Data Requests

const express = require('express');
const crypto = require('crypto');

const app = express();
app.use('/webhooks/m2m', express.raw({ type: 'application/json' }));

const WEBHOOK_SECRET = process.env.M2M_WEBHOOK_SECRET;
const API_KEY = process.env.M2M_API_KEY;

// Verify webhook signature
function verifySignature(req) {
  const signature = req.headers['x-m2m-signature'];
  const timestamp = req.headers['x-m2m-timestamp'];
  const body = req.body.toString();
  
  const expected = crypto
    .createHmac('sha256', WEBHOOK_SECRET)
    .update(`${timestamp}.${body}`)
    .digest('hex');
  
  return crypto.timingSafeEqual(
    Buffer.from(signature.replace('sha256=', '')),
    Buffer.from(expected)
  );
}

// Fetch user data from your database
async function getUserData(referenceId, requiredFields) {
  const user = await db.users.findUnique({
    where: { id: referenceId }
  });
  
  if (!user) return null;
  
  const userData = {};
  
  // Map your fields to M2M fields
  if (requiredFields.includes('name.secondName') && user.middleName) {
    userData.name = userData.name || {};
    userData.name.secondName = user.middleName;
  }
  
  if (requiredFields.includes('name.secondLastName') && user.maternalSurname) {
    userData.name = userData.name || {};
    userData.name.secondLastName = user.maternalSurname;
  }
  
  if (requiredFields.includes('idNumber') && user.governmentId) {
    userData.idNumber = user.governmentId;
  }
  
  if (requiredFields.includes('idType') && user.idDocumentType) {
    userData.idType = user.idDocumentType;
  }
  
  if (requiredFields.includes('dob') && user.dateOfBirth) {
    userData.dob = user.dateOfBirth.toISOString().split('T')[0];
  }
  
  return userData;
}

// Send data to M2M
async function respondToDataRequest(replyEndpoint, referenceId, userData) {
  const response = await fetch(replyEndpoint, {
    method: 'PUT',
    headers: {
      'X-API-Key': API_KEY,
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({ referenceId, userData })
  });
  
  return response.json();
}

// Webhook handler
app.post('/webhooks/m2m', async (req, res) => {
  // Verify signature
  if (!verifySignature(req)) {
    return res.status(401).send('Invalid signature');
  }
  
  const event = JSON.parse(req.body);
  
  // Acknowledge immediately
  res.status(200).send('OK');
  
  // Handle data request asynchronously
  if (event.event === 'user.data_request') {
    try {
      const { referenceId, requiredFields, replyEndpoint } = event.data;
      
      // Fetch user data
      const userData = await getUserData(referenceId, requiredFields);
      
      if (userData && Object.keys(userData).length > 0) {
        // Send to M2M
        const result = await respondToDataRequest(
          replyEndpoint,
          referenceId,
          userData
        );
        
        console.log('Data request fulfilled:', result);
      } else {
        console.log('No data available for user:', referenceId);
      }
    } catch (error) {
      console.error('Error handling data request:', error);
    }
  }
});

app.listen(3000);