From 44393a0c4a33b09d9566f948dd46cb748704f584 Mon Sep 17 00:00:00 2001
From: Heejin Jung <54030948+kes02@users.noreply.github.com>
Date: Wed, 5 Aug 2026 19:45:16 +0900
Subject: [PATCH] feat: add KRW to the preferred currency picker

KRW was the one major Asian currency missing from the picker added in
#2490, so won-billed users converted USD estimates by hand.

No new exchange-rate logic is needed: fetchLatestRatesIfNeeded already
merges every rate in the open.er-api.com payload, which carries KRW.
Listing the code in supportedCurrencies is what opens the
requiresLiveRates gate, so selecting KRW triggers the same live-fetch and
24h-cache path as the existing currencies. The hardcoded fallback rate is
only read before the first successful fetch.

KRW is zero-decimal and currencyString pins en_US, so ICU resolves the
fraction digits and won renders without a fractional separator on any
host.

Refs #2449

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
---
 Sources/CodexBar/PreferencesGeneralPane.swift | 2 ++
 Sources/CodexBarCore/CurrencyExchange.swift   | 3 ++-
 Tests/CodexBarTests/UsageFormatterTests.swift | 7 +++++++
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/Sources/CodexBar/PreferencesGeneralPane.swift b/Sources/CodexBar/PreferencesGeneralPane.swift
index db9f290da2..d8750a5c1f 100644
--- a/Sources/CodexBar/PreferencesGeneralPane.swift
+++ b/Sources/CodexBar/PreferencesGeneralPane.swift
@@ -82,6 +82,7 @@ enum PreferredCurrencyOption: String, CaseIterable, Identifiable {
     case eur = "EUR"
     case cny = "CNY"
     case jpy = "JPY"
+    case krw = "KRW"
     case cad = "CAD"
     case aud = "AUD"
     case hkd = "HKD"
@@ -101,6 +102,7 @@ enum PreferredCurrencyOption: String, CaseIterable, Identifiable {
         case .eur: "EUR (€)"
         case .cny: "CNY (¥)"
         case .jpy: "JPY (¥)"
+        case .krw: "KRW (₩)"
         case .cad: "CAD ($)"
         case .aud: "AUD ($)"
         case .hkd: "HKD ($)"
diff --git a/Sources/CodexBarCore/CurrencyExchange.swift b/Sources/CodexBarCore/CurrencyExchange.swift
index b6e47a5301..bf8b96d9a2 100644
--- a/Sources/CodexBarCore/CurrencyExchange.swift
+++ b/Sources/CodexBarCore/CurrencyExchange.swift
@@ -15,7 +15,7 @@ public final class CurrencyExchange: @unchecked Sendable {
 
     /// All currency codes supported by the converter.
     public static let supportedCurrencies: [String] = [
-        "USD", "GBP", "EUR", "CNY", "JPY", "CAD", "AUD", "HKD", "TWD", "SGD", "INR",
+        "USD", "GBP", "EUR", "CNY", "JPY", "KRW", "CAD", "AUD", "HKD", "TWD", "SGD", "INR",
     ]
 
     private let lock = NSLock()
@@ -27,6 +27,7 @@ public final class CurrencyExchange: @unchecked Sendable {
         "EUR": 0.92,
         "CNY": 7.27,
         "JPY": 154.0,
+        "KRW": 1428.90,
         "CAD": 1.38,
         "AUD": 1.55,
         "HKD": 7.80,
diff --git a/Tests/CodexBarTests/UsageFormatterTests.swift b/Tests/CodexBarTests/UsageFormatterTests.swift
index bc03694e77..b68b64ac57 100644
--- a/Tests/CodexBarTests/UsageFormatterTests.swift
+++ b/Tests/CodexBarTests/UsageFormatterTests.swift
@@ -511,6 +511,12 @@ struct UsageFormatterTests {
         let explicitCNY = UsageFormatter.convertedCostString(10.0, preferredCurrency: "CNY", providerCurrency: "USD")
         #expect(explicitCNY.contains("¥"))
 
+        let krwRate = exchange.rate(for: "KRW") ?? 1428.90
+        #expect(abs((exchange.convert(usdAmount: 10.0, to: "KRW") ?? 0) - 10.0 * krwRate) < epsilon)
+        let explicitKRW = UsageFormatter.convertedCostString(10.0, preferredCurrency: "KRW", providerCurrency: "USD")
+        #expect(explicitKRW.contains("₩"))
+        #expect(!explicitKRW.contains("."))
+
         #expect(exchange.convert(amount: 10.0, from: "CHF", to: "USD") == nil)
         let unavailable = UsageFormatter.convertedCostString(
             10.0,
@@ -528,6 +534,7 @@ struct UsageFormatterTests {
         #expect(!CurrencyExchange.requiresLiveRates(preferredCurrencyCode: "CHF"))
         #expect(CurrencyExchange.requiresLiveRates(preferredCurrencyCode: "GBP"))
         #expect(CurrencyExchange.requiresLiveRates(preferredCurrencyCode: " eur "))
+        #expect(CurrencyExchange.requiresLiveRates(preferredCurrencyCode: "KRW"))
     }
 
     @Test