server.js

import express from 'express';
import cors from 'cors';
import helmet from 'helmet';
import compression from 'compression';
import { fileURLToPath } from 'url';
import { dirname, join } from 'path';
import dotenv from 'dotenv';
import { createServer } from 'http';
import { WebSocketServer } from 'ws';

// Import our custom modules
import { setupRoutes } from './src/routes/index.js';
import { initializeServices } from './src/services/index.js';
import { setupWebSocket } from './src/websocket/chatSocket.js';
import { rateLimiter } from './src/middleware/rateLimiter.js';
import { errorHandler } from './src/middleware/errorHandler.js';
import { logger } from './src/utils/logger.js';

// Load environment variables
dotenv.config();

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

class RAGChatbotServer {
    constructor() {
        this.app = express();
        this.server = createServer(this.app);
        this.wss = new WebSocketServer({ server: this.server });
        this.port = process.env.PORT || 3000;
    }

    async initialize() {
        try {
            // Initialize services
            await initializeServices();
            
            // Setup middleware
            this.setupMiddleware();
            
            // Setup routes
            this.setupRoutes();
            
            // Setup WebSocket
            this.setupWebSocket();
            
            // Setup error handling
            this.setupErrorHandling();
            
            logger.info('Server initialized successfully');
        } catch (error) {
            logger.error('Failed to initialize server:', error);
            process.exit(1);
        }
    }

    setupMiddleware() {
        // Security middleware
        this.app.use(helmet({
            contentSecurityPolicy: {
                directives: {
                    defaultSrc: ["'self'"],
                    styleSrc: ["'self'", "'unsafe-inline'", "https://cdnjs.cloudflare.com"],
                    scriptSrc: ["'self'", "'unsafe-inline'", "https://cdnjs.cloudflare.com"],
                    imgSrc: ["'self'", "data:", "https:"],
                    connectSrc: ["'self'", "ws:", "wss:"],
                },
            },
        }));

        // CORS configuration
        this.app.use(cors({
            origin: process.env.CORS_ORIGIN || 'http://localhost:3000',
            credentials: true
        }));

        // Compression
        this.app.use(compression());

        // Body parsing
        this.app.use(express.json({ limit: '50mb' }));
        this.app.use(express.urlencoded({ extended: true, limit: '50mb' }));

        // Rate limiting
        this.app.use(rateLimiter);

        // Static files
        this.app.use(express.static(join(__dirname, 'public')));

        // Request logging
        this.app.use((req, res, next) => {
            logger.info(`${req.method} ${req.path} - ${req.ip}`);
            next();
        });
    }

    setupRoutes() {
        setupRoutes(this.app);
    }

    setupWebSocket() {
        setupWebSocket(this.wss);
    }

    setupErrorHandling() {
        this.app.use(errorHandler);
    }

    async start() {
        await this.initialize();
        
        this.server.listen(this.port, () => {
            logger.info(`🤖 RAG Q&A Chatbot Server running on port ${this.port}`);
            logger.info(`🌐 Open your browser to: http://localhost:${this.port}`);
            logger.info(`📚 Upload documents and start chatting!`);
        });

        // Graceful shutdown
        process.on('SIGTERM', () => this.shutdown());
        process.on('SIGINT', () => this.shutdown());
    }

    shutdown() {
        logger.info('Shutting down server...');
        this.server.close(() => {
            logger.info('Server closed');
            process.exit(0);
        });
    }
}

// Start the server
const server = new RAGChatbotServer();
server.start().catch(error => {
    logger.error('Failed to start server:', error);
    process.exit(1);
});

export default server;