const express = require('express');
const rateLimit = require('express-rate-limit');
const fs = require('fs');

const app = express();
app.set('trust proxy', true);
const PORT = process.env.PORT || 3000;

// Load reasons from JSON
const reasons = JSON.parse(fs.readFileSync('./reasons.json', 'utf-8'));

// Load OpenAPI schema
const openapiSchema = JSON.parse(fs.readFileSync('./openapi.json', 'utf-8'));

// Rate limiter: 120 requests per minute per IP
const limiter = rateLimit({
  windowMs: 60 * 1000, // 1 minute
  max: 120,
  keyGenerator: (req, res) => {
    return req.headers['cf-connecting-ip'] || req.ip; // Fallback if header missing (or for non-CF)
  },
  message: { error: "Too many requests, please try again later. (120 reqs/min/IP)" }
});

app.use(limiter);

// Serve OpenAPI schema
app.get('/openapi.json', (req, res) => {
  const ip = req.headers['x-forwarded-for'] || req.ip;
  const timestamp = new Date().toISOString();
  console.log(`[${timestamp}] OpenAPI schema request from IP: ${ip}`);
  res.json(openapiSchema);
});

// Random rejection reason endpoint
app.get('/', (req, res) => {
  const ip = req.headers['x-forwarded-for'] || req.ip;
  const timestamp = new Date().toISOString();
  console.log(`[${timestamp}] Request from IP: ${ip}`);
  const reason = reasons[Math.floor(Math.random() * reasons.length)];
  res.json({ reason });
});

app.get('/health', (req, res) => {
  const ip = req.headers['x-forwarded-for'] || req.ip;
  const timestamp = new Date().toISOString();
  console.log(`[${timestamp}] Request from IP: ${ip}`);
  res.json({"status": "ok"});
});

// Start server only if this file is run directly
if (require.main === module) {
  app.listen(PORT, () => {
    console.log(`No-as-a-Service is running on port ${PORT}`);
  });
}

module.exports = app;