Stirling-PDF/frontend/src/hooks/usePdfSignatureDetection.ts

import { useState, useEffect } from 'react';
import * as pdfjsLib from 'pdfjs-dist';

export interface PdfSignatureDetectionResult {
  hasDigitalSignatures: boolean;
  isChecking: boolean;
}

export const usePdfSignatureDetection = (files: File[]): PdfSignatureDetectionResult => {
  const [hasDigitalSignatures, setHasDigitalSignatures] = useState(false);
  const [isChecking, setIsChecking] = useState(false);

  useEffect(() => {
    const checkForDigitalSignatures = async () => {
      if (files.length === 0) {
        setHasDigitalSignatures(false);
        return;
      }

      setIsChecking(true);
      let foundSignature = false;

      try {
        // Set up PDF.js worker
        pdfjsLib.GlobalWorkerOptions.workerSrc = '/pdfjs-legacy/pdf.worker.mjs';

        for (const file of files) {
          const arrayBuffer = await file.arrayBuffer();
          
          try {
            const pdf = await pdfjsLib.getDocument({ data: arrayBuffer }).promise;

            for (let i = 1; i <= pdf.numPages; i++) {
              const page = await pdf.getPage(i);
              const annotations = await page.getAnnotations({ intent: 'display' });

              annotations.forEach(annotation => {
                if (annotation.subtype === 'Widget' && annotation.fieldType === 'Sig') {
                  foundSignature = true;
                }
              });

              if (foundSignature) break;
            }
          } catch (error) {
            console.warn('Error analyzing PDF for signatures:', error);
          }

          if (foundSignature) break;
        }
      } catch (error) {
        console.warn('Error checking for digital signatures:', error);
      }

      setHasDigitalSignatures(foundSignature);
      setIsChecking(false);
    };

    checkForDigitalSignatures();
  }, [files]);

  return {
    hasDigitalSignatures,
    isChecking
  };
};