/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
    *
    * This program and the accompanying materials are dual-licensed under
    * either the terms of the Eclipse Public License v1.0 as published by
    * the Eclipse Foundation
    *
    *   or (per the licensee's choosing)
   *
   * under the terms of the GNU Lesser General Public License version 2.1
   * as published by the Free Software Foundation.
   */
  package ch.qos.logback.core.net;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Date;
  import java.util.List;
  import java.util.Properties;
  import java.util.concurrent.Future;
  
  import jakarta.mail.Message;
  import jakarta.mail.Multipart;
  import jakarta.mail.Session;
  import jakarta.mail.Transport;
  import jakarta.mail.internet.AddressException;
  import jakarta.mail.internet.InternetAddress;
  import jakarta.mail.internet.MimeBodyPart;
  import jakarta.mail.internet.MimeMessage;
  import jakarta.mail.internet.MimeMultipart;
  import javax.naming.Context;
  
  import ch.qos.logback.core.AppenderBase;
  import ch.qos.logback.core.CoreConstants;
  import ch.qos.logback.core.Layout;
  import ch.qos.logback.core.boolex.EvaluationException;
  import ch.qos.logback.core.boolex.EventEvaluator;
  import ch.qos.logback.core.helpers.CyclicBuffer;
  import ch.qos.logback.core.pattern.PatternLayoutBase;
  import ch.qos.logback.core.sift.DefaultDiscriminator;
  import ch.qos.logback.core.sift.Discriminator;
  import ch.qos.logback.core.spi.CyclicBufferTracker;
  import ch.qos.logback.core.util.ContentTypeUtil;
  import ch.qos.logback.core.util.JNDIUtil;
  import ch.qos.logback.core.util.OptionHelper;
  
  // Contributors:
  // Andrey Rybin charset encoding support http://jira.qos.ch/browse/LBCORE-69
  
  /**
   * An abstract class that provides support for sending events to an email
   * address.
   * <p>
   * See http://logback.qos.ch/manual/appenders.html#SMTPAppender for further
   * documentation.
   *
   * @author Ceki G&uuml;lc&uuml;
   * @author S&eacute;bastien Pennec
   */
  public abstract class SMTPAppenderBase<E> extends AppenderBase<E> {
  
      static InternetAddress[] EMPTY_IA_ARRAY = new InternetAddress[0];
      // ~ 14 days
      static final long MAX_DELAY_BETWEEN_STATUS_MESSAGES = 1228800 * CoreConstants.MILLIS_IN_ONE_SECOND;
  
      long lastTrackerStatusPrint = 0;
      long delayBetweenStatusMessages = 300 * CoreConstants.MILLIS_IN_ONE_SECOND;
  
      protected Layout<E> subjectLayout;
      protected Layout<E> layout;
  
      private List<PatternLayoutBase<E>> toPatternLayoutList = new ArrayList<PatternLayoutBase<E>>();
      private String from;
      private String subjectStr = null;
      private String smtpHost;
      private int smtpPort = 25;
      private boolean starttls = false;
      private boolean ssl = false;
      private boolean sessionViaJNDI = false;
      private String jndiLocation = CoreConstants.JNDI_COMP_PREFIX + "/mail/Session";
  
      String username;
      String password;
      String localhost;
  
      boolean asynchronousSending = true;
      protected Future<?> asynchronousSendingFuture = null;
      private String charsetEncoding = "UTF-8";
  
      protected Session session;
  
      protected EventEvaluator<E> eventEvaluator;
  
      protected Discriminator<E> discriminator = new DefaultDiscriminator<E>();
      protected CyclicBufferTracker<E> cbTracker;
  
      private int errorCount = 0;
  
     /**
      * return a layout for the subject string as appropriate for the module. If the
      * subjectStr parameter is null, then a default value for subjectStr should be
      * used.
      *
      * @param subjectStr
      * @return a layout as appropriate for the module
      */
     abstract protected Layout<E> makeSubjectLayout(String subjectStr);
 
     /**
      * Start the appender
      */
     public void start() {
 
         if (cbTracker == null) {
             cbTracker = new CyclicBufferTracker<E>();
         }
 
         if (sessionViaJNDI)
             session = lookupSessionInJNDI();
         else
             session = buildSessionFromProperties();
 
         if (session == null) {
             addError("Failed to obtain javax.mail.Session. Cannot start.");
             return;
         }
 
         subjectLayout = makeSubjectLayout(subjectStr);
 
         started = true;
     }
 
     private Session lookupSessionInJNDI() {
         addInfo("Looking up javax.mail.Session at JNDI location [" + jndiLocation + "]");
         try {
             Context initialContext = JNDIUtil.getInitialContext();
             Object obj = JNDIUtil.lookupObject(initialContext, jndiLocation);
             return (Session) obj;
         } catch (Exception e) {
             addError("Failed to obtain javax.mail.Session from JNDI location [" + jndiLocation + "]", e);
             return null;
         }
     }
 
     private Session buildSessionFromProperties() {
         Properties props = new Properties(OptionHelper.getSystemProperties());
         if (smtpHost != null) {
             props.put("mail.smtp.host", smtpHost);
         }
         props.put("mail.smtp.port", Integer.toString(smtpPort));
 
         if (localhost != null) {
             props.put("mail.smtp.localhost", localhost);
         }
 
         LoginAuthenticator loginAuthenticator = null;
 
         if (!OptionHelper.isNullOrEmptyOrAllSpaces(username)) {
             loginAuthenticator = new LoginAuthenticator(username, password);
             props.put("mail.smtp.auth", "true");
         }
 
         if (isSTARTTLS() && isSSL()) {
             addError("Both SSL and StartTLS cannot be enabled simultaneously");
         } else {
             if (isSTARTTLS()) {
                 // see also http://jira.qos.ch/browse/LOGBACK-193
                 props.put("mail.smtp.starttls.enable", "true");
                 props.put("mail.transport.protocol", "true");
             }
             if (isSSL()) {
                 props.put("mail.smtp.ssl.enable", "true");
             }
         }
 
         // props.put("mail.debug", "true");
 
         return Session.getInstance(props, loginAuthenticator);
     }
 
     /**
      * Perform SMTPAppender specific appending actions, delegating some of them to a
      * subclass and checking if the event triggers an e-mail to be sent.
      */
     protected void append(E eventObject) {
 
         if (!checkEntryConditions()) {
             return;
         }
 
         String key = discriminator.getDiscriminatingValue(eventObject);
         long now = System.currentTimeMillis();
         final CyclicBuffer<E> cb = cbTracker.getOrCreate(key, now);
         subAppend(cb, eventObject);
 
         try {
             if (eventEvaluator.evaluate(eventObject)) {
                 // clone the CyclicBuffer before sending out asynchronously
                 CyclicBuffer<E> cbClone = new CyclicBuffer<E>(cb);
                 // see http://jira.qos.ch/browse/LBCLASSIC-221
                 cb.clear();
 
                 if (asynchronousSending) {
                     // perform actual sending asynchronously
                     SenderRunnable senderRunnable = new SenderRunnable(cbClone, eventObject);
                     this.asynchronousSendingFuture = context.getExecutorService().submit(senderRunnable);
                 } else {
                     // synchronous sending
                     sendBuffer(cbClone, eventObject);
                 }
             }
         } catch (EvaluationException ex) {
             errorCount++;
             if (errorCount < CoreConstants.MAX_ERROR_COUNT) {
                 addError("SMTPAppender's EventEvaluator threw an Exception-", ex);
             }
         }
 
         // immediately remove the buffer if asked by the user
         if (eventMarksEndOfLife(eventObject)) {
             cbTracker.endOfLife(key);
         }
 
         cbTracker.removeStaleComponents(now);
 
         if (lastTrackerStatusPrint + delayBetweenStatusMessages < now) {
             addInfo("SMTPAppender [" + name + "] is tracking [" + cbTracker.getComponentCount() + "] buffers");
             lastTrackerStatusPrint = now;
             // quadruple 'delay' assuming less than max delay
             if (delayBetweenStatusMessages < MAX_DELAY_BETWEEN_STATUS_MESSAGES) {
                 delayBetweenStatusMessages *= 4;
             }
         }
     }
 
     abstract protected boolean eventMarksEndOfLife(E eventObject);
 
     abstract protected void subAppend(CyclicBuffer<E> cb, E eventObject);
 
     /**
      * This method determines if there is a sense in attempting to append.
      * <p>
      * It checks whether there is a set output target and also if there is a set
      * layout. If these checks fail, then the boolean value <code>false</code> is
      * returned.
      */
     public boolean checkEntryConditions() {
         if (!this.started) {
             addError("Attempting to append to a non-started appender: " + this.getName());
             return false;
         }
 
         if (this.eventEvaluator == null) {
             addError("No EventEvaluator is set for appender [" + name + "].");
             return false;
         }
 
         if (this.layout == null) {
             addError("No layout set for appender named [" + name
                     + "]. For more information, please visit http://logback.qos.ch/codes.html#smtp_no_layout");
             return false;
         }
         return true;
     }
 
     synchronized public void stop() {
         this.started = false;
     }
 
     InternetAddress getAddress(String addressStr) {
         try {
             return new InternetAddress(addressStr);
         } catch (AddressException e) {
             addError("Could not parse address [" + addressStr + "].", e);
             return null;
         }
     }
 
     private List<InternetAddress> parseAddress(E event) {
         int len = toPatternLayoutList.size();
 
         List<InternetAddress> iaList = new ArrayList<InternetAddress>();
 
         for (int i = 0; i < len; i++) {
             try {
                 PatternLayoutBase<E> emailPL = toPatternLayoutList.get(i);
                 String emailAdrr = emailPL.doLayout(event);
                 if (emailAdrr == null || emailAdrr.length() == 0) {
                     continue;
                 }
                 InternetAddress[] tmp = InternetAddress.parse(emailAdrr, true);
                 iaList.addAll(Arrays.asList(tmp));
             } catch (AddressException e) {
                 addError("Could not parse email address for [" + toPatternLayoutList.get(i) + "] for event [" + event
                         + "]", e);
                 return iaList;
             }
         }
 
         return iaList;
     }
 
     /**
      * Returns value of the <b>toList</b> option.
      */
     public List<PatternLayoutBase<E>> getToList() {
         return toPatternLayoutList;
     }
 
     /**
      * Allows to extend classes to update mime message (e.g.: Add headers)
      */
     protected void updateMimeMsg(MimeMessage mimeMsg, CyclicBuffer<E> cb, E lastEventObject) {
     }
 
     /**
      * Send the contents of the cyclic buffer as an e-mail message.
      */
     @SuppressWarnings("null")
     protected void sendBuffer(CyclicBuffer<E> cb, E lastEventObject) {
 
         // Note: this code already owns the monitor for this
         // appender. This frees us from needing to synchronize on 'cb'.
         try {
             MimeBodyPart part = new MimeBodyPart();
 
             StringBuffer sbuf = new StringBuffer();
 
             String header = layout.getFileHeader();
             if (header != null) {
                 sbuf.append(header);
             }
             String presentationHeader = layout.getPresentationHeader();
             if (presentationHeader != null) {
                 sbuf.append(presentationHeader);
             }
             fillBuffer(cb, sbuf);
             String presentationFooter = layout.getPresentationFooter();
             if (presentationFooter != null) {
                 sbuf.append(presentationFooter);
             }
             String footer = layout.getFileFooter();
             if (footer != null) {
                 sbuf.append(footer);
             }
 
             String subjectStr = "Undefined subject";
             if (subjectLayout != null) {
                 subjectStr = subjectLayout.doLayout(lastEventObject);
 
                 // The subject must not contain new-line characters, which cause
                 // an SMTP error (LOGBACK-865). Truncate the string at the first
                 // new-line character.
                 int newLinePos = (subjectStr != null) ? subjectStr.indexOf('\n') : -1;
                 if (newLinePos > -1) {
                     subjectStr = subjectStr.substring(0, newLinePos);
                 }
             }
 
             MimeMessage mimeMsg = new MimeMessage(session);
 
             if (from != null) {
                 mimeMsg.setFrom(getAddress(from));
             } else {
                 mimeMsg.setFrom();
             }
 
             mimeMsg.setSubject(subjectStr, charsetEncoding);
 
             List<InternetAddress> destinationAddresses = parseAddress(lastEventObject);
             if (destinationAddresses.isEmpty()) {
                 addInfo("Empty destination address. Aborting email transmission");
                 return;
             }
 
             InternetAddress[] toAddressArray = destinationAddresses.toArray(EMPTY_IA_ARRAY);
             mimeMsg.setRecipients(Message.RecipientType.TO, toAddressArray);
 
             String contentType = layout.getContentType();
 
             if (ContentTypeUtil.isTextual(contentType)) {
                 part.setText(sbuf.toString(), charsetEncoding, ContentTypeUtil.getSubType(contentType));
             } else {
                 part.setContent(sbuf.toString(), layout.getContentType());
             }
 
             Multipart mp = new MimeMultipart();
             mp.addBodyPart(part);
             mimeMsg.setContent(mp);
 
             // Added the feature to update mime message before sending the email
             updateMimeMsg(mimeMsg, cb, lastEventObject);
 
             mimeMsg.setSentDate(new Date());
             addInfo("About to send out SMTP message \"" + subjectStr + "\" to " + Arrays.toString(toAddressArray));
             Transport.send(mimeMsg);
         } catch (Exception e) {
             addError("Error occurred while sending e-mail notification.", e);
         }
     }
 
     abstract protected void fillBuffer(CyclicBuffer<E> cb, StringBuffer sbuf);
 
     /**
      * Returns value of the <b>From</b> option.
      */
     public String getFrom() {
         return from;
     }
 
     /**
      * Returns value of the <b>Subject</b> option.
      */
     public String getSubject() {
         return subjectStr;
     }
 
     /**
      * The <b>From</b> option takes a string value which should be an e-mail address
      * of the sender.
      */
     public void setFrom(String from) {
         this.from = from;
     }
 
     /**
      * The <b>Subject</b> option takes a string value which should be the subject
      * of the e-mail message.
      */
     public void setSubject(String subject) {
         this.subjectStr = subject;
     }
 
     /**
      * Alias for smtpHost
      *
      * @param smtpHost
      */
     public void setSMTPHost(String smtpHost) {
         setSmtpHost(smtpHost);
     }
 
     /**
      * The <b>smtpHost</b> option takes a string value which should be the host
      * name of the SMTP server that will send the e-mail message.
      */
     public void setSmtpHost(String smtpHost) {
         this.smtpHost = smtpHost;
     }
 
     /**
      * Alias for getSmtpHost().
      */
     public String getSMTPHost() {
         return getSmtpHost();
     }
 
     /**
      * Returns value of the <b>SMTPHost</b> option.
      */
     public String getSmtpHost() {
         return smtpHost;
     }
 
     /**
      * Alias for {@link #setSmtpPort}.
      *
      * @param port
      */
     public void setSMTPPort(int port) {
         setSmtpPort(port);
     }
 
     /**
      * The port where the SMTP server is running. Default value is 25.
      *
      * @param port
      */
     public void setSmtpPort(int port) {
         this.smtpPort = port;
     }
 
     /**
      * Alias for {@link #getSmtpPort}
      *
      * @return
      */
     public int getSMTPPort() {
         return getSmtpPort();
     }
 
     /**
      * See {@link #setSmtpPort}
      *
      * @return
      */
     public int getSmtpPort() {
         return smtpPort;
     }
 
     public String getLocalhost() {
         return localhost;
     }
 
     /**
      * Set the "mail.smtp.localhost" property to the value passed as parameter to
      * this method.
      * 
      * <p>
      * Useful in case the hostname for the client host is not fully qualified and as
      * a consequence the SMTP server rejects the clients HELO/EHLO command.
      * </p>
      *
      * @param localhost
      */
     public void setLocalhost(String localhost) {
         this.localhost = localhost;
     }
 
     public CyclicBufferTracker<E> getCyclicBufferTracker() {
         return cbTracker;
     }
 
     public void setCyclicBufferTracker(CyclicBufferTracker<E> cbTracker) {
         this.cbTracker = cbTracker;
     }
 
     public Discriminator<E> getDiscriminator() {
         return discriminator;
     }
 
     public void setDiscriminator(Discriminator<E> discriminator) {
         this.discriminator = discriminator;
     }
 
     public boolean isAsynchronousSending() {
         return asynchronousSending;
     }
 
     /**
      * By default, SMTAppender transmits emails asynchronously. For synchronous
      * email transmission set asynchronousSending to 'false'.
      *
      * @param asynchronousSending determines whether sending is done asynchronously
      *                            or not
      * @since 1.0.4
      */
     public void setAsynchronousSending(boolean asynchronousSending) {
         this.asynchronousSending = asynchronousSending;
     }
 
     public void addTo(String to) {
         if (to == null || to.length() == 0) {
             throw new IllegalArgumentException("Null or empty <to> property");
         }
         PatternLayoutBase<E> plb = makeNewToPatternLayout(to.trim());
         plb.setContext(context);
         plb.start();
         this.toPatternLayoutList.add(plb);
     }
 
     abstract protected PatternLayoutBase<E> makeNewToPatternLayout(String toPattern);
 
     public List<String> getToAsListOfString() {
         List<String> toList = new ArrayList<String>();
         for (PatternLayoutBase<E> plb : toPatternLayoutList) {
             toList.add(plb.getPattern());
         }
         return toList;
     }
 
     public boolean isSTARTTLS() {
         return starttls;
     }
 
     public void setSTARTTLS(boolean startTLS) {
         this.starttls = startTLS;
     }
 
     public boolean isSSL() {
         return ssl;
     }
 
     public void setSSL(boolean ssl) {
         this.ssl = ssl;
     }
 
     /**
      * The <b>EventEvaluator</b> option takes a string value representing the name
      * of the class implementing the {@link EventEvaluator} interface. A
      * corresponding object will be instantiated and assigned as the event evaluator
      * for the SMTPAppender.
      */
     public void setEvaluator(EventEvaluator<E> eventEvaluator) {
         this.eventEvaluator = eventEvaluator;
     }
 
     public String getUsername() {
         return username;
     }
 
     public void setUsername(String username) {
         this.username = username;
     }
 
     public String getPassword() {
         return password;
     }
 
     public void setPassword(String password) {
         this.password = password;
     }
 
     /**
      * @return the charset encoding value
      * @see #setCharsetEncoding(String)
      */
     public String getCharsetEncoding() {
         return charsetEncoding;
     }
 
     public String getJndiLocation() {
         return jndiLocation;
     }
 
     /**
      * Set the location where a {@link jakarta.mail.Session} resource is located in
      * JNDI. Default value is "java:comp/env/mail/Session".
      *
      * @param jndiLocation
      * @since 1.0.6
      */
     public void setJndiLocation(String jndiLocation) {
         this.jndiLocation = jndiLocation;
     }
 
     public boolean isSessionViaJNDI() {
         return sessionViaJNDI;
     }
 
     /**
      * If set to true, a {@link jakarta.mail.Session} resource will be retrieved from
      * JNDI. Default is false.
      *
      * @param sessionViaJNDI whether to obtain a javax.mail.Session by JNDI
      * @since 1.0.6
      */
     public void setSessionViaJNDI(boolean sessionViaJNDI) {
         this.sessionViaJNDI = sessionViaJNDI;
     }
 
     /**
      * Set the character set encoding of the outgoing email messages. The default
      * encoding is "UTF-8" which usually works well for most purposes.
      *
      * @param charsetEncoding
      */
     public void setCharsetEncoding(String charsetEncoding) {
         this.charsetEncoding = charsetEncoding;
     }
 
     public Layout<E> getLayout() {
         return layout;
     }
 
     public void setLayout(Layout<E> layout) {
         this.layout = layout;
     }
 
     class SenderRunnable implements Runnable {
 
         final CyclicBuffer<E> cyclicBuffer;
         final E e;
 
         SenderRunnable(CyclicBuffer<E> cyclicBuffer, E e) {
             this.cyclicBuffer = cyclicBuffer;
             this.e = e;
         }
 
         public void run() {
             sendBuffer(cyclicBuffer, e);
         }
     }
 }