feat(translation): add translation button, works with offline downloaded languages

WorterBuch/TranslationService.swift

@@ -0,0 +1,34 @@
+//
+//  TranslationService.swift
+//  WorterBuch
+//
+//  Created by Claude on 07.12.2025.
+//
+
+import Foundation
+import Translation
+
+@available(iOS 18.0, *)
+class TranslationService {
+    static func translate(text: String, from sourceLanguage: String = "de", to targetLanguage: String = "en") async -> String? {
+        do {
+            let sourceLocale = Locale.Language(identifier: sourceLanguage)
+            let targetLocale = Locale.Language(identifier: targetLanguage)
+
+            print("Attempting translation from \(sourceLanguage) to \(targetLanguage)")
+
+            // Create session - requires language pack to be installed
+            let session = TranslationSession(installedSource: sourceLocale, target: targetLocale)
+
+            let response = try await session.translate(text)
+            return response.targetText
+        } catch {
+            print("Translation error: \(error)")
+            print("To enable translation:")
+            print("1. Open the Translate app on your iPad")
+            print("2. Download German language pack")
+            print("3. Try the translate button again")
+            return nil
+        }
+    }
+}

WorterBuch/VocabularyFieldCell.swift

@@ -12,6 +12,8 @@ struct VocabularyFieldCell: View {
     let drawing: PKDrawing
     let text: String
     let onTap: () -> Void
+    var showTranslateButton: Bool = false
+    var onTranslate: (() -> Void)? = nil
 
     var body: some View {
         VStack(alignment: .leading, spacing: 4) {
@@ -41,19 +43,30 @@ struct VocabularyFieldCell: View {
             }
 
             // Transcribed text - selectable but not editable
-            if !text.isEmpty {
-                SelectableTextView(
-                    text: text.lowercased(),
-                    font: .preferredFont(forTextStyle: .body),
-                    textColor: .label
-                )
-                .frame(maxWidth: .infinity, alignment: .leading)
-                .frame(height: 40)
-            } else {
-                Text(" ")
-                    .font(.body)
+            HStack(spacing: 8) {
+                if !text.isEmpty {
+                    SelectableTextView(
+                        text: text.lowercased(),
+                        font: .preferredFont(forTextStyle: .body),
+                        textColor: .label
+                    )
                     .frame(maxWidth: .infinity, alignment: .leading)
                     .frame(height: 40)
+                } else {
+                    Text(" ")
+                        .font(.body)
+                        .frame(maxWidth: .infinity, alignment: .leading)
+                        .frame(height: 40)
+                }
+
+                if showTranslateButton, let onTranslate = onTranslate {
+                    Button(action: onTranslate) {
+                        Image(systemName: "arrow.right.arrow.left.circle.fill")
+                            .foregroundColor(.blue)
+                            .font(.system(size: 20))
+                    }
+                    .frame(width: 40, height: 40)
+                }
             }
         }
         .padding(8)

WorterBuch/VocabularyGridView.swift

@@ -86,7 +86,8 @@ struct VocabularyGridView: View {
                             entry: entry,
                             onSelectField: { fieldType in
                                 openFieldEditor(for: entry, fieldType: fieldType)
-                            }
+                            },
+                            onTranslate: translateEntry
                         )
                         .listRowInsets(EdgeInsets(top: 6, leading: 12, bottom: 6, trailing: 12))
                         .listRowSeparator(.hidden)
@@ -211,11 +212,35 @@ struct VocabularyGridView: View {
             print("Error saving context: \(nsError), \(nsError.userInfo)")
         }
     }
+
+    private func translateEntry(_ entry: VocabularyEntry) {
+        guard let germanText = entry.germanWordText, !germanText.isEmpty else { return }
+        guard entry.englishTranslationText?.isEmpty ?? true else { return }
+
+        Task {
+            if #available(iOS 18.0, *) {
+                if let translation = await TranslationService.translate(text: germanText) {
+                    await MainActor.run {
+                        entry.englishTranslationText = translation
+                        saveContext()
+                    }
+                }
+            } else {
+                print("Translation requires iOS 18.0 or later")
+            }
+        }
+    }
 }
 
 struct VocabularyEntryRow: View {
     @ObservedObject var entry: VocabularyEntry
     let onSelectField: (FieldType) -> Void
+    let onTranslate: (VocabularyEntry) -> Void
+
+    var shouldShowTranslateButton: Bool {
+        !(entry.germanWordText?.isEmpty ?? true) &&
+        (entry.englishTranslationText?.isEmpty ?? true)
+    }
 
     var body: some View {
         HStack(spacing: 12) {
@@ -239,7 +264,9 @@ struct VocabularyEntryRow: View {
             VocabularyFieldCell(
                 drawing: entry.englishTranslationPKDrawing,
                 text: entry.englishTranslationText ?? "",
-                onTap: { onSelectField(.englishTranslation) }
+                onTap: { onSelectField(.englishTranslation) },
+                showTranslateButton: shouldShowTranslateButton,
+                onTranslate: { onTranslate(entry) }
             )
             .frame(maxWidth: .infinity)
         }