dcrouter/test/suite/smtpclient_email-composition/test.cep-04.bcc-handling.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('CEP-04: Basic BCC handling', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // Create email with BCC recipients
  const email = new Email({
    from: 'sender@example.com',
    to: ['visible@example.com'],
    cc: ['copied@example.com'],
    bcc: ['hidden1@example.com', 'hidden2@example.com'],
    subject: 'Test BCC Handling',
    text: 'This message has BCC recipients'
  });

  // Send the email
  const result = await smtpClient.sendMail(email);
  expect(result).toBeTruthy();
  expect(result.accepted).toBeArray();
  
  // All recipients (including BCC) should be accepted
  const totalRecipients = [...email.to, ...email.cc, ...email.bcc];
  expect(result.accepted.length).toEqual(totalRecipients.length);
  
  console.log('BCC recipients processed:', email.bcc.length);
  console.log('Total recipients:', totalRecipients.length);

  await smtpClient.close();
});

tap.test('CEP-04: BCC header exclusion', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // Create email with BCC
  const email = new Email({
    from: 'sender@example.com',
    to: ['recipient@example.com'],
    bcc: ['secret@example.com'],
    subject: 'BCC Header Test',
    text: 'Testing BCC header exclusion'
  });

  // Monitor the actual SMTP commands
  let dataContent = '';
  const originalSendCommand = smtpClient.sendCommand.bind(smtpClient);
  let inDataPhase = false;

  smtpClient.sendCommand = async (command: string) => {
    if (command === 'DATA') {
      inDataPhase = true;
    } else if (inDataPhase && command === '.') {
      inDataPhase = false;
    } else if (inDataPhase) {
      dataContent += command + '\n';
    }
    return originalSendCommand(command);
  };

  await smtpClient.sendMail(email);

  // Verify BCC header is not in the message
  expect(dataContent.toLowerCase()).not.toInclude('bcc:');
  console.log('Verified: BCC header not included in message data');

  // Verify other headers are present
  expect(dataContent.toLowerCase()).toInclude('to:');
  expect(dataContent.toLowerCase()).toInclude('from:');
  expect(dataContent.toLowerCase()).toInclude('subject:');

  await smtpClient.close();
});

tap.test('CEP-04: Large BCC list handling', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 10000,
    debug: true
  });

  await smtpClient.connect();

  // Create email with many BCC recipients
  const bccCount = 50;
  const bccRecipients = Array.from({ length: bccCount }, 
    (_, i) => `bcc${i + 1}@example.com`
  );

  const email = new Email({
    from: 'sender@example.com',
    to: ['visible@example.com'],
    bcc: bccRecipients,
    subject: 'Large BCC List Test',
    text: `This message has ${bccCount} BCC recipients`
  });

  console.log(`Sending email with ${bccCount} BCC recipients...`);
  
  const startTime = Date.now();
  const result = await smtpClient.sendMail(email);
  const elapsed = Date.now() - startTime;

  expect(result).toBeTruthy();
  expect(result.accepted).toBeArray();
  
  // All BCC recipients should be processed
  expect(result.accepted).toIncludeAllMembers(bccRecipients);
  
  console.log(`Processed ${bccCount} BCC recipients in ${elapsed}ms`);
  console.log(`Average time per recipient: ${(elapsed / bccCount).toFixed(2)}ms`);

  await smtpClient.close();
});

tap.test('CEP-04: BCC-only email', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // Create email with only BCC recipients (no TO or CC)
  const email = new Email({
    from: 'sender@example.com',
    bcc: ['hidden1@example.com', 'hidden2@example.com', 'hidden3@example.com'],
    subject: 'BCC-Only Email',
    text: 'This email has only BCC recipients'
  });

  const result = await smtpClient.sendMail(email);
  expect(result).toBeTruthy();
  expect(result.accepted.length).toEqual(email.bcc.length);

  console.log('Successfully sent BCC-only email to', email.bcc.length, 'recipients');

  // Verify the email has appropriate headers
  let hasToHeader = false;
  const originalSendCommand = smtpClient.sendCommand.bind(smtpClient);
  
  smtpClient.sendCommand = async (command: string) => {
    if (command.toLowerCase().includes('to:')) {
      hasToHeader = true;
    }
    return originalSendCommand(command);
  };

  // Send another BCC-only email to check headers
  await smtpClient.sendMail(new Email({
    from: 'sender@example.com',
    bcc: ['test@example.com'],
    subject: 'Header Check',
    text: 'Checking headers'
  }));

  // Some implementations add "To: undisclosed-recipients:;" for BCC-only emails
  console.log('Email has TO header:', hasToHeader);

  await smtpClient.close();
});

tap.test('CEP-04: Mixed recipient types', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // Create email with all recipient types
  const email = new Email({
    from: 'sender@example.com',
    to: ['to1@example.com', 'to2@example.com'],
    cc: ['cc1@example.com', 'cc2@example.com', 'cc3@example.com'],
    bcc: ['bcc1@example.com', 'bcc2@example.com', 'bcc3@example.com', 'bcc4@example.com'],
    subject: 'Mixed Recipients Test',
    text: 'Testing all recipient types together'
  });

  // Track RCPT TO commands
  const rcptCommands: string[] = [];
  const originalSendCommand = smtpClient.sendCommand.bind(smtpClient);
  
  smtpClient.sendCommand = async (command: string) => {
    if (command.startsWith('RCPT TO:')) {
      rcptCommands.push(command);
    }
    return originalSendCommand(command);
  };

  const result = await smtpClient.sendMail(email);

  // Verify all recipients received RCPT TO
  const totalExpected = email.to.length + email.cc.length + email.bcc.length;
  expect(rcptCommands.length).toEqual(totalExpected);
  
  console.log('Recipient breakdown:');
  console.log(`  TO: ${email.to.length} recipients`);
  console.log(`  CC: ${email.cc.length} recipients`);
  console.log(`  BCC: ${email.bcc.length} recipients`);
  console.log(`  Total RCPT TO commands: ${rcptCommands.length}`);

  // Verify each recipient type
  for (const recipient of email.to) {
    expect(rcptCommands).toIncludeAnyMembers([`RCPT TO:<${recipient}>`]);
  }
  for (const recipient of email.cc) {
    expect(rcptCommands).toIncludeAnyMembers([`RCPT TO:<${recipient}>`]);
  }
  for (const recipient of email.bcc) {
    expect(rcptCommands).toIncludeAnyMembers([`RCPT TO:<${recipient}>`]);
  }

  await smtpClient.close();
});

tap.test('CEP-04: BCC with special characters', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // BCC addresses with special characters
  const specialBccAddresses = [
    'user+tag@example.com',
    'first.last@example.com',
    'user_name@example.com',
    '"quoted string"@example.com',
    'user@sub.domain.example.com'
  ];

  const email = new Email({
    from: 'sender@example.com',
    to: ['visible@example.com'],
    bcc: specialBccAddresses,
    subject: 'BCC Special Characters Test',
    text: 'Testing BCC with special character addresses'
  });

  const result = await smtpClient.sendMail(email);
  expect(result).toBeTruthy();
  
  console.log('BCC addresses with special characters processed:');
  specialBccAddresses.forEach((addr, i) => {
    const accepted = result.accepted.includes(addr);
    console.log(`  ${i + 1}. ${addr} - ${accepted ? 'Accepted' : 'Rejected'}`);
  });

  await smtpClient.close();
});

tap.test('CEP-04: BCC duplicate handling', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // Create email with duplicate addresses across recipient types
  const email = new Email({
    from: 'sender@example.com',
    to: ['shared@example.com', 'unique1@example.com'],
    cc: ['shared@example.com', 'unique2@example.com'],
    bcc: ['shared@example.com', 'unique3@example.com', 'unique3@example.com'], // Duplicate in BCC
    subject: 'Duplicate Recipients Test',
    text: 'Testing duplicate handling across recipient types'
  });

  // Track unique RCPT TO commands
  const rcptSet = new Set<string>();
  const originalSendCommand = smtpClient.sendCommand.bind(smtpClient);
  
  smtpClient.sendCommand = async (command: string) => {
    if (command.startsWith('RCPT TO:')) {
      rcptSet.add(command);
    }
    return originalSendCommand(command);
  };

  const result = await smtpClient.sendMail(email);

  console.log('Duplicate handling results:');
  console.log(`  Total addresses provided: ${email.to.length + email.cc.length + email.bcc.length}`);
  console.log(`  Unique RCPT TO commands: ${rcptSet.size}`);
  console.log(`  Duplicates detected: ${(email.to.length + email.cc.length + email.bcc.length) - rcptSet.size}`);

  // The client should handle duplicates appropriately
  expect(rcptSet.size).toBeLessThanOrEqual(email.to.length + email.cc.length + email.bcc.length);

  await smtpClient.close();
});

tap.test('CEP-04: BCC performance impact', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 10000,
    debug: false // Quiet for performance test
  });

  await smtpClient.connect();

  // Test performance with different BCC counts
  const bccCounts = [0, 10, 25, 50];
  const results: { count: number; time: number }[] = [];

  for (const count of bccCounts) {
    const bccRecipients = Array.from({ length: count }, 
      (_, i) => `bcc${i}@example.com`
    );

    const email = new Email({
      from: 'sender@example.com',
      to: ['recipient@example.com'],
      bcc: bccRecipients,
      subject: `Performance Test - ${count} BCCs`,
      text: 'Performance testing'
    });

    const startTime = Date.now();
    await smtpClient.sendMail(email);
    const elapsed = Date.now() - startTime;

    results.push({ count, time: elapsed });
  }

  console.log('\nBCC Performance Impact:');
  console.log('BCC Count | Time (ms) | Per-recipient (ms)');
  console.log('----------|-----------|-------------------');
  
  results.forEach(r => {
    const perRecipient = r.count > 0 ? (r.time / r.count).toFixed(2) : 'N/A';
    console.log(`${r.count.toString().padEnd(9)} | ${r.time.toString().padEnd(9)} | ${perRecipient}`);
  });

  // Performance should scale linearly with BCC count
  if (results.length >= 2) {
    const timeIncrease = results[results.length - 1].time - results[0].time;
    const countIncrease = results[results.length - 1].count - results[0].count;
    const msPerBcc = countIncrease > 0 ? timeIncrease / countIncrease : 0;
    
    console.log(`\nAverage time per BCC recipient: ${msPerBcc.toFixed(2)}ms`);
  }

  await smtpClient.close();
});

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

export default tap.start();