dcrouter/test/suite/smtpclient_rfc-compliance/test.crfc-04.response-codes.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('CRFC-04: should handle SMTP response codes correctly (RFC 5321)', async (tools) => {
  const testId = 'CRFC-04-response-codes';
  console.log(`\n${testId}: Testing SMTP response code compliance...`);

  let scenarioCount = 0;

  // Scenario 1: 2xx success response codes
  await (async () => {
    scenarioCount++;
    console.log(`\nScenario ${scenarioCount}: Testing 2xx success response codes`);
    
    const testServer = await createTestServer({
      onConnection: async (socket) => {
        console.log('  [Server] Client connected');
        socket.write('220 responses.example.com Service ready\r\n');
        
        socket.on('data', (data) => {
          const command = data.toString().trim();
          console.log(`  [Server] Received: ${command}`);
          
          if (command.startsWith('EHLO')) {
            // 250 - Requested mail action okay, completed
            socket.write('250-responses.example.com\r\n');
            socket.write('250-SIZE 10485760\r\n');
            socket.write('250 OK\r\n');
          } else if (command.startsWith('MAIL FROM:')) {
            // 250 - Requested mail action okay, completed
            socket.write('250 2.1.0 Sender OK\r\n');
          } else if (command.startsWith('RCPT TO:')) {
            // 250 - Requested mail action okay, completed
            socket.write('250 2.1.5 Recipient OK\r\n');
          } else if (command === 'DATA') {
            // 354 - Start mail input; end with <CRLF>.<CRLF>
            socket.write('354 Start mail input; end with <CRLF>.<CRLF>\r\n');
          } else if (command === '.') {
            // 250 - Requested mail action okay, completed
            socket.write('250 2.0.0 Message accepted for delivery\r\n');
          } else if (command === 'QUIT') {
            // 221 - Service closing transmission channel
            socket.write('221 2.0.0 Service closing transmission channel\r\n');
            socket.end();
          } else if (command === 'NOOP') {
            // 250 - Requested mail action okay, completed
            socket.write('250 2.0.0 OK\r\n');
          } else if (command === 'RSET') {
            // 250 - Requested mail action okay, completed
            socket.write('250 2.0.0 Reset OK\r\n');
          }
        });
      }
    });

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

    const email = new plugins.smartmail.Email({
      from: 'sender@example.com',
      to: ['recipient@example.com'],
      subject: '2xx response test',
      text: 'Testing 2xx success response codes'
    });

    const result = await smtpClient.sendMail(email);
    console.log('  All 2xx success codes handled correctly');
    expect(result).toBeDefined();
    expect(result.messageId).toBeDefined();

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

  // Scenario 2: 4xx temporary failure response codes
  await (async () => {
    scenarioCount++;
    console.log(`\nScenario ${scenarioCount}: Testing 4xx temporary failure response codes`);
    
    let attemptCount = 0;
    
    const testServer = await createTestServer({
      onConnection: async (socket) => {
        attemptCount++;
        console.log(`  [Server] Client connected (attempt ${attemptCount})`);
        socket.write('220 responses.example.com Service ready\r\n');
        
        socket.on('data', (data) => {
          const command = data.toString().trim();
          console.log(`  [Server] Received: ${command}`);
          
          if (command.startsWith('EHLO')) {
            socket.write('250-responses.example.com\r\n');
            socket.write('250 OK\r\n');
          } else if (command.startsWith('MAIL FROM:')) {
            if (attemptCount === 1) {
              // 451 - Requested action aborted: local error in processing
              socket.write('451 4.3.0 Temporary system failure, try again later\r\n');
            } else {
              socket.write('250 OK\r\n');
            }
          } else if (command.startsWith('RCPT TO:')) {
            const address = command.match(/<(.+)>/)?.[1] || '';
            
            if (address.includes('full')) {
              // 452 - Requested action not taken: insufficient system storage
              socket.write('452 4.2.2 Mailbox full, try again later\r\n');
            } else if (address.includes('busy')) {
              // 450 - Requested mail action not taken: mailbox unavailable
              socket.write('450 4.2.1 Mailbox busy, try again later\r\n');
            } else {
              socket.write('250 OK\r\n');
            }
          } else if (command === 'DATA') {
            socket.write('354 Start mail input\r\n');
          } else if (command === '.') {
            if (attemptCount === 1) {
              // 421 - Service not available, closing transmission channel
              socket.write('421 4.3.2 System shutting down, try again later\r\n');
              socket.end();
            } else {
              socket.write('250 OK\r\n');
            }
          } else if (command === 'QUIT') {
            socket.write('221 Bye\r\n');
            socket.end();
          }
        });
      }
    });

    // Test temporary failures with retry
    const smtpClient = createSmtpClient({
      host: testServer.hostname,
      port: testServer.port,
      secure: false
    });

    // First attempt with temporary failure
    const email = new plugins.smartmail.Email({
      from: 'sender@example.com',
      to: ['recipient@example.com'],
      subject: '4xx response test',
      text: 'Testing 4xx temporary failure codes'
    });

    try {
      await smtpClient.sendMail(email);
      console.log('  Unexpected: First attempt succeeded');
    } catch (error) {
      console.log('  Expected: Temporary failure on first attempt');
      expect(error.responseCode).toBeGreaterThanOrEqual(400);
      expect(error.responseCode).toBeLessThan(500);
    }

    // Second attempt should succeed
    const retryResult = await smtpClient.sendMail(email);
    console.log('  Retry after temporary failure succeeded');
    expect(retryResult).toBeDefined();

    // Test specific 4xx codes
    const tempFailureEmail = new plugins.smartmail.Email({
      from: 'sender@example.com',
      to: ['full@example.com', 'busy@example.com'],
      subject: 'Specific 4xx test',
      text: 'Testing specific temporary failure codes'
    });

    try {
      const result = await smtpClient.sendMail(tempFailureEmail);
      console.log(`  Partial delivery: ${result.rejected?.length || 0} rejected`);
      expect(result.rejected?.length).toBeGreaterThan(0);
    } catch (error) {
      console.log('  Multiple 4xx failures handled');
    }

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

  // Scenario 3: 5xx permanent failure response codes
  await (async () => {
    scenarioCount++;
    console.log(`\nScenario ${scenarioCount}: Testing 5xx permanent failure response codes`);
    
    const testServer = await createTestServer({
      onConnection: async (socket) => {
        console.log('  [Server] Client connected');
        socket.write('220 responses.example.com Service ready\r\n');
        
        socket.on('data', (data) => {
          const command = data.toString().trim();
          console.log(`  [Server] Received: ${command}`);
          
          if (command.startsWith('EHLO')) {
            socket.write('250-responses.example.com\r\n');
            socket.write('250 OK\r\n');
          } else if (command.startsWith('MAIL FROM:')) {
            const address = command.match(/<(.+)>/)?.[1] || '';
            
            if (address.includes('blocked')) {
              // 550 - Requested action not taken: mailbox unavailable
              socket.write('550 5.1.1 Sender blocked\r\n');
            } else if (address.includes('invalid')) {
              // 553 - Requested action not taken: mailbox name not allowed
              socket.write('553 5.1.8 Invalid sender address format\r\n');
            } else {
              socket.write('250 OK\r\n');
            }
          } else if (command.startsWith('RCPT TO:')) {
            const address = command.match(/<(.+)>/)?.[1] || '';
            
            if (address.includes('unknown')) {
              // 550 - Requested action not taken: mailbox unavailable
              socket.write('550 5.1.1 User unknown\r\n');
            } else if (address.includes('disabled')) {
              // 551 - User not local; please try <forward-path>
              socket.write('551 5.1.6 User account disabled\r\n');
            } else if (address.includes('relay')) {
              // 554 - Transaction failed
              socket.write('554 5.7.1 Relay access denied\r\n');
            } else {
              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();
          } else if (command.startsWith('INVALID')) {
            // 500 - Syntax error, command unrecognized
            socket.write('500 5.5.1 Command not recognized\r\n');
          } else if (command === 'MAIL') {
            // 501 - Syntax error in parameters or arguments
            socket.write('501 5.5.4 Syntax error in MAIL command\r\n');
          }
        });
      }
    });

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

    // Test various 5xx permanent failures
    const testCases = [
      { from: 'blocked@example.com', to: 'recipient@example.com', desc: 'blocked sender' },
      { from: 'sender@example.com', to: 'unknown@example.com', desc: 'unknown recipient' },
      { from: 'sender@example.com', to: 'disabled@example.com', desc: 'disabled user' },
      { from: 'sender@example.com', to: 'relay@external.com', desc: 'relay denied' }
    ];

    for (const testCase of testCases) {
      console.log(`  Testing ${testCase.desc}...`);
      
      const email = new plugins.smartmail.Email({
        from: testCase.from,
        to: [testCase.to],
        subject: `5xx test: ${testCase.desc}`,
        text: `Testing 5xx permanent failure: ${testCase.desc}`
      });

      try {
        await smtpClient.sendMail(email);
        console.log(`    Unexpected: ${testCase.desc} succeeded`);
      } catch (error) {
        console.log(`    Expected: ${testCase.desc} failed with 5xx`);
        expect(error.responseCode).toBeGreaterThanOrEqual(500);
        expect(error.responseCode).toBeLessThan(600);
      }
    }

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

  // Scenario 4: Multi-line response handling
  await (async () => {
    scenarioCount++;
    console.log(`\nScenario ${scenarioCount}: Testing multi-line response handling`);
    
    const testServer = await createTestServer({
      onConnection: async (socket) => {
        console.log('  [Server] Client connected');
        socket.write('220-responses.example.com ESMTP Service Ready\r\n');
        socket.write('220-This server supports multiple extensions\r\n');
        socket.write('220 Please proceed with EHLO\r\n');
        
        socket.on('data', (data) => {
          const command = data.toString().trim();
          console.log(`  [Server] Received: ${command}`);
          
          if (command.startsWith('EHLO')) {
            // Multi-line EHLO response
            socket.write('250-responses.example.com Hello client\r\n');
            socket.write('250-SIZE 10485760\r\n');
            socket.write('250-8BITMIME\r\n');
            socket.write('250-STARTTLS\r\n');
            socket.write('250-ENHANCEDSTATUSCODES\r\n');
            socket.write('250-PIPELINING\r\n');
            socket.write('250-DSN\r\n');
            socket.write('250 HELP\r\n');  // Last line ends with space
          } 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; end with <CRLF>.<CRLF>\r\n');
          } else if (command === '.') {
            // Multi-line success response
            socket.write('250-Message accepted for delivery\r\n');
            socket.write('250-Queue ID: ABC123\r\n');
            socket.write('250 Thank you\r\n');
          } else if (command === 'HELP') {
            // Multi-line help response
            socket.write('214-This server supports the following commands:\r\n');
            socket.write('214-EHLO HELO MAIL RCPT DATA\r\n');
            socket.write('214-RSET NOOP QUIT HELP\r\n');
            socket.write('214 For more info visit http://example.com/help\r\n');
          } else if (command === 'QUIT') {
            socket.write('221-Thank you for using our service\r\n');
            socket.write('221 Goodbye\r\n');
            socket.end();
          }
        });
      }
    });

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

    const email = new plugins.smartmail.Email({
      from: 'sender@example.com',
      to: ['recipient@example.com'],
      subject: 'Multi-line response test',
      text: 'Testing multi-line SMTP response handling'
    });

    const result = await smtpClient.sendMail(email);
    console.log('  Multi-line responses handled correctly');
    expect(result).toBeDefined();
    expect(result.response).toContain('Queue ID');

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

  // Scenario 5: Response code format validation
  await (async () => {
    scenarioCount++;
    console.log(`\nScenario ${scenarioCount}: Testing response code format validation`);
    
    const testServer = await createTestServer({
      onConnection: async (socket) => {
        console.log('  [Server] Client connected');
        socket.write('220 responses.example.com ESMTP\r\n');
        
        let commandCount = 0;
        
        socket.on('data', (data) => {
          commandCount++;
          const command = data.toString().trim();
          console.log(`  [Server] Received: ${command}`);
          
          if (command.startsWith('EHLO')) {
            socket.write('250-responses.example.com\r\n');
            socket.write('250 OK\r\n');
          } else if (command.startsWith('MAIL FROM:')) {
            // Test various response code formats
            if (commandCount === 2) {
              // Valid 3-digit code
              socket.write('250 OK\r\n');
            } else {
              socket.write('250 OK\r\n');
            }
          } else if (command.startsWith('RCPT TO:')) {
            const address = command.match(/<(.+)>/)?.[1] || '';
            
            if (address.includes('enhanced')) {
              // Enhanced status code format (RFC 3463)
              socket.write('250 2.1.5 Recipient OK\r\n');
            } else if (address.includes('detailed')) {
              // Detailed response with explanation
              socket.write('250 OK: Recipient accepted for delivery to local mailbox\r\n');
            } else {
              socket.write('250 OK\r\n');
            }
          } else if (command === 'DATA') {
            socket.write('354 Start mail input; end with <CRLF>.<CRLF>\r\n');
          } else if (command === '.') {
            // Response with timestamp
            const timestamp = new Date().toISOString();
            socket.write(`250 OK: Message accepted at ${timestamp}\r\n`);
          } else if (command === 'QUIT') {
            socket.write('221 Service closing transmission channel\r\n');
            socket.end();
          }
        });
      }
    });

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

    // Test with recipients that trigger different response formats
    const email = new plugins.smartmail.Email({
      from: 'sender@example.com',
      to: ['enhanced@example.com', 'detailed@example.com', 'normal@example.com'],
      subject: 'Response format test',
      text: 'Testing SMTP response code format compliance'
    });

    const result = await smtpClient.sendMail(email);
    console.log('  Various response code formats handled');
    expect(result).toBeDefined();
    expect(result.response).toContain('Message accepted');

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

  // Scenario 6: Error recovery and continuation
  await (async () => {
    scenarioCount++;
    console.log(`\nScenario ${scenarioCount}: Testing error recovery and continuation`);
    
    const testServer = await createTestServer({
      onConnection: async (socket) => {
        console.log('  [Server] Client connected');
        socket.write('220 responses.example.com ESMTP\r\n');
        
        let errorCount = 0;
        
        socket.on('data', (data) => {
          const command = data.toString().trim();
          console.log(`  [Server] Received: ${command}`);
          
          if (command.startsWith('EHLO')) {
            socket.write('250-responses.example.com\r\n');
            socket.write('250 OK\r\n');
          } else if (command.startsWith('MAIL FROM:')) {
            socket.write('250 OK\r\n');
          } else if (command.startsWith('RCPT TO:')) {
            const address = command.match(/<(.+)>/)?.[1] || '';
            
            if (address.includes('error1')) {
              errorCount++;
              socket.write('550 5.1.1 First error - user unknown\r\n');
            } else if (address.includes('error2')) {
              errorCount++;
              socket.write('551 5.1.6 Second error - user not local\r\n');
            } else {
              socket.write('250 OK\r\n');
            }
          } else if (command === 'DATA') {
            if (errorCount > 0) {
              console.log(`  [Server] ${errorCount} errors occurred, but continuing`);
            }
            socket.write('354 Start mail input\r\n');
          } else if (command === '.') {
            socket.write(`250 OK: Message accepted despite ${errorCount} recipient errors\r\n`);
          } else if (command === 'RSET') {
            console.log('  [Server] Transaction reset');
            errorCount = 0;
            socket.write('250 OK\r\n');
          } else if (command === 'QUIT') {
            socket.write('221 Bye\r\n');
            socket.end();
          } else {
            // Unknown command
            socket.write('500 5.5.1 Command not recognized\r\n');
          }
        });
      }
    });

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

    // Test with mix of valid and invalid recipients
    const email = new plugins.smartmail.Email({
      from: 'sender@example.com',
      to: ['error1@example.com', 'valid@example.com', 'error2@example.com', 'another-valid@example.com'],
      subject: 'Error recovery test',
      text: 'Testing error handling and recovery'
    });

    const result = await smtpClient.sendMail(email);
    console.log(`  Partial delivery: ${result.accepted?.length || 0} accepted, ${result.rejected?.length || 0} rejected`);
    expect(result).toBeDefined();
    expect(result.accepted?.length).toBeGreaterThan(0);
    expect(result.rejected?.length).toBeGreaterThan(0);

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

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