feat: added a spreadsheet to PDF converter for Excel files with MIME …

backend/pom.xml

@@ -458,5 +458,10 @@
             <classifier>osx-aarch_64</classifier>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.apache.poi</groupId>
+            <artifactId>poi-ooxml</artifactId>
+            <version>5.4.1</version>
+        </dependency>
     </dependencies>
 </project>

backend/src/main/java/eu/bbmri_eric/negotiator/attachment/AttachmentConversionServiceImpl.java

@@ -18,6 +18,8 @@ public class AttachmentConversionServiceImpl implements AttachmentConversionServ
   private static final String CONTENT_TYPE_TIKA_OOXML = "application/x-tika-ooxml";
   private static final String CONTENT_TYPE_DOC = "application/msword";
   private static final String CONTENT_TYPE_TIKA_MSOFFICE = "application/x-tika-msoffice";
+  private static final String CONTENT_TYPE_TIKA_XLSX =
+      "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
 
   private final AttachmentService attachmentService;
 
@@ -117,6 +119,7 @@ private FileTypeConverter getConverter(String contentType) {
       }
       case CONTENT_TYPE_DOCX, CONTENT_TYPE_TIKA_OOXML -> new DocxConverter();
       case CONTENT_TYPE_DOC, CONTENT_TYPE_TIKA_MSOFFICE -> new DocConverter();
+      case CONTENT_TYPE_TIKA_XLSX -> new XlsxConverter();
       default -> {
         throw new IllegalArgumentException("Unsupported content type");
       }

backend/src/main/java/eu/bbmri_eric/negotiator/attachment/XlsxConverter.java

@@ -0,0 +1,171 @@
+package eu.bbmri_eric.negotiator.attachment;
+
+import eu.bbmri_eric.negotiator.common.exceptions.PdfGenerationException;
+import java.awt.Color;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import lombok.extern.apachecommons.CommonsLog;
+import org.apache.pdfbox.pdmodel.PDDocument;
+import org.apache.pdfbox.pdmodel.PDPage;
+import org.apache.pdfbox.pdmodel.PDPageContentStream;
+import org.apache.pdfbox.pdmodel.common.PDRectangle;
+import org.apache.pdfbox.pdmodel.font.PDType1Font;
+import org.apache.pdfbox.pdmodel.font.Standard14Fonts;
+import org.apache.poi.ss.usermodel.Cell;
+import org.apache.poi.ss.usermodel.Row;
+import org.apache.poi.ss.usermodel.Sheet;
+import org.apache.poi.ss.usermodel.Workbook;
+import org.apache.poi.xssf.usermodel.XSSFWorkbook;
+
+/** Converter for XLSX (Excel) files to PDF format. */
+@CommonsLog
+class XlsxConverter implements FileTypeConverter {
+  /** Page margin in points. */
+  private static final float MARGIN = 50;
+
+  /** Font size for cell text. */
+  private static final float FONT_SIZE = 10;
+
+  /** Line leading (spacing between rows). */
+  private static final float LEADING = 14;
+
+  /** Padding inside cells. */
+  private static final float CELL_PADDING = 5;
+
+  /** Minimum width for columns. */
+  private static final float MIN_COLUMN_WIDTH = 60;
+
+  @Override
+  public byte[] convertToPdf(final byte[] xlsxBytes) throws IOException, PdfGenerationException {
+    if (xlsxBytes == null || xlsxBytes.length == 0) {
+      throw new IllegalArgumentException("Input XLSX bytes are null or empty");
+    }
+
+    log.debug("Converting XLSX to PDF, input size: " + xlsxBytes.length);
+
+    try (ByteArrayInputStream xlsxInputStream = new ByteArrayInputStream(xlsxBytes);
+        Workbook workbook = new XSSFWorkbook(xlsxInputStream);
+        PDDocument document = new PDDocument();
+        ByteArrayOutputStream pdfOutputStream = new ByteArrayOutputStream()) {
+
+      for (int sheetIndex = 0; sheetIndex < workbook.getNumberOfSheets(); sheetIndex++) {
+        Sheet sheet = workbook.getSheetAt(sheetIndex);
+        if (sheet.getPhysicalNumberOfRows() > 0) {
+          convertSheetToPdf(document, sheet);
+        }
+      }
+
+      if (document.getNumberOfPages() == 0) {
+        document.addPage(new PDPage(PDRectangle.A4));
+      }
+
+      document.save(pdfOutputStream);
+      byte[] result = pdfOutputStream.toByteArray();
+      log.debug("Successfully converted XLSX to PDF, output size: " + result.length);
+      return result;
+    } catch (Exception e) {
+      log.error("Error converting XLSX to PDF: " + e.getMessage(), e);
+      throw new PdfGenerationException();
+    }
+  }
+
+  private void convertSheetToPdf(final PDDocument document, final Sheet sheet) throws IOException {
+    PDPage page = new PDPage(PDRectangle.A4);
+    document.addPage(page);
+
+    try (PDPageContentStream contentStream =
+        new PDPageContentStream(document, page, PDPageContentStream.AppendMode.APPEND, true)) {
+
+      float pageWidth = page.getMediaBox().getWidth() - (2 * MARGIN);
+      float yPosition =
+          drawSheetHeader(contentStream, sheet.getSheetName(), page.getMediaBox().getHeight());
+
+      int maxCols = calculateMaxColumns(sheet);
+
+      float columnWidth = maxCols > 0 ? pageWidth / maxCols : MIN_COLUMN_WIDTH;
+      columnWidth = Math.max(columnWidth, MIN_COLUMN_WIDTH);
+
+      for (Row row : sheet) {
+        if (yPosition < MARGIN + LEADING) {
+          break;
+        }
+        drawRow(contentStream, row, yPosition, columnWidth, maxCols);
+        yPosition -= LEADING;
+      }
+    }
+  }
+
+  private float drawSheetHeader(
+      PDPageContentStream contentStream, String sheetName, float pageHeight) throws IOException {
+    float yPosition = pageHeight - MARGIN;
+    contentStream.beginText();
+    contentStream.setFont(new PDType1Font(Standard14Fonts.FontName.HELVETICA_BOLD), FONT_SIZE + 2);
+    contentStream.newLineAtOffset(MARGIN, yPosition);
+    contentStream.showText("Sheet: " + sheetName);
+    contentStream.endText();
+    return yPosition - (LEADING * 2);
+  }
+
+  private int calculateMaxColumns(Sheet sheet) {
+    int maxCols = 0;
+    for (Row row : sheet) {
+      if (row.getLastCellNum() > maxCols) {
+        maxCols = row.getLastCellNum();
+      }
+    }
+    return maxCols;
+  }
+
+  private void drawRow(
+      PDPageContentStream contentStream, Row row, float yPosition, float columnWidth, int maxCols)
+      throws IOException {
+    float xPosition = MARGIN;
+    for (int cellIndex = 0; cellIndex < maxCols; cellIndex++) {
+      Cell cell = row.getCell(cellIndex);
+      drawCell(contentStream, cell, xPosition, yPosition, columnWidth);
+      xPosition += columnWidth;
+    }
+  }
+
+  private void drawCell(PDPageContentStream contentStream, Cell cell, float x, float y, float width)
+      throws IOException {
+    String cellValue = getCellValueAsString(cell);
+
+    contentStream.setStrokingColor(Color.LIGHT_GRAY);
+    contentStream.addRect(x, y - LEADING, width, LEADING);
+    contentStream.stroke();
+
+    if (cellValue != null && !cellValue.isEmpty()) {
+      contentStream.beginText();
+      contentStream.setFont(new PDType1Font(Standard14Fonts.FontName.HELVETICA), FONT_SIZE);
+      contentStream.newLineAtOffset(x + CELL_PADDING, y - FONT_SIZE);
+      String displayText = truncateText(cellValue, width - (2 * CELL_PADDING));
+      contentStream.showText(displayText);
+      contentStream.endText();
+    }
+  }
+
+  private String getCellValueAsString(final Cell cell) {
+    if (cell == null) {
+      return "";
+    }
+
+    return switch (cell.getCellType()) {
+      case STRING -> cell.getStringCellValue();
+      case NUMERIC -> String.valueOf(cell.getNumericCellValue());
+      case BOOLEAN -> String.valueOf(cell.getBooleanCellValue());
+      case FORMULA -> cell.getCellFormula();
+      case BLANK -> "";
+      default -> "";
+    };
+  }
+
+  private String truncateText(final String text, final float maxWidth) {
+    int maxChars = (int) (maxWidth / (FONT_SIZE * 0.6));
+    if (text.length() > maxChars) {
+      return text.substring(0, Math.max(0, maxChars - 3)) + "...";
+    }
+    return text;
+  }
+}