OAuth callback

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

const CLIENT_ID = process.env.CLIENT_ID;
const CLIENT_SECRET = process.env.CLIENT_SECRET; // store this securely
const REDIRECT_URI = process.env.REDIRECT_URI; // same redirect URI used in the authorize endpoint

app.get('/auth/callback', async (req, res) => {
  console.log('Received callback with query:', req.query);
  try {
    const { code, error, error_description } = req.query;

    // Handle errors
    if (error) {
      return res.status(400).json({
        error: error,
        error_description: error_description
      });
    }

    if (!code) {
      return res.status(400).json({ error: 'Authorization code not provided' });
    }

    // Optionally validate the state parameter here if you provided one in the authorize request

    const params = new URLSearchParams();
    params.append('grant_type', 'authorization_code');
    params.append('code', code);
    params.append('client_id', CLIENT_ID);
    params.append('client_secret', CLIENT_SECRET);
    params.append('redirect_uri', REDIRECT_URI);

    // Exchange authorization code for tokens
    const tokenResponse = await axios.post('https://api.light.inc/oauth/token', params, {
      headers: {
        'Accept': 'application/json',
        'Content-Type': 'application/x-www-form-urlencoded'
      },
    });

    // Store tokens in your database, preferably encrypted
    // saveTokens(tokenResponse.data);

    res.json({ success: true });
  } catch (error) {
    res.status(500).json(error.response?.data || { error: error.message });
  }
});

const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
    console.log(`Server is running on port ${PORT}`);
});