Show each wallet's balance in USD

apps/ios/Koins/AppModel.swift

@@ -15,6 +15,8 @@ final class AppModel: ObservableObject {
   @Published var moneroReady = false
   @Published var moneroAddress: String?
   @Published var moneroAccounts: [MoneroAccount] = []
+  @Published var prices = PriceService.Prices()
+
   /// Whether the app is behind the biometric lock screen right now.
   @Published var locked = false
 
@@ -53,6 +55,28 @@ final class AppModel: ObservableObject {
 
   var symbol: String { chain.symbol }
 
+  // MARK: - Fiat display
+
+  private static let fiatFormatter: NumberFormatter = {
+    let formatter = NumberFormatter()
+    formatter.numberStyle = .currency
+    formatter.currencyCode = "USD"
+    formatter.locale = Locale(identifier: "en_US")
+    return formatter
+  }()
+
+  /// The current chain's balance in USD, when a price is known.
+  var fiatBalance: String? {
+    let price = chain == .xrp ? prices.xrp : prices.xmr
+    guard let price, let amount = Decimal(string: balance.total) else { return nil }
+    let usd = amount * Decimal(price)
+    return Self.fiatFormatter.string(from: usd as NSDecimalNumber)
+  }
+
+  private func refreshPrices() async {
+    prices = await PriceService.shared.prices()
+  }
+
   // MARK: - Biometric lock
 
   func authenticate() async {
@@ -112,6 +136,7 @@ final class AppModel: ObservableObject {
     showCached(chain)
     await refresh(force: true)
     startAutoRefresh()
+    Task { await refreshPrices() }
   }
 
   private func adoptMoneroWallet(named name: String) async {
@@ -263,6 +288,7 @@ final class AppModel: ObservableObject {
     refreshToken = token
     let requestChain = chain
     errorMessage = nil
+    await refreshPrices()
     if chain == .xrp, let wallet = xrpWallet {
       do {
         async let balanceCall = XRPWalletService.shared.balance(address: wallet.address)

apps/ios/Koins/Support/PriceService.swift

@@ -0,0 +1,79 @@
+import Foundation
+
+/// USD prices for the two tickers the wallet supports, fetched from a public
+/// price API and cached briefly so a screen does not fetch on every refresh.
+final class PriceService {
+  static let shared = PriceService()
+
+  struct Prices: Codable {
+    var xrp: Double?
+    var xmr: Double?
+    var fetchedAt: Date?
+  }
+
+  private static let cacheLifetime: TimeInterval = 60
+  private var memory: Prices?
+  private var inFlight: Task<Prices, Never>?
+
+  private init() {}
+
+  func prices() async -> Prices {
+    if let memory, let fetchedAt = memory.fetchedAt,
+       Date().timeIntervalSince(fetchedAt) < Self.cacheLifetime {
+      return memory
+    }
+    if let inFlight { return await inFlight.value }
+
+    let task = Task<Prices, Never> { [weak self] in
+      guard let self else { return Prices(fetchedAt: nil) }
+      let prices = await self.fetch()
+      self.memory = prices
+      return prices
+    }
+    inFlight = task
+    let result = await task.value
+    inFlight = nil
+    return result
+  }
+
+  private func fetch() async -> Prices {
+    if let prices = try? await fromCoinGecko() { return prices }
+    return (try? await fromKraken()) ?? Prices(fetchedAt: nil)
+  }
+
+  private func fromCoinGecko() async throws -> Prices {
+    guard let url = URL(string: "https://api.coingecko.com/api/v3/simple/price?ids=monero,ripple&vs_currencies=usd") else {
+      throw XRPError.network("Invalid price endpoint")
+    }
+    let (data, response) = try await URLSession.shared.data(from: url)
+    guard let http = response as? HTTPURLResponse, (200..<300).contains(http.statusCode) else {
+      throw XRPError.network("CoinGecko request failed")
+    }
+    let json = try JSONSerialization.jsonObject(with: data) as? [String: Any] ?? [:]
+    return Prices(
+      xrp: (json["ripple"] as? [String: Any]).flatMap { ($0["usd"] as? NSNumber)?.doubleValue },
+      xmr: (json["monero"] as? [String: Any]).flatMap { ($0["usd"] as? NSNumber)?.doubleValue },
+      fetchedAt: Date())
+  }
+
+  private func fromKraken() async throws -> Prices {
+    guard let url = URL(string: "https://api.kraken.com/0/public/Ticker?pair=XRPUSD,XMRUSD") else {
+      throw XRPError.network("Invalid price endpoint")
+    }
+    let (data, response) = try await URLSession.shared.data(from: url)
+    guard let http = response as? HTTPURLResponse, (200..<300).contains(http.statusCode) else {
+      throw XRPError.network("Kraken request failed")
+    }
+    let json = try JSONSerialization.jsonObject(with: data) as? [String: Any] ?? [:]
+    let result = json["result"] as? [String: Any] ?? [:]
+
+    func lastTrade(_ key: String) -> Double? {
+      (result[key] as? [String: Any])
+        .flatMap { entry in (entry["c"] as? [Any])?.first }
+        .flatMap { ($0 as? String).flatMap(Double.init) }
+    }
+    return Prices(xrp: lastTrade("XXRPZUSD") ?? lastTrade("XRPUSD"),
+                  xmr: lastTrade("XXMRZUSD") ?? lastTrade("XMRUSD"),
+                  fetchedAt: Date())
+  }
+}

apps/ios/Koins/Views/DashboardViews.swift

@@ -24,6 +24,11 @@ struct DashboardView: View {
           Text("\(model.balance.total) \(model.symbol)")
             .font(.system(size: 32, weight: .bold, design: .rounded))
             .foregroundStyle(Theme.text)
+          if let fiat = model.fiatBalance {
+            Text("\(fiat)")
+              .font(.system(size: 13, weight: .medium))
+              .foregroundStyle(Theme.muted)
+          }
           if model.chain == .xmr, model.balance.unlocked != model.balance.total {
             Text("\(model.balance.unlocked) \(model.symbol) spendable now")
               .font(.system(size: 11))

apps/ios/Koins/Views/RootView.swift

@@ -183,6 +183,11 @@ struct HomeView: View {
             Text("\(model.balance.total) \(model.symbol)")
               .font(.system(size: 30, weight: .bold, design: .rounded))
               .foregroundStyle(Theme.text)
+            if let fiat = model.fiatBalance {
+              Text("\(fiat)")
+                .font(.system(size: 13, weight: .medium))
+                .foregroundStyle(Theme.muted)
+            }
             if model.chain == .xmr, model.balance.unlocked != model.balance.total {
               Text("\(model.balance.unlocked) \(model.symbol) unlocked")
                 .font(.system(size: 11))