fix(POM-423): UI modules cancellation (#359)

Ensure that UI module lifecycle is ended properly (meaning completion
invocation and related events) when screen is dismissed "externally"
(e.g. interactively by user or programatically). Fix affects
following screens: card tokenization, card update and native
alternative payment.

Minor improvements:
* Accept full card number when resolving issuer information.
* Resolve actor related warnings in UI module
* Prevent errors from redundant fonts registration in generated code

Example/Example/Sources/UI/Modules/AlternativePayments/ViewModel/AlternativePaymentsViewModel.swift

@@ -165,7 +165,9 @@ final class AlternativePaymentsViewModel: ObservableObject {
             let configuration = PONativeAlternativePaymentConfiguration(
                 invoiceId: invoice.id,
                 gatewayConfigurationId: gatewayConfigurationId,
-                secondaryAction: .cancel(),
+                secondaryAction: .cancel(
+                    confirmation: .init()
+                ),
                 paymentConfirmation: .init(
                     showProgressIndicatorAfter: 5,
                     confirmButton: .init(),

Sources/ProcessOut/Sources/Generated/Fonts+Generated.swift

@@ -44,7 +44,7 @@ internal enum FontFamily {
   }
   internal static let allCustomFonts: [FontConvertible] = [WorkSans.all].flatMap { $0 }
   internal static func registerAllCustomFonts() {
-    allCustomFonts.forEach { $0.register() }
+    allCustomFonts.forEach { $0.registerIfNeeded() }
   }
 }
 // swiftlint:enable identifier_name line_length type_body_length

Sources/ProcessOut/Sources/Generated/Sourcery+Generated.swift

@@ -80,7 +80,7 @@ extension POCardsService {
     /// Allows to retrieve card issuer information based on IIN.
     /// 
     /// - Parameters:
-    ///   - iin: Card issuer identification number. Corresponds to the first 6 or 8 digits of the main card number.
+    ///   - iin: Card issuer identification number. Length should be at least 6 otherwise error is thrown.
     @discardableResult
     public func issuerInformation(
         iin: String,

Sources/ProcessOut/Sources/Services/Cards/DefaultCardsService.swift

@@ -24,8 +24,10 @@ final class DefaultCardsService: POCardsService {
 
     // MARK: - POCardsService
 
-    func issuerInformation(iin: String) async throws -> POCardIssuerInformation {
-        try await repository.issuerInformation(iin: iin)
+    func issuerInformation(iin cardNumber: String) async throws -> POCardIssuerInformation {
+        // todo(andrii-vysotskyi): indicate in method arguments that method accepts full card number
+        let iin = try issuerIdentificationNumber(of: cardNumber)
+        return try await repository.issuerInformation(iin: iin)
     }
 
     func tokenize(request: POCardTokenizationRequest) async throws -> POCard {
@@ -62,4 +64,18 @@ final class DefaultCardsService: POCardsService {
     private let applePayAuthorizationSession: ApplePayAuthorizationSession
     private let applePayCardTokenizationRequestMapper: ApplePayCardTokenizationRequestMapper
     private let applePayErrorMapper: POPassKitPaymentErrorMapper
+
+    // MARK: - Private Methods
+
+    private func issuerIdentificationNumber(of cardNumber: String) throws -> String {
+        let iinLength: Int, filteredNumber = cardNumber.filter(\.isNumber)
+        if filteredNumber.count >= 8 {
+            iinLength = 8
+        } else if filteredNumber.count >= 6 {
+            iinLength = 6
+        } else {
+            throw POFailure(message: "IIN must have at least 6 digits.", code: .generic(.mobile))
+        }
+        return String(filteredNumber.prefix(iinLength))
+    }
 }

Sources/ProcessOut/Sources/Services/Cards/POCardsService.swift

@@ -14,7 +14,7 @@ public protocol POCardsService: POService { // sourcery: AutoCompletion
     /// Allows to retrieve card issuer information based on IIN.
     ///
     /// - Parameters:
-    ///   - iin: Card issuer identification number. Corresponds to the first 6 or 8 digits of the main card number.
+    ///   - iin: Card issuer identification number. Length should be at least 6 otherwise error is thrown.
     func issuerInformation(iin: String) async throws -> POCardIssuerInformation
 
     /// Tokenizes a card. You can use the card for a single payment by creating a card token with it. If you want

Sources/ProcessOut/Sources/UI/Modules/NativeAlternativePaymentMethod/Interactor/PONativeAlternativePaymentMethodDelegate.swift

@@ -19,3 +19,20 @@ public protocol PONativeAlternativePaymentMethodDelegate: AnyObject {
         for parameters: [PONativeAlternativePaymentMethodParameter], completion: @escaping ([String: String]) -> Void
     )
 }
+
+extension PONativeAlternativePaymentMethodDelegate {
+
+    /// Method provides an ability to supply default values for given parameters. It is not mandatory
+    /// to provide defaults for all parameters.
+    ///
+    /// - Returns: Dictionary where key is a parameter key, and value is desired default.
+    @_spi(PO)
+    @MainActor
+    public func nativeAlternativePayment(
+        defaultValuesFor parameters: [PONativeAlternativePaymentMethodParameter]
+    ) async -> [String: String] {
+        await withCheckedContinuation { continuation in
+            nativeAlternativePaymentMethodDefaultValues(for: parameters) { continuation.resume(returning: $0) }
+        }
+    }
+}

Sources/ProcessOutUI/Sources/Core/Interactor/BaseInteractor.swift

@@ -23,7 +23,6 @@ class BaseInteractor<State>: Interactor {
     var didChange: (() -> Void)?
     var willChange: ((State) -> Void)?
 
-    @MainActor
     func start() {
         // Does nothing
     }

Sources/ProcessOutUI/Sources/Core/Interactor/Interactor.swift

@@ -5,6 +5,7 @@
 //  Created by Andrii Vysotskyi on 19.10.2023.
 //
 
+@MainActor
 protocol Interactor<State>: AnyObject {
 
     associatedtype State

Sources/ProcessOutUI/Sources/Core/ViewModel/AnyViewModel.swift

@@ -27,6 +27,10 @@ final class AnyViewModel<State>: ViewModel {
         base.start()
     }
 
+    func stop() {
+        base.stop()
+    }
+
     var state: State {
         get { base.state }
         set { base.state = newValue }
@@ -50,6 +54,10 @@ private class ViewModelBox<T>: AnyViewModelBase<T.State> where T: ViewModel {
         base.start()
     }
 
+    override func stop() {
+        base.stop()
+    }
+
     override var state: T.State {
         get { base.state }
         set { base.state = newValue }
@@ -64,6 +72,10 @@ private class AnyViewModelBase<State>: ViewModel {
         fatalError("Not implemented")
     }
 
+    func stop() {
+        fatalError("Not implemented")
+    }
+
     var state: State {
         get { fatalError("Not implemented") }
         set { fatalError("Not implemented") }

Sources/ProcessOutUI/Sources/Core/ViewModel/ViewModel.swift

@@ -7,6 +7,7 @@
 
 import Combine
 
+@MainActor
 protocol ViewModel<State>: ObservableObject {
 
     associatedtype State
@@ -16,4 +17,14 @@ protocol ViewModel<State>: ObservableObject {
 
     /// Starts view model.
     func start()
+
+    /// Cancels view model.
+    func stop()
+}
+
+extension ViewModel {
+
+    func stop() {
+        // Ignored
+    }
 }

Sources/ProcessOutUI/Sources/Modules/CardTokenization/Interactor/CardTokenizationInteractor.swift

@@ -7,6 +7,7 @@
 
 import ProcessOut
 
+@MainActor
 protocol CardTokenizationInteractor: Interactor<CardTokenizationInteractorState> {
 
     /// Delegate.

Sources/ProcessOutUI/Sources/Modules/CardTokenization/Interactor/CardTokenizationInteractorState.swift

@@ -10,36 +10,43 @@ import ProcessOut
 
 enum CardTokenizationInteractorState {
 
-    typealias ParameterId = WritableKeyPath<Started, Parameter>
+    struct Started {
 
-    struct Parameter {
+        /// Number of the card.
+        var number: Parameter
 
-        /// Parameter identifier
-        let id: ParameterId
+        /// Expiry date of the card.
+        var expiration: Parameter
 
-        /// Actual parameter value.
-        var value: String = ""
+        /// Card Verification Code of the card.
+        var cvc: Parameter
 
-        /// Indicates whether parameter is valid.
-        var isValid = true
+        /// Name of cardholder.
+        var cardholderName: Parameter
 
-        /// Boolean flag indicating whether parameter should be collected.
-        var shouldCollect = true // todo(andrii-vysotskyi): consider migrating to optional parameters
+        /// Card issuer information based on number.
+        var issuerInformation: POCardIssuerInformation?
 
-        /// Available parameter values.
-        var availableValues: [ParameterValue] = []
+        /// Preferred scheme.
+        var preferredScheme: POCardScheme?
 
-        /// Formatter that can be used to format this parameter.
-        var formatter: Formatter?
+        /// Billing address parameters.
+        var address: AddressParameters
+
+        /// Indicates whether card should be saved for future payments.
+        var shouldSaveCard: Bool = false
+
+        /// The most recent error message.
+        var recentErrorMessage: String?
     }
 
-    struct ParameterValue: Decodable, Hashable {
+    struct Tokenizing {
 
-        /// Display name of value.
-        let displayName: String
+        /// Started state snapshot.
+        let snapshot: Started
 
-        /// Actual parameter value.
-        let value: String
+        /// Tokenization task.
+        let task: Task<Void, Never>
     }
 
     struct AddressParameters {
@@ -66,60 +73,68 @@ enum CardTokenizationInteractorState {
         var specification: AddressSpecification
     }
 
-    struct Started {
-
-        /// Number of the card.
-        var number: Parameter
-
-        /// Expiry date of the card.
-        var expiration: Parameter
-
-        /// Card Verification Code of the card.
-        var cvc: Parameter
+    struct Parameter {
 
-        /// Name of cardholder.
-        var cardholderName: Parameter
+        /// Parameter identifier
+        let id: ParameterId
 
-        /// Card issuer information based on number.
-        var issuerInformation: POCardIssuerInformation?
+        /// Actual parameter value.
+        var value: String = ""
 
-        /// Preferred scheme.
-        var preferredScheme: POCardScheme?
+        /// Indicates whether parameter is valid.
+        var isValid = true
 
-        /// Billing address parameters.
-        var address: AddressParameters
+        /// Boolean flag indicating whether parameter should be collected.
+        var shouldCollect = true // todo(andrii-vysotskyi): consider migrating to optional parameters
 
-        /// Indicates whether card should be saved for future payments.
-        var shouldSaveCard: Bool = false
+        /// Available parameter values.
+        var availableValues: [ParameterValue] = []
 
-        /// The most recent error message.
-        var recentErrorMessage: String?
+        /// Formatter that can be used to format this parameter.
+        var formatter: Formatter?
     }
 
-    struct Tokenized {
+    struct ParameterValue: Decodable, Hashable {
 
-        /// Tokenized card.
-        let card: POCard
+        /// Display name of value.
+        let displayName: String
 
-        /// Full card number.
-        let cardNumber: String
+        /// Actual parameter value.
+        let value: String
     }
 
+    typealias ParameterId = WritableKeyPath<Started, Parameter>
+
     case idle
 
     /// Interactor has started and is ready.
     case started(Started)
 
     /// Card information is currently being tokenized.
-    case tokenizing(snapshot: Started)
+    case tokenizing(Tokenizing)
 
     /// Card was successfully tokenized. This is a sink state.
-    case tokenized(Tokenized)
+    case tokenized
 
     /// Card tokenization did end with unrecoverable failure. This is a sink state.
     case failure(POFailure)
 }
 
+extension CardTokenizationInteractorState {
+
+    /// Boolean variable that indicates whether the current state is a sink state.
+    ///
+    /// A sink state is a special kind of state where, once entered, no other state transitions are possible.
+    var isSink: Bool {
+        switch self {
+        case .tokenized, .failure:
+            return true
+        default:
+            return false
+        }
+    }
+}
+
 extension CardTokenizationInteractorState.AddressParameters {
 
     /// Boolean value that allows to determine whether all parameters are valid.