s3 bucket integration for image storage

backend/src/main/java/com/aiteacher/document/VisionDescriptionService.java

@@ -3,12 +3,10 @@ package com.aiteacher.document;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.ai.chat.client.ChatClient;
-import org.springframework.core.io.FileSystemResource;
+import org.springframework.core.io.ByteArrayResource;
 import org.springframework.stereotype.Service;
 import org.springframework.util.MimeTypeUtils;
 
-import java.nio.file.Path;
-
 /**
  * Generates a clinical text description for an extracted figure image
  * using the OpenAI vision model via Spring AI ChatClient.
@@ -32,17 +30,16 @@ public class VisionDescriptionService {
     /**
      * Returns a description string. Falls back to the provided caption if vision fails.
      */
-    public String describe(Path imagePath, String captionFallback) {
+    public String describe(byte[] imageBytes, String captionFallback) {
         try {
             return chatClient.prompt()
                 .user(u -> u
                     .text(PROMPT)
-                    .media(MimeTypeUtils.IMAGE_PNG, new FileSystemResource(imagePath.toFile())))
+                    .media(MimeTypeUtils.IMAGE_PNG, new ByteArrayResource(imageBytes)))
                 .call()
                 .content();
         } catch (Exception ex) {
-            log.warn("Vision description failed for {}: {} — using caption as fallback",
-                imagePath.getFileName(), ex.getMessage());
+            log.warn("Vision description failed: {} — using caption as fallback", ex.getMessage());
             return captionFallback != null ? captionFallback : "Figure";
         }
     }