import express from 'express';
import cors from 'cors';
import dotenv from 'dotenv';
import path from 'path';
import fs from 'fs';
import { fileURLToPath } from 'url';
import { createServer } from 'http';
import rateLimit from 'express-rate-limit';
import { initDB } from './db/index.js';
import { validateConfig, config } from './config.js';
import { errorHandler } from './middleware/errorHandler.js';
import { initializeSocket } from './sockets/index.js';
import authRoutes from './routes/auth.js';
import challengeRoutes from './routes/challenges.js';
import predictionRoutes from './routes/predictions.js';
import friendRoutes from './routes/friends.js';
import tmdbRoutes from './routes/tmdb.js';
import leaderboardRoutes from './routes/leaderboard.js';

dotenv.config();

// Validate environment configuration
validateConfig();

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const app = express();
const httpServer = createServer(app);

// Initialize Socket.io
initializeSocket(httpServer);

// Rate limiting
const authLimiter = rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 5, // 5 requests per window
  message: { error: 'Too many authentication attempts, please try again later.' },
  standardHeaders: true,
  legacyHeaders: false,
});

const apiLimiter = rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 100, // 100 requests per window
  message: { error: 'Too many requests, please try again later.' },
  standardHeaders: true,
  legacyHeaders: false,
});

const tmdbLimiter = rateLimit({
  windowMs: 60 * 1000, // 1 minute
  max: 20, // 20 requests per minute
  message: { error: 'Too many search requests, please slow down.' },
  standardHeaders: true,
  legacyHeaders: false,
});

// Middleware
app.use(cors());
app.use(express.json());

// API Routes
app.use('/api/auth', authLimiter, authRoutes);
app.use('/api/challenges', apiLimiter, challengeRoutes);
app.use('/api/predictions', apiLimiter, predictionRoutes);
app.use('/api/friends', apiLimiter, friendRoutes);
app.use('/api/tmdb', tmdbLimiter, tmdbRoutes);
app.use('/api/leaderboard', apiLimiter, leaderboardRoutes);

// Health check
app.get('/api/health', (req, res) => {
  res.json({ status: 'ok', message: "What's The Point API" });
});

// Serve static frontend files (for production)
const frontendPath = path.join(__dirname, '../../frontend/dist');
const frontendExists = fs.existsSync(frontendPath);

if (frontendExists) {
  app.use(express.static(frontendPath));

  // Serve index.html for all non-API routes (SPA support)
  app.get('*', (req, res) => {
    res.sendFile(path.join(frontendPath, 'index.html'));
  });
} else {
  console.log('ℹ️  Frontend dist not found - running in API-only mode (dev)');
  app.get('*', (req, res) => {
    res.json({ 
      message: "What's The Point API - Frontend running separately",
      frontend: "http://192.168.1.175:5173"
    });
  });
}

// Error handling middleware (must be last)
app.use(errorHandler);

const PORT = config.server.port;

// Initialize database and start server
initDB()
  .then(() => {
    httpServer.listen(PORT, '0.0.0.0', () => {
      console.log(`✅ Server running on port ${PORT}`);
      console.log(`🔌 Socket.io ready for real-time updates`);
    });
  })
  .catch(err => {
    console.error('Failed to start server:', err);
    process.exit(1);
  });