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

// Store processed events to prevent duplicates
const processedEvents = new Set();

app.post('/webhooks/pro-pitbox', express.json(), async (req, res) => {
  // 1. Verify webhook signature
  const signature = req.headers['x-propitbox-signature'];
  const payload = JSON.stringify(req.body);
  
  if (!verifySignature(payload, signature, process.env.WEBHOOK_SECRET)) {
    return res.status(401).send('Invalid signature');
  }
  
  // 2. Respond immediately
  res.status(200).send('OK');
  
  // 3. Process asynchronously
  setImmediate(async () => {
    const event = req.body;
    
    // Check for duplicate events
    if (processedEvents.has(event.id)) {
      console.log('Duplicate event, skipping:', event.id);
      return;
    }
    
    processedEvents.add(event.id);
    
    try {
      // Handle different event types
      switch (event.type) {
        case 'vehicle.created':
          await handleVehicleCreated(event.data);
          break;
        case 'maintenance.task.created':
          await handleMaintenanceCreated(event.data);
          break;
        case 'parts.inventory.low':
          await handleLowInventory(event.data);
          break;
        default:
          console.log('Unhandled event type:', event.type);
      }
    } catch (error) {
      console.error('Error processing webhook:', error);
      // Send to error tracking service
    }
  });
});

async function handleVehicleCreated(data) {
  console.log('New vehicle:', data.vehicle.name);
  // Add to internal database, send notification, etc.
}

async function handleMaintenanceCreated(data) {
  console.log('Maintenance scheduled:', data.task.type);
  // Update calendar, send reminder, etc.
}

async function handleLowInventory(data) {
  console.log('Low stock alert:', data.part.name);
  // Create purchase order, notify team, etc.
}