feat: offer no-key MyMemory translation provider

Sources/Conjure/TranslationController.swift

@@ -5,8 +5,11 @@ import Security
 @MainActor
 final class TranslationController: NSViewController {
     private let keyField = NSSecureTextField()
+    private let provider = NSPopUpButton()
+    private let credentials = NSStackView()
+    private var usesMyMemory: Bool { provider.indexOfSelectedItem == 0 }
     private let output = NSTextView()
-    private let status = NSTextField(wrappingLabelWithString: "English → Japanese · gpt-6-luna · Text is sent to OpenAI only when you translate.")
+    private let status = NSTextField(wrappingLabelWithString: "")
     private let translateButton = NSButton(title: "Translate ↵", target: nil, action: nil)
     private var task: Task<Void, Never>?
     var input: (() -> String)?
@@ -23,12 +26,17 @@ final class TranslationController: NSViewController {
         let title = NSTextField(labelWithString: "Conjure Translate · English → Japanese")
         title.font = .systemFont(ofSize: 13, weight: .semibold)
         let heading = NSStackView(views: [back, title, NSView()])
+        provider.addItems(withTitles: ["MyMemory (no key)", "OpenAI · gpt-6-luna"])
+        provider.selectItem(at: UserDefaults.standard.string(forKey: "translationProvider") == "openai" ? 1 : 0)
+        provider.setAccessibilityLabel("Translation provider")
+        provider.target = self
+        provider.action = #selector(providerChanged)
         keyField.placeholderString = "OpenAI API key (saved in Keychain)"
         keyField.setAccessibilityLabel("OpenAI API key")
         keyField.widthAnchor.constraint(greaterThanOrEqualToConstant: 220).isActive = true
         let save = NSButton(title: "Save Key", target: self, action: #selector(saveKey))
         let forget = NSButton(title: "Forget Key", target: self, action: #selector(forgetKey))
-        let credentials = NSStackView(views: [keyField, save, forget])
+        for control in [keyField, save, forget] { credentials.addArrangedSubview(control) }
         credentials.distribution = .fill
         translateButton.target = self
         translateButton.action = #selector(translate)
@@ -48,7 +56,7 @@ final class TranslationController: NSViewController {
         output.textContainer?.widthTracksTextView = true
         status.textColor = SunsetPalette.secondaryText
         status.font = .systemFont(ofSize: 12)
-        let stack = NSStackView(views: [heading, credentials, scroll, status, translateButton])
+        let stack = NSStackView(views: [heading, provider, credentials, scroll, status, translateButton])
         stack.orientation = .vertical
         stack.alignment = .leading
         stack.spacing = 12
@@ -64,6 +72,7 @@ final class TranslationController: NSViewController {
             scroll.heightAnchor.constraint(greaterThanOrEqualToConstant: 100),
             status.widthAnchor.constraint(equalTo: stack.widthAnchor),
         ])
+        updateProvider()
     }
 
     @objc func goBack() {
@@ -77,7 +86,20 @@ final class TranslationController: NSViewController {
         task = nil
         translateButton.isEnabled = true
         output.string = ""
-        status.stringValue = "Press Return to translate English → Japanese with gpt-6-luna."
+        status.stringValue = usesMyMemory
+            ? "MyMemory · No key · 500 bytes/request · 5,000 characters/day. Text is sent to MyMemory; avoid sensitive content."
+            : "OpenAI · gpt-6-luna · Text is sent to OpenAI only when you translate."
+    }
+
+    @objc private func providerChanged() {
+        UserDefaults.standard.set(usesMyMemory ? "mymemory" : "openai", forKey: "translationProvider")
+        keyField.stringValue = ""
+        updateProvider()
+    }
+
+    private func updateProvider() {
+        credentials.isHidden = usesMyMemory
+        inputChanged()
     }
 
     @objc private func saveKey() {
@@ -122,22 +144,29 @@ final class TranslationController: NSViewController {
             status.stringValue = "Enter English text in the search bar."
             return
         }
-        if !keyField.stringValue.isEmpty { saveKey(); guard keyField.stringValue.isEmpty else { return } }
-        var query = Self.credential
-        query[kSecReturnData as String] = true
-        var item: CFTypeRef?
-        let result = SecItemCopyMatching(query as CFDictionary, &item)
-        guard result == errSecSuccess, let data = item as? Data, let key = String(data: data, encoding: .utf8) else {
-            if result == errSecItemNotFound { status.stringValue = "Enter and save your OpenAI API key first." }
-            else { showKeychainError(result) }
-            return
+        let myMemory = usesMyMemory
+        var key = ""
+        if !myMemory {
+            if !keyField.stringValue.isEmpty { saveKey(); guard keyField.stringValue.isEmpty else { return } }
+            var query = Self.credential
+            query[kSecReturnData as String] = true
+            var item: CFTypeRef?
+            let result = SecItemCopyMatching(query as CFDictionary, &item)
+            guard result == errSecSuccess, let data = item as? Data, let savedKey = String(data: data, encoding: .utf8) else {
+                if result == errSecItemNotFound { status.stringValue = "Enter and save your OpenAI API key first." }
+                else { showKeychainError(result) }
+                return
+            }
+            key = savedKey
         }
         output.string = ""
         status.stringValue = "Translating…"
         translateButton.isEnabled = false
         task = Task { [weak self] in
             do {
-                let translation = try await TranslationAPI.translate(text, apiKey: key)
+                let translation = try await myMemory
+                    ? MyMemoryAPI.translate(text)
+                    : TranslationAPI.translate(text, apiKey: key)
                 guard !Task.isCancelled, let self else { return }
                 self.output.string = translation
                 self.status.stringValue = "Japanese · Select text to copy (⌘C)."

Sources/ConjureKit/MyMemoryAPI.swift

@@ -0,0 +1,47 @@
+import Foundation
+
+public enum MyMemoryAPI {
+    public static func translate(_ text: String) async throws -> String {
+        try await translate(text) { try await URLSession.shared.data(for: $0) }
+    }
+
+    static func translate(
+        _ text: String, load: @Sendable (URLRequest) async throws -> (Data, URLResponse)
+    ) async throws -> String {
+        guard !text.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty else {
+            throw Failure(message: "Enter English text to translate.")
+        }
+        guard text.utf8.count <= 500 else {
+            throw Failure(message: "MyMemory allows at most 500 UTF-8 bytes per translation. Shorten the text or choose OpenAI.")
+        }
+        var url = URLComponents(string: "https://api.mymemory.translated.net/get")!
+        url.queryItems = [URLQueryItem(name: "q", value: text), URLQueryItem(name: "langpair", value: "en|ja")]
+        let request = URLRequest(url: url.url!, cachePolicy: .reloadIgnoringLocalCacheData, timeoutInterval: 30)
+        let (data, response) = try await load(request)
+        try Task.checkCancellation()
+        guard let response = response as? HTTPURLResponse, (200...299).contains(response.statusCode) else {
+            throw Failure(message: "MyMemory request failed. Try again later or choose OpenAI.")
+        }
+        let result = try JSONDecoder().decode(Response.self, from: data)
+        guard result.quotaFinished != true, result.responseStatus != 429 else {
+            throw Failure(message: "MyMemory's anonymous daily quota is exhausted. Try later or choose OpenAI.")
+        }
+        guard result.responseStatus == 200,
+              let translation = result.responseData?.translatedText,
+              !translation.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty else {
+            throw Failure(message: "MyMemory returned no successful translation. Try again later or choose OpenAI.")
+        }
+        return translation
+    }
+
+    private struct Response: Decodable {
+        let responseStatus: Int
+        let quotaFinished: Bool?
+        let responseData: Translation?
+        struct Translation: Decodable { let translatedText: String? }
+    }
+    private struct Failure: LocalizedError {
+        let message: String
+        var errorDescription: String? { message }
+    }
+}