feat: add German language support (de-DE)

app/api/generate/scene-content/route.ts

@@ -67,7 +67,8 @@ export async function POST(req: NextRequest) {
     // Ensure outline has language from stageInfo (fallback for older outlines)
     const outline: SceneOutline = {
       ...rawOutline,
-      language: rawOutline.language || (stageInfo?.language as 'zh-CN' | 'en-US') || 'zh-CN',
+      language:
+        rawOutline.language || (stageInfo?.language as 'zh-CN' | 'en-US' | 'de-DE') || 'zh-CN',
     };
 
     // ── Model resolution from request headers ──

app/api/generate/scene-outlines-stream/route.ts

@@ -121,7 +121,11 @@ export async function POST(req: NextRequest) {
 
     // Build prompt (same logic as generateSceneOutlinesFromRequirements)
     let availableImagesText =
-      requirements.language === 'zh-CN' ? '无可用图片' : 'No images available';
+      requirements.language === 'zh-CN'
+        ? '无可用图片'
+        : requirements.language === 'de-DE'
+          ? 'Keine Bilder verfügbar'
+          : 'No images available';
     let visionImages: Array<{ id: string; src: string }> | undefined;
 
     if (pdfImages && pdfImages.length > 0) {
@@ -179,9 +183,17 @@ export async function POST(req: NextRequest) {
         ? pdfText.substring(0, MAX_PDF_CONTENT_CHARS)
         : requirements.language === 'zh-CN'
           ? '无'
-          : 'None',
+          : requirements.language === 'de-DE'
+            ? 'Keine'
+            : 'None',
       availableImages: availableImagesText,
-      researchContext: researchContext || (requirements.language === 'zh-CN' ? '无' : 'None'),
+      researchContext:
+        researchContext ||
+        (requirements.language === 'zh-CN'
+          ? '无'
+          : requirements.language === 'de-DE'
+            ? 'Keine'
+            : 'None'),
       mediaGenerationPolicy,
       teacherContext,
     });

app/api/quiz-grade/route.ts

@@ -38,20 +38,29 @@ export async function POST(req: NextRequest) {
     const { model: languageModel } = resolveModelFromHeaders(req);
 
     const isZh = language === 'zh-CN';
+    const isDe = language === 'de-DE';
 
     const systemPrompt = isZh
       ? `你是一位专业的教育评估专家。请根据题目和学生答案进行评分并给出简短评语。
 必须以如下 JSON 格式回复（不要包含其他内容）：
 {"score": <0到${points}的整数>, "comment": "<一两句评语>"}`
-      : `You are a professional educational assessor. Grade the student's answer and provide brief feedback.
+      : isDe
+        ? `Sie sind ein professioneller Bildungsprüfer. Bewerten Sie die Antwort des Schülers und geben Sie ein kurzes Feedback.
+Sie müssen ausschließlich in folgendem JSON-Format antworten (kein anderer Inhalt):
+{"score": <Ganze Zahl von 0 bis ${points}>, "comment": "<Ein oder zwei Sätze Feedback>"}`
+        : `You are a professional educational assessor. Grade the student's answer and provide brief feedback.
 You must reply in the following JSON format only (no other content):
 {"score": <integer from 0 to ${points}>, "comment": "<one or two sentences of feedback>"}`;
 
     const userPrompt = isZh
       ? `题目：${question}
 满分：${points}分
 ${commentPrompt ? `评分要点：${commentPrompt}\n` : ''}学生答案：${userAnswer}`
-      : `Question: ${question}
+      : isDe
+        ? `Frage: ${question}
+Volle Punktzahl: ${points} Punkte
+${commentPrompt ? `Bewertungsrichtlinien: ${commentPrompt}\n` : ''}Antwort des Schülers: ${userAnswer}`
+        : `Question: ${question}
 Full marks: ${points} points
 ${commentPrompt ? `Grading guidance: ${commentPrompt}\n` : ''}Student answer: ${userAnswer}`;
 
@@ -83,7 +92,9 @@ ${commentPrompt ? `Grading guidance: ${commentPrompt}\n` : ''}Student answer: ${
         score: Math.round(points * 0.5),
         comment: isZh
           ? '已作答，请参考标准答案。'
-          : 'Answer received. Please refer to the standard answer.',
+          : isDe
+            ? 'Antwort erhalten. Bitte beachten Sie die Musterantwort.'
+            : 'Answer received. Please refer to the standard answer.',
       };
     }
 

app/classroom/[id]/page.tsx

@@ -142,8 +142,18 @@ export default function ClassroomDetailPage() {
       // Resume media generation for any tasks not yet in IndexedDB.
       // generateMediaForOutlines skips already-completed tasks automatically.
       generationStartedRef.current = true;
-      generateMediaForOutlines(outlines, stage.id).catch((err) => {
-        log.warn('[Classroom] Media generation resume error:', err);
+
+      // Load generation params to get the imageMapping for manual uploads
+      const genParamsStr = sessionStorage.getItem('generationParams');
+      const params = genParamsStr ? JSON.parse(genParamsStr) : {};
+      const storageIds = (params.pdfImages || [])
+        .map((img: { storageId?: string }) => img.storageId)
+        .filter(Boolean);
+
+      loadImageMapping(storageIds).then((imageMapping) => {
+        generateMediaForOutlines(outlines, stage.id, undefined, imageMapping).catch((err) => {
+          log.warn('[Classroom] Media generation resume error:', err);
+        });
       });
     }
   }, [loading, error, generateRemaining]);

app/generation-preview/page.tsx

@@ -267,8 +267,8 @@ function GenerationPreviewContent() {
         const updatedSession = {
           ...currentSession,
           pdfText,
-          pdfImages,
-          imageStorageIds,
+          pdfImages: [...(currentSession.pdfImages || []), ...pdfImages],
+          imageStorageIds: [...(currentSession.imageStorageIds || []), ...imageStorageIds],
           pdfStorageKey: undefined, // Clear so we don't re-parse
         };
         setSession(updatedSession);
@@ -339,11 +339,49 @@ function GenerationPreviewContent() {
         activeSteps = getActiveSteps(currentSession);
       }
 
+      // ── Handle manually uploaded images ──
+      const manualPdfImages: PdfImage[] = [];
+
+      if (
+        currentSession.uploadedImageStorageIds &&
+        currentSession.uploadedImageStorageIds.length > 0
+      ) {
+        log.debug('Loading manually uploaded images');
+        currentSession.uploadedImageStorageIds.forEach((storageId, i) => {
+          const uploadedId = `uploaded_img_${i + 1}`;
+          manualPdfImages.push({
+            id: uploadedId,
+            src: '',
+            pageNumber: 1,
+            description: 'Manually uploaded image',
+            storageId,
+          });
+        });
+
+        // Add them to the session's pdfImages if not already there
+        const existingUploaded = (currentSession.pdfImages || []).some((img) =>
+          img.id.startsWith('uploaded_img_'),
+        );
+        if (!existingUploaded) {
+          currentSession = {
+            ...currentSession,
+            pdfImages: [...(currentSession.pdfImages || []), ...manualPdfImages],
+          };
+          setSession(currentSession);
+          sessionStorage.setItem('generationSession', JSON.stringify(currentSession));
+        }
+      }
+
       // Load imageMapping early (needed for both outline and scene generation)
       let imageMapping: ImageMapping = {};
-      if (currentSession.imageStorageIds && currentSession.imageStorageIds.length > 0) {
+      const allImageStorageIds = [
+        ...(currentSession.imageStorageIds || []),
+        ...(currentSession.uploadedImageStorageIds || []),
+      ];
+
+      if (allImageStorageIds.length > 0) {
         log.debug('Loading images from IndexedDB');
-        imageMapping = await loadImageMapping(currentSession.imageStorageIds);
+        imageMapping = await loadImageMapping(allImageStorageIds);
       } else if (
         currentSession.imageMapping &&
         Object.keys(currentSession.imageMapping).length > 0

app/generation-preview/types.ts

@@ -25,6 +25,8 @@ export interface GenerationSessionState {
   // Web search context
   researchContext?: string;
   researchSources?: Array<{ title: string; url: string }>;
+  // Manually uploaded images (along with PDF)
+  uploadedImageStorageIds?: string[];
 }
 
 export type GenerationStep = {

app/page.tsx

@@ -55,13 +55,15 @@ const RECENT_OPEN_STORAGE_KEY = 'recentClassroomsOpen';
 
 interface FormState {
   pdfFile: File | null;
+  imageFiles: File[];
   requirement: string;
-  language: 'zh-CN' | 'en-US';
+  language: 'zh-CN' | 'en-US' | 'de-DE';
   webSearch: boolean;
 }
 
 const initialFormState: FormState = {
   pdfFile: null,
+  imageFiles: [],
   requirement: '',
   language: 'zh-CN',
   webSearch: false,
@@ -101,10 +103,15 @@ function HomePage() {
       const savedLanguage = localStorage.getItem(LANGUAGE_STORAGE_KEY);
       const updates: Partial<FormState> = {};
       if (savedWebSearch === 'true') updates.webSearch = true;
-      if (savedLanguage === 'zh-CN' || savedLanguage === 'en-US') {
+      if (savedLanguage === 'zh-CN' || savedLanguage === 'en-US' || savedLanguage === 'de-DE') {
         updates.language = savedLanguage;
       } else {
-        const detected = navigator.language?.startsWith('zh') ? 'zh-CN' : 'en-US';
+        const lang = navigator.language;
+        const detected = lang?.startsWith('zh')
+          ? 'zh-CN'
+          : lang?.startsWith('de')
+            ? 'de-DE'
+            : 'en-US';
         updates.language = detected;
       }
       if (Object.keys(updates).length > 0) {
@@ -251,13 +258,6 @@ function HomePage() {
 
     try {
       const userProfile = useUserProfileStore.getState();
-      const requirements: UserRequirements = {
-        requirement: form.requirement,
-        language: form.language,
-        userNickname: userProfile.nickname || undefined,
-        userBio: userProfile.bio || undefined,
-        webSearch: form.webSearch || undefined,
-      };
 
       let pdfStorageKey: string | undefined;
       let pdfFileName: string | undefined;
@@ -279,12 +279,31 @@ function HomePage() {
         }
       }
 
+      // Store manually uploaded images
+      const uploadedImageStorageIds: string[] = [];
+      for (const imageFile of form.imageFiles) {
+        const key = await storePdfBlob(imageFile); // use storePdfBlob for any binary data
+        uploadedImageStorageIds.push(key);
+      }
+
+      const requirements: UserRequirements = {
+        requirement: form.requirement,
+        language: form.language,
+        userNickname: userProfile.nickname || undefined,
+        userBio: userProfile.bio || undefined,
+        webSearch: form.webSearch || undefined,
+        uploadedImageStorageIds:
+          uploadedImageStorageIds.length > 0 ? uploadedImageStorageIds : undefined,
+      };
+
       const sessionState = {
         sessionId: nanoid(),
         requirements,
         pdfText: '',
         pdfImages: [],
         imageStorageIds: [],
+        uploadedImageStorageIds:
+          uploadedImageStorageIds.length > 0 ? uploadedImageStorageIds : undefined,
         pdfStorageKey,
         pdfFileName,
         pdfProviderId,
@@ -338,7 +357,7 @@ function HomePage() {
             }}
             className="flex items-center gap-1 px-3 py-1.5 rounded-full text-xs font-bold text-gray-500 dark:text-gray-400 hover:bg-white dark:hover:bg-gray-700 hover:text-gray-800 dark:hover:text-gray-200 hover:shadow-sm transition-all"
           >
-            {locale === 'zh-CN' ? 'CN' : 'EN'}
+            {locale === 'zh-CN' ? 'CN' : locale === 'de-DE' ? 'DE' : 'EN'}
           </button>
           {languageOpen && (
             <div className="absolute top-full mt-2 right-0 bg-white dark:bg-gray-800 border border-gray-200 dark:border-gray-700 rounded-lg shadow-lg overflow-hidden z-50 min-w-[120px]">
@@ -368,6 +387,19 @@ function HomePage() {
               >
                 English
               </button>
+              <button
+                onClick={() => {
+                  setLocale('de-DE');
+                  setLanguageOpen(false);
+                }}
+                className={cn(
+                  'w-full px-4 py-2 text-left text-sm hover:bg-gray-100 dark:hover:bg-gray-700 transition-colors',
+                  locale === 'de-DE' &&
+                    'bg-purple-50 dark:bg-purple-900/20 text-purple-600 dark:text-purple-400',
+                )}
+              >
+                Deutsch
+              </button>
             </div>
           )}
         </div>
@@ -558,6 +590,8 @@ function HomePage() {
                   }}
                   pdfFile={form.pdfFile}
                   onPdfFileChange={(f) => updateForm('pdfFile', f)}
+                  imageFiles={form.imageFiles}
+                  onImageFilesChange={(fs) => updateForm('imageFiles', fs)}
                   onPdfError={setError}
                 />
               </div>