dcrouter/ts/mail/delivery/classes.smtpserver.ts

import * as plugins from '../../plugins.js';
import * as paths from '../../paths.js';
import { Email } from '../core/classes.email.js';
import type { UnifiedEmailServer } from '../routing/classes.unified.email.server.js';
import { logger } from '../../logger.js';
import { 
  SecurityLogger, 
  SecurityLogLevel, 
  SecurityEventType,
  IPReputationChecker, 
  ReputationThreshold 
} from '../../security/index.js';

import type {
  ISmtpServerOptions,
  ISmtpSession,
  EmailProcessingMode
} from './interfaces.js';
import { SmtpState } from './interfaces.js';

// Import refactored SMTP server components
import { 
  SmtpServer,
  createSmtpServer,
  type ISmtpServer
} from './smtpserver/index.js';

/**
 * Legacy SMTP Server implementation that uses the refactored modular version
 * Maintains the original API for backward compatibility
 */
export class SMTPServer {
  // Public properties used by existing code
  public emailServerRef: UnifiedEmailServer;
  
  // Protected properties for test access
  protected server: plugins.net.Server;
  protected secureServer?: plugins.tls.Server;
  
  // Original properties maintained for compatibility
  private smtpServerOptions: ISmtpServerOptions;
  private sessions: Map<plugins.net.Socket | plugins.tls.TLSSocket, ISmtpSession>;
  private sessionTimeouts: Map<string, NodeJS.Timeout>;
  private hostname: string;
  private sessionIdCounter: number = 0;
  private connectionCount: number = 0;
  private maxConnections: number = 100;
  private cleanupInterval?: NodeJS.Timeout;
  
  // New refactored server implementation
  private smtpServerImpl: ISmtpServer;

  constructor(emailServerRefArg: UnifiedEmailServer, optionsArg: ISmtpServerOptions) {
    console.log('SMTPServer instance is being created (using refactored implementation)...');

    // Store original arguments and properties for backward compatibility
    this.emailServerRef = emailServerRefArg;
    this.smtpServerOptions = optionsArg;
    this.sessions = new Map();
    this.sessionTimeouts = new Map();
    this.hostname = optionsArg.hostname || 'mail.lossless.one';
    this.maxConnections = optionsArg.maxConnections || 100;
    
    // Log enhanced server configuration
    const socketTimeout = optionsArg.socketTimeout || 300000;
    const connectionTimeout = optionsArg.connectionTimeout || 30000;
    const cleanupFrequency = optionsArg.cleanupInterval || 5000;
    
    logger.log('info', 'SMTP server configuration', {
      hostname: this.hostname,
      maxConnections: this.maxConnections,
      socketTimeout: socketTimeout,
      connectionTimeout: connectionTimeout,
      cleanupInterval: cleanupFrequency,
      tlsEnabled: !!(optionsArg.key && optionsArg.cert),
      starttlsEnabled: !!(optionsArg.key && optionsArg.cert),
      securePort: optionsArg.securePort
    });

    // Create the refactored SMTP server implementation
    this.smtpServerImpl = createSmtpServer(emailServerRefArg, optionsArg);
    
    // Initialize server properties to support existing test code
    // These will be properly set during the listen() call
    this.server = new plugins.net.Server();
    
    if (optionsArg.key && optionsArg.cert) {
      try {
        // Convert certificates to Buffer format for Node.js TLS
        // This helps prevent ASN.1 encoding issues when Node parses the certificates
        const key = Buffer.from(optionsArg.key.trim());
        const cert = Buffer.from(optionsArg.cert.trim());
        const ca = optionsArg.ca ? Buffer.from(optionsArg.ca.trim()) : undefined;
        
        logger.log('debug', 'Creating TLS server with certificates', {
          keyBufferLength: key.length,
          certBufferLength: cert.length,
          caBufferLength: ca ? ca.length : 0
        });
        
        // TLS configuration for secure connections
        const tlsOptions: plugins.tls.TlsOptions = {
          key: key,
          cert: cert,
          ca: ca,
          // Recommended security options
          minVersion: 'TLSv1.2',
          honorCipherOrder: true,
          // Allow self-signed certificates for test environments
          rejectUnauthorized: false,
          // Enable session reuse for better performance
          sessionTimeout: 300,
          // Add cipher suites for better compatibility with clients
          ciphers: 'HIGH:!aNULL:!MD5:!RC4',
          // Allow client-initiated renegotiation for SMTP
          allowRenegotiation: true
        };
        
        this.secureServer = plugins.tls.createServer(tlsOptions);
        
        logger.log('info', 'TLS server created successfully');
      } catch (error) {
        logger.log('error', `Failed to create secure server: ${error instanceof Error ? error.message : String(error)}`, { 
          error: error instanceof Error ? error.stack : String(error)
        });
      }
    }
    
    // Set up session events to maintain legacy behavior
    const sessionManager = this.smtpServerImpl.getSessionManager();
    
    // Track sessions for backward compatibility
    sessionManager.on('created', (session, socket) => {
      this.sessions.set(socket, session);
      this.connectionCount++;
    });
    
    sessionManager.on('completed', (session, socket) => {
      this.sessions.delete(socket);
      this.connectionCount--;
    });
  }
  
  /**
   * Start the SMTP server and listen on the specified port
   * @returns A promise that resolves when the server is listening
   */
  public listen(): Promise<void> {
    return new Promise<void>((resolve, reject) => {
      this.smtpServerImpl.listen()
        .then(() => {
          // Get created servers for test compatibility
          // Get the actual server instances for backward compatibility
          const netServer = (this.smtpServerImpl as any).server;
          if (netServer) {
            this.server = netServer;
          }
          
          const tlsServer = (this.smtpServerImpl as any).secureServer;
          if (tlsServer) {
            this.secureServer = tlsServer;
          }
          
          resolve();
        })
        .catch(err => {
          logger.log('error', `Failed to start SMTP server: ${err.message}`, { 
            stack: err.stack 
          });
          reject(err);
        });
    });
  }
  
  /**
   * Stop the SMTP server
   * @returns A promise that resolves when the server has stopped
   */
  public close(): Promise<void> {
    return new Promise<void>((resolve, reject) => {
      this.smtpServerImpl.close()
        .then(() => {
          // Clean up legacy resources
          this.sessions.clear();
          for (const timeoutId of this.sessionTimeouts.values()) {
            clearTimeout(timeoutId);
          }
          this.sessionTimeouts.clear();
          
          if (this.cleanupInterval) {
            clearInterval(this.cleanupInterval);
            this.cleanupInterval = undefined;
          }
          
          resolve();
        })
        .catch(err => {
          logger.log('error', `Failed to stop SMTP server: ${err.message}`, { 
            stack: err.stack 
          });
          reject(err);
        });
    });
  }
  
  /**
   * @deprecated Use the refactored implementation directly
   * Maintained for backward compatibility
   */
  private handleNewConnection(socket: plugins.net.Socket): void {
    logger.log('warn', 'Using deprecated handleNewConnection method');
  }
  
  /**
   * @deprecated Use the refactored implementation directly
   * Maintained for backward compatibility
   */
  private handleNewSecureConnection(socket: plugins.tls.TLSSocket): void {
    logger.log('warn', 'Using deprecated handleNewSecureConnection method');
  }
  
  /**
   * @deprecated Use the refactored implementation directly
   * Maintained for backward compatibility
   */
  private cleanupIdleSessions(): void {
    // This is now handled by the session manager in the refactored implementation
  }
  
  /**
   * @deprecated Use the refactored implementation directly
   * Maintained for backward compatibility
   */
  private generateSessionId(): string {
    return `${Date.now()}-${++this.sessionIdCounter}`;
  }
  
  /**
   * @deprecated Use the refactored implementation directly
   * Maintained for backward compatibility
   */
  private removeSession(socket: plugins.net.Socket | plugins.tls.TLSSocket): void {
    // This is now handled by the session manager in the refactored implementation
  }
  
  /**
   * @deprecated Use the refactored implementation directly
   * Maintained for backward compatibility
   */
  private processCommand(socket: plugins.net.Socket | plugins.tls.TLSSocket, line: string): void {
    // This is now handled by the command handler in the refactored implementation
  }
  
  /**
   * @deprecated Use the refactored implementation directly
   * Maintained for backward compatibility
   */
  private handleDataChunk(socket: plugins.net.Socket | plugins.tls.TLSSocket, chunk: string): void {
    // This is now handled by the data handler in the refactored implementation
  }
  
  /**
   * @deprecated Use the refactored implementation directly
   * Maintained for backward compatibility
   */
  private sendResponse(socket: plugins.net.Socket | plugins.tls.TLSSocket, response: string): void {
    try {
      socket.write(`${response}\r\n`);
    } catch (error) {
      logger.log('error', `Error sending response: ${error instanceof Error ? error.message : 'Unknown error'}`, {
        response,
        remoteAddress: socket.remoteAddress,
        remotePort: socket.remotePort
      });
    }
  }
  
  /**
   * Get the current active connection count
   * @returns Number of active connections
   */
  public getConnectionCount(): number {
    return this.connectionCount;
  }
  
  /**
   * Get the refactored SMTP server implementation
   * This provides access to the new implementation for future use
   */
  public getSmtpServerImpl(): ISmtpServer {
    return this.smtpServerImpl;
  }
}