const express = require('express');
const proxy = require('express-http-proxy');
const bodyParser = require('body-parser');
const app = express();

const targetUrl = 'https://api.openai.com';
const openaiKey = process.env.OPENAI_KEY;
const adminPassword = 'securepassword'; // Never use hard-coded sensitive passwords in production
const port = 7860;

app.use(bodyParser.json());

// In-memory configuration "database"
let ipConfigurations = {};

// Rate limit middleware
app.use('/api', (req, res, next) => {
  const ip = req.headers['x-forwarded-for'] || req.connection.remoteAddress;
  const config = ipConfigurations[ip] || { limit: 2, requestCount: 0, nextAvailableTime: Date.now() };

  if (new Date() < new Date(config.nextAvailableTime) || config.requestCount >= config.limit) {
    return res.status(429).json({
      error: true,
      message: 'You have reached your maximum request limit.',
      nextAvailableRequestTime: getNextAvailableRequestTime(config)
    });
  }

  // Increment the request count
  config.requestCount++;
  ipConfigurations[ip] = config; // Update config for the IP
  console.log(`Allowed request for ${ip}: ${config.requestCount} of ${config.limit}`);
  next();
}, proxy(targetUrl, {
  proxyReqOptDecorator: (proxyReqOpts, srcReq) => {
    proxyReqOpts.headers['Authorization'] = 'Bearer ' + openaiKey;
    return proxyReqOpts;
  },
}));

// Admin route to update IP configurations
app.post('/admin/config', (req, res) => {
  const { password, ip, limit } = req.body;

  if (password !== adminPassword) {
    return res.status(403).send("Unauthorized");
  }

  ipConfigurations[ip] = { limit: limit, requestCount: 0, nextAvailableTime: Date.now() };
  res.send(`Configuration set for IP ${ip} with limit ${limit}`);
});

// Helper function to get next available request time
function getNextAvailableRequestTime(config) {
  const resetTime = new Date(config.nextAvailableTime);
  return resetTime.toISOString();
}

// Start the express server
app.listen(port, () => {
  console.log(`Reverse proxy server running on port ${port}.`);
});