Add thai support in summary

backend/src/main/java/com/aiteacher/concept/ConceptReportController.java

@@ -25,10 +25,12 @@ public class ConceptReportController {
     }
 
     @PostMapping
-    public ResponseEntity<ConceptReportResponse> generate(@PathVariable String id) {
+    public ResponseEntity<ConceptReportResponse> generate(
+            @PathVariable String id,
+            @RequestParam(defaultValue = "en") String language) {
         Topic topic = topicRepository.findById(id)
             .orElseThrow(() -> new NoSuchElementException("Topic not found."));
-        return ResponseEntity.ok(conceptReportService.generateReport(topic));
+        return ResponseEntity.ok(conceptReportService.generateReport(topic, language));
     }
 
     @GetMapping

backend/src/main/java/com/aiteacher/concept/ConceptReportService.java

@@ -60,7 +60,7 @@ public class ConceptReportService {
         this.objectMapper = objectMapper;
     }
 
-    public ConceptReportResponse generateReport(Topic topic) {
+    public ConceptReportResponse generateReport(Topic topic, String language) {
         List<Book> readyBooks = bookRepository.findAll().stream()
             .filter(b -> b.getStatus() == BookStatus.READY)
             .toList();
@@ -106,7 +106,7 @@ public class ConceptReportService {
             if (mf == null || mf.isEmpty()) continue;
             if (facet == ConceptFacet.OTHER) continue; // skip OTHER bucket in the rendered report
 
-            String prompt = buildFacetPrompt(topic, facet, mf, sectionLabel, figureLabel);
+            String prompt = buildFacetPrompt(topic, facet, mf, sectionLabel, figureLabel, language);
             String markdown = chatClient.prompt()
                 .system(SYSTEM_PROMPT)
                 .user(prompt)
@@ -151,7 +151,8 @@ public class ConceptReportService {
 
     private String buildFacetPrompt(Topic topic, ConceptFacet facet, MergedFacet mf,
                                      Map<String, String> sectionLabel,
-                                     Map<String, String> figureLabel) {
+                                     Map<String, String> figureLabel,
+                                     String language) {
         StringBuilder sb = new StringBuilder();
         sb.append("CONCEPT: ").append(topic.getName()).append("\n");
         sb.append("FACET: ").append(facet.displayTitle()).append("\n\n");
@@ -181,6 +182,17 @@ public class ConceptReportService {
         sb.append("Write the ").append(facet.displayTitle()).append(" section of a concept report on \"")
           .append(topic.getName())
           .append("\". Stay strictly within this facet. Use the [S#]/[F#] labels above for citations.");
+
+        if ("th".equalsIgnoreCase(language)) {
+            sb.append("\n\nIMPORTANT: Write the narrative in Thai. ")
+              .append("Keep all medical, anatomical, surgical, pharmacological, and clinical ")
+              .append("terminology in English (e.g., cerebellopontine angle, glioblastoma, craniotomy, ")
+              .append("dexamethasone). Do NOT translate disease names, anatomical structures, drug names, ")
+              .append("procedures, eponyms, or imaging modalities. Translate only connective prose, ")
+              .append("explanations, and general descriptions. Citation labels [S#]/[F#] stay unchanged. ")
+              .append("The sentinel string for insufficient context must remain exactly: ")
+              .append("\"The uploaded books do not contain sufficient information on this aspect.\"");
+        }
         return sb.toString();
     }
 

backend/src/main/java/com/aiteacher/topic/TopicController.java

@@ -26,11 +26,13 @@ public class TopicController {
     }
 
     @PostMapping("/{id}/summary")
-    public ResponseEntity<TopicSummaryResponse> generateSummary(@PathVariable String id) {
+    public ResponseEntity<TopicSummaryResponse> generateSummary(
+            @PathVariable String id,
+            @RequestParam(defaultValue = "en") String language) {
         Topic topic = topicRepository.findById(id)
             .orElseThrow(() -> new NoSuchElementException("Topic not found."));
 
-        TopicSummaryResponse response = topicSummaryService.generateSummary(topic);
+        TopicSummaryResponse response = topicSummaryService.generateSummary(topic, language);
         return ResponseEntity.ok(response);
     }
 

backend/src/main/java/com/aiteacher/topic/TopicSummaryService.java

@@ -59,7 +59,7 @@ public class TopicSummaryService {
         this.objectMapper = objectMapper;
     }
 
-    public TopicSummaryResponse generateSummary(Topic topic) {
+    public TopicSummaryResponse generateSummary(Topic topic, String language) {
         List<Book> readyBooks = bookRepository.findAll().stream()
             .filter(b -> b.getStatus() == BookStatus.READY)
             .toList();
@@ -82,7 +82,7 @@ public class TopicSummaryService {
         log.debug("Topic reports for '{}': {} sections, {} figures retrieved",
             topic.getName(), allSections.size(), allFigures.size());
 
-        String contextPrompt = buildContextPrompt(question, allSections, allFigures);
+        String contextPrompt = buildContextPrompt(question, allSections, allFigures, language);
         String summary = chatClient.prompt()
             .system(SYSTEM_PROMPT)
             .user(contextPrompt)
@@ -142,7 +142,8 @@ public class TopicSummaryService {
 
     private String buildContextPrompt(String question,
                                       List<SectionEntity> sections,
-                                      List<FigureEntity> figures) {
+                                      List<FigureEntity> figures,
+                                      String language) {
         StringBuilder sb = new StringBuilder();
 
         if (!sections.isEmpty()) {
@@ -169,6 +170,17 @@ public class TopicSummaryService {
         }
 
         sb.append("QUESTION:\n").append(question);
+
+        if ("th".equalsIgnoreCase(language)) {
+            sb.append("\n\nIMPORTANT: Write the narrative in Thai. ")
+              .append("Keep all medical, anatomical, surgical, pharmacological, and clinical ")
+              .append("terminology in English (e.g., cerebellopontine angle, glioblastoma, craniotomy, ")
+              .append("dexamethasone). Do NOT translate disease names, anatomical structures, drug names, ")
+              .append("procedures, eponyms, or imaging modalities. Translate only connective prose, ")
+              .append("explanations, and general descriptions. Citation labels [S#]/[F#] stay unchanged. ")
+              .append("The sentinel string for insufficient context must remain exactly: ")
+              .append("\"The uploaded books do not contain sufficient information on this topic.\"");
+        }
         return sb.toString();
     }