feat(storage): add comprehensive tests for StorageManager with memory, filesystem, and custom function backends

feat(email): implement EmailSendJob class for robust email delivery with retry logic and MX record resolution

feat(mail): restructure mail module exports for simplified access to core and delivery functionalities

ts/mail/delivery/smtpserver/tls-handler.ts

@@ -110,84 +110,100 @@ export class TlsHandler implements ITlsHandler {
   }
   
   /**
-   * Upgrade a connection to TLS using Deno-native implementation
+   * Upgrade a connection to TLS
    * @param socket - Client socket
    */
-  public async startTLS(socket: plugins.net.Socket): Promise<plugins.tls.TLSSocket | any> {
+  public async startTLS(socket: plugins.net.Socket): Promise<plugins.tls.TLSSocket> {
     // Get the session for this socket
     const session = this.smtpServer.getSessionManager().getSession(socket);
-
+    
     try {
-      // Use the unified STARTTLS implementation (Deno-native)
-      const { performStartTLS } = await import('./starttls-handler.ts');
-
-      SmtpLogger.info('Starting STARTTLS upgrade', {
-        remoteAddress: socket.remoteAddress,
-        remotePort: socket.remotePort
-      });
-
+      // Import the enhanced STARTTLS handler
+      // This uses a more robust approach to TLS upgrades
+      const { performStartTLS } = await import('./starttls-handler.js');
+      
+      SmtpLogger.info('Using enhanced STARTTLS implementation');
+      
+      // Use the enhanced STARTTLS handler with better error handling and socket management
       const serverOptions = this.smtpServer.getOptions();
       const tlsSocket = await performStartTLS(socket, {
         key: serverOptions.key,
         cert: serverOptions.cert,
         ca: serverOptions.ca,
-        session,
+        session: session,
         sessionManager: this.smtpServer.getSessionManager(),
         connectionManager: this.smtpServer.getConnectionManager(),
+        // Callback for successful upgrade
         onSuccess: (secureSocket) => {
-          SmtpLogger.info('TLS connection successfully established', {
+          SmtpLogger.info('TLS connection successfully established via enhanced STARTTLS', {
             remoteAddress: secureSocket.remoteAddress,
-            remotePort: secureSocket.remotePort
+            remotePort: secureSocket.remotePort,
+            protocol: secureSocket.getProtocol() || 'unknown',
+            cipher: secureSocket.getCipher()?.name || 'unknown'
           });
-
+          
+          // Log security event
           SmtpLogger.logSecurityEvent(
             SecurityLogLevel.INFO,
             SecurityEventType.TLS_NEGOTIATION,
-            'STARTTLS successful',
-            {},
+            'STARTTLS successful with enhanced implementation',
+            { 
+              protocol: secureSocket.getProtocol(),
+              cipher: secureSocket.getCipher()?.name
+            },
             secureSocket.remoteAddress,
             undefined,
             true
           );
         },
+        // Callback for failed upgrade
         onFailure: (error) => {
-          SmtpLogger.error(`STARTTLS failed: ${error.message}`, {
+          SmtpLogger.error(`Enhanced STARTTLS failed: ${error.message}`, {
             sessionId: session?.id,
             remoteAddress: socket.remoteAddress,
             error
           });
-
+          
+          // Log security event
           SmtpLogger.logSecurityEvent(
             SecurityLogLevel.ERROR,
             SecurityEventType.TLS_NEGOTIATION,
-            'STARTTLS failed',
+            'Enhanced STARTTLS failed',
             { error: error.message },
             socket.remoteAddress,
             undefined,
             false
           );
         },
+        // Function to update session state
         updateSessionState: this.smtpServer.getSessionManager().updateSessionState?.bind(this.smtpServer.getSessionManager())
       });
-
+      
+      // If STARTTLS failed with the enhanced implementation, log the error
       if (!tlsSocket) {
+        SmtpLogger.warn('Enhanced STARTTLS implementation failed to create TLS socket', {
+          sessionId: session?.id,
+          remoteAddress: socket.remoteAddress
+        });
         throw new Error('Failed to create TLS socket');
       }
-
+      
       return tlsSocket;
     } catch (error) {
+      // Log STARTTLS failure
       SmtpLogger.error(`Failed to upgrade connection to TLS: ${error instanceof Error ? error.message : String(error)}`, {
         remoteAddress: socket.remoteAddress,
         remotePort: socket.remotePort,
         error: error instanceof Error ? error : new Error(String(error)),
         stack: error instanceof Error ? error.stack : 'No stack trace available'
       });
-
+      
+      // Log security event
       SmtpLogger.logSecurityEvent(
         SecurityLogLevel.ERROR,
         SecurityEventType.TLS_NEGOTIATION,
         'Failed to upgrade connection to TLS',
-        {
+        { 
           error: error instanceof Error ? error.message : String(error),
           stack: error instanceof Error ? error.stack : 'No stack trace available'
         },
@@ -195,7 +211,8 @@ export class TlsHandler implements ITlsHandler {
         undefined,
         false
       );
-
+      
+      // Destroy the socket on error
       socket.destroy();
       throw error;
     }