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

const app = express();
app.use(express.json());

// Configuration
const CONFIG = {
  apiKey: 'YOUR_API_KEY',
  apiUrl: 'https://api.ooppay.io/api/v1',
  webhookSecret: 'YOUR_WEBHOOK_SECRET'
};

// Create payment order
app.post('/create-payment', async (req, res) => {
  try {
    const { orderId, amount } = req.body;
    
    const response = await axios.post(`${CONFIG.apiUrl}/orders`, {
      merchant_order_id: orderId,
      amount: amount.toString(),
      callback_url: 'https://your-domain.com/webhook',
      expire_minutes: 30
    }, {
      headers: {
        'Authorization': `Bearer ${CONFIG.apiKey}`,
        'Content-Type': 'application/json'
      }
    });
    
    res.json({
      success: true,
      data: response.data
    });
  } catch (error) {
    res.status(500).json({
      success: false,
      error: error.message
    });
  }
});

// Handle payment callback
app.post('/webhook', (req, res) => {
  const signature = req.headers['x-signature'];
  const timestamp = req.headers['x-timestamp'];
  
  // Verify signature
  if (!verifyWebhookSignature(req.body, signature, timestamp, CONFIG.webhookSecret)) {
    return res.status(400).send('Invalid signature');
  }
  
  // Handle successful payment
  if (req.body.status === 'paid') {
    console.log(`Payment successful for order ${req.body.order_id}`);
    console.log(`Net amount received: ${req.body.net_amount} USDT`);
    
    // Execute your business logic here
    deliverProduct(req.body.merchant_order_id, req.body.net_amount);
  }
  
  res.status(200).send('OK');
});

function verifyWebhookSignature(payload, signature, timestamp, secret) {
  const { order_id, merchant_order_id, status } = payload;
  const data = order_id + merchant_order_id + status + timestamp;
  const expectedSignature = crypto
    .createHmac('sha256', secret)
    .update(data)
    .digest('hex');
  return signature === expectedSignature;
}

function deliverProduct(orderId, amount) {
  // Implement your product delivery logic
  console.log(`Delivering product for order ${orderId}, amount: ${amount} USDT`);
}

app.listen(3000, () => {
  console.log('Server running on port 3000');
});