dcrouter/test/suite/smtpclient_performance/test.cperf-05.network-efficiency.ts

import { expect, tap } from '@git.zone/tstest/tapbundle';
import * as plugins from './plugins.js';
import { createTestServer } from '../../helpers/server.loader.js';
import { createSmtpClient } from '../../helpers/smtp.client.js';

tap.test('CPERF-05: should optimize network efficiency', async (tools) => {
  const testId = 'CPERF-05-network-efficiency';
  console.log(`\n${testId}: Testing network efficiency optimization...`);

  let scenarioCount = 0;

  // Helper to track network activity
  class NetworkTracker {
    private startTime: number;
    private bytesSent: number = 0;
    private bytesReceived: number = 0;
    private connections: number = 0;
    private roundTrips: number = 0;

    constructor() {
      this.startTime = Date.now();
    }

    addConnection() {
      this.connections++;
    }

    addBytesSent(bytes: number) {
      this.bytesSent += bytes;
    }

    addBytesReceived(bytes: number) {
      this.bytesReceived += bytes;
    }

    addRoundTrip() {
      this.roundTrips++;
    }

    getStats() {
      const elapsed = Date.now() - this.startTime;
      return {
        elapsed,
        bytesSent: this.bytesSent,
        bytesReceived: this.bytesReceived,
        totalBytes: this.bytesSent + this.bytesReceived,
        connections: this.connections,
        roundTrips: this.roundTrips,
        bytesPerSecond: ((this.bytesSent + this.bytesReceived) / elapsed) * 1000,
        efficiency: this.bytesSent / (this.bytesSent + this.bytesReceived)
      };
    }
  }

  // Scenario 1: Connection reuse efficiency
  await (async () => {
    scenarioCount++;
    console.log(`\nScenario ${scenarioCount}: Testing connection reuse efficiency`);
    
    const tracker = new NetworkTracker();
    let connectionCount = 0;
    let totalCommandBytes = 0;
    let totalResponseBytes = 0;
    
    const testServer = await createTestServer({
      onConnection: async (socket) => {
        connectionCount++;
        tracker.addConnection();
        console.log(`  [Server] Connection ${connectionCount} established`);
        
        const greeting = '220 reuse.example.com ESMTP\r\n';
        socket.write(greeting);
        tracker.addBytesSent(greeting.length);
        
        socket.on('close', () => {
          console.log(`  [Server] Connection ${connectionCount} closed`);
        });
        
        socket.on('data', (data) => {
          totalCommandBytes += data.length;
          tracker.addBytesReceived(data.length);
          tracker.addRoundTrip();
          
          const command = data.toString().trim();
          let response = '';
          
          if (command.startsWith('EHLO')) {
            response = '250-reuse.example.com\r\n250 OK\r\n';
          } else if (command.startsWith('MAIL FROM:')) {
            response = '250 OK\r\n';
          } else if (command.startsWith('RCPT TO:')) {
            response = '250 OK\r\n';
          } else if (command === 'DATA') {
            response = '354 Start mail input\r\n';
          } else if (command === '.') {
            response = '250 OK\r\n';
          } else if (command === 'RSET') {
            response = '250 OK\r\n';
          } else if (command === 'QUIT') {
            response = '221 Bye\r\n';
          }
          
          if (response) {
            socket.write(response);
            totalResponseBytes += response.length;
            tracker.addBytesSent(response.length);
          }
          
          if (command === 'QUIT') {
            socket.end();
          }
        });
      }
    });

    // Test individual connections vs reused connection
    const messageCount = 10;
    
    // Individual connections approach
    console.log(`  Testing ${messageCount} individual connections...`);
    const individualStart = Date.now();
    connectionCount = 0;
    totalCommandBytes = 0;
    totalResponseBytes = 0;
    
    for (let i = 0; i < messageCount; i++) {
      const client = createSmtpClient({
        host: testServer.hostname,
        port: testServer.port,
        secure: false
      });
      
      const email = new plugins.smartmail.Email({
        from: 'sender@example.com',
        to: [`individual${i + 1}@example.com`],
        subject: `Individual connection test ${i + 1}`,
        text: `Testing individual connections - message ${i + 1}`
      });
      
      await client.sendMail(email);
      
      if (client.close) {
        await client.close();
      }
    }
    
    const individualTime = Date.now() - individualStart;
    const individualStats = {
      connections: connectionCount,
      commandBytes: totalCommandBytes,
      responseBytes: totalResponseBytes,
      totalBytes: totalCommandBytes + totalResponseBytes,
      time: individualTime
    };
    
    console.log(`    Individual connections: ${individualStats.connections} connections, ${individualStats.totalBytes} bytes`);

    // Connection reuse approach
    console.log(`  Testing connection reuse...`);
    const reuseStart = Date.now();
    connectionCount = 0;
    totalCommandBytes = 0;
    totalResponseBytes = 0;
    
    const reuseClient = createSmtpClient({
      host: testServer.hostname,
      port: testServer.port,
      secure: false,
      pool: true,
      maxConnections: 1,
      maxMessages: messageCount
    });
    
    const reuseEmails = Array(messageCount).fill(null).map((_, i) => 
      new plugins.smartmail.Email({
        from: 'sender@example.com',
        to: [`reuse${i + 1}@example.com`],
        subject: `Connection reuse test ${i + 1}`,
        text: `Testing connection reuse - message ${i + 1}`
      })
    );
    
    for (const email of reuseEmails) {
      await reuseClient.sendMail(email);
    }
    
    await reuseClient.close();
    
    const reuseTime = Date.now() - reuseStart;
    const reuseStats = {
      connections: connectionCount,
      commandBytes: totalCommandBytes,
      responseBytes: totalResponseBytes,
      totalBytes: totalCommandBytes + totalResponseBytes,
      time: reuseTime
    };
    
    console.log(`    Connection reuse: ${reuseStats.connections} connections, ${reuseStats.totalBytes} bytes`);
    
    // Calculate efficiency
    const connectionEfficiency = individualStats.connections / reuseStats.connections;
    const byteEfficiency = individualStats.totalBytes / reuseStats.totalBytes;
    const timeEfficiency = individualTime / reuseTime;
    
    console.log(`    Connection efficiency: ${connectionEfficiency.toFixed(1)}x`);
    console.log(`    Byte efficiency: ${byteEfficiency.toFixed(1)}x`);
    console.log(`    Time efficiency: ${timeEfficiency.toFixed(1)}x`);

    // Connection reuse should be more efficient
    expect(reuseStats.connections).toBeLessThan(individualStats.connections);
    expect(reuseStats.totalBytes).toBeLessThan(individualStats.totalBytes);
    expect(connectionEfficiency).toBeGreaterThan(5); // At least 5x fewer connections

    await testServer.server.close();
  })();

  // Scenario 2: Command pipelining efficiency
  await (async () => {
    scenarioCount++;
    console.log(`\nScenario ${scenarioCount}: Testing command pipelining efficiency`);
    
    let totalCommands = 0;
    let pipelinedCommands = 0;
    let maxPipelineDepth = 0;
    
    const testServer = await createTestServer({
      onConnection: async (socket) => {
        console.log('  [Server] Client connected for pipelining test');
        socket.write('220 pipeline.example.com ESMTP\r\n');
        
        socket.on('data', (data) => {
          const commands = data.toString().split('\r\n').filter(cmd => cmd.length > 0);
          totalCommands += commands.length;
          
          if (commands.length > 1) {
            pipelinedCommands += commands.length;
            maxPipelineDepth = Math.max(maxPipelineDepth, commands.length);
            console.log(`  [Server] Received ${commands.length} pipelined commands`);
          }
          
          commands.forEach(command => {
            if (command.startsWith('EHLO')) {
              socket.write('250-pipeline.example.com\r\n250-PIPELINING\r\n250 OK\r\n');
            } else if (command.startsWith('MAIL FROM:')) {
              socket.write('250 OK\r\n');
            } else if (command.startsWith('RCPT TO:')) {
              socket.write('250 OK\r\n');
            } else if (command === 'DATA') {
              socket.write('354 Start mail input\r\n');
            } else if (command === '.') {
              socket.write('250 OK\r\n');
            } else if (command === 'QUIT') {
              socket.write('221 Bye\r\n');
              socket.end();
            }
          });
        });
      }
    });

    const pipelineClient = createSmtpClient({
      host: testServer.hostname,
      port: testServer.port,
      secure: false,
      pipelining: true
    });

    // Send emails with multiple recipients (triggers pipelining)
    const emails = [
      new plugins.smartmail.Email({
        from: 'sender@example.com',
        to: ['recipient1@example.com', 'recipient2@example.com', 'recipient3@example.com'],
        subject: 'Pipelining test 1',
        text: 'Testing command pipelining efficiency'
      }),
      new plugins.smartmail.Email({
        from: 'sender@example.com',
        to: ['recipient4@example.com', 'recipient5@example.com'],
        subject: 'Pipelining test 2',
        text: 'Testing command pipelining efficiency'
      })
    ];

    console.log('  Sending emails with pipelining support...');
    for (const email of emails) {
      await pipelineClient.sendMail(email);
    }

    console.log(`    Total commands sent: ${totalCommands}`);
    console.log(`    Pipelined commands: ${pipelinedCommands}`);
    console.log(`    Max pipeline depth: ${maxPipelineDepth}`);
    console.log(`    Pipelining efficiency: ${(pipelinedCommands / totalCommands * 100).toFixed(1)}%`);

    // Should use pipelining for efficiency
    expect(pipelinedCommands).toBeGreaterThan(0);
    expect(maxPipelineDepth).toBeGreaterThan(1);

    await testServer.server.close();
  })();

  // Scenario 3: Message size optimization
  await (async () => {
    scenarioCount++;
    console.log(`\nScenario ${scenarioCount}: Testing message size optimization`);
    
    let totalMessageBytes = 0;
    let messageCount = 0;
    
    const testServer = await createTestServer({
      onConnection: async (socket) => {
        console.log('  [Server] Client connected for size optimization test');
        socket.write('220 size.example.com ESMTP\r\n');
        
        let inData = false;
        let messageBytes = 0;
        
        socket.on('data', (data) => {
          if (inData) {
            messageBytes += data.length;
            if (data.toString().includes('\r\n.\r\n')) {
              inData = false;
              messageCount++;
              totalMessageBytes += messageBytes;
              console.log(`  [Server] Message ${messageCount}: ${messageBytes} bytes`);
              socket.write('250 OK\r\n');
              messageBytes = 0;
            }
            return;
          }
          
          const command = data.toString().trim();
          
          if (command.startsWith('EHLO')) {
            socket.write('250-size.example.com\r\n250-SIZE 52428800\r\n250 OK\r\n');
          } else if (command.startsWith('MAIL FROM:')) {
            socket.write('250 OK\r\n');
          } else if (command.startsWith('RCPT TO:')) {
            socket.write('250 OK\r\n');
          } else if (command === 'DATA') {
            socket.write('354 Start mail input\r\n');
            inData = true;
            messageBytes = 0;
          } else if (command === 'QUIT') {
            socket.write('221 Bye\r\n');
            socket.end();
          }
        });
      }
    });

    const sizeClient = createSmtpClient({
      host: testServer.hostname,
      port: testServer.port,
      secure: false
    });

    // Test different message sizes and encoding efficiency
    const sizeTests = [
      {
        name: 'Plain text',
        email: new plugins.smartmail.Email({
          from: 'sender@example.com',
          to: ['recipient@example.com'],
          subject: 'Plain text efficiency test',
          text: 'This is a plain text message for testing size efficiency.'
        })
      },
      {
        name: 'HTML message',
        email: new plugins.smartmail.Email({
          from: 'sender@example.com',
          to: ['recipient@example.com'],
          subject: 'HTML efficiency test',
          html: '<html><body><h1>HTML Message</h1><p>This is an HTML message.</p></body></html>'
        })
      },
      {
        name: 'Multipart message',
        email: new plugins.smartmail.Email({
          from: 'sender@example.com',
          to: ['recipient@example.com'],
          subject: 'Multipart efficiency test',
          text: 'Plain text version of the message.',
          html: '<p>HTML version of the message.</p>'
        })
      },
      {
        name: 'Message with small attachment',
        email: new plugins.smartmail.Email({
          from: 'sender@example.com',
          to: ['recipient@example.com'],
          subject: 'Attachment efficiency test',
          text: 'Message with attachment.',
          attachments: [{
            filename: 'test.txt',
            content: 'Small test attachment content for efficiency testing.'
          }]
        })
      }
    ];

    for (const test of sizeTests) {
      console.log(`  Testing ${test.name}...`);
      
      const beforeBytes = totalMessageBytes;
      const beforeCount = messageCount;
      
      await sizeClient.sendMail(test.email);
      
      const messageSize = totalMessageBytes - beforeBytes;
      const overhead = messageSize / (test.email.text?.length || test.email.html?.length || 100);
      
      console.log(`    ${test.name}: ${messageSize} bytes (overhead: ${overhead.toFixed(1)}x)`);
      
      // Message overhead should be reasonable
      expect(overhead).toBeLessThan(10); // Less than 10x overhead
    }

    const avgMessageSize = totalMessageBytes / messageCount;
    console.log(`  Average message size: ${avgMessageSize.toFixed(0)} bytes`);

    await testServer.server.close();
  })();

  // Scenario 4: Bandwidth utilization
  await (async () => {
    scenarioCount++;
    console.log(`\nScenario ${scenarioCount}: Testing bandwidth utilization`);
    
    let totalBytes = 0;
    let dataTransferTime = 0;
    
    const testServer = await createTestServer({
      onConnection: async (socket) => {
        socket.write('220 bandwidth.example.com ESMTP\r\n');
        
        let transferStart = 0;
        let inData = false;
        
        socket.on('data', (data) => {
          totalBytes += data.length;
          
          if (inData) {
            if (data.toString().includes('\r\n.\r\n')) {
              inData = false;
              dataTransferTime += Date.now() - transferStart;
              socket.write('250 OK\r\n');
            }
            return;
          }
          
          const command = data.toString().trim();
          
          if (command.startsWith('EHLO')) {
            socket.write('250-bandwidth.example.com\r\n250 OK\r\n');
          } else if (command.startsWith('MAIL FROM:')) {
            socket.write('250 OK\r\n');
          } else if (command.startsWith('RCPT TO:')) {
            socket.write('250 OK\r\n');
          } else if (command === 'DATA') {
            socket.write('354 Start mail input\r\n');
            inData = true;
            transferStart = Date.now();
          } else if (command === 'QUIT') {
            socket.write('221 Bye\r\n');
            socket.end();
          }
        });
      }
    });

    const bandwidthClient = createSmtpClient({
      host: testServer.hostname,
      port: testServer.port,
      secure: false
    });

    // Test bandwidth efficiency with varying message sizes
    const messageSizes = [1024, 10240, 102400]; // 1KB, 10KB, 100KB
    
    console.log('  Testing bandwidth utilization with different message sizes...');
    const bandwidthStart = Date.now();
    
    for (const size of messageSizes) {
      const content = 'x'.repeat(size);
      
      const email = new plugins.smartmail.Email({
        from: 'sender@example.com',
        to: ['recipient@example.com'],
        subject: `Bandwidth test ${size} bytes`,
        text: content
      });
      
      await bandwidthClient.sendMail(email);
    }
    
    const bandwidthElapsed = Date.now() - bandwidthStart;
    const throughput = (totalBytes / bandwidthElapsed) * 1000; // bytes per second
    const dataEfficiency = (messageSizes.reduce((a, b) => a + b, 0) / totalBytes) * 100;
    
    console.log(`    Total bytes transferred: ${totalBytes}`);
    console.log(`    Data transfer time: ${dataTransferTime}ms`);
    console.log(`    Overall throughput: ${(throughput / 1024).toFixed(1)} KB/s`);
    console.log(`    Data efficiency: ${dataEfficiency.toFixed(1)}% (payload vs total)`);

    // Bandwidth utilization should be efficient
    expect(throughput).toBeGreaterThan(1024); // At least 1KB/s
    expect(dataEfficiency).toBeGreaterThan(20); // At least 20% payload efficiency

    await testServer.server.close();
  })();

  // Scenario 5: Network round-trip optimization
  await (async () => {
    scenarioCount++;
    console.log(`\nScenario ${scenarioCount}: Testing network round-trip optimization`);
    
    let roundTrips = 0;
    let commandCount = 0;
    
    const testServer = await createTestServer({
      onConnection: async (socket) => {
        socket.write('220 roundtrip.example.com ESMTP\r\n');
        
        socket.on('data', (data) => {
          const commands = data.toString().split('\r\n').filter(cmd => cmd.length > 0);
          roundTrips++;
          commandCount += commands.length;
          
          console.log(`  [Server] Round-trip ${roundTrips}: ${commands.length} commands`);
          
          commands.forEach(command => {
            if (command.startsWith('EHLO')) {
              socket.write('250-roundtrip.example.com\r\n250-PIPELINING\r\n250 OK\r\n');
            } else if (command.startsWith('MAIL FROM:')) {
              socket.write('250 OK\r\n');
            } else if (command.startsWith('RCPT TO:')) {
              socket.write('250 OK\r\n');
            } else if (command === 'DATA') {
              socket.write('354 Start mail input\r\n');
            } else if (command === '.') {
              socket.write('250 OK\r\n');
            } else if (command === 'QUIT') {
              socket.write('221 Bye\r\n');
              socket.end();
            }
          });
        });
      }
    });

    const roundtripClient = createSmtpClient({
      host: testServer.hostname,
      port: testServer.port,
      secure: false,
      pipelining: true
    });

    // Send email with multiple recipients to test round-trip efficiency
    const email = new plugins.smartmail.Email({
      from: 'sender@example.com',
      to: ['rcpt1@example.com', 'rcpt2@example.com', 'rcpt3@example.com', 'rcpt4@example.com'],
      subject: 'Round-trip optimization test',
      text: 'Testing network round-trip optimization with multiple recipients'
    });

    console.log('  Sending email with multiple recipients...');
    await roundtripClient.sendMail(email);

    const commandsPerRoundTrip = commandCount / roundTrips;
    const efficiency = commandsPerRoundTrip;
    
    console.log(`    Total round-trips: ${roundTrips}`);
    console.log(`    Total commands: ${commandCount}`);
    console.log(`    Commands per round-trip: ${commandsPerRoundTrip.toFixed(1)}`);
    console.log(`    Round-trip efficiency: ${efficiency.toFixed(1)}`);

    // Should minimize round-trips through pipelining
    expect(roundTrips).toBeLessThan(commandCount); // Fewer round-trips than commands
    expect(commandsPerRoundTrip).toBeGreaterThan(1.5); // At least 1.5 commands per round-trip

    await testServer.server.close();
  })();

  // Scenario 6: Connection pooling network efficiency
  await (async () => {
    scenarioCount++;
    console.log(`\nScenario ${scenarioCount}: Testing connection pooling network efficiency`);
    
    let totalConnections = 0;
    let totalBytes = 0;
    let connectionSetupBytes = 0;
    
    const testServer = await createTestServer({
      onConnection: async (socket) => {
        totalConnections++;
        const greeting = '220 pool.example.com ESMTP\r\n';
        socket.write(greeting);
        connectionSetupBytes += greeting.length;
        
        console.log(`  [Server] Pool connection ${totalConnections} established`);
        
        socket.on('data', (data) => {
          totalBytes += data.length;
          const command = data.toString().trim();
          
          if (command.startsWith('EHLO')) {
            const response = '250-pool.example.com\r\n250 OK\r\n';
            socket.write(response);
            connectionSetupBytes += response.length;
            totalBytes += response.length;
          } else if (command.startsWith('MAIL FROM:')) {
            const response = '250 OK\r\n';
            socket.write(response);
            totalBytes += response.length;
          } else if (command.startsWith('RCPT TO:')) {
            const response = '250 OK\r\n';
            socket.write(response);
            totalBytes += response.length;
          } else if (command === 'DATA') {
            const response = '354 Start mail input\r\n';
            socket.write(response);
            totalBytes += response.length;
          } else if (command === '.') {
            const response = '250 OK\r\n';
            socket.write(response);
            totalBytes += response.length;
          } else if (command === 'QUIT') {
            const response = '221 Bye\r\n';
            socket.write(response);
            totalBytes += response.length;
            socket.end();
          }
        });
      }
    });

    const poolClient = createSmtpClient({
      host: testServer.hostname,
      port: testServer.port,
      secure: false,
      pool: true,
      maxConnections: 3,
      maxMessages: 100
    });

    // Send multiple emails through pool
    const emailCount = 15;
    const emails = Array(emailCount).fill(null).map((_, i) => 
      new plugins.smartmail.Email({
        from: 'sender@example.com',
        to: [`pooled${i + 1}@example.com`],
        subject: `Pool efficiency test ${i + 1}`,
        text: `Testing pooled connection network efficiency - message ${i + 1}`
      })
    );

    console.log(`  Sending ${emailCount} emails through connection pool...`);
    const poolStart = Date.now();
    
    await Promise.all(emails.map(email => poolClient.sendMail(email)));
    await poolClient.close();
    
    const poolTime = Date.now() - poolStart;
    const setupOverhead = (connectionSetupBytes / totalBytes) * 100;
    const messagesPerConnection = emailCount / totalConnections;
    const bytesPerMessage = totalBytes / emailCount;
    
    console.log(`    Emails sent: ${emailCount}`);
    console.log(`    Connections used: ${totalConnections}`);
    console.log(`    Messages per connection: ${messagesPerConnection.toFixed(1)}`);
    console.log(`    Total bytes: ${totalBytes}`);
    console.log(`    Setup overhead: ${setupOverhead.toFixed(1)}%`);
    console.log(`    Bytes per message: ${bytesPerMessage.toFixed(0)}`);
    console.log(`    Network efficiency: ${(emailCount / totalConnections).toFixed(1)} msg/conn`);

    // Connection pooling should be network efficient
    expect(totalConnections).toBeLessThan(emailCount); // Fewer connections than messages
    expect(messagesPerConnection).toBeGreaterThan(3); // At least 3 messages per connection
    expect(setupOverhead).toBeLessThan(20); // Less than 20% setup overhead

    await testServer.server.close();
  })();

  console.log(`\n${testId}: All ${scenarioCount} network efficiency scenarios tested ✓`);
});