feat: Add alerts for attachment extraction status and improve UI state handling after processing.

feat: add page and document level support for adding atttachments

public/workers/add-attachments.worker.js

@@ -1,28 +1,89 @@
 self.importScripts('/coherentpdf.browser.min.js');
 
-function addAttachmentsToPDFInWorker(pdfBuffer, attachmentBuffers, attachmentNames) {
+function parsePageRange(rangeString, totalPages) {
+  const pages = new Set();
+  const parts = rangeString.split(',').map(s => s.trim());
+
+  for (const part of parts) {
+    if (part.includes('-')) {
+      const [start, end] = part.split('-').map(s => parseInt(s.trim(), 10));
+      if (isNaN(start) || isNaN(end)) continue;
+      for (let i = Math.max(1, start); i <= Math.min(totalPages, end); i++) {
+        pages.add(i);
+      }
+    } else {
+      const pageNum = parseInt(part, 10);
+      if (!isNaN(pageNum) && pageNum >= 1 && pageNum <= totalPages) {
+        pages.add(pageNum);
+      }
+    }
+  }
+
+  return Array.from(pages).sort((a, b) => a - b);
+}
+
+function addAttachmentsToPDFInWorker(pdfBuffer, attachmentBuffers, attachmentNames, attachmentLevel, pageRange) {
   try {
     const uint8Array = new Uint8Array(pdfBuffer);
-    
+
     let pdf;
     try {
       pdf = coherentpdf.fromMemory(uint8Array, '');
     } catch (error) {
-      self.postMessage({
-        status: 'error',
-        message: `Failed to load PDF. Error: ${error.message || error}`
-      });
+      const errorMsg = error.message || error.toString();
+
+      if (errorMsg.includes('Failed to read PDF') ||
+        errorMsg.includes('Could not read object') ||
+        errorMsg.includes('No /Root entry') ||
+        errorMsg.includes('PDFError')) {
+        self.postMessage({
+          status: 'error',
+          message: 'The PDF file has structural issues and cannot be processed. The file may be corrupted, incomplete, or created with non-standard tools. Please try:\n\n• Opening and re-saving the PDF in another PDF viewer\n• Using a different PDF file\n• Repairing the PDF with a PDF repair tool'
+        });
+      } else {
+        self.postMessage({
+          status: 'error',
+          message: `Failed to load PDF: ${errorMsg}`
+        });
+      }
       return;
     }
 
-    // Add each attachment to the PDF
+    const totalPages = coherentpdf.pages(pdf);
+
+    let targetPages = [];
+    if (attachmentLevel === 'page') {
+      if (!pageRange) {
+        self.postMessage({
+          status: 'error',
+          message: 'Page range is required for page-level attachments.'
+        });
+        coherentpdf.deletePdf(pdf);
+        return;
+      }
+      targetPages = parsePageRange(pageRange, totalPages);
+      if (targetPages.length === 0) {
+        self.postMessage({
+          status: 'error',
+          message: 'Invalid page range specified.'
+        });
+        coherentpdf.deletePdf(pdf);
+        return;
+      }
+    }
+
     for (let i = 0; i < attachmentBuffers.length; i++) {
       try {
         const attachmentData = new Uint8Array(attachmentBuffers[i]);
         const attachmentName = attachmentNames[i];
-        
-        // Attach file at document level (page 0)
-        coherentpdf.attachFileFromMemory(attachmentData, attachmentName, pdf);
+
+        if (attachmentLevel === 'document') {
+          coherentpdf.attachFileFromMemory(attachmentData, attachmentName, pdf);
+        } else {
+          for (const pageNum of targetPages) {
+            coherentpdf.attachFileToPageFromMemory(attachmentData, attachmentName, pdf, pageNum);
+          }
+        }
       } catch (error) {
         console.warn(`Failed to attach file ${attachmentNames[i]}:`, error);
         self.postMessage({
@@ -33,13 +94,13 @@ function addAttachmentsToPDFInWorker(pdfBuffer, attachmentBuffers, attachmentNam
         return;
       }
     }
-    
+
     // Save the modified PDF
     const modifiedBytes = coherentpdf.toMemory(pdf, false, false);
     coherentpdf.deletePdf(pdf);
 
     const buffer = modifiedBytes.buffer.slice(
-      modifiedBytes.byteOffset, 
+      modifiedBytes.byteOffset,
       modifiedBytes.byteOffset + modifiedBytes.byteLength
     );
 
@@ -47,7 +108,7 @@ function addAttachmentsToPDFInWorker(pdfBuffer, attachmentBuffers, attachmentNam
       status: 'success',
       modifiedPDF: buffer
     }, [buffer]);
-    
+
   } catch (error) {
     self.postMessage({
       status: 'error',
@@ -61,9 +122,11 @@ function addAttachmentsToPDFInWorker(pdfBuffer, attachmentBuffers, attachmentNam
 self.onmessage = (e) => {
   if (e.data.command === 'add-attachments') {
     addAttachmentsToPDFInWorker(
-      e.data.pdfBuffer, 
-      e.data.attachmentBuffers, 
-      e.data.attachmentNames
+      e.data.pdfBuffer,
+      e.data.attachmentBuffers,
+      e.data.attachmentNames,
+      e.data.attachmentLevel || 'document',
+      e.data.pageRange || ''
     );
   }
 };