Feat: Reverse-pages for mulit-pdf

- Added new state pdfDocs: [ ]
- Made tweaks for new state in fileHandler.ts

src/js/logic/reverse-pages.ts

@@ -3,29 +3,35 @@ import { downloadFile } from '../utils/helpers.js';
 import { state } from '../state.js';
 
 import { PDFDocument as PDFLibDocument } from 'pdf-lib';
+import JSZip from 'jszip';
 
 export async function reversePages() {
-  if (!state.pdfDoc) {
+  const pdfDocs = Array.isArray(state.pdfDocs) ? state.pdfDocs : state.pdfDoc ? [state.pdfDoc] : [];
+  if (!pdfDocs.length) {
     showAlert('Error', 'PDF not loaded.');
     return;
   }
   showLoader('Reversing page order...');
   try {
-    const newPdf = await PDFLibDocument.create();
-    const pageCount = state.pdfDoc.getPageCount();
-    const reversedIndices = Array.from(
-      { length: pageCount },
-      (_, i) => pageCount - 1 - i
-    );
+    const zip = new JSZip();
+    for (let j = 0; j < pdfDocs.length; j++) {
+      const pdfDoc = pdfDocs[j];
+      const newPdf = await PDFLibDocument.create();
+      const pageCount = pdfDoc.getPageCount();
+      const reversedIndices = Array.from(
+        { length: pageCount },
+        (_, i) => pageCount - 1 - i
+      );
 
-    const copiedPages = await newPdf.copyPages(state.pdfDoc, reversedIndices);
-    copiedPages.forEach((page: any) => newPdf.addPage(page));
+      const copiedPages = await newPdf.copyPages(pdfDoc, reversedIndices);
+      copiedPages.forEach((page: any) => newPdf.addPage(page));
 
-    const newPdfBytes = await newPdf.save();
-    downloadFile(
-      new Blob([new Uint8Array(newPdfBytes)], { type: 'application/pdf' }),
-      'reversed.pdf'
-    );
+      const newPdfBytes = await newPdf.save();
+      const fileName = pdfDocs.length > 1 ? `reversed_${j + 1}.pdf` : 'reversed.pdf';
+      zip.file(fileName, newPdfBytes);
+    }
+    const zipBlob = await zip.generateAsync({ type: 'blob' });
+    downloadFile(zipBlob, 'reversed_pdfs.zip');
   } catch (e) {
     console.error(e);
     showAlert('Error', 'Could not reverse the PDF pages.');