Add Pay with Transfer (bank transfer) payment method

  Introduce a new bank transfer charge flow spanning both PaystackCore and
  PaystackUI.

  PaystackCore:
  - Add payWithTransfer endpoint (PayWithTransferService + Paystack
    extension) with request/response models
  - Add PayWithTransferPusherResponse for subscription-based status updates
  - Add MerchantChannelSettings and wire bank_transfer into channel options

  PaystackUI:
  - Add BankTransfer flow (Views, ViewModel, Repository, Models) with a
    state machine covering account details, confirming, delayed
    confirmation, taking-longer, and refund-initiated phases
  - Add shared components: AccountDetailRow, ChangePaymentMethodFooter,
    TimelineNode, and a bank picker sheet
  - Surface bank transfer as a selectable channel in the charge flow

  Tests:
  - Cover the endpoint, status mapping, view model, repository, and
    provider catalog, plus Pusher fixtures for each transfer status

Author: peter-paystack

Package.swift

@@ -43,7 +43,13 @@ let package = Package(
                 .copy("API/Transactions/Resources/VerifyAccessCode.json"),
                 .copy("API/Charge/Resources/ChargeAuthenticationResponse.json"),
                 .copy("API/Other/Resources/AddressStatesResponse.json"),
-                .copy("API/Charge/Resources/ChargeMobileMoneyResponse.json")
+                .copy("API/Charge/Resources/ChargeMobileMoneyResponse.json"),
+                .copy("API/Charge/Resources/PayWithTransferResponse.json"),
+                .copy("API/Charge/Resources/PayWithTransferPusherSuccess.json"),
+                .copy("API/Charge/Resources/PayWithTransferPusherCreditReceived.json"),
+                .copy("API/Charge/Resources/PayWithTransferPusherCreditPending.json"),
+                .copy("API/Charge/Resources/PayWithTransferPusherCreditRejected.json"),
+                .copy("API/Charge/Resources/PayWithTransferPusherIncorrectAmount.json")
 
             ])
     ]

Sources/PaystackSDK/API/Charge/PayWithTransfer.swift

@@ -0,0 +1,44 @@
+import Foundation
+
+/// Public Pay-with-Transfer surface. Used by the UI module to provision a
+/// virtual bank account and listen for Pusher status updates ; can also be
+/// called directly by integrators driving their own UI on top of
+/// `PaystackCore`.
+public extension Paystack {
+
+    private var service: PayWithTransferService {
+        return PayWithTransferServiceImplementation(config: config)
+    }
+
+    /// Provisions a one-time virtual bank account for the customer to make
+    /// a transfer to. The response's `pusherChannel` should be subscribed
+    /// to via ``listenForTransferResponse(onChannel:)`` for real-time
+    /// status updates ; the response's `accountExpiresAt` drives the
+    /// customer-facing countdown.
+    ///
+    /// - Parameter request: Required configuration for the virtual account.
+    ///   `preferredProvider` is optional — when omitted, the backend picks
+    ///   a default (typically `paystack-titan`).
+    /// - Returns: A ``Service`` with the ``PayWithTransferResponse`` payload.
+    func payWithTransfer(_ request: PayWithTransferRequest)
+        -> Service<PayWithTransferResponse> {
+        return service.postPayWithTransfer(request)
+    }
+
+    /// Listens for Pay-with-Transfer status updates on the Pusher channel
+    /// returned by ``payWithTransfer(_:)``. The underlying listener is
+    /// single-shot per the existing `PusherSubscriptionListener` contract,
+    /// so callers that need to keep listening through transient statuses
+    /// must re-subscribe after each event.
+    ///
+    /// - Parameter channelName: The `pusherChannel` value returned from
+    ///   `payWithTransfer` (e.g. `PWT6215047322`).
+    /// - Returns: A ``Service`` carrying a ``PayWithTransferPusherResponse``
+    ///   on the first event the channel emits.
+    func listenForTransferResponse(onChannel channelName: String)
+        -> Service<PayWithTransferPusherResponse> {
+        let subscription: any Subscription = PusherSubscription(
+            channelName: channelName, eventName: "response")
+        return Service(subscription)
+    }
+}

Sources/PaystackSDK/API/Charge/PayWithTransferService.swift

@@ -0,0 +1,21 @@
+import Foundation
+
+protocol PayWithTransferService: PaystackService {
+    func postPayWithTransfer(_ request: PayWithTransferRequest)
+        -> Service<PayWithTransferResponse>
+}
+
+struct PayWithTransferServiceImplementation: PayWithTransferService {
+
+    var config: PaystackConfig
+
+    var parentPath: String {
+        return "checkout"
+    }
+
+    func postPayWithTransfer(_ request: PayWithTransferRequest)
+        -> Service<PayWithTransferResponse> {
+        return post("/pay_with_transfer", request)
+            .asService()
+    }
+}

Sources/PaystackSDK/Core/Models/Models/PayWithTransferPusherResponse.swift

@@ -0,0 +1,19 @@
+import Foundation
+
+public struct PayWithTransferPusherResponse: Codable, Equatable {
+    public let status: String
+    public let message: String
+    public let data: PayWithTransferEventData?
+    public let errors: [String]?
+}
+
+public struct PayWithTransferEventData: Codable, Equatable {
+    public let messageType: String?
+    public let transactionId: String?
+    public let referenceId: String?
+    public let reference: String?
+    public let trxref: String?
+    public let trans: String?
+    public let response: String?
+    public let redirecturl: String?
+}

Sources/PaystackSDK/Core/Models/Models/PayWithTransferRequest.swift

@@ -0,0 +1,15 @@
+import Foundation
+
+public struct PayWithTransferRequest: Codable, Equatable {
+    public let fulfilLateNotification: Bool
+    public let transactionId: Int
+    public let preferredProvider: String?
+
+    public init(fulfilLateNotification: Bool,
+                transactionId: Int,
+                preferredProvider: String? = nil) {
+        self.fulfilLateNotification = fulfilLateNotification
+        self.transactionId = transactionId
+        self.preferredProvider = preferredProvider
+    }
+}

Sources/PaystackSDK/Core/Models/Models/PayWithTransferResponse.swift

@@ -0,0 +1,24 @@
+import Foundation
+
+public struct PayWithTransferResponse: Codable, Equatable {
+    public let status: Bool
+    public let message: String
+    public let data: PayWithTransferData
+}
+
+public struct PayWithTransferData: Codable, Equatable {
+    public let accountName: String
+    public let accountNumber: String
+    public let transactionReference: String
+    public let bank: TransferBank
+    public let accountExpiresAt: Date
+    public let assignmentExpiresAt: Date
+    public let transactionId: String
+    public let pusherChannel: String
+}
+
+public struct TransferBank: Codable, Equatable {
+    public let slug: String
+    public let name: String
+    public let id: Int
+}

Sources/PaystackSDK/Core/Models/Models/VerifyAccessCode/ChannelOptions.swift

@@ -17,7 +17,7 @@ public struct ChannelOptions: Codable {
     enum CodingKeys: String, CodingKey {
         case ussd
         case qrCode = "qr"
-        case bankTransfer = "bank_transfer"
+        case bankTransfer
         case mobileMoney
     }
 }

Sources/PaystackSDK/Core/Models/Models/VerifyAccessCode/MerchantChannelSettings.swift

@@ -0,0 +1,17 @@
+import Foundation
+
+public struct MerchantChannelSettings: Codable, Equatable {
+    public var bankTransfer: BankTransferMerchantSettings?
+
+    public init(bankTransfer: BankTransferMerchantSettings? = nil) {
+        self.bankTransfer = bankTransfer
+    }
+}
+
+public struct BankTransferMerchantSettings: Codable, Equatable {
+    public var fulfilLateNotification: Bool?
+
+    public init(fulfilLateNotification: Bool? = nil) {
+        self.fulfilLateNotification = fulfilLateNotification
+    }
+}

Sources/PaystackSDK/Core/Models/Models/VerifyAccessCode/VerifyAccessCodeData.swift

@@ -12,11 +12,13 @@ public struct VerifyAccessCodeData: Decodable {
     public var currency: String
     public var channels: [Channel]
     public var channelOptions: ChannelOptions
+    public var merchantChannelSettings: MerchantChannelSettings?
     public var publicEncryptionKey: String
 
     public init(id: Int?, email: String, amount: Decimal, reference: String, accessCode: String,
                 merchantLogo: String? = nil, merchantName: String, domain: Domain,
                 currency: String, channels: [Channel], channelOptions: ChannelOptions,
+                merchantChannelSettings: MerchantChannelSettings? = nil,
                 publicEncryptionKey: String) {
         self.id = id
         self.email = email
@@ -29,6 +31,7 @@ public struct VerifyAccessCodeData: Decodable {
         self.currency = currency
         self.channels = channels
         self.channelOptions = channelOptions
+        self.merchantChannelSettings = merchantChannelSettings
         self.publicEncryptionKey = publicEncryptionKey
     }
 }

Sources/PaystackSDK/Core/Utils/DateFormatter.swift

@@ -4,7 +4,8 @@ public extension DateFormatter {
 
     static var paystackFormatter: DateFormatter {
         let formatter = DateFormatter()
-        formatter.locale = .current
+        formatter.locale = Locale(identifier: "en_US_POSIX")
+        formatter.timeZone = TimeZone(identifier: "UTC")
         formatter.dateFormat = DateFormat.paystack.rawValue
         return formatter
     }