vvet_backend_1/routes/panRoutes.js

// const express = require('express');
// const multer = require('multer');
// const path = require('path');
// const fs = require('fs');
// const sharp = require('sharp');
// const tesseract = require('tesseract.js');
// const axios = require('axios');


// const router = express.Router();

// // Create the upload folder if it doesn't exist
// const uploadPath = path.join(__dirname, "../uploads/pan");
// if (!fs.existsSync(uploadPath)) {
//   fs.mkdirSync(uploadPath, { recursive: true });
// }

// // Set up multer storage
// const storage = multer.diskStorage({
//   destination: function (req, file, cb) {
//     cb(null, uploadPath);
//   },
//   filename: function (req, file, cb) {
//     const uniqueName = `${Date.now()}-${file.originalname}`;
//     cb(null, uniqueName);
//   }
// });

// // Accept only one file with field name 'panImage'
// const upload = multer({
//   storage: storage,
//   limits: { fileSize: 5 * 1024 * 1024 }, // 5MB max
// }).single('panImage');

// // Preprocess the image (convert to grayscale and increase contrast)
// async function preprocessImage(imagePath) {
//   const outputPath = imagePath.replace('.jpeg', '-processed.jpeg'); // New path for the processed image

//   await sharp(imagePath)
//     .resize(800) // Resize the image for better OCR accuracy
//     .grayscale() // Convert to grayscale
//     .normalize() // Enhance contrast
//     .toFile(outputPath);

//   return outputPath;
// }

// router.post('/api/verify-pan', (req, res) => {
//   upload(req, res, async function (err) {
//     if (err instanceof multer.MulterError) {
//       console.error('Multer error:', err);
//       return res.status(400).json({ error: 'Multer error', detail: err.message });
//     } else if (err) {
//       console.error('Unknown error:', err);
//       return res.status(500).json({ error: 'Unknown error', detail: err.message });
//     }

//     if (!req.file) {
//       return res.status(400).json({ error: 'No PAN image uploaded' });
//     }

//     const { pan } = req.body;
//     if (!pan) {
//       return res.status(400).json({ error: 'PAN number is required' });
//     }


//     console.log('Received PAN:', pan);
//     console.log('Saved file path:', req.file.path);

//     try {
//       // Preprocess the image
//       const processedImagePath = await preprocessImage(req.file.path);

//       // Run OCR on the preprocessed image
//       const { data: { text } } = await tesseract.recognize(
//         processedImagePath,
//         'eng', // English language
//         {
//           logger: (m) => console.log(m),
//         }
//       );

//       console.log('Extracted text from image:', text);

//       if (!text || text.trim().length === 0) {
//         return res.status(400).json({ error: 'Failed to extract text from image' });
//       }

//       // Clean up extracted text and PAN number
//       const cleanedExtractedText = text.replace(/\s+/g, '').toUpperCase();
//       const cleanedPanNumber = pan.replace(/\s+/g, '').toUpperCase();

//       const matchedPANs = cleanedExtractedText.match(/[A-Z]{5}[0-9]{4}[A-Z]/g) || [];

//     console.log("Extracted PAN candidates:", matchedPANs);

//     if (matchedPANs.includes(cleanedPanNumber)) {
//         return res.status(200).json({
//           verified: true,
//           message: 'PAN verified successfully',
//           pan,
//           imageUrl: `/uploads/pan/${req.file.filename}`,
//         });
//       } else {
//         return res.status(400).json({
//             error: true,
//             verified: false,
//             message: 'PAN mismatch',
//             pan,
//             imageUrl: `/uploads/pan/${req.file.filename}`,
//         });
//       }
//     } catch (error) {
//       console.error('Error during OCR:', error);
//       return res.status(500).json({ error: 'Error during OCR', detail: error.message });
//     }
//   });
// });

// module.exports = router;

const express = require('express');
const multer = require('multer');
const path = require('path');
const fs = require('fs');
const sharp = require('sharp');
const tesseract = require('tesseract.js');
const router = express.Router();

// Create the upload folder if it doesn't exist
const uploadPath = path.join(__dirname, "../uploads/pan");
if (!fs.existsSync(uploadPath)) {
  fs.mkdirSync(uploadPath, { recursive: true });
}

// Set up multer storage
const storage = multer.diskStorage({
  destination: function (req, file, cb) {
    cb(null, uploadPath); // Destination folder for uploaded files
  },
  filename: function (req, file, cb) {
    const uniqueName = `${Date.now()}-${file.originalname}`;
    cb(null, uniqueName); // Store files with a unique name
  }
});

// Accept only one file with the field name 'panImage'
const upload = multer({
  storage: storage,
  limits: { fileSize: 5 * 1024 * 1024 }, // 5MB max
}).single('panImage');

// Preprocess the image (convert to grayscale and enhance contrast)
async function preprocessImage(imagePath) {
  const outputPath = imagePath.replace('.jpeg', '-processed.jpeg'); // Processed image path
  await sharp(imagePath)
    .resize(800) // Resize image for better OCR accuracy
    .grayscale() // Convert to grayscale
    .normalize() // Enhance contrast
    .toFile(outputPath); // Save processed image

  return outputPath;
}

// PAN verification API endpoint
router.post('/api/verify-pan', (req, res) => {
  upload(req, res, async function (err) {
    // Handle multer errors
    if (err instanceof multer.MulterError) {
      console.error('Multer error:', err);
      return res.status(400).json({ error: 'Multer error', detail: err.message });
    } else if (err) {
      console.error('Unknown error:', err);
      return res.status(500).json({ error: 'Unknown error', detail: err.message });
    }

    if (!req.file) {
      return res.status(400).json({ error: 'No PAN image uploaded' });
    }

    const { pan } = req.body;
    if (!pan) {
      return res.status(400).json({ error: 'PAN number is required' });
    }

    console.log('Received PAN:', pan);
    console.log('Saved file path:', req.file.path);

    try {
      // Preprocess the image before running OCR
      const processedImagePath = await preprocessImage(req.file.path);

      // Run OCR to extract text from the image
      const { data: { text } } = await tesseract.recognize(
        processedImagePath,
        'eng', // Use English for OCR
        {
          logger: (m) => console.log(m), // Optional: log progress
        }
      );

      console.log('Extracted text from image:', text);

      // Ensure the extracted text is valid
      if (!text || text.trim().length === 0) {
        return res.status(400).json({ error: 'Failed to extract text from image' });
      }

      // Clean up extracted text and compare with the provided PAN number
      const cleanedExtractedText = text.replace(/\s+/g, '').toUpperCase();
      const cleanedPanNumber = pan.replace(/\s+/g, '').toUpperCase();

      const matchedPANs = cleanedExtractedText.match(/[A-Z]{5}[0-9]{4}[A-Z]/g) || [];

      console.log("Extracted PAN candidates:", matchedPANs);

      // Check if the extracted PAN matches the provided PAN
      if (matchedPANs.includes(cleanedPanNumber)) {
        return res.status(200).json({
          verified: true,
          message: 'PAN verified successfully',
          pan,
          imageUrl: `/uploads/pan/${req.file.filename}`,
        });
      } else {
        return res.status(400).json({
          verified: false,
          message: 'PAN mismatch',
          pan,
          imageUrl: `/uploads/pan/${req.file.filename}`,
        });
      }
    } catch (error) {
      console.error('Error during OCR:', error);
      return res.status(500).json({ error: 'Error during OCR', detail: error.message });
    }
  });
});

module.exports = router;