Stirling-PDF/src/main/java/stirling/software/SPDF/utils/PdfUtils.java

package stirling.software.SPDF.utils;

import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

import javax.imageio.ImageIO;

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDPageContentStream;
import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;
import org.apache.pdfbox.rendering.ImageType;
import org.apache.pdfbox.rendering.PDFRenderer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;

import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.pdf.PdfWriter;
import com.spire.pdf.PdfDocument;

public class PdfUtils {

    private static final Logger logger = LoggerFactory.getLogger(PdfUtils.class);

    public static byte[] convertToPdf(InputStream imageStream) throws IOException {

        // Create a File object for the image
        File imageFile = new File("image.jpg");

        try (FileOutputStream fos = new FileOutputStream(imageFile); InputStream input = imageStream) {
            byte[] buffer = new byte[1024];
            int len;
            // Read from the input stream and write to the file
            while ((len = input.read(buffer)) != -1) {
                fos.write(buffer, 0, len);
            }
            logger.info("Image successfully written to file: {}", imageFile.getAbsolutePath());
        } catch (IOException e) {
            logger.error("Error writing image to file: {}", imageFile.getAbsolutePath(), e);
            throw e;
        }

        try (PDDocument doc = new PDDocument()) {
            // Create a new PDF page
            PDPage page = new PDPage();
            doc.addPage(page);

            // Create an image object from the image file
            PDImageXObject image = PDImageXObject.createFromFileByContent(imageFile, doc);

            try (PDPageContentStream contentStream = new PDPageContentStream(doc, page)) {
                // Draw the image onto the page
                contentStream.drawImage(image, 0, 0);
                logger.info("Image successfully added to PDF");
            } catch (IOException e) {
                logger.error("Error adding image to PDF", e);
                throw e;
            }

            // Create a ByteArrayOutputStream to save the PDF to
            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
            doc.save(byteArrayOutputStream);
            logger.info("PDF successfully saved to byte array");
            return byteArrayOutputStream.toByteArray();
        }
    }

    public static byte[] convertFromPdf(byte[] inputStream, String imageType, ImageType colorType, boolean singleImage, int DPI)
            throws IOException, Exception {
        try (PDDocument document = PDDocument.load(new ByteArrayInputStream(inputStream))) {
            PDFRenderer pdfRenderer = new PDFRenderer(document);
            int pageCount = document.getNumberOfPages();
            List<BufferedImage> images = new ArrayList<>();

            // Create images of all pages
            for (int i = 0; i < pageCount; i++) {
                images.add(pdfRenderer.renderImageWithDPI(i, 300, colorType));
            }
            
            if (singleImage) {
                // Combine all images into a single big image
                BufferedImage combined = new BufferedImage(images.get(0).getWidth(), images.get(0).getHeight() * pageCount, BufferedImage.TYPE_INT_RGB);
                Graphics g = combined.getGraphics();
                for (int i = 0; i < images.size(); i++) {
                    g.drawImage(images.get(i), 0, i * images.get(0).getHeight(), null);
                }
                images = Arrays.asList(combined);
            }

            // Create a ByteArrayOutputStream to save the image(s) to
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            if (singleImage) {
                // Write the image to the output stream
                ImageIO.write(images.get(0), imageType, baos);

                // Log that the image was successfully written to the byte array
                logger.info("Image successfully written to byte array");
            } else {
                // Zip the images and return as byte array
                try (ZipOutputStream zos = new ZipOutputStream(baos)) {
                    for (int i = 0; i < images.size(); i++) {
                        BufferedImage image = images.get(i);
                        try (ByteArrayOutputStream baosImage = new ByteArrayOutputStream()) {
                            ImageIO.write(image, imageType, baosImage);

                            // Add the image to the zip file
                            zos.putNextEntry(new ZipEntry(String.format("page_%d.%s", i + 1, imageType.toLowerCase())));
                            zos.write(baosImage.toByteArray());
                        }
                    }
                    // Log that the images were successfully written to the byte array
                    logger.info("Images successfully written to byte array as a zip");
                }
            }
            return baos.toByteArray();
        } catch (IOException e) {
            // Log an error message if there is an issue converting the PDF to an image
            logger.error("Error converting PDF to image", e);
            throw e;
        }
    }

    public static byte[] overlayImage(byte[] pdfBytes, byte[] imageBytes, float x, float y) throws IOException {

        try (PDDocument document = PDDocument.load(new ByteArrayInputStream(pdfBytes))) {
            // Get the first page of the PDF
            PDPage page = document.getPage(0);
            try (PDPageContentStream contentStream = new PDPageContentStream(document, page, PDPageContentStream.AppendMode.APPEND, true)) {
                // Create an image object from the image bytes
                PDImageXObject image = PDImageXObject.createFromByteArray(document, imageBytes, "");
                // Draw the image onto the page at the specified x and y coordinates
                contentStream.drawImage(image, x, y);
                logger.info("Image successfully overlayed onto PDF");
            }
            // Create a ByteArrayOutputStream to save the PDF to
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            document.save(baos);
            logger.info("PDF successfully saved to byte array");
            return baos.toByteArray();
        } catch (IOException e) {
            // Log an error message if there is an issue overlaying the image onto the PDF
            logger.error("Error overlaying image onto PDF", e);
            throw e;
        }
    }

    public static ResponseEntity<byte[]> iTextDocToWebResponse(Document document, String docName) throws IOException, DocumentException {
        // Close the document
        document.close();
        
        // Open Byte Array and save document to it
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        PdfWriter.getInstance(document, baos).close();
        

        return PdfUtils.boasToWebResponse(baos, docName);
    }
    
    public static ResponseEntity<byte[]> pdfDocToWebResponse(PdfDocument document, String docName) throws IOException {

        // Open Byte Array and save document to it
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        document.saveToStream(baos);
        // Close the document
        document.close();

        return PdfUtils.boasToWebResponse(baos, docName);
    }

    public static ResponseEntity<byte[]> pdfDocToWebResponse(PDDocument document, String docName) throws IOException {

        // Open Byte Array and save document to it
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        document.save(baos);
        // Close the document
        document.close();

        return PdfUtils.boasToWebResponse(baos, docName);
    }

    public static ResponseEntity<byte[]> boasToWebResponse(ByteArrayOutputStream baos, String docName) throws IOException {
        return PdfUtils.bytesToWebResponse(baos.toByteArray(), docName);

    }

    public static ResponseEntity<byte[]> bytesToWebResponse(byte[] bytes, String docName) throws IOException {

        // Return the PDF as a response
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_PDF);
        headers.setContentLength(bytes.length);
        headers.setContentDispositionFormData("attachment", docName);
        return new ResponseEntity<>(bytes, headers, HttpStatus.OK);
    }
}