first implementation - image/drawing integration

backend/src/main/java/com/aiteacher/book/BookService.java

@@ -1,11 +1,13 @@
 package com.aiteacher.book;
 
+import org.springframework.beans.factory.annotation.Value;
 import org.springframework.stereotype.Service;
 import org.springframework.web.multipart.MultipartFile;
 
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.List;
 import java.util.NoSuchElementException;
 import java.util.UUID;
@@ -15,10 +17,15 @@ public class BookService {
 
     private final BookRepository bookRepository;
     private final BookEmbeddingService bookEmbeddingService;
+    private final Path bookStoragePath;
 
-    public BookService(BookRepository bookRepository, BookEmbeddingService bookEmbeddingService) {
+    public BookService(
+            BookRepository bookRepository,
+            BookEmbeddingService bookEmbeddingService,
+            @Value("${app.figure-storage.base-path:./uploads}") String basePath) {
         this.bookRepository = bookRepository;
         this.bookEmbeddingService = bookEmbeddingService;
+        this.bookStoragePath = Paths.get(basePath).toAbsolutePath().normalize().resolve("books");
     }
 
     public Book upload(MultipartFile file) throws IOException {
@@ -28,20 +35,35 @@ public class BookService {
         }
 
         String title = deriveTitle(originalFilename);
-
         Book book = new Book(title, originalFilename, file.getSize());
         book = bookRepository.save(book);
 
-        // Write to a temp file so the async task can read it
-        Path tempFile = Files.createTempFile("aiteacher-", "-" + book.getId() + ".pdf");
-        file.transferTo(tempFile.toFile());
+        // Persist PDF in a stable location for potential re-embedding
+        Files.createDirectories(bookStoragePath);
+        Path pdfPath = bookStoragePath.resolve(book.getId() + ".pdf");
+        file.transferTo(pdfPath.toFile());
 
         UUID bookId = book.getId();
-        Path pdfPath = tempFile;
-        String bookTitle = title;
+        bookEmbeddingService.embedBook(bookId, title, pdfPath);
+        return book;
+    }
 
-        bookEmbeddingService.embedBook(bookId, bookTitle, pdfPath);
+    public Book reembed(UUID id) {
+        Book book = bookRepository.findById(id)
+            .orElseThrow(() -> new NoSuchElementException("Book not found."));
 
+        if (book.getStatus() == BookStatus.PROCESSING) {
+            throw new IllegalStateException("Book is already being processed.");
+        }
+
+        Path pdfPath = bookStoragePath.resolve(id + ".pdf");
+        if (!Files.exists(pdfPath)) {
+            throw new IllegalStateException(
+                "Original PDF not found. Please re-upload the book before re-embedding.");
+        }
+
+        bookEmbeddingService.deleteBookChunks(id);
+        bookEmbeddingService.embedBook(id, book.getTitle(), pdfPath);
         return book;
     }
 
@@ -63,14 +85,21 @@ public class BookService {
         }
 
         bookEmbeddingService.deleteBookChunks(id);
+
+        // Delete the stored PDF
+        Path pdfPath = bookStoragePath.resolve(id + ".pdf");
+        try {
+            Files.deleteIfExists(pdfPath);
+        } catch (IOException ex) {
+            // Non-fatal — log only
+        }
+
         bookRepository.deleteById(id);
     }
 
     private String deriveTitle(String filename) {
-        // Strip .pdf extension and replace separators with spaces
         String name = filename.replaceAll("(?i)\\.pdf$", "");
         name = name.replaceAll("[-_]", " ");
-        // Capitalise first letter
         if (!name.isEmpty()) {
             name = Character.toUpperCase(name.charAt(0)) + name.substring(1);
         }