text: import { PDFDocument, StandardFonts, degrees } from 'pdf-lib';
  
  import { fetchAsset, writePdf } from './assets';
  
  const createDonorPdf = async () => {
    const pdfDoc = await PDFDocument.create();
    const helveticaFont = await pdfDoc.embedFont(StandardFonts.Helvetica);
  
    const page = pdfDoc.addPage([500, 500]);
  
    page.moveTo(50, 225);
    page.setFont(helveticaFont);
    page.setFontSize(50);
    page.drawText('I am upside down!');
    page.setRotation(degrees(180));
  
    return pdfDoc;
  };
  
  export default async () => {
    const [
      withMissingEndstreamEolAndPollutedCtmBytes,
      normalBytes,
      withUpdateSectionsBytes,
      linearizedWithObjectStreamsBytes,
      withLargePageCountBytes,
    ] = await Promise.all([
      fetchAsset('pdfs/with_missing_endstream_eol_and_polluted_ctm.pdf'),
      fetchAsset('pdfs/normal.pdf'),
      fetchAsset('pdfs/with_update_sections.pdf'),
      fetchAsset('pdfs/linearized_with_object_streams.pdf'),
      fetchAsset('pdfs/with_large_page_count.pdf'),
    ]);
  
    const pdfDoc = await PDFDocument.load(
      withMissingEndstreamEolAndPollutedCtmBytes,
    );
  
    const allDonorPdfBytes = [
      normalBytes,
      withUpdateSectionsBytes,
      linearizedWithObjectStreamsBytes,
      withLargePageCountBytes,
    ];
  
    for (let idx = 0, len = allDonorPdfBytes.length; idx < len; idx++) {
      const donorBytes = allDonorPdfBytes[idx];
      const donorPdf = await PDFDocument.load(donorBytes);
      const [donorPage] = await pdfDoc.copyPages(donorPdf, [0]);
      pdfDoc.addPage(donorPage);
    }
  
    const anotherDonorPdf = await createDonorPdf();
    const [anotherDonorPage] = await pdfDoc.copyPages(anotherDonorPdf, [0]);
    pdfDoc.insertPage(1, anotherDonorPage);
  
    const savedBytes = await pdfDoc.save();
    const sizeOfCreatedPdf = savedBytes.length;
  
    let sizeOfAllDonorPdfs = (await anotherDonorPdf.save()).length;
    for (let idx = 0, len = allDonorPdfBytes.length; idx < len; idx++) {
      sizeOfAllDonorPdfs += allDonorPdfBytes[idx].length;
    }
  
    const base64Pdf = await pdfDoc.saveAsBase64({ dataUri: true });
  
    return { base64Pdf };
  
    // const pdfBytes = await pdfDoc.save();
  
    // const path = await writePdf(pdfBytes);
  
    // return { base64Pdf: `file://${path}` };
  };
  