package edu.jiangxin.apktoolbox.pdf;
   
   import com.itextpdf.kernel.pdf.*;
   import org.apache.logging.log4j.LogManager;
   import org.apache.logging.log4j.Logger;
   import org.apache.pdfbox.Loader;
   import org.apache.pdfbox.pdmodel.PDDocument;
   import org.apache.pdfbox.pdmodel.PDDocumentCatalog;
   import org.apache.pdfbox.pdmodel.PDPage;
  import org.apache.pdfbox.pdmodel.PDPageTree;
  import org.apache.pdfbox.pdmodel.encryption.ProtectionPolicy;
  import org.apache.pdfbox.pdmodel.encryption.SecurityHandler;
  import org.apache.pdfbox.text.PDFTextStripper;
  
  import java.io.File;
  import java.io.IOException;
  
  public class PdfUtils {
      private static final Logger LOGGER = LogManager.getLogger(PdfUtils.class.getSimpleName());
      public static boolean isScannedPdf(File file, int threshold) {
          int length = 0;
  
          try (PDDocument document = Loader.loadPDF(file)) {
              boolean isEncrypted = document.isEncrypted();
              if (isEncrypted) {
                  document.setAllSecurityToBeRemoved(true);
              }
  
              PDFTextStripper stripper = new PDFTextStripper();
              String text = stripper.getText(document).trim();
              length = text.length();
          } catch (IOException e) {
              LOGGER.error("Error reading PDF file: {}", e.getMessage());
              return false;
          }
          LOGGER.info("Processing file: {}, text size: {}", file.getPath(), length);
          return length < threshold;
      }
  
      public static boolean isEncryptedPdf(File file) {
          boolean isEncrypted;
  
          try (PDDocument document = Loader.loadPDF(file)) {
              isEncrypted = document.isEncrypted();
          } catch (IOException e) {
              LOGGER.error("Error reading PDF file: {}", e.getMessage());
              return false;
          }
          LOGGER.info("Processing file: {}, is encrypted: {}", file.getPath(), isEncrypted);
          return isEncrypted;
      }
  
      public static boolean isNonOutlinePdf(File file) {
          boolean hasOutline = false;
  
          try (PDDocument document = Loader.loadPDF(file)) {
              boolean isEncrypted = document.isEncrypted();
              if (isEncrypted) {
                  document.setAllSecurityToBeRemoved(true);
              }
  
              if (document.getDocumentCatalog() != null && document.getDocumentCatalog().getDocumentOutline() != null) {
                  hasOutline = true;
              }
          } catch (IOException e) {
              LOGGER.error("Error reading PDF file: {}", e.getMessage());
              return false;
          }
          LOGGER.info("Processing file: {}, has outline: {}", file.getPath(), hasOutline);
          return !hasOutline;
      }
  
      public static boolean hasAnnotations(File file) {
          boolean hasAnnotations = false;
  
          try (PDDocument document = Loader.loadPDF(file)) {
              boolean isEncrypted = document.isEncrypted();
              if (isEncrypted) {
                  document.setAllSecurityToBeRemoved(true);
              }
              PDDocumentCatalog catalog = document.getDocumentCatalog();
              if (catalog == null) {
                  return false;
              }
              PDPageTree pages = document.getDocumentCatalog().getPages();
              if (pages == null || pages.getCount() == 0) {
                  return false;
              }
  
              for (PDPage page : pages) {
                  if (page.getAnnotations() != null && !page.getAnnotations().isEmpty()) {
                      int pageNumber = page.getCOSObject().getInt("PageNumber", 0);
                      String subType = page.getAnnotations().get(0).getSubtype();
                      LOGGER.info("Found annotations on page: {}, subType: {}", pageNumber, subType);
                      if (!subType.equals("Link")) {
                          hasAnnotations = true;
                          break; // No need to check further if we found annotations
                      }
                  }
             }
         } catch (IOException e) {
             LOGGER.error("Error reading PDF file: {}", e.getMessage());
             return hasAnnotations;
         }
         LOGGER.info("Processing file: {}, has annotations: {}", file.getPath(), hasAnnotations);
         return hasAnnotations;
     }
 
     public static void removePassword(File encryptedFile, File targetDir) {
         try (PDDocument document = Loader.loadPDF(encryptedFile)) {
             boolean isEncrypted = document.isEncrypted();
             if (isEncrypted) {
                 document.setAllSecurityToBeRemoved(true);
             }
             String targetFilePath = targetDir.getAbsolutePath() + File.separator + encryptedFile.getName();
             document.save(targetFilePath);
             LOGGER.info("Remove password success: {}", targetFilePath);
         } catch (IOException e) {
             LOGGER.error("Error processing PDF file: {}", e.getMessage());
         }
     }
 
     public static void removePasswordWithIText(File encryptedFile, File targetDir) {
         PdfReader reader;
         try {
             reader = new PdfReader(encryptedFile).setUnethicalReading(true);
         } catch (IOException e) {
             LOGGER.error("Error reading PDF file: {}", e.getMessage());
             return;
         }
         String targetFilePath = targetDir.getAbsolutePath() + File.separator + encryptedFile.getName();
 
         try (PdfDocument pdfDoc = new PdfDocument(reader,
                 new PdfWriter(targetFilePath))) {
             LOGGER.info("Remove password success: {}", targetFilePath);
         } catch (IOException e) {
             LOGGER.error("Error writing PDF file: {}", e.getMessage());
         }
     }
 }