send transaction implemented in swift example app

Author: Borja Castellano

packages/swift-sdk/Sources/SwiftDashSDK/Core/SPV/SPVClient.swift

@@ -144,7 +144,7 @@ class SPVClient: @unchecked Sendable {
     }
 
     func getSyncProgress() -> SPVSyncProgress {
-        guard let ptr = dash_spv_ffi_client_get_sync_progress(client) else {
+        guard let ptr = dash_spv_ffi_client_get_manager_sync_progress(client) else {
             print("[SPV][GetSyncProgress] Failed to get sync progress (Should only fail if client is nil, but client is not nil)")
             return SPVSyncProgress.default()
         }
@@ -266,7 +266,7 @@ class SPVClient: @unchecked Sendable {
     func destroy() {
         dash_spv_ffi_client_destroy(client)
         dash_spv_ffi_config_destroy(config)
-        
+
         client = nil
         config = nil
     }
@@ -293,6 +293,24 @@ class SPVClient: @unchecked Sendable {
         }
     }
 
+    // MARK: - Broadcast transactions
+    func broadcastTransaction(_ transactionData: Data) throws {
+        try transactionData.withUnsafeBytes { (ptr: UnsafeRawBufferPointer) in
+            guard let txBytes = ptr.bindMemory(to: UInt8.self).baseAddress else {
+                throw SPVError.transactionBroadcastFailed("Invalid transaction data pointer")
+            }
+            let result = dash_spv_ffi_client_broadcast_transaction(
+                client,
+                txBytes,
+                UInt(transactionData.count),
+            )
+
+            if result != 0 {
+                throw SPVError.transactionBroadcastFailed(SPVClient.getLastDashFFIError())
+            }
+        }
+    }
+
     // MARK: - Wallet Manager Access
 
     /// Produce a Swift wallet manager that shares the SPV client's underlying wallet state.
@@ -316,6 +334,7 @@ public enum SPVError: LocalizedError {
     case alreadySyncing
     case syncFailed(String)
     case storageOperationFailed(String)
+    case transactionBroadcastFailed(String)
 
     public var errorDescription: String? {
         switch self {
@@ -335,6 +354,8 @@ public enum SPVError: LocalizedError {
             return "Sync failed: \(reason)"
         case let .storageOperationFailed(reason):
             return reason
+        case let .transactionBroadcastFailed(reason):
+            return "Transaction broadcast failed: \(reason)"
         }
     }
 }

packages/swift-sdk/Sources/SwiftDashSDK/Core/SPV/SPVTypes.swift

@@ -53,7 +53,7 @@ public enum SPVSyncState: UInt32, Sendable {
 
 public struct SPVBlockHeadersProgress: Sendable {
     public let state: SPVSyncState
-    public let currentHeight: UInt32
+    public let tipHeight: UInt32
     public let targetHeight: UInt32
     public let processed: UInt32
     public let buffered: UInt32
@@ -62,7 +62,7 @@ public struct SPVBlockHeadersProgress: Sendable {
 
     public init(_ ffi: FFIBlockHeadersProgress) {
         state = SPVSyncState(rawValue: ffi.state.rawValue) ?? .unknown
-        currentHeight = ffi.tip_height
+        tipHeight = ffi.tip_height
         targetHeight = ffi.target_height
         processed = ffi.processed
         buffered = ffi.buffered

packages/swift-sdk/Sources/SwiftDashSDK/Core/Services/WalletService.swift

@@ -84,9 +84,9 @@ func print(_ items: Any..., separator: String = " ", terminator: String = "\n")
     Swift.print(output, terminator: terminator)
 }
 
-// DESIGN NOTE: This class feels like something that should be in the example app, 
+// DESIGN NOTE: This class feels like something that should be in the example app,
 // we, as sdk developers, provide the tools and ffi wrappers, but how to
-// use them depends on the sdk user, for example, by implementing the SPV event 
+// use them depends on the sdk user, for example, by implementing the SPV event
 // handlers, the user can decide what to do with the events, but if we implement them in the sdk
 // we are taking that decision for them, and maybe not all users want the same thing
 @MainActor
@@ -96,82 +96,82 @@ public class WalletService: ObservableObject {
     @Published public var masternodesEnabled = true
     @Published public var lastSyncError: Error?
     @Published var network: AppNetwork
-    
+
     // Internal properties
     private var modelContainer: ModelContainer
-    
+
     // SPV Client and Wallet wrappers
     private var spvClient: SPVClient
     public private(set) var walletManager: CoreWalletManager
 
     public init(modelContainer: ModelContainer, network: AppNetwork) {
         self.modelContainer = modelContainer
         self.network = network
-        
+
         LoggingPreferences.configure()
-        
+
         let dataDir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first?.appendingPathComponent("SPV").appendingPathComponent(network.rawValue).path
-        
+
         // For simplicity, lets unwrap the error. This can only fail due to
-        // IO errors when working with the internal storage system, I don't 
+        // IO errors when working with the internal storage system, I don't
         // see how we can recover from that right now easily
         let spvClient = try! SPVClient(
             network: network.sdkNetwork,
             dataDir: dataDir,
             startHeight: 0,
         )
-        
+
         self.spvClient = spvClient
-        
+
         // Create the SDK wallet manager by reusing the SPV client's shared manager
         // TODO: Investigate this error
         self.walletManager = try! CoreWalletManager(spvClient: spvClient, modelContainer: modelContainer)
-        
+
         spvClient.setProgressUpdateEventHandler(SPVProgressUpdateEventHandlerImpl(walletService: self))
         spvClient.setSyncEventsHandler(SPVSyncEventsHandlerImpl(walletService: self))
         spvClient.setNetworkEventsHandler(SPVNetworkEventsHandlerImpl(walletService: self))
         spvClient.setWalletEventsHandler(SPVWalletEventsHandlerImpl(walletService: self))
     }
-    
+
     deinit {
         spvClient.stopSync()
         spvClient.destroy()
     }
-    
+
     private func initializeNewSPVClient() {
       SDKLogger.log("Initializing SPV Client for \(self.self.network.rawValue)...", minimumLevel: .medium)
-      
+
       let dataDir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first?.appendingPathComponent("SPV").appendingPathComponent(self.network.rawValue).path
-      
+
       // This ensures no memory leaks when creating a new client
       // and unlocks the storage in case we are about to use the same (we probably are)
       self.spvClient.destroy()
-      
+
       // For simplicity, lets unwrap the error. This can only fail due to
-      // IO errors when working with the internal storage system, I don't 
+      // IO errors when working with the internal storage system, I don't
       // see how we can recover from that right now easily
       self.spvClient = try! SPVClient(
           network: self.self.network.sdkNetwork,
           dataDir: dataDir,
           startHeight: 0,
       )
-      
+
       self.spvClient.setProgressUpdateEventHandler(SPVProgressUpdateEventHandlerImpl(walletService: self))
       self.spvClient.setSyncEventsHandler(SPVSyncEventsHandlerImpl(walletService: self))
       self.spvClient.setNetworkEventsHandler(SPVNetworkEventsHandlerImpl(walletService: self))
       self.spvClient.setWalletEventsHandler(SPVWalletEventsHandlerImpl(walletService: self))
-      
+
       try! self.spvClient.setMasternodeSyncEnabled(self.masternodesEnabled)
-      
+
       SDKLogger.log("✅ SPV Client initialized successfully for \(self.network.rawValue) (deferred start)", minimumLevel: .medium)
-      
+
       // Create the SDK wallet manager by reusing the SPV client's shared manager
       // TODO: Investigate this error
       self.walletManager = try! CoreWalletManager(spvClient: self.spvClient, modelContainer: self.modelContainer)
-      
+
       SDKLogger.log("✅ WalletManager wrapper initialized successfully", minimumLevel: .medium)
     }
-    
+
     // MARK: - Trusted Mode / Masternode Sync
     public func setMasternodesEnabled(_ enabled: Bool) {
         masternodesEnabled = enabled
@@ -203,10 +203,14 @@ public class WalletService: ObservableObject {
       // pausing and resuming is not supported so, the trick is the following,
       // stop the old client and create a new one in its initial state xd
       spvClient.stopSync()
-      
+
       self.initializeNewSPVClient()
     }
 
+    public func broadcastTransaction(_ data: Data) throws {
+        try self.spvClient.broadcastTransaction(data)
+    }
+
     public func clearSpvStorage() {
         if syncProgress.state.isRunning() {
             print("[SPV][Clear] Sync task is running, cannot clear storage")
@@ -236,17 +240,17 @@ public class WalletService: ObservableObject {
 
     public func switchNetwork(to network: AppNetwork) async {
         guard network != self.network else { return }
-        
+
         print("=== WalletService.switchNetwork START ===")
         print("Switching from \(self.network.rawValue) to \(network.rawValue)")
-        
+
         self.network = network
 
         self.stopSync()
-        
+
         print("=== WalletService.switchNetwork END ===")
     }
-    
+
     // MARK: - SPV Event Handlers implementations
 
     internal final class SPVProgressUpdateEventHandlerImpl: SPVProgressUpdateEventHandler, Sendable {
@@ -329,7 +333,7 @@ public class WalletService: ObservableObject {
             _ amount: Int64,
             _ addresses: [String]
         ) {}
-    
+
         func onBalanceUpdated(
             _ walletId: String,
             _ spendable: UInt64,

packages/swift-sdk/Sources/SwiftDashSDK/Core/Wallet/CoreWalletManager.swift

@@ -142,6 +142,16 @@ public class CoreWalletManager: ObservableObject {
 
     // MARK: - Account Management
 
+    /// Build a signed transaction
+    /// - Parameters:
+    ///   - accountIndex: The account index to use
+    ///   - outputs: The transaction outputs
+    ///   - feePerKB: Fee per kilobyte in satoshis
+    /// - Returns: The unsigned transaction bytes
+    public func buildSignedTransaction(for wallet: HDWallet, accIndex: UInt32, outputs: [Transaction.Output], feeRate: FeeRate) throws -> (Data, UInt64) {
+        try sdkWalletManager.buildSignedTransaction(for: wallet, accIndex: accIndex, outputs: outputs, feeRate: feeRate)
+    }
+
     /// Get transactions for a wallet
     /// - Parameters:
     ///   - wallet: The wallet to get transactions for

packages/swift-sdk/Sources/SwiftDashSDK/KeyWallet/ManagedAccount.swift

@@ -50,8 +50,6 @@ public class ManagedAccount {
         return managed_core_account_get_utxo_count(handle)
     }
 
-    // MARK: - Transactions
-
     /// Get all transactions for this account
     /// - Returns: Array of transactions
     public func getTransactions() -> [WalletTransaction] {

packages/swift-sdk/Sources/SwiftDashSDK/KeyWallet/Transaction.swift

@@ -1,12 +1,18 @@
 import Foundation
 import DashSDKFFI
 
-/// Result of building and signing a transaction
-public struct BuildAndSignResult: Sendable {
-    /// The signed transaction bytes
-    public let transactionData: Data
-    /// The fee paid in duffs
-    public let fee: UInt64
+public enum FeeRate {
+    case economy
+    case normal
+    case priority
+
+    func intoDuffPerKB() -> UInt64 {
+        switch self {
+        case .economy: return 500
+        case .normal: return 1000
+        case .priority: return 2000
+        }
+    }
 }
 
 /// Transaction utilities for wallet operations
@@ -23,9 +29,8 @@ public class Transaction {
         }
 
         func toFFI() -> FFITxOutput {
-            return address.withCString { addressCStr in
-                FFITxOutput(address: addressCStr, amount: amount)
-            }
+            let cString = strdup(address)
+            return FFITxOutput(address: cString, amount: amount)
         }
     }
 

packages/swift-sdk/Sources/SwiftDashSDK/KeyWallet/WalletManager.swift

@@ -387,6 +387,60 @@ public class WalletManager {
         return success
     }
 
+    /// Build a signed transaction
+    /// - Parameters:
+    ///   - accountIndex: The account index to use
+    ///   - outputs: The transaction outputs
+    ///   - feePerKB: Fee per kilobyte in satoshis
+    /// - Returns: The unsigned transaction bytes and the fee
+    public func buildSignedTransaction(for wallet: HDWallet, accIndex: UInt32, outputs: [Transaction.Output], feeRate: FeeRate) throws -> (Data, UInt64) {
+        guard !outputs.isEmpty else {
+            throw KeyWalletError.invalidInput("Transaction must have at least one output")
+        }
+
+        var error = FFIError()
+        var txBytesPtr: UnsafeMutablePointer<UInt8>?
+        var txLen: size_t = 0
+
+        var fee: UInt64 = 0
+
+        let wallet = try self.getWallet(id: wallet.walletId)!
+
+        let ffiOutputs = outputs.map { $0.toFFI() }
+
+        let success = ffiOutputs.withUnsafeBufferPointer { outputsPtr in
+            wallet_build_and_sign_transaction(
+                self.handle,
+                wallet.ffiHandle,
+                accIndex,
+                outputsPtr.baseAddress,
+                outputs.count,
+                feeRate.intoDuffPerKB(),
+                &fee,
+                &txBytesPtr,
+                &txLen,
+                &error)
+        }
+
+        defer {
+            if error.message != nil {
+                error_message_free(error.message)
+            }
+            if let ptr = txBytesPtr {
+                transaction_bytes_free(ptr)
+            }
+        }
+
+        guard success, let ptr = txBytesPtr else {
+            throw KeyWalletError(ffiError: error)
+        }
+
+        // Copy the transaction data before freeing
+        let txData = Data(bytes: ptr, count: txLen)
+
+        return (txData, fee)
+    }
+
     // MARK: - Block Height Management
 
     /// Get the current block height for a network

packages/swift-sdk/SwiftExampleApp/SwiftExampleApp/Core/Views/CoreContentView.swift

@@ -18,7 +18,7 @@ struct CoreContentView: View {
     // Display helpers
     private var headerHeightsDisplay: String? {
         let headers = walletService.syncProgress.headers
-        let cur = (headers?.currentHeight ?? 0) + (headers?.buffered ?? 0)
+        let cur = (headers?.tipHeight ?? 0) + (headers?.buffered ?? 0)
         let tot = headers?.targetHeight ?? 0
 
         return heightDisplay(numerator: cur, denominator: tot)