feat: complete translation language controls and styling

Tests/ConjureKitTests/MyMemoryTests.swift

@@ -38,6 +38,19 @@ import Testing
     #expect(translation == "こんにちは")
 }
 
+@Test func myMemoryRequestsReversePairAndOnlyUsesMatchingFallback() async throws {
+    let body = #"{"responseStatus":200,"responseData":{"translatedText":""},"matches":[{"segment":"おはよう","translation":"間違い","source":"en","target":"ja"},{"segment":"おはよう","translation":"bonjour","source":"ja","target":"fr"},{"segment":"おはようございます","translation":"Good morning!","source":"ja","target":"en"},{"segment":"おはよう","translation":"Good morning","source":"ja-JP","target":"en-GB"}]}"#
+    let translation = try await MyMemoryAPI.translate(
+        "おはよう", sourceLanguage: "ja", targetLanguage: "en"
+    ) { request in
+        let items = try #require(URLComponents(url: request.url!, resolvingAgainstBaseURL: false)?.queryItems)
+        #expect(items.contains(URLQueryItem(name: "q", value: "おはよう")))
+        #expect(items.contains(URLQueryItem(name: "langpair", value: "ja|en")))
+        return (Data(body.utf8), HTTPURLResponse(url: request.url!, statusCode: 200, httpVersion: nil, headerFields: nil)!)
+    }
+    #expect(translation == "Good morning")
+}
+
 @Test func myMemoryNeverUsesMatchesToBypassFailureOrReplacePrimaryTranslation() async throws {
     let matches = #""matches":[{"segment":"hello","translation":"こんにちは","source":"en","target":"ja"}]"#
     for metadata in [#""responseStatus":403"#, #""responseStatus":200,"quotaFinished":true"#] {

Tests/ConjureKitTests/TranslationExecutionTests.swift

@@ -5,13 +5,13 @@ import Testing
 
 @MainActor
 private final class TranslationRequests {
-    var inputs: [(text: String, key: String?)] = []
+    var inputs: [(text: String, source: String, target: String, key: String?)] = []
     var pending: [CheckedContinuation<String, any Error>] = []
     var returned = 0
 
     // Deliberately ignore cancellation: the controller must reject late completions itself.
-    func translate(_ text: String, key: String? = nil) async throws -> String {
-        inputs.append((text, key))
+    func translate(_ text: String, source: String, target: String, key: String? = nil) async throws -> String {
+        inputs.append((text, source, target, key))
         defer { returned += 1 }
         return try await withCheckedThrowingContinuation { pending.append($0) }
     }
@@ -58,6 +58,50 @@ private func descendants(_ view: NSView) -> [NSView] { [view] + view.subviews.fl
 
 @Suite(.serialized)
 struct TranslationExecutionTests {
+@Test @MainActor
+func languageActionsInvalidateOldResultsAndApplyTheSelectedPair() async throws {
+    _ = NSApplication.shared
+    let suite = "TranslateLanguages.\(UUID().uuidString)"
+    let defaults = UserDefaults(suiteName: suite)!
+    defer { defaults.removePersistentDomain(forName: suite) }
+    let requests = TranslationRequests()
+    let tool = TranslationController(defaults: defaults,
+        myMemory: { try await requests.translate($0, source: $1, target: $2) })
+    tool.input = { "こんにちは" }
+    let window = NSWindow(contentRect: NSRect(x: 0, y: 0, width: 750, height: 474),
+        styleMask: .borderless, backing: .buffered, defer: false)
+    window.isReleasedWhenClosed = false
+    window.contentView = tool.view
+    defer { tool.close(); window.orderOut(nil) }
+    let output = try #require(descendants(tool.view).compactMap { $0 as? NSTextView }.first)
+    tool.performPrimaryAction()
+    try await waitForTranslation { requests.pending.count == 1 }
+    let languages = try #require(descendants(tool.view).compactMap { $0 as? NSButton }
+        .first { $0.accessibilityLabel() == "Translation languages" })
+    languages.performClick(nil)
+    let host = try #require(window.contentView)
+    let search = try #require(descendants(host).compactMap { $0 as? NSSearchField }.first)
+    search.stringValue = "swap"
+    search.delegate?.controlTextDidChange?(Notification(name: NSControl.textDidChangeNotification, object: search))
+    #expect(tool.handle(#selector(NSResponder.insertNewline(_:))))
+    #expect(tool.sourceLanguage == "ja")
+    #expect(tool.targetLanguage == "en")
+    requests.pending[0].resume(returning: "obsolete")
+    try await waitForTranslation { requests.returned == 1 }
+    #expect(output.string.isEmpty)
+    tool.performPrimaryAction()
+    try await waitForTranslation { requests.pending.count == 2 }
+    #expect(requests.inputs[1].source == "ja")
+    #expect(requests.inputs[1].target == "en")
+    requests.pending[1].resume(returning: "Hello")
+    try await waitForTranslation { output.string == "Hello" }
+    tool.setLanguages(source: "de", target: "fr")
+    #expect(output.string.isEmpty)
+    let reopened = TranslationController(defaults: defaults)
+    #expect(reopened.sourceLanguage == "de")
+    #expect(reopened.targetLanguage == "fr")
+}
+
 @Test @MainActor
 func primaryActionCopiesCompletedTranslationAndResetsAfterEditing() async throws {
     _ = NSApplication.shared
@@ -70,7 +114,7 @@ func primaryActionCopiesCompletedTranslationAndResetsAfterEditing() async throws
     }
     let requests = TranslationRequests()
     let tool = TranslationController(defaults: defaults,
-        myMemory: { try await requests.translate($0) }, pasteboard: pasteboard)
+        myMemory: { try await requests.translate($0, source: $1, target: $2) }, pasteboard: pasteboard)
     tool.input = { "Hello" }
     var dismissed = false
     tool.dismiss = { dismissed = true }
@@ -107,8 +151,8 @@ func translationExecutionIsExplicitAndMyMemoryNeverTouchesCredentials() async th
     keys.value = "private-key"
     let requests = TranslationRequests()
     let tool = TranslationController(defaults: defaults, credentials: keys.store,
-        myMemory: { try await requests.translate($0) },
-        openAI: { try await requests.translate($0, key: $1) })
+        myMemory: { try await requests.translate($0, source: $1, target: $2) },
+        openAI: { try await requests.translate($0, source: $1, target: $2, key: $3) })
     tool.input = { "Hello" }
     let views = descendants(tool.view)
     let output = try #require(views.compactMap { $0 as? NSTextView }.first)
@@ -135,8 +179,8 @@ func translationExecutionRejectsOldCompletionsWithoutClearingNewRequests() async
     keys.value = "saved-key"
     let requests = TranslationRequests()
     let tool = TranslationController(defaults: defaults, credentials: keys.store,
-        myMemory: { try await requests.translate($0) },
-        openAI: { try await requests.translate($0, key: $1) })
+        myMemory: { try await requests.translate($0, source: $1, target: $2) },
+        openAI: { try await requests.translate($0, source: $1, target: $2, key: $3) })
     var input = "first"
     tool.input = { input }
     let views = descendants(tool.view)
@@ -190,8 +234,8 @@ func translationExecutionRecoversFromCredentialAndRequestFailures() async throws
     let keys = TranslationKeys()
     let requests = TranslationRequests()
     let tool = TranslationController(defaults: defaults, credentials: keys.store,
-        myMemory: { try await requests.translate($0) },
-        openAI: { try await requests.translate($0, key: $1) })
+        myMemory: { try await requests.translate($0, source: $1, target: $2) },
+        openAI: { try await requests.translate($0, source: $1, target: $2, key: $3) })
     tool.input = { "Hello" }
     let views = descendants(tool.view)
     let settings = TranslationSettingsController(credentials: keys.store)

Tests/ConjureKitTests/TranslationTests.swift

@@ -12,6 +12,8 @@ import Testing
         #expect(body["model"] as? String == "gpt-6-luna")
         #expect(body["input"] as? String == "Good morning")
         #expect(body["store"] as? Bool == false)
+        let instructions = try #require(body["instructions"] as? String)
+        #expect(instructions.contains("from en to ja"))
         return (Data(#"{"status":"completed","output":[{"type":"reasoning"},{"content":[{"type":"output_text","text":"おはようございます"}]}]}"#.utf8),
                 HTTPURLResponse(url: request.url!, statusCode: 200, httpVersion: nil, headerFields: nil)!)
     }
@@ -26,6 +28,20 @@ import Testing
     }
 }
 
+@Test func translationSendsReverseLanguagePairToOpenAI() async throws {
+    let text = try await TranslationAPI.translate(
+        "おはようございます", apiKey: "test-key", sourceLanguage: "ja", targetLanguage: "en"
+    ) { request in
+        let body = try #require(JSONSerialization.jsonObject(with: request.httpBody!) as? [String: Any])
+        let instructions = try #require(body["instructions"] as? String)
+        #expect(instructions.contains("from ja to en"))
+        #expect(body["input"] as? String == "おはようございます")
+        return (Data(#"{"status":"completed","output":[{"content":[{"type":"output_text","text":"Good morning"}]}]}"#.utf8),
+                HTTPURLResponse(url: request.url!, statusCode: 200, httpVersion: nil, headerFields: nil)!)
+    }
+    #expect(text == "Good morning")
+}
+
 @Test @MainActor func translationCommandBackNavigationRestoresSearch() throws {
     _ = NSApplication.shared
     let launcher = LauncherWindowController()