feat: add PDF password prompt and centralized pdf-lib loader with auto-repair

src/js/utils/load-pdf-document.ts

@@ -1,14 +1,68 @@
 import { PDFDocument } from 'pdf-lib';
+import { initializeQpdf } from './helpers.js';
 
 type LoadOptions = Parameters<typeof PDFDocument.load>[1];
 type PDFDocumentInstance = Awaited<ReturnType<typeof PDFDocument.load>>;
 
+async function repairPdfBytes(pdf: Uint8Array): Promise<Uint8Array | null> {
+  try {
+    const qpdf = await initializeQpdf();
+    qpdf.FS.writeFile('/input.pdf', pdf);
+
+    try {
+      qpdf.callMain(['/input.pdf', '--decrypt', '/output.pdf']);
+    } catch (e) {
+      console.warn('[loadPdfDocument] qpdf repair warning:', e);
+    }
+
+    let repaired: Uint8Array | null = null;
+    try {
+      repaired = qpdf.FS.readFile('/output.pdf', { encoding: 'binary' });
+    } catch (e) {
+      console.warn('[loadPdfDocument] Failed to read repaired output:', e);
+    }
+
+    try {
+      qpdf.FS.unlink('/input.pdf');
+    } catch (e) {
+      console.warn('[loadPdfDocument] Cleanup error:', e);
+    }
+    try {
+      qpdf.FS.unlink('/output.pdf');
+    } catch (e) {
+      console.warn('[loadPdfDocument] Cleanup error:', e);
+    }
+
+    return repaired;
+  } catch (e) {
+    console.warn('[loadPdfDocument] qpdf not available for repair:', e);
+    return null;
+  }
+}
+
 export async function loadPdfDocument(
   pdf: Uint8Array | ArrayBuffer,
   options?: LoadOptions
 ): Promise<PDFDocumentInstance> {
-  return PDFDocument.load(pdf, {
+  const loadOpts = {
     ignoreEncryption: true,
+    throwOnInvalidObject: false,
     ...options,
-  });
+  };
+
+  const inputBytes = pdf instanceof Uint8Array ? pdf : new Uint8Array(pdf);
+  const repaired = await repairPdfBytes(inputBytes);
+
+  if (repaired) {
+    try {
+      return await PDFDocument.load(repaired, loadOpts);
+    } catch (e) {
+      console.warn(
+        '[loadPdfDocument] Failed to load repaired PDF, falling back to original:',
+        e
+      );
+    }
+  }
+
+  return PDFDocument.load(pdf, loadOpts);
 }