feat: pay contacts via spark

Bitkit.xcodeproj/project.pbxproj

@@ -1269,7 +1269,7 @@
 			repositoryURL = "https://github.com/synonymdev/bitkit-core";
 			requirement = {
 				kind = exactVersion;
-				version = "0.8.0-rc11";
+				version = "0.8.0-swaps.3";
 			};
 		};
 		96E493A22C942FD1000E8BC2 /* XCRemoteSwiftPackageReference "swift-secp256k1" */ = {

Bitkit/Constants/Env.swift

@@ -228,6 +228,19 @@ enum Env {
         return electrumServerUrl(for: network)
     }
 
+    /// Whether a Paykit payment may route through a Pubky Swaps provider when no balance reaches the contact's
+    /// endpoints. Regtest debug builds with `PUBKY_SWAPS_ROUTES=true` only.
+    static var isPubkySwapsRouteEnabled: Bool {
+        isDebug && network == .regtest && boolConfigValue("PUBKY_SWAPS_ROUTES")
+    }
+
+    /// Swap providers to ask besides the user's contacts, from `PUBKY_SWAPS_PROVIDERS` (comma-separated pubkys).
+    static var pubkySwapsProviders: [String] {
+        (configValue("PUBKY_SWAPS_PROVIDERS") ?? "").split(separator: ",")
+            .map { $0.trimmingCharacters(in: .whitespaces) }
+            .filter { !$0.isEmpty }
+    }
+
     static var trezorBridgeEnabled: Bool {
         (isDebug || isE2E) && boolConfigValue("TREZOR_BRIDGE")
     }

Bitkit/Managers/SparkManager.swift

@@ -14,6 +14,8 @@ import Observation
 @Observable @MainActor
 final class SparkManager: ChannelFreeLightningRail {
     static let shared = SparkManager()
+    nonisolated static let routeService = "spark"
+    private nonisolated static let routeAtomicity = "trusted"
     private nonisolated(unsafe) static let exitStateChanged = PassthroughSubject<Void, Never>()
     /// Fires once Spark connects and whenever its unilateral exit data changes, so the exit data backup is redone.
     nonisolated static var exitStateChangedPublisher: AnyPublisher<Void, Never> {
@@ -253,6 +255,41 @@ final class SparkManager: ChannelFreeLightningRail {
         try await refresh()
     }
 
+    /// A Paykit route that withdraws exactly `amountSats` to the contact's on-chain `endpoint` at medium speed, with
+    /// Spark's fee on top, or nil while Spark cannot send it. bitkit-core weighs it against the Pubky Swaps providers.
+    func withdrawalRouteLeg(endpoint: PaykitEndpoint, amountSats: UInt64) async throws -> ServiceRouteLeg? {
+        guard isReady, balanceSats >= amountSats else { return nil }
+        let prepared = try await prepareSend(paymentRequest: endpoint.value, amountSats: amountSats)
+        guard case let .bitcoinAddress(_, feeQuote) = prepared.paymentMethod else {
+            throw AppError(message: "Unexpected Spark payment method", debugMessage: "\(prepared.paymentMethod)")
+        }
+        let debitSats = amountSats + feeQuote.speedMedium.userFeeSat
+        guard !feeQuote.isEstimate, balanceSats >= debitSats else { return nil }
+        return ServiceRouteLeg(
+            service: Self.routeService,
+            endpoint: endpoint,
+            deliveredSat: amountSats,
+            debitSat: debitSats,
+            atomicity: Self.routeAtomicity,
+            validUntilUnix: feeQuote.expiresAt
+        )
+    }
+
+    /// Withdraws exactly `amountSats` to the on-chain `address` at medium speed and returns the withdrawal's txid.
+    func withdraw(to address: String, amountSats: UInt64) async throws -> String {
+        let prepared = try await prepareSend(paymentRequest: address, amountSats: amountSats)
+        let response = try await requireSdk().sendPayment(request: SendPaymentRequest(
+            prepareResponse: prepared,
+            options: .bitcoinAddress(confirmationSpeed: .medium)
+        ))
+        Logger.info("Sent Spark withdrawal '\(response.payment.id)' with status '\(response.payment.status)'", context: "SparkManager")
+        try await refresh()
+        if case let .withdraw(txId) = response.payment.details {
+            return txId
+        }
+        return response.payment.id
+    }
+
     /// What a unilateral exit needs if the Spark operators stop cooperating; it can reach several MB.
     func exportExitState() async throws -> String {
         try await requireSdk().exportUnilateralExitState().exitState

Bitkit/Resources/Localization/ar.lproj/Localizable.strings

@@ -1021,6 +1021,7 @@
 "wallet__send_sync_long_title" = "مشاكل\n<accent>الاتصال</accent>";
 "wallet__send_sync_long_description" = "يبدو أنك غير متصل. يرجى التحقق من اتصالك. سيحاول Bitkit إعادة الاتصال كل بضع ثوانٍ.";
 "wallet__send_to" = "إلى";
+"wallet__send_swap_route" = "المسار";
 "wallet__recipient_contact" = "جهة الاتصال";
 "wallet__recipient_invoice" = "لصق فاتورة";
 "wallet__recipient_manual" = "إدخال يدوي";

Bitkit/Resources/Localization/ca.lproj/Localizable.strings

@@ -1140,6 +1140,7 @@
 "wallet__send_sync_long_title" = "Problemes de\n<accent>connexió</accent>";
 "wallet__send_sync_long_description" = "Sembla que estàs desconnectat. Comprova la connexió. Bitkit intentarà tornar a connectar-se cada pocs segons.";
 "wallet__send_to" = "A";
+"wallet__send_swap_route" = "Ruta";
 "wallet__recipient_contact" = "Contacte";
 "wallet__recipient_invoice" = "Enganxa factura";
 "wallet__recipient_manual" = "Introdueix manualment";

Bitkit/Resources/Localization/cs.lproj/Localizable.strings

@@ -1247,6 +1247,7 @@
 "wallet__send_sync_long_title" = "<accent>Problémy</accent>\ns připojením";
 "wallet__send_sync_long_description" = "Zdá se, že jste odpojeni. Zkontrolujte prosím připojení. Bitkit se bude každých několik sekund pokoušet znovu připojit.";
 "wallet__send_to" = "Komu";
+"wallet__send_swap_route" = "Trasa";
 "wallet__recipient_contact" = "Kontakt";
 "wallet__recipient_invoice" = "Vložit fakturu";
 "wallet__recipient_manual" = "Zadat ručně";

Bitkit/Resources/Localization/de.lproj/Localizable.strings

@@ -1245,6 +1245,7 @@
 "wallet__send_sync_long_title" = "<accent>Verbindungs-</accent>\nprobleme";
 "wallet__send_sync_long_description" = "Anscheinend bist du nicht verbunden. Bitte überprüfe deine Verbindung. Bitkit versucht alle paar Sekunden, sich erneut zu verbinden.";
 "wallet__send_to" = "An";
+"wallet__send_swap_route" = "Route";
 "wallet__recipient_contact" = "Kontakt";
 "wallet__recipient_invoice" = "Rechnung einfügen";
 "wallet__recipient_manual" = "Manuell eingeben";

Bitkit/Resources/Localization/el.lproj/Localizable.strings

@@ -1039,6 +1039,7 @@
 "wallet__send_sync_long_title" = "<accent>Προβλήματα</accent>\nσύνδεσης";
 "wallet__send_sync_long_description" = "Φαίνεται ότι είστε αποσυνδεδεμένοι. Ελέγξτε τη σύνδεσή σας. Το Bitkit θα προσπαθεί να επανασυνδεθεί κάθε λίγα δευτερόλεπτα.";
 "wallet__send_to" = "Προς";
+"wallet__send_swap_route" = "Διαδρομή";
 "wallet__recipient_contact" = "Επαφή";
 "wallet__recipient_invoice" = "Επικόλληση Τιμολογίου";
 "wallet__recipient_manual" = "Χειροκίνητη Εισαγωγή";

Bitkit/Resources/Localization/en.lproj/Localizable.strings

@@ -1260,6 +1260,7 @@
 "wallet__send_sync_long_title" = "<accent>Connection</accent>\nissues";
 "wallet__send_sync_long_description" = "It appears you’re disconnected. Please check your connection. Bitkit will try to reconnect every few seconds.";
 "wallet__send_to" = "To";
+"wallet__send_swap_route" = "Route";
 "wallet__recipient_contact" = "Contact";
 "wallet__recipient_invoice" = "Paste Invoice";
 "wallet__recipient_manual" = "Enter Manually";

Bitkit/Resources/Localization/es-419.lproj/Localizable.strings

@@ -1250,6 +1250,7 @@
 "wallet__send_sync_long_title" = "Problemas de\n<accent>conexión</accent>";
 "wallet__send_sync_long_description" = "Parece que está desconectado. Revise su conexión. Bitkit intentará reconectarse cada pocos segundos.";
 "wallet__send_to" = "Para";
+"wallet__send_swap_route" = "Ruta";
 "wallet__recipient_contact" = "Contacto";
 "wallet__recipient_invoice" = "Pegar factura";
 "wallet__recipient_manual" = "Introducir manualmente";

Bitkit/Resources/Localization/es.lproj/Localizable.strings

@@ -1157,6 +1157,7 @@
 "wallet__send_sync_long_title" = "Problemas de\n<accent>conexión</accent>";
 "wallet__send_sync_long_description" = "Parece que está desconectado. Compruebe su conexión. Bitkit intentará reconectarse cada pocos segundos.";
 "wallet__send_to" = "Para";
+"wallet__send_swap_route" = "Ruta";
 "wallet__recipient_contact" = "Contactar";
 "wallet__recipient_invoice" = "Pegar factura";
 "wallet__recipient_manual" = "Introducir manualmente";

Bitkit/Resources/Localization/fr.lproj/Localizable.strings

@@ -1258,6 +1258,7 @@
 "wallet__send_sync_long_title" = "Problèmes de\n<accent>connexion</accent>";
 "wallet__send_sync_long_description" = "Il semble que vous soyez déconnecté. Veuillez vérifier votre connexion. Bitkit tentera de se reconnecter toutes les quelques secondes.";
 "wallet__send_to" = "Pour";
+"wallet__send_swap_route" = "Itinéraire";
 "wallet__recipient_contact" = "Contact";
 "wallet__recipient_invoice" = "Coller la facture";
 "wallet__recipient_manual" = "Entrer manuellement";

Bitkit/Resources/Localization/it.lproj/Localizable.strings

@@ -1223,6 +1223,7 @@
 "wallet__send_sync_long_title" = "Problemi di\n<accent>connessione</accent>";
 "wallet__send_sync_long_description" = "Sembra che tu sia disconnesso. Controlla la connessione. Bitkit proverà a riconnettersi ogni pochi secondi.";
 "wallet__send_to" = "A";
+"wallet__send_swap_route" = "Percorso";
 "wallet__recipient_contact" = "Contatto";
 "wallet__recipient_invoice" = "Incolla fattura";
 "wallet__recipient_manual" = "Inserisci Manualmente";

Bitkit/Resources/Localization/nl.lproj/Localizable.strings

@@ -1253,6 +1253,7 @@
 "wallet__send_sync_long_title" = "<accent>Verbindings</accent>\nproblemen";
 "wallet__send_sync_long_description" = "Het lijkt erop dat u niet verbonden bent. Controleer uw verbinding. Bitkit probeert om de paar seconden opnieuw verbinding te maken.";
 "wallet__send_to" = "Naar";
+"wallet__send_swap_route" = "Route";
 "wallet__recipient_contact" = "Contact";
 "wallet__recipient_invoice" = "Factuur Plakken";
 "wallet__recipient_manual" = "Handmatig Invoeren";

Bitkit/Resources/Localization/pl.lproj/Localizable.strings

@@ -1257,6 +1257,7 @@
 "wallet__send_sync_long_title" = "<accent>Problemy</accent>\nz połączeniem";
 "wallet__send_sync_long_description" = "Wygląda na to, że nie masz połączenia. Sprawdź połączenie. Bitkit będzie próbował połączyć się ponownie co kilka sekund.";
 "wallet__send_to" = "Do";
+"wallet__send_swap_route" = "Trasa";
 "wallet__recipient_contact" = "Kontakt";
 "wallet__recipient_invoice" = "Wklej fakturę";
 "wallet__recipient_manual" = "Wprowadź ręcznie";

Bitkit/Resources/Localization/pt-BR.lproj/Localizable.strings

@@ -1258,6 +1258,7 @@
 "wallet__send_sync_long_title" = "Problemas de\n<accent>conexão</accent>";
 "wallet__send_sync_long_description" = "Parece que você está desconectado. Verifique sua conexão. A Bitkit tentará se reconectar a cada poucos segundos.";
 "wallet__send_to" = "Para";
+"wallet__send_swap_route" = "Rota";
 "wallet__recipient_contact" = "Contato";
 "wallet__recipient_invoice" = "Colar Invoice";
 "wallet__recipient_manual" = "Inserir Manualmente";

Bitkit/Resources/Localization/pt.lproj/Localizable.strings

@@ -1012,6 +1012,7 @@
 "wallet__send_sync_long_title" = "Problemas\n<accent>de ligação</accent>";
 "wallet__send_sync_long_description" = "Parece que está desligado. Verifique a sua ligação. A Bitkit vai tentar voltar a ligar a cada poucos segundos.";
 "wallet__send_to" = "Para";
+"wallet__send_swap_route" = "Rota";
 "wallet__recipient_contact" = "Contato";
 "wallet__recipient_invoice" = "Colar Invoice";
 "wallet__recipient_manual" = "Inserir Manualmente";

Bitkit/Resources/Localization/ru.lproj/Localizable.strings

@@ -1242,6 +1242,7 @@
 "wallet__send_sync_long_title" = "<accent>Проблемы</accent>\nс подключением";
 "wallet__send_sync_long_description" = "Похоже, вы отключены. Проверьте подключение. Bitkit будет пытаться переподключиться каждые несколько секунд.";
 "wallet__send_to" = "Кому";
+"wallet__send_swap_route" = "Маршрут";
 "wallet__recipient_contact" = "Контакт";
 "wallet__recipient_invoice" = "Вставить Инвойс";
 "wallet__recipient_manual" = "Ввести Вручную";

Bitkit/Services/PubkySwapsRouteService.swift

@@ -0,0 +1,128 @@
+import BitkitCore
+import Foundation
+
+/// A Paykit payment routed through a Pubky Swaps provider or a service the wallet holds a balance on: the endpoint,
+/// the route once quoted (a provider's quote or a service leg), and the provider's name.
+struct PaykitSwapRoute: Equatable {
+    let endpoint: PaykitEndpoint
+    var quote: PubkySwapRouteQuote?
+    var providerName: String?
+    var serviceLeg: ServiceRouteLeg?
+
+    var deliveredSat: UInt64? {
+        quote?.deliveredSat ?? serviceLeg?.deliveredSat
+    }
+
+    var totalFeeSat: UInt64? {
+        quote?.totalFeeSat ?? serviceLeg.map { $0.debitSat - $0.deliveredSat }
+    }
+}
+
+/// Routes a Paykit payment through a Pubky Swaps provider when no balance the wallet holds reaches an endpoint the
+/// contact published. bitkit-core picks the provider and checks its quote, contract and hold invoice; the wallet pays
+/// the hold invoice from spending and bitkit-core claims the provider's lockup straight to the contact's address.
+enum PubkySwapsRouteService {
+    private static let claimFeeRateSatVb: UInt64 = 2
+    private static let pollInterval: Duration = .seconds(2)
+    private static let claimTimeout: TimeInterval = 10 * 60
+
+    static var isEnabled: Bool {
+        Env.isPubkySwapsRouteEnabled
+    }
+
+    /// A contact whose only endpoints are on-chain, paid when savings cannot cover it but spending can.
+    static func route(for context: ContactPaymentContext, address: String, onchainBalanceSats: UInt64,
+                      lightningBalanceSats: UInt64) -> PaykitSwapRoute?
+    {
+        guard isEnabled, context.incomingPaymentRequest == nil, !address.isEmpty,
+              !context.endpoints.isEmpty, context.endpoints.allSatisfy({ $0.methodId.onchainNetwork != nil }),
+              onchainBalanceSats <= UInt64(Env.dustLimit), lightningBalanceSats > 0,
+              let methodId = context.endpoints.first?.methodId
+        else { return nil }
+        return PaykitSwapRoute(endpoint: PaykitEndpoint(methodId: methodId.rawValue, value: address))
+    }
+
+    static func quote(
+        amountSats: UInt64,
+        endpoint: PaykitEndpoint,
+        lightningSpendableSats: UInt64,
+        onchainSpendableSats: UInt64,
+        contacts: [String]
+    ) async throws -> PaykitRoute {
+        // Providers come from the user's own graph: every contact is asked for its swap offer.
+        let candidates = contacts + Env.pubkySwapsProviders
+        let serviceLegs = await serviceLegs(endpoint: endpoint, amountSats: amountSats)
+        Logger.debug("Routing Paykit payment via \(candidates.map(PubkyPublicKeyFormat.redacted))", context: "PubkySwapsRoute")
+        let (mnemonic, passphrase) = try secrets()
+        return try await pubkySwapsRoutePaykitPayment(
+            request: PaykitRouteRequest(
+                amountSat: amountSats,
+                contactEndpoints: [endpoint],
+                lightningSpendableSat: lightningSpendableSats,
+                onchainSpendableSat: onchainSpendableSats,
+                providers: candidates,
+                feeRateSatVb: claimFeeRateSatVb,
+                serviceLegs: serviceLegs
+            ),
+            network: Env.bitkitCoreNetwork,
+            mnemonic: mnemonic,
+            bip39Passphrase: passphrase
+        )
+    }
+
+    /// Legs through the services the wallet holds a balance on, which compete with the providers on fee.
+    private static func serviceLegs(endpoint: PaykitEndpoint, amountSats: UInt64) async -> [ServiceRouteLeg] {
+        do {
+            return try await SparkManager.shared.withdrawalRouteLeg(endpoint: endpoint, amountSats: amountSats).map { [$0] } ?? []
+        } catch {
+            Logger.warn("No Spark route to \(endpoint.methodId): \(error)", context: "PubkySwapsRoute")
+            return []
+        }
+    }
+
+    /// Runs a service leg the router picked and returns the txid that pays the contact.
+    static func pay(_ leg: ServiceRouteLeg) async throws -> String {
+        guard leg.service == SparkManager.routeService else {
+            throw AppError(message: "Unsupported route service", debugMessage: leg.service)
+        }
+        return try await SparkManager.shared.withdraw(to: leg.endpoint.value, amountSats: leg.deliveredSat)
+    }
+
+    static func commit(quoteId: String) async throws -> PubkySwapRoutePayment {
+        let (mnemonic, passphrase) = try secrets()
+        return try await pubkySwapsCommitRoute(
+            quoteId: quoteId,
+            electrumUrl: Env.electrumServerUrl,
+            mnemonic: mnemonic,
+            bip39Passphrase: passphrase
+        )
+    }
+
+    /// Advance the swap until bitkit-core claims the lockup to the contact, returning the claim txid.
+    static func awaitClaim(swapId: String) async throws -> String {
+        let deadline = Date().addingTimeInterval(claimTimeout)
+        while true {
+            let (mnemonic, passphrase) = try secrets()
+            let status = try await pubkySwapsAdvance(swapId: swapId, mnemonic: mnemonic, bip39Passphrase: passphrase)
+            switch status.state {
+            case let .claimed(txid):
+                return txid
+            case let .failed(reason):
+                throw AppError(message: reason, debugMessage: nil)
+            default:
+                Logger.debug("Pubky Swaps route \(swapId): \(status.state)", context: "PubkySwapsRoute")
+            }
+            guard Date() < deadline else {
+                throw AppError(message: "Swap \(swapId) not claimed yet", debugMessage: "\(status.state)")
+            }
+            try await Task.sleep(for: pollInterval)
+        }
+    }
+
+    private static func secrets() throws -> (String, String?) {
+        guard let mnemonic = try Keychain.loadString(key: .bip39Mnemonic(index: 0)) else {
+            throw AppError(message: "Mnemonic not found", debugMessage: nil)
+        }
+        return (mnemonic, try? Keychain.loadString(key: .bip39Passphrase(index: 0)))
+    }
+}

Bitkit/ViewModels/AppViewModel.swift

@@ -167,6 +167,7 @@ class AppViewModel: ObservableObject {
     @Published var contactPaymentContext: ContactPaymentContext?
     private(set) var didRejectScannedPayment = false
     @Published var paykitUsesUsdt = false
+    @Published var paykitSwapRoute: PaykitSwapRoute?
     @Published var paykitReviewedAmount: PaykitAmount?
     @Published var paykitPaymentTerms: PaykitRequestPricing.Payment?
 
@@ -1019,6 +1020,18 @@ extension AppViewModel {
             // Fallback to on-chain if address is available
             guard !invoice.address.isEmpty, validateIncomingOnchainPaymentRequestAmount(requestedAmount ?? invoice.amountSatoshis) else { return }
 
+            if let context = contactPaymentContext, let route = PubkySwapsRouteService.route(
+                for: context,
+                address: invoice.address,
+                onchainBalanceSats: max(paymentState.spendableOnchainBalanceSats, alternativeOnchainBalanceSats),
+                lightningBalanceSats: paymentState.totalLightningBalanceSats
+            ) {
+                handleScannedOnchainInvoice(invoice)
+                paykitSwapRoute = route
+                selectedWalletToPayFrom = .lightning
+                return
+            }
+
             // If node is running, validate balance immediately
             if paymentState.isNodeRunning {
                 let onchainBalance = max(
@@ -1364,6 +1377,7 @@ extension AppViewModel {
         sendStateOwnerID = ownerID
         sendStateGeneration = UUID()
         paykitUsesUsdt = false
+        paykitSwapRoute = nil
         paykitReviewedAmount = nil
         paykitPaymentTerms = nil
         scannedLightningInvoice = nil