/*
    * Licensed under the GPL License. You may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *   https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
    *
    * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
    * WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
    * PURPOSE.
   */
  package psiprobe.tools;
  
  import java.io.PrintStream;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  import java.util.Properties;
  
  import javax.activation.DataHandler;
  import javax.activation.DataSource;
  import javax.mail.Message;
  import javax.mail.MessagingException;
  import javax.mail.Part;
  import javax.mail.Session;
  import javax.mail.Transport;
  import javax.mail.internet.AddressException;
  import javax.mail.internet.InternetAddress;
  import javax.mail.internet.MimeBodyPart;
  import javax.mail.internet.MimeMessage;
  import javax.mail.internet.MimeMultipart;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.beans.factory.annotation.Value;
  
  /**
   * Facade for sending emails with the JavaMail API.
   */
  public class Mailer {
  
    /** The Constant PROPERTY_KEY_SMTP. */
    public static final String PROPERTY_KEY_SMTP = "mail.smtp.host";
  
    /** The Constant logger. */
    private static final Logger logger = LoggerFactory.getLogger(Mailer.class);
  
    /** The from. */
    private String from;
  
    /** The smtp. */
    private String smtp;
  
    /** The default to. */
    private String defaultTo;
  
    /** The subject prefix. */
    private String subjectPrefix;
  
    /**
     * Instantiates a new mailer.
     */
    public Mailer() {
      this(null);
    }
  
    /**
     * Instantiates a new mailer.
     *
     * @param from the from
     */
    public Mailer(String from) {
      this(from, null);
    }
  
    /**
     * Instantiates a new mailer.
     *
     * @param from the from
     * @param smtp the smtp
     */
    public Mailer(String from, String smtp) {
      this.smtp = smtp;
      this.from = from;
    }
  
    /**
     * Gets the from.
     *
     * @return the from
     */
    public String getFrom() {
      return from;
    }
  
    /**
     * Gets the smtp.
     *
     * @return the smtp
     */
   public String getSmtp() {
     if (smtp == null) {
       return System.getProperty(PROPERTY_KEY_SMTP);
     }
     return smtp;
   }
 
   /**
    * Sets the from.
    *
    * @param from the new from
    */
   public void setFrom(String from) {
     this.from = from;
   }
 
   /**
    * Sets the smtp.
    *
    * @param smtp the new smtp
    */
   public void setSmtp(String smtp) {
     this.smtp = smtp;
   }
 
   /**
    * Gets the default to.
    *
    * @return the default to
    */
   public String getDefaultTo() {
     return defaultTo;
   }
 
   /**
    * Sets the default to.
    *
    * @param defaultTo the new default to
    */
   @Value("${psiprobe.tools.mail.to}")
   public void setDefaultTo(String defaultTo) {
     this.defaultTo = defaultTo;
   }
 
   /**
    * Gets the subject prefix.
    *
    * @return the subject prefix
    */
   public String getSubjectPrefix() {
     return subjectPrefix;
   }
 
   /**
    * Sets the subject prefix.
    *
    * @param subjectPrefix the new subject prefix
    */
   @Value("${psiprobe.tools.mail.subjectPrefix}")
   public void setSubjectPrefix(String subjectPrefix) {
     this.subjectPrefix = subjectPrefix;
   }
 
   /**
    * Send.
    *
    * @param mailMessage the mail message
    *
    * @throws MessagingException the messaging exception
    */
   public void send(MailMessage mailMessage) throws MessagingException {
     Properties props = (Properties) System.getProperties().clone();
     if (smtp != null) {
       props.put(PROPERTY_KEY_SMTP, smtp);
     }
 
     try (PrintStream debugOut =
         LogOutputStream.createPrintStream(logger, LogOutputStream.LEVEL_DEBUG)) {
       Session session = Session.getDefaultInstance(props);
       session.setDebug(true);
       session.setDebugOut(debugOut);
 
       MimeMessage message = createMimeMessage(session, mailMessage);
       logger.debug("Sending message");
       Transport.send(message);
     }
   }
 
   /**
    * Creates the mime message.
    *
    * @param session the session
    * @param mailMessage the mail message
    *
    * @return the mime message
    *
    * @throws MessagingException the messaging exception
    */
   private MimeMessage createMimeMessage(Session session, MailMessage mailMessage)
       throws MessagingException {
 
     String subject = mailMessage.getSubject();
     if (subjectPrefix != null && !subjectPrefix.isEmpty()) {
       subject = subjectPrefix + " " + subject;
     }
 
     MimeMultipart content = new MimeMultipart("related");
 
     // Create attachments
     DataSource[] attachments = mailMessage.getAttachmentsArray();
     for (DataSource attachment : attachments) {
       MimeBodyPart attachmentPart = createAttachmentPart(attachment);
       content.addBodyPart(attachmentPart);
     }
 
     // Create message body
     MimeBodyPart bodyPart = createMessageBodyPart(mailMessage.getBody(), mailMessage.isBodyHtml());
     content.addBodyPart(bodyPart);
 
     MimeMessage message = new MimeMessage(session);
     if (from == null) {
       // Uses mail.from property
       message.setFrom();
     } else {
       message.setFrom(new InternetAddress(from));
     }
 
     InternetAddress[] to = createAddresses(mailMessage.getToArray());
     if (to.length == 0) {
       to = InternetAddress.parse(defaultTo);
     }
     message.setRecipients(Message.RecipientType.TO, to);
 
     InternetAddress[] cc = createAddresses(mailMessage.getCcArray());
     message.setRecipients(Message.RecipientType.CC, cc);
 
     InternetAddress[] bcc = createAddresses(mailMessage.getBccArray());
     message.setRecipients(Message.RecipientType.BCC, bcc);
 
     message.setSubject(subject);
     message.setContent(content);
     return message;
   }
 
   /**
    * Creates the addresses.
    *
    * @param addresses the addresses
    *
    * @return the Internet address[]
    *
    * @throws AddressException the address exception
    */
   private static InternetAddress[] createAddresses(String[] addresses) throws AddressException {
     List<InternetAddress> result = new ArrayList<>(addresses.length);
     for (String address : addresses) {
       InternetAddress[] parsedAddresses = InternetAddress.parse(address);
       result.addAll(Arrays.asList(parsedAddresses));
     }
     return result.toArray(new InternetAddress[result.size()]);
   }
 
   /**
    * Creates the attachment part.
    *
    * @param attachment the attachment
    *
    * @return the mime body part
    *
    * @throws MessagingException the messaging exception
    */
   private static MimeBodyPart createAttachmentPart(DataSource attachment)
       throws MessagingException {
 
     MimeBodyPart attachmentPart = new MimeBodyPart();
     attachmentPart.setDataHandler(new DataHandler(attachment));
     attachmentPart.setDisposition(Part.ATTACHMENT);
     attachmentPart.setFileName(attachment.getName());
     return attachmentPart;
   }
 
   /**
    * Creates the message body part.
    *
    * @param body the body
    * @param html the html
    *
    * @return the mime body part
    *
    * @throws MessagingException the messaging exception
    */
   private static MimeBodyPart createMessageBodyPart(String body, boolean html)
       throws MessagingException {
     MimeBodyPart bodyPart = new MimeBodyPart();
     bodyPart.setText(body);
     bodyPart.setHeader("content-type", html ? "text/html" : "text/plain");
     return bodyPart;
   }
 
 }