analytics/src/main/java/cz/senslog/analyzer/broker/email/EmailServerConnection.java

package cz.senslog.analyzer.broker.email;

import jakarta.mail.*;
import jakarta.mail.internet.InternetAddress;
import jakarta.mail.internet.MimeBodyPart;
import jakarta.mail.internet.MimeMessage;
import jakarta.mail.internet.MimeMultipart;
import java.util.Map;
import java.util.Properties;

import static jakarta.mail.Message.RecipientType.TO;

public class EmailServerConnection {

    private final EmailServerConfig config;

    public EmailServerConnection(EmailServerConfig config) {
        this.config = config;
    }

    private Session openSession(EmailServerConfig config) {
        Properties props = new Properties();
        props.put("mail.smtp.host", config.getSmtpHost());
        props.put("mail.smtp.port", config.getSmtpPort());
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");

        Authenticator auth = new Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(config.getUsername(), config.getPassword());
            }
        };
        return Session.getInstance(props, auth);
    }

    public void send(String content, Map<String, String> subjectVariables, EmailMessageConfig messageConfig) throws MessagingException {
        Session session = openSession(config);
        Message message = new MimeMessage(session);
        message.setFrom(new InternetAddress(messageConfig.getSenderEmail()));
        String recipients = String.join(",",messageConfig.getRecipientEmails());
        message.setRecipients(TO, InternetAddress.parse(recipients));

        String subjectPattern = messageConfig.getSubject();
        for (Map.Entry<String, String> varEntry : subjectVariables.entrySet()) {
            if (subjectPattern.contains(varEntry.getKey())) {
                subjectPattern = subjectPattern.replace(varEntry.getKey(), varEntry.getValue());
            }
        }
        message.setSubject(subjectPattern);

        MimeBodyPart mimeBodyPart = new MimeBodyPart();
        mimeBodyPart.setContent(content, "text/html;charset=UTF-8");

        Multipart multipart = new MimeMultipart();
        multipart.addBodyPart(mimeBodyPart);
        message.setContent(multipart);

        Transport.send(message);
    }
}