feat: add shared multi-currency pricing

src/app/layout.tsx

@@ -19,6 +19,7 @@ import { QueryProvider } from "@/providers/QueryProvider";
 import { DevToolsSwitcher } from "@/components/ui/DevToolsSwitcher";
 import { OnboardingProvider } from "@/providers/OnboardingProvider";
 import OnboardingTour from "@/components/layout/OnboardingTour";
+import { CurrencyProvider } from "@/hooks/useCurrency";
 
 const geistSans = Geist({
   variable: "--font-geist-sans",
@@ -136,22 +137,24 @@ export default function RootLayout({
           disableTransitionOnChange
         >
           <AuthProvider>
-            <QueryProvider>
-              <WalletProvider>
-                <ModalProvider>
-                  <OnboardingProvider>
-                    <AppLayout
-                      headerSlot={<NavBar />}
-                      footerSlot={<Footer />}
-                    >
-                      {children}
-                      <OnboardingTour />
-                    </AppLayout>
-                    <DevToolsSwitcher />
-                  </OnboardingProvider>
-                </ModalProvider>
-              </WalletProvider>
-            </QueryProvider>
+            <CurrencyProvider>
+              <QueryProvider>
+                <WalletProvider>
+                  <ModalProvider>
+                    <OnboardingProvider>
+                      <AppLayout
+                        headerSlot={<NavBar />}
+                        footerSlot={<Footer />}
+                      >
+                        {children}
+                        <OnboardingTour />
+                      </AppLayout>
+                      <DevToolsSwitcher />
+                    </OnboardingProvider>
+                  </ModalProvider>
+                </WalletProvider>
+              </QueryProvider>
+            </CurrencyProvider>
           </AuthProvider>
         </ThemeProvider>
         {/* Register service worker after page is interactive */}

src/components/home/layout/navbar.tsx

@@ -7,6 +7,9 @@ import { usePathname } from "next/navigation";
 import { ThemeToggle } from "@/components/ui/theme-toggle";
 import CreateWalletModal from "@/components/CreateWalletModal";
 import { useWallet } from "@/providers/WalletProvider";
+import { useCurrency, type DisplayCurrency } from "@/hooks/useCurrency";
+
+const DISPLAY_CURRENCIES: DisplayCurrency[] = ["XLM", "USD", "EUR", "GBP", "JPY"];
 
 function shortenAddress(address: string): string {
   return `${address.slice(0, 4)}…${address.slice(-4)}`;
@@ -18,6 +21,7 @@ export default function NavBar() {
   const [copied, setCopied] = useState(false);
   const pathname = usePathname() ?? "";
   const { address, balance, network, isLoading, isWrongNetwork, disconnect } = useWallet();
+  const { selectedCurrency, setSelectedCurrency, convert } = useCurrency();
 
   const authRoutes = ["/login", "/sign-in", "/sign-up"];
   if (authRoutes.includes(pathname)) return null;
@@ -115,6 +119,17 @@ export default function NavBar() {
               <div className="hidden md:flex items-center space-x-4 ml-6">
                 <ThemeToggle />
 
+                <select
+                  value={selectedCurrency}
+                  onChange={(event) => setSelectedCurrency(event.target.value as DisplayCurrency)}
+                  className="rounded-lg border border-border bg-card/40 px-2 py-1.5 text-xs font-medium text-foreground transition-colors hover:border-purple-500 focus:outline-none focus:ring-1 focus:ring-purple-500 cursor-pointer"
+                  aria-label="Select display currency"
+                >
+                  {DISPLAY_CURRENCIES.map((currency) => (
+                    <option key={currency} value={currency}>{currency}</option>
+                  ))}
+                </select>
+
                 {isLandingPage ? (
                   <>
                     <Link href="/login">
@@ -138,7 +153,7 @@ export default function NavBar() {
                       </span>
                       {balance && (
                         <span className="text-xs font-mono text-muted-foreground border-l border-border/40 pl-2">
-                          {balance} XLM
+                          {convert(Number(balance))}
                         </span>
                       )}
                       <button
@@ -208,6 +223,20 @@ export default function NavBar() {
                 </Link>
 
                 <div className="pt-2 border-t border-border/40">
+                  <label className="flex items-center justify-between text-sm">
+                    <span>Currency</span>
+                    <select
+                      value={selectedCurrency}
+                      onChange={(event) => setSelectedCurrency(event.target.value as DisplayCurrency)}
+                      className="rounded-lg border border-border bg-card px-2 py-1 text-xs"
+                      aria-label="Select display currency"
+                    >
+                      {DISPLAY_CURRENCIES.map((currency) => (
+                        <option key={currency} value={currency}>{currency}</option>
+                      ))}
+                    </select>
+                  </label>
+
                   {address ? (
                     <button
                       onClick={disconnect}

src/components/marketplace/BookSessionModal.tsx

@@ -5,6 +5,7 @@ import { ChevronRight, CheckCircle, CalendarClock } from "lucide-react";
 import { Modal } from "@/components/ui/Modal";
 import { Button } from "@/components/ui/Button";
 import { Badge } from "@/components/ui/Badge";
+import { useCurrency } from "@/hooks/useCurrency";
 
 interface BookSessionModalProps {
   expertName: string;
@@ -26,6 +27,9 @@ export default function BookSessionModal({
   const [currentStep, setCurrentStep] = useState<Step>("deposit");
   const [isProcessing, setIsProcessing] = useState(false);
   const [reservationId, setReservationId] = useState<string | null>(null);
+  const { convert, selectedCurrency } = useCurrency();
+  const slotFeeXlm = Number.parseFloat(slotFee);
+  const displaySlotFee = Number.isFinite(slotFeeXlm) ? convert(slotFeeXlm) : `${slotFee} XLM`;
 
   const handleDeposit = async () => {
     setIsProcessing(true);
@@ -61,7 +65,12 @@ export default function BookSessionModal({
               </div>
               <div className="border-t border-white/10 pt-4 flex items-center justify-between">
                 <span className="text-sm text-white/60">Slot Reservation Fee</span>
-                <span className="text-lg font-bold text-purple-400">{slotFee} XLM</span>
+                <div className="text-right">
+                  <span className="text-lg font-bold text-purple-400">{displaySlotFee}</span>
+                  {selectedCurrency !== "XLM" && (
+                    <p className="text-xs text-white/50">{slotFee} XLM</p>
+                  )}
+                </div>
               </div>
             </div>
 
@@ -122,7 +131,7 @@ export default function BookSessionModal({
                 <h3 className="text-xl font-bold">Session Reserved!</h3>
                 <p className="text-sm text-white/60 max-w-sm">
                   Your appointment with <span className="text-white font-semibold">{expertName}</span> has been secured.
-                  The slot fee of <span className="text-purple-400 font-semibold">{slotFee} XLM</span> will be applied to your final session invoice.
+                  The slot fee of <span className="text-purple-400 font-semibold">{displaySlotFee}</span>{selectedCurrency !== "XLM" ? ` (${slotFee} XLM)` : ""} will be applied to your final session invoice.
                 </p>
               </div>
             </div>

src/components/marketplace/ExpertCard.tsx

@@ -16,7 +16,7 @@ interface ExpertCardProps {
 export default function ExpertCard({ expert }: ExpertCardProps) {
     const queryClient = useQueryClient();
     const { multiplier, isSurgeActive } = useSurgeMultiplier();
-    const { rates } = useCurrency();
+    const { convert, selectedCurrency } = useCurrency();
 
     const handleMouseEnter = () => {
         prefetchExpert(queryClient, expert.id);
@@ -25,9 +25,8 @@ export default function ExpertCard({ expert }: ExpertCardProps) {
     // Calculate surge percentage for display
     const surgePercent = Math.round((multiplier - 1) * 100);
 
-    // Calculate hourly and per-minute USD rates
-    const hourlyRateUSD = rates ? expert.hourlyRate * rates.usd : null;
-    const minuteRateUSD = hourlyRateUSD ? hourlyRateUSD / 60 : null;
+    const displayHourlyRate = convert(expert.hourlyRate);
+    const displayMinuteRate = convert(expert.hourlyRate / 60);
 
     return (
         <Link href={`/explore-experts/${expert.id}`}>
@@ -74,11 +73,11 @@ export default function ExpertCard({ expert }: ExpertCardProps) {
                                 className="font-bold text-lg text-purple-400 cursor-help"
                                 title="Rate may increase during high demand periods"
                             >
-                                {expert.hourlyRate} XLM/hr
+                                {displayHourlyRate} / hr
                             </span>
-                            {minuteRateUSD && (
+                            {selectedCurrency !== 'XLM' && (
                                 <span className="text-sm text-gray-400">
-                                    (${minuteRateUSD.toFixed(2)} / min)
+                                    {expert.hourlyRate.toFixed(4)} XLM/hr ({displayMinuteRate} / min)
                                 </span>
                             )}
                             {isSurgeActive && (

src/components/profile/ExpertDetails.tsx

@@ -140,10 +140,7 @@ interface ExpertDetailsProps {
 }
 
 export default function ExpertDetails({ expert, onBookClick }: ExpertDetailsProps) {
-  const { rates } = useCurrency();
-
-  // Calculate USD rates
-  const hourlyRateUSD = rates ? expert.hourlyRate * rates.usd : null;
+  const { convert, selectedCurrency } = useCurrency();
 
 
   return (
@@ -209,10 +206,10 @@ export default function ExpertDetails({ expert, onBookClick }: ExpertDetailsProp
                 <div className="text-sm text-gray-400">Total Sessions</div>
               </div>
               <div className="bg-black/30 rounded-lg p-4">
-                <div className="text-2xl font-bold text-purple-400">{expert.hourlyRate} XLM/hr</div>
-                <div className="text-sm text-gray-400">
-                  {hourlyRateUSD ? `($${hourlyRateUSD.toFixed(2)} / hr)` : 'Hourly Rate'}
-                </div>
+                <div className="text-2xl font-bold text-purple-400">{convert(expert.hourlyRate)} / hr</div>
+                {selectedCurrency !== "XLM" && (
+                  <div className="text-sm text-gray-400">{expert.hourlyRate.toFixed(4)} XLM/hr</div>
+                )}
               </div>
               <div className="bg-black/30 rounded-lg p-4">
                 <div className="text-2xl font-bold text-purple-400">{expert.reviews}</div>

src/hooks/useCurrency.ts

@@ -1,6 +1,6 @@
 "use client";
 
-import { useState, useEffect, useCallback } from "react";
+import { createContext, createElement, useState, useEffect, useCallback, useContext } from "react";
 
 // ─── Types ────────────────────────────────────────────────────────────────────
 
@@ -21,6 +21,8 @@ export interface UseCurrencyReturn {
   isLoading: boolean;
 }
 
+const CurrencyContext = createContext<UseCurrencyReturn | null>(null);
+
 // ─── Constants ────────────────────────────────────────────────────────────────
 
 const COINGECKO_URL =
@@ -46,7 +48,7 @@ const CURRENCY_DECIMALS: Record<DisplayCurrency, number> = {
 
 // ─── Hook ─────────────────────────────────────────────────────────────────────
 
-export function useCurrency(): UseCurrencyReturn {
+function useCurrencyState(): UseCurrencyReturn {
   const [selectedCurrency, setSelectedCurrency] =
     useState<DisplayCurrency>("USD");
   const [rates, setRates] = useState<CurrencyRates | null>(null);
@@ -103,3 +105,19 @@ export function useCurrency(): UseCurrencyReturn {
 
   return { selectedCurrency, setSelectedCurrency, rates, convert, isLoading };
 }
+
+export function CurrencyProvider({ children }: { children: React.ReactNode }) {
+  const value = useCurrencyState();
+
+  return createElement(CurrencyContext.Provider, { value }, children);
+}
+
+export function useCurrency(): UseCurrencyReturn {
+  const context = useContext(CurrencyContext);
+
+  if (!context) {
+    throw new Error("useCurrency must be used within a CurrencyProvider");
+  }
+
+  return context;
+}