dcrouter/test/suite/smtpclient_error-handling/test.cerr-06.invalid-recipients.ts

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

let testServer: any;

tap.test('setup test SMTP server', async () => {
  testServer = await startTestSmtpServer();
  expect(testServer).toBeTruthy();
  expect(testServer.port).toBeGreaterThan(0);
});

tap.test('CERR-06: Invalid email address formats', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    validateEmails: true,
    debug: true
  });

  await smtpClient.connect();

  // Test various invalid email formats
  const invalidEmails = [
    { email: 'notanemail', error: 'Missing @ symbol' },
    { email: '@example.com', error: 'Missing local part' },
    { email: 'user@', error: 'Missing domain' },
    { email: 'user name@example.com', error: 'Space in local part' },
    { email: 'user@domain with spaces.com', error: 'Space in domain' },
    { email: 'user@@example.com', error: 'Double @ symbol' },
    { email: 'user@.com', error: 'Domain starts with dot' },
    { email: 'user@domain.', error: 'Domain ends with dot' },
    { email: 'user..name@example.com', error: 'Consecutive dots' },
    { email: '.user@example.com', error: 'Starts with dot' },
    { email: 'user.@example.com', error: 'Ends with dot' },
    { email: 'user@domain..com', error: 'Consecutive dots in domain' },
    { email: 'user<>@example.com', error: 'Invalid characters' },
    { email: 'user@domain>.com', error: 'Invalid domain characters' }
  ];

  console.log('Testing invalid email formats:');
  
  for (const test of invalidEmails) {
    console.log(`\nTesting: ${test.email} (${test.error})`);
    
    const email = new Email({
      from: 'sender@example.com',
      to: [test.email],
      subject: 'Invalid recipient test',
      text: 'Testing invalid email handling'
    });

    try {
      await smtpClient.sendMail(email);
      console.log('  Unexpected success - email was accepted');
    } catch (error) {
      console.log(`  Expected error: ${error.message}`);
      expect(error.message).toMatch(/invalid|syntax|format|address/i);
    }
  }

  await smtpClient.close();
});

tap.test('CERR-06: Non-existent recipients', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // Test non-existent recipients
  const nonExistentRecipients = [
    'doesnotexist@example.com',
    'nosuchuser@example.com',
    'randomuser12345@example.com',
    'deleted-account@example.com'
  ];

  for (const recipient of nonExistentRecipients) {
    console.log(`\nTesting non-existent recipient: ${recipient}`);
    
    const email = new Email({
      from: 'sender@example.com',
      to: [recipient],
      subject: 'Non-existent recipient test',
      text: 'Testing non-existent recipient handling'
    });

    // Monitor RCPT TO response
    let rcptResponse = '';
    const originalSendCommand = smtpClient.sendCommand.bind(smtpClient);
    
    smtpClient.sendCommand = async (command: string) => {
      const response = await originalSendCommand(command);
      if (command.startsWith('RCPT TO')) {
        rcptResponse = response;
      }
      return response;
    };

    try {
      await smtpClient.sendMail(email);
      console.log('  Email accepted (may bounce later)');
    } catch (error) {
      console.log(`  Rejected: ${error.message}`);
      
      // Common rejection codes
      const rejectionCodes = ['550', '551', '553', '554'];
      const hasRejectionCode = rejectionCodes.some(code => error.message.includes(code));
      
      if (hasRejectionCode) {
        console.log('  Recipient rejected by server');
      }
    }
  }

  await smtpClient.close();
});

tap.test('CERR-06: Mixed valid and invalid recipients', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    continueOnRecipientError: true, // Continue even if some recipients fail
    debug: true
  });

  await smtpClient.connect();

  const email = new Email({
    from: 'sender@example.com',
    to: [
      'valid1@example.com',
      'invalid@format',
      'valid2@example.com',
      'nonexistent@example.com',
      'valid3@example.com'
    ],
    subject: 'Mixed recipients test',
    text: 'Testing mixed valid/invalid recipients'
  });

  // Track recipient results
  const recipientResults: { [email: string]: { accepted: boolean; error?: string } } = {};
  
  smtpClient.on('recipient-result', (result) => {
    recipientResults[result.email] = {
      accepted: result.accepted,
      error: result.error
    };
  });

  console.log('\nSending to mixed valid/invalid recipients...');
  
  try {
    const result = await smtpClient.sendMail(email);
    
    console.log('\nResults:');
    console.log(`  Accepted: ${result.accepted?.length || 0}`);
    console.log(`  Rejected: ${result.rejected?.length || 0}`);
    
    if (result.accepted && result.accepted.length > 0) {
      console.log('\nAccepted recipients:');
      result.accepted.forEach(email => console.log(`  ✓ ${email}`));
    }
    
    if (result.rejected && result.rejected.length > 0) {
      console.log('\nRejected recipients:');
      result.rejected.forEach(rejection => {
        console.log(`  ✗ ${rejection.email}: ${rejection.reason}`);
      });
    }
  } catch (error) {
    console.log('Complete failure:', error.message);
  }

  await smtpClient.close();
});

tap.test('CERR-06: Recipient validation methods', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // Test VRFY command (if supported)
  console.log('\nTesting recipient validation methods:');
  
  // 1. VRFY command
  try {
    const vrfyResponse = await smtpClient.sendCommand('VRFY user@example.com');
    console.log('VRFY response:', vrfyResponse.trim());
    
    if (vrfyResponse.startsWith('252')) {
      console.log('  Server cannot verify but will accept');
    } else if (vrfyResponse.startsWith('250') || vrfyResponse.startsWith('251')) {
      console.log('  Address verified');
    } else if (vrfyResponse.startsWith('550')) {
      console.log('  Address not found');
    } else if (vrfyResponse.startsWith('502')) {
      console.log('  VRFY command not implemented');
    }
  } catch (error) {
    console.log('VRFY error:', error.message);
  }

  // 2. EXPN command (if supported)
  try {
    const expnResponse = await smtpClient.sendCommand('EXPN postmaster');
    console.log('\nEXPN response:', expnResponse.trim());
  } catch (error) {
    console.log('EXPN error:', error.message);
  }

  // 3. Null sender probe (common validation technique)
  console.log('\nTesting null sender probe:');
  
  const probeEmail = new Email({
    from: '', // Null sender
    to: ['test@example.com'],
    subject: 'Address verification probe',
    text: 'This is an address verification probe'
  });

  try {
    // Just test RCPT TO, don't actually send
    await smtpClient.sendCommand('MAIL FROM:<>');
    const rcptResponse = await smtpClient.sendCommand('RCPT TO:<test@example.com>');
    console.log('Null sender probe result:', rcptResponse.trim());
    await smtpClient.sendCommand('RSET');
  } catch (error) {
    console.log('Null sender probe failed:', error.message);
  }

  await smtpClient.close();
});

tap.test('CERR-06: International email addresses', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    supportInternational: true,
    debug: true
  });

  await smtpClient.connect();

  // Check for SMTPUTF8 support
  const ehloResponse = await smtpClient.sendCommand('EHLO testclient.example.com');
  const supportsSmtpUtf8 = ehloResponse.includes('SMTPUTF8');
  
  console.log(`\nSMTPUTF8 support: ${supportsSmtpUtf8}`);

  // Test international email addresses
  const internationalEmails = [
    'user@例え.jp',
    'користувач@приклад.укр',
    'usuario@ejemplo.españ',
    '用户@例子.中国',
    'user@tëst.com'
  ];

  for (const recipient of internationalEmails) {
    console.log(`\nTesting international address: ${recipient}`);
    
    const email = new Email({
      from: 'sender@example.com',
      to: [recipient],
      subject: 'International recipient test',
      text: 'Testing international email addresses'
    });

    try {
      await smtpClient.sendMail(email);
      console.log('  Accepted (SMTPUTF8 working)');
    } catch (error) {
      if (!supportsSmtpUtf8) {
        console.log('  Expected rejection - no SMTPUTF8 support');
      } else {
        console.log(`  Error: ${error.message}`);
      }
    }
  }

  await smtpClient.close();
});

tap.test('CERR-06: Recipient limits', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 10000,
    debug: true
  });

  await smtpClient.connect();

  // Test recipient limits
  const recipientCounts = [10, 50, 100, 200, 500, 1000];
  
  for (const count of recipientCounts) {
    console.log(`\nTesting ${count} recipients...`);
    
    // Generate recipients
    const recipients = Array.from({ length: count }, (_, i) => `user${i}@example.com`);
    
    const email = new Email({
      from: 'sender@example.com',
      to: recipients,
      subject: `Testing ${count} recipients`,
      text: 'Testing recipient limits'
    });

    const startTime = Date.now();
    let acceptedCount = 0;
    let rejectedCount = 0;

    // Monitor RCPT TO responses
    const originalSendCommand = smtpClient.sendCommand.bind(smtpClient);
    
    smtpClient.sendCommand = async (command: string) => {
      const response = await originalSendCommand(command);
      
      if (command.startsWith('RCPT TO')) {
        if (response.startsWith('250')) {
          acceptedCount++;
        } else if (response.match(/^[45]/)) {
          rejectedCount++;
          
          // Check for recipient limit errors
          if (response.match(/too many|limit|maximum/i)) {
            console.log(`  Recipient limit reached at ${acceptedCount} recipients`);
          }
        }
      }
      
      return response;
    };

    try {
      await smtpClient.sendMail(email);
      const elapsed = Date.now() - startTime;
      
      console.log(`  Success: ${acceptedCount} accepted, ${rejectedCount} rejected`);
      console.log(`  Time: ${elapsed}ms (${(elapsed/count).toFixed(2)}ms per recipient)`);
    } catch (error) {
      console.log(`  Error after ${acceptedCount} recipients: ${error.message}`);
      
      if (error.message.match(/too many|limit/i)) {
        console.log('  Server recipient limit exceeded');
        break; // Don't test higher counts
      }
    }

    // Reset for next test
    await smtpClient.sendCommand('RSET');
  }

  await smtpClient.close();
});

tap.test('CERR-06: Recipient error codes', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // Common recipient error codes and their meanings
  const errorCodes = [
    { code: '550 5.1.1', meaning: 'User unknown', permanent: true },
    { code: '551 5.1.6', meaning: 'User has moved', permanent: true },
    { code: '552 5.2.2', meaning: 'Mailbox full', permanent: true },
    { code: '553 5.1.3', meaning: 'Invalid address syntax', permanent: true },
    { code: '554 5.7.1', meaning: 'Relay access denied', permanent: true },
    { code: '450 4.1.1', meaning: 'Temporary user lookup failure', permanent: false },
    { code: '451 4.1.8', meaning: 'Sender address rejected', permanent: false },
    { code: '452 4.2.2', meaning: 'Mailbox full (temporary)', permanent: false }
  ];

  console.log('\nRecipient error code reference:');
  
  errorCodes.forEach(error => {
    console.log(`\n${error.code}: ${error.meaning}`);
    console.log(`  Type: ${error.permanent ? 'Permanent failure' : 'Temporary failure'}`);
    console.log(`  Action: ${error.permanent ? 'Bounce immediately' : 'Queue and retry'}`);
  });

  await smtpClient.close();
});

tap.test('CERR-06: Catch-all and wildcard handling', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // Test catch-all and wildcard addresses
  const wildcardTests = [
    '*@example.com',
    'catchall@*',
    '*@*.com',
    'user+*@example.com',
    'sales-*@example.com'
  ];

  console.log('\nTesting wildcard/catch-all addresses:');
  
  for (const recipient of wildcardTests) {
    console.log(`\nTesting: ${recipient}`);
    
    const email = new Email({
      from: 'sender@example.com',
      to: [recipient],
      subject: 'Wildcard test',
      text: 'Testing wildcard recipient'
    });

    try {
      await smtpClient.sendMail(email);
      console.log('  Accepted (server may expand wildcard)');
    } catch (error) {
      console.log(`  Rejected: ${error.message}`);
      
      // Wildcards typically rejected as invalid syntax
      expect(error.message).toMatch(/invalid|syntax|format/i);
    }
  }

  await smtpClient.close();
});

tap.test('CERR-06: Recipient validation timing', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    recipientValidationTimeout: 3000,
    debug: true
  });

  await smtpClient.connect();

  // Test validation timing for different scenarios
  const timingTests = [
    { email: 'quick@example.com', expectedTime: 'fast' },
    { email: 'slow.lookup@remote-domain.com', expectedTime: 'slow' },
    { email: 'timeout@unresponsive-server.com', expectedTime: 'timeout' }
  ];

  console.log('\nTesting recipient validation timing:');
  
  for (const test of timingTests) {
    console.log(`\nValidating: ${test.email}`);
    
    const startTime = Date.now();
    
    try {
      await smtpClient.sendCommand(`RCPT TO:<${test.email}>`);
      const elapsed = Date.now() - startTime;
      
      console.log(`  Response time: ${elapsed}ms`);
      console.log(`  Expected: ${test.expectedTime}`);
      
      if (test.expectedTime === 'timeout' && elapsed >= 3000) {
        console.log('  Validation timed out as expected');
      }
    } catch (error) {
      const elapsed = Date.now() - startTime;
      console.log(`  Error after ${elapsed}ms: ${error.message}`);
    }
    
    await smtpClient.sendCommand('RSET');
  }

  await smtpClient.close();
});

tap.test('cleanup test SMTP server', async () => {
  if (testServer) {
    await testServer.stop();
  }
});

export default tap.start();