dcrouter/test/suite/smtpclient_reliability/test.crel-07.resource-cleanup.ts

import { tap, expect } from '@git.zone/tstest/tapbundle';
import { createTestServer } from '../../helpers/server.loader.js';
import { createTestSmtpClient } from '../../helpers/smtp.client.js';
import { Email } from '../../../ts/mail/core/classes.email.js';

// Helper function to count active resources
const getResourceCounts = () => {
  const usage = process.memoryUsage();
  return {
    memory: Math.round(usage.heapUsed / 1024 / 1024 * 100) / 100, // MB
    handles: (process as any)._getActiveHandles ? (process as any)._getActiveHandles().length : 0,
    requests: (process as any)._getActiveRequests ? (process as any)._getActiveRequests().length : 0
  };
};

// Scenario 1: Basic Resource Cleanup
tap.test('CREL-07: Basic Resource Cleanup', async () => {
  console.log('\n🧹 Testing SMTP Client Resource Cleanup');
  console.log('=' .repeat(60));
  
  let connections = 0;
  let disconnections = 0;
  
  const testServer = await createTestServer({
    onConnection: (socket: any) => {
      connections++;
      console.log(`  [Server] Connection opened (total: ${connections})`);
      
      socket.on('close', () => {
        disconnections++;
        console.log(`  [Server] Connection closed (total closed: ${disconnections})`);
      });
    }
  });

  try {
    const initialResources = getResourceCounts();
    console.log(`  Initial resources: ${initialResources.memory}MB memory, ${initialResources.handles} handles`);

    console.log('  Creating SMTP clients and sending emails...');
    const clients = [];
    
    // Create multiple clients
    for (let i = 0; i < 3; i++) {
      const smtpClient = createTestSmtpClient({
        host: testServer.hostname,
        port: testServer.port
      });
      
      clients.push(smtpClient);

      // Send a test email
      const email = new Email({
        from: `sender${i}@cleanup.test`,
        to: [`recipient${i}@cleanup.test`],
        subject: `Cleanup Test ${i + 1}`,
        text: `Testing connection cleanup ${i + 1}`
      });

      try {
        await smtpClient.sendMail(email);
        console.log(`  ✓ Client ${i + 1} email sent`);
      } catch (error) {
        console.log(`  ✗ Client ${i + 1} failed: ${error.message}`);
      }
    }

    const afterSending = getResourceCounts();
    console.log(`  After sending: ${afterSending.memory}MB memory, ${afterSending.handles} handles`);

    console.log('  Closing all clients...');
    for (let i = 0; i < clients.length; i++) {
      console.log(`  Closing client ${i + 1}...`);
      clients[i].close();
      await new Promise(resolve => setTimeout(resolve, 100));
    }

    // Wait for cleanup to complete
    await new Promise(resolve => setTimeout(resolve, 500));

    const finalResources = getResourceCounts();
    console.log(`\n  Resource cleanup assessment:`);
    console.log(`  Initial: ${initialResources.memory}MB memory, ${initialResources.handles} handles`);
    console.log(`  Final: ${finalResources.memory}MB memory, ${finalResources.handles} handles`);
    console.log(`  Connections opened: ${connections}`);
    console.log(`  Connections closed: ${disconnections}`);
    console.log(`  Cleanup: ${disconnections >= connections - 1 ? 'Complete' : 'Incomplete'}`);

    expect(disconnections).toBeGreaterThanOrEqual(connections - 1);

  } finally {
    testServer.server.close();
  }
});

// Scenario 2: Multiple Close Safety
tap.test('CREL-07: Multiple Close Safety', async () => {
  console.log('\n🔁 Testing multiple close calls safety...');
  
  const testServer = await createTestServer({});

  try {
    const smtpClient = createTestSmtpClient({
      host: testServer.hostname,
      port: testServer.port
    });

    // Send a test email
    const email = new Email({
      from: 'sender@multiclose.test',
      to: ['recipient@multiclose.test'],
      subject: 'Multiple Close Test',
      text: 'Testing multiple close calls'
    });

    console.log('  Sending test email...');
    await smtpClient.sendMail(email);
    console.log('  ✓ Email sent successfully');

    console.log('  Attempting multiple close calls...');
    let closeErrors = 0;
    
    for (let i = 0; i < 5; i++) {
      try {
        smtpClient.close();
        console.log(`  ✓ Close call ${i + 1} completed`);
      } catch (error) {
        closeErrors++;
        console.log(`  ✗ Close call ${i + 1} error: ${error.message}`);
      }
    }

    console.log(`  Close errors: ${closeErrors}`);
    console.log(`  Safety: ${closeErrors === 0 ? 'Safe' : 'Issues detected'}`);

    expect(closeErrors).toEqual(0);

  } finally {
    testServer.server.close();
  }
});

// Scenario 3: Error Recovery and Cleanup
tap.test('CREL-07: Error Recovery and Cleanup', async () => {
  console.log('\n❌ Testing error recovery and cleanup...');
  
  let errorMode = false;
  let requestCount = 0;
  
  const testServer = await createTestServer({
    onConnection: (socket: any) => {
      requestCount++;
      if (errorMode && requestCount % 2 === 0) {
        console.log(`  [Server] Simulating connection error`);
        setTimeout(() => socket.destroy(), 50);
      }
    }
  });

  try {
    const smtpClient = createTestSmtpClient({
      host: testServer.hostname,
      port: testServer.port,
      connectionTimeout: 2000
    });

    console.log('  Phase 1: Normal operation...');
    const normalEmail = new Email({
      from: 'sender@test.com',
      to: ['recipient@test.com'],
      subject: 'Normal Test',
      text: 'Testing normal operation'
    });

    let normalResult = false;
    try {
      await smtpClient.sendMail(normalEmail);
      normalResult = true;
      console.log('  ✓ Normal operation successful');
    } catch (error) {
      console.log('  ✗ Normal operation failed');
    }

    console.log('  Phase 2: Error injection...');
    errorMode = true;
    
    let errorCount = 0;
    for (let i = 0; i < 3; i++) {
      try {
        const errorEmail = new Email({
          from: 'sender@error.test',
          to: ['recipient@error.test'],
          subject: `Error Test ${i + 1}`,
          text: 'Testing error handling'
        });
        await smtpClient.sendMail(errorEmail);
        console.log(`  ✓ Email ${i + 1} sent (recovered)`);
      } catch (error) {
        errorCount++;
        console.log(`  ✗ Email ${i + 1} failed as expected`);
      }
    }

    console.log('  Phase 3: Recovery...');
    errorMode = false;
    
    const recoveryEmail = new Email({
      from: 'sender@recovery.test',
      to: ['recipient@recovery.test'],
      subject: 'Recovery Test',
      text: 'Testing recovery'
    });

    let recovered = false;
    try {
      await smtpClient.sendMail(recoveryEmail);
      recovered = true;
      console.log('  ✓ Recovery successful');
    } catch (error) {
      console.log('  ✗ Recovery failed');
    }
    
    // Close and cleanup
    smtpClient.close();
    
    console.log(`\n  Error recovery assessment:`);
    console.log(`  Normal operation: ${normalResult ? 'Success' : 'Failed'}`);
    console.log(`  Errors encountered: ${errorCount}`);
    console.log(`  Recovery: ${recovered ? 'Successful' : 'Failed'}`);

    expect(normalResult).toEqual(true);
    expect(errorCount).toBeGreaterThan(0);

  } finally {
    testServer.server.close();
  }
});

// Scenario 4: Rapid Connect/Disconnect
tap.test('CREL-07: Rapid Connect/Disconnect Cycles', async () => {
  console.log('\n⚡ Testing rapid connect/disconnect cycles...');
  
  const testServer = await createTestServer({});

  try {
    console.log('  Performing rapid connect/disconnect cycles...');
    let successful = 0;
    let failed = 0;
    
    for (let cycle = 0; cycle < 5; cycle++) {
      const smtpClient = createTestSmtpClient({
        host: testServer.hostname,
        port: testServer.port,
        connectionTimeout: 1000
      });

      try {
        // Quick verify to establish connection
        await smtpClient.verify();
        successful++;
        console.log(`  ✓ Cycle ${cycle + 1}: Connected`);
      } catch (error) {
        failed++;
        console.log(`  ✗ Cycle ${cycle + 1}: Failed`);
      }

      // Immediately close
      smtpClient.close();
      
      // Brief pause between cycles
      await new Promise(resolve => setTimeout(resolve, 50));
    }

    console.log(`\n  Rapid cycle results:`);
    console.log(`  Successful connections: ${successful}`);
    console.log(`  Failed connections: ${failed}`);
    console.log(`  Success rate: ${(successful / (successful + failed) * 100).toFixed(1)}%`);

    expect(successful).toBeGreaterThan(0);

  } finally {
    testServer.server.close();
  }
});

tap.test('CREL-07: Test Summary', async () => {
  console.log('\n✅ CREL-07: Resource Cleanup Reliability Tests completed');
  console.log('🧹 All resource cleanup scenarios tested successfully');
});

tap.start();