/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements. See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache license, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License. You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the license for the specific language governing permissions and
   * limitations under the license.
   */
  
  package org.apache.logging.log4j.core.appender;
  
  import org.apache.logging.log4j.core.config.plugins.Plugin;
  import org.apache.logging.log4j.core.config.plugins.PluginAttr;
  import org.apache.logging.log4j.core.config.plugins.PluginElement;
  import org.apache.logging.log4j.core.config.plugins.PluginFactory;
  import org.apache.logging.log4j.core.filter.ThresholdFilter;
  import org.apache.logging.log4j.core.layout.HTMLLayout;
  import org.apache.logging.log4j.core.net.SMTPManager;
  import org.apache.logging.log4j.core.Filter;
  import org.apache.logging.log4j.core.Layout;
  import org.apache.logging.log4j.core.LogEvent;
  
  /**
   * Send an e-mail when a specific logging event occurs, typically on errors or
   * fatal errors.
   *
   * <p>
   * The number of logging events delivered in this e-mail depend on the value of
   * <b>BufferSize</b> option. The <code>SMTPAppender</code> keeps only the last
   * <code>BufferSize</code> logging events in its cyclic buffer. This keeps
   * memory requirements at a reasonable level while still delivering useful
   * application context.
   *
   * By default, an email message will formatted as HTML. This can be modified by
   * setting a layout for the appender.
   *
   * By default, an email message will be sent when an ERROR or higher severity
   * message is appended. This can be modified by setting a filter for the
   * appender.
   */
  @Plugin(name = "SMTP", type = "Core", elementType = "appender", printObject = true)
  public final class SMTPAppender extends AbstractAppender {
  
      private static final int DEFAULT_BUFFER_SIZE = 512;
  
      /** The SMTP Manager */
      protected final SMTPManager manager;
  
      private SMTPAppender(final String name, final Filter filter, final Layout<?> layout, final SMTPManager manager,
                           final boolean handleExceptions) {
          super(name, filter, layout, handleExceptions);
          this.manager = manager;
      }
  
      /**
       * Create a SMTPAppender.
       *
       * @param name
       *            The name of the Appender.
       * @param to
       *            The comma-separated list of recipient email addresses.
       * @param cc
       *            The comma-separated list of CC email addresses.
       * @param bcc
       *            The comma-separated list of BCC email addresses.
       * @param from
       *            The email address of the sender.
       * @param replyTo
       *            The comma-separated list of reply-to email addresses.
       * @param subject The subject of the email message.
       * @param smtpProtocol The SMTP transport protocol (such as "smtps", defaults to "smtp").
       * @param smtpHost
       *            The SMTP hostname to send to.
       * @param smtpPortNum
       *            The SMTP port to send to.
       * @param smtpUsername
       *            The username required to authenticate against the SMTP server.
       * @param smtpPassword
       *            The password required to authenticate against the SMTP server.
       * @param smtpDebug
       *            Enable mail session debuging on STDOUT.
       * @param bufferSizeNum
       *            How many log events should be buffered for inclusion in the
       *            message?
       * @param layout
       *            The layout to use (defaults to HTMLLayout).
       * @param filter
       *            The Filter or null (defaults to ThresholdFilter, level of
       *            ERROR).
       * @param suppressExceptions
       *            "true" if exceptions should be hidden from the application,
      *            "false" otherwise (defaults to "true").
      * @return The SMTPAppender.
      */
     @PluginFactory
     public static SMTPAppender createAppender(@PluginAttr("name") final String name,
                                               @PluginAttr("to") final String to,
                                               @PluginAttr("cc") final String cc,
                                               @PluginAttr("bcc") final String bcc,
                                               @PluginAttr("from") final String from,
                                               @PluginAttr("replyTo") final String replyTo,
                                               @PluginAttr("subject") final String subject,
                                               @PluginAttr("smtpProtocol") final String smtpProtocol,
                                               @PluginAttr("smtpHost") final String smtpHost,
                                               @PluginAttr("smtpPort") final String smtpPortNum,
                                               @PluginAttr("smtpUsername") final String smtpUsername,
                                               @PluginAttr("smtpPassword") final String smtpPassword,
                                               @PluginAttr("smtpDebug") final String smtpDebug,
                                               @PluginAttr("bufferSize") final String bufferSizeNum,
                                               @PluginElement("layout") Layout<?> layout,
                                               @PluginElement("filter") Filter filter,
                                               @PluginAttr("suppressExceptions") final String suppressExceptions) {
         if (name == null) {
             LOGGER.error("No name provided for SMTPAppender");
             return null;
         }
 
         final boolean isHandleExceptions = suppressExceptions == null ? true : Boolean.valueOf(suppressExceptions);
         final int smtpPort = smtpPortNum == null ? 0 : Integer.parseInt(smtpPortNum);
         final boolean isSmtpDebug = smtpDebug == null ? false : Boolean.valueOf(smtpDebug);
         final int bufferSize = bufferSizeNum == null ? DEFAULT_BUFFER_SIZE : Integer.valueOf(bufferSizeNum);
 
         if (layout == null) {
             layout = HTMLLayout.createLayout(null, null, null, null, null, null);
         }
         if (filter == null) {
             filter = ThresholdFilter.createFilter(null, null, null);
         }
 
         final SMTPManager manager = SMTPManager.getSMTPManager(to, cc, bcc, from, replyTo, subject, smtpProtocol,
             smtpHost, smtpPort, smtpUsername, smtpPassword, isSmtpDebug, filter.toString(),  bufferSize);
         if (manager == null) {
             return null;
         }
 
         return new SMTPAppender(name, filter, layout, manager, isHandleExceptions);
     }
 
     /**
      * Capture all events in CyclicBuffer.
      * @param event The Log event.
      * @return true if the event should be filtered.
      */
     @Override
     public boolean isFiltered(final LogEvent event) {
         final boolean filtered = super.isFiltered(event);
         if (filtered) {
             manager.add(event);
         }
         return filtered;
     }
 
     /**
      * Perform SMTPAppender specific appending actions, mainly adding the event
      * to a cyclic buffer and checking if the event triggers an e-mail to be
      * sent.
      * @param event The Log event.
      */
     public void append(final LogEvent event) {
         manager.sendEvents(getLayout(), event);
     }
 }