fix: match cert and audit log page dimensions to source document (#2473)

packages/lib/server-only/pdf/get-page-size.ts

@@ -1,4 +1,10 @@
 import type { PDFPage } from '@cantoo/pdf-lib';
+import type { PDF } from '@libpdf/core';
+
+import { PDF_SIZE_A4_72PPI } from '../../constants/pdf';
+
+const MIN_CERT_PAGE_WIDTH = 300;
+const MIN_CERT_PAGE_HEIGHT = 300;
 
 /**
  * Gets the effective page size for PDF operations.
@@ -16,3 +22,20 @@ export const getPageSize = (page: PDFPage) => {
 
   return cropBox;
 };
+
+export const getLastPageDimensions = (pdfDoc: PDF): { width: number; height: number } => {
+  const lastPage = pdfDoc.getPage(pdfDoc.getPageCount() - 1);
+
+  if (!lastPage) {
+    return PDF_SIZE_A4_72PPI;
+  }
+
+  const width = Math.round(lastPage.width);
+  const height = Math.round(lastPage.height);
+
+  if (width < MIN_CERT_PAGE_WIDTH || height < MIN_CERT_PAGE_HEIGHT) {
+    return PDF_SIZE_A4_72PPI;
+  }
+
+  return { width, height };
+};