platformservice/ts/mta/mta.classes.emailsendjob.ts

import * as plugins from './plugins.js';
import * as paths from './paths.js';
import { Email } from './mta.classes.email.js';
import { EmailSignJob } from './mta.classes.emailsignjob.js';
import type { MTA } from './mta.classes.mta.js';

export class EmailSendJob {
  mtaRef: MTA;
  private email: Email;
  private socket: plugins.net.Socket | plugins.tls.TLSSocket = null;
  private mxRecord: string = null;

  constructor(mtaRef: MTA, emailArg: Email) {
    this.email = emailArg;
    this.mtaRef = mtaRef;
  }

  async send(): Promise<void> {
    const domain = this.email.to.split('@')[1];
    const addresses = await this.resolveMx(domain);
    addresses.sort((a, b) => a.priority - b.priority);
    this.mxRecord = addresses[0].exchange;

    console.log(`Using ${this.mxRecord} as mail server for domain ${domain}`);

    this.socket = plugins.net.connect(25, this.mxRecord);
    await this.processInitialResponse();
    await this.sendCommand(`EHLO ${this.email.from.split('@')[1]}\r\n`, '250');
    try {
      await this.sendCommand('STARTTLS\r\n', '220');
      this.socket = plugins.tls.connect({ socket: this.socket, rejectUnauthorized: false });
      await this.processTLSUpgrade(this.email.from.split('@')[1]);
    } catch (error) {
      console.log('Error sending STARTTLS command:', error);
      console.log('Continuing with unencrypted connection...');
    }

    await this.sendMessage();
  }

  private resolveMx(domain: string): Promise<plugins.dns.MxRecord[]> {
    return new Promise((resolve, reject) => {
      plugins.dns.resolveMx(domain, (err, addresses) => {
        if (err) {
          console.error('Error resolving MX:', err);
          reject(err);
        } else {
          resolve(addresses);
        }
      });
    });
  }

  private processInitialResponse(): Promise<void> {
    return new Promise((resolve, reject) => {
      this.socket.once('data', (data) => {
        const response = data.toString();
        if (!response.startsWith('220')) {
          console.error('Unexpected initial server response:', response);
          reject(new Error(`Unexpected initial server response: ${response}`));
        } else {
          console.log('Received initial server response:', response);
          console.log('Connected to server, sending EHLO...');
          resolve();
        }
      });
    });
  }

  private processTLSUpgrade(domain: string): Promise<void> {
    return new Promise((resolve, reject) => {
      this.socket.once('secureConnect', async () => {
        console.log('TLS started successfully');
        try {
          await this.sendCommand(`EHLO ${domain}\r\n`, '250');
          resolve();
        } catch (err) {
          console.error('Error sending EHLO after TLS upgrade:', err);
          reject(err);
        }
      });
    });
  }

  private sendCommand(command: string, expectedResponseCode?: string): Promise<void> {
    return new Promise((resolve, reject) => {
      this.socket.write(command, (error) => {
        if (error) {
          reject(error);
          return;
        }

        if (!expectedResponseCode) {
          resolve();
          return;
        }

        this.socket.once('data', (data) => {
          const response = data.toString();
          if (response.startsWith('221')) {
            this.socket.destroy();
            resolve();
          }
          if (!response.startsWith(expectedResponseCode)) {
            reject(new Error(`Unexpected server response: ${response}`));
          } else {
            resolve();
          }
        });
      });
    });
  }

  private async sendMessage(): Promise<void> {
    console.log('Preparing email message...');
    const messageId = `<${plugins.uuid.v4()}@${this.email.from.split('@')[1]}>`;
  
    // Create a boundary for the email parts
    const boundary = '----=_NextPart_' + plugins.uuid.v4();
  
    const headers = {
      From: this.email.from,
      To: this.email.to,
      Subject: this.email.subject,
      'Content-Type': `multipart/mixed; boundary="${boundary}"`,
    };
  
    // Construct the body of the message
    let body = `--${boundary}\r\nContent-Type: text/html; charset=utf-8\r\n\r\n${this.email.text}\r\n`;
  
    // Then, the attachments
    for (let attachment of this.email.attachments) {
      body += `--${boundary}\r\nContent-Type: ${attachment.contentType}; name="${attachment.filename}"\r\n`;
      body += 'Content-Transfer-Encoding: base64\r\n';
      body += `Content-Disposition: attachment; filename="${attachment.filename}"\r\n\r\n`;
      body += attachment.content.toString('base64') + '\r\n';
    }
  
    // End of email
    body += `--${boundary}--\r\n`;
  
    // Create an instance of DKIMSigner
    const dkimSigner = new EmailSignJob(this.mtaRef, {
      domain: this.email.getFromDomain(), // Replace with your domain
      selector: `mta`, // Replace with your DKIM selector
      headers: headers,
      body: body,
    });
  
    // Construct the message with DKIM-Signature header
    let message = `Message-ID: ${messageId}\r\nFrom: ${this.email.from}\r\nTo: ${this.email.to}\r\nSubject: ${this.email.subject}\r\nContent-Type: multipart/mixed; boundary="${boundary}"\r\n\r\n`;
    message += body;
  
    let signatureHeader = await dkimSigner.getSignatureHeader(message);
    message = `${signatureHeader}${message}`;
  
    plugins.smartfile.fs.ensureDirSync(paths.sentEmailsDir);
    plugins.smartfile.memory.toFsSync(message, plugins.path.join(paths.sentEmailsDir, `${Date.now()}.eml`));
  
  
    // Adding necessary commands before sending the actual email message
    await this.sendCommand(`MAIL FROM:<${this.email.from}>\r\n`, '250');
    await this.sendCommand(`RCPT TO:<${this.email.to}>\r\n`, '250');
    await this.sendCommand(`DATA\r\n`, '354');
    
    // Now send the message content
    await this.sendCommand(message);
    await this.sendCommand('\r\n.\r\n', '250');
  
    await this.sendCommand('QUIT\r\n', '221');
    console.log('Email message sent successfully!');
  }
}