2StoreProduct.swift

@@ -81,4 +81,8 @@ extension SK2StoreProduct: ISKProduct {
             StoreProductDiscount(discount: $0, currencyCode: self.currencyCode)
         } ?? []
     }
+
+    var subscriptionGroupIdentifier: String? {
+        product.subscription?.subscriptionGroupID
+    }
 }

Sources/Flare/Classes/Models/PromotionalOffer.swift

@@ -0,0 +1,90 @@
+//
+// Flare
+// Copyright © 2024 Space Code. All rights reserved.
+//
+
+import Foundation
+import StoreKit
+
+// MARK: - PromotionalOffer
+
+public final class PromotionalOffer: NSObject, Sendable {
+    // MARK: Properties
+
+    public let discount: StoreProductDiscount
+    public let signedData: SignedData
+
+    // MARK: Initialization
+
+    public init(discount: StoreProductDiscount, signedData: SignedData) {
+        self.discount = discount
+        self.signedData = signedData
+    }
+}
+
+// MARK: PromotionalOffer.SignedData
+
+public extension PromotionalOffer {
+    final class SignedData: NSObject, Sendable {
+        // MARK: Properties
+
+        public let identifier: String
+        public let keyIdentifier: String
+        public let nonce: UUID
+        public let signature: String
+        public let timestamp: Int
+
+        public init(identifier: String, keyIdentifier: String, nonce: UUID, signature: String, timestamp: Int) {
+            self.identifier = identifier
+            self.keyIdentifier = keyIdentifier
+            self.nonce = nonce
+            self.signature = signature
+            self.timestamp = timestamp
+        }
+    }
+}
+
+// MARK: - Convenience Initializators
+
+extension PromotionalOffer.SignedData {
+    convenience init(paymentDiscount: SKPaymentDiscount) {
+        self.init(
+            identifier: paymentDiscount.identifier,
+            keyIdentifier: paymentDiscount.keyIdentifier,
+            nonce: paymentDiscount.nonce,
+            signature: paymentDiscount.signature,
+            timestamp: paymentDiscount.timestamp.intValue
+        )
+    }
+}
+
+// MARK: - Helpers
+
+extension PromotionalOffer.SignedData {
+    var skPromotionalOffer: SKPaymentDiscount {
+        SKPaymentDiscount(
+            identifier: identifier,
+            keyIdentifier: keyIdentifier,
+            nonce: nonce,
+            signature: signature,
+            timestamp: .init(integerLiteral: timestamp)
+        )
+    }
+
+    @available(iOS 15.0, tvOS 15.0, watchOS 8.0, macOS 12.0, *)
+    var promotionalOffer: Product.PurchaseOption {
+        get throws {
+            guard let data = Data(base64Encoded: signature) else {
+                throw IAPError.failedToDecodeSignature(signature: signature)
+            }
+
+            return .promotionalOffer(
+                offerID: identifier,
+                keyID: keyIdentifier,
+                nonce: nonce,
+                signature: data,
+                timestamp: timestamp
+            )
+        }
+    }
+}