/*
    * Copyright 2005-2010 the original author or authors.
    *
    * Licensed 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.springframework.ws.transport.mail;
  
  import java.util.Properties;
  import javax.mail.Folder;
  import javax.mail.FolderClosedException;
  import javax.mail.Message;
  import javax.mail.MessagingException;
  import javax.mail.Session;
  import javax.mail.Store;
  import javax.mail.URLName;
  import javax.mail.internet.AddressException;
  import javax.mail.internet.InternetAddress;
  
  import org.springframework.scheduling.SchedulingAwareRunnable;
  import org.springframework.util.Assert;
  import org.springframework.ws.WebServiceMessageFactory;
  import org.springframework.ws.transport.WebServiceMessageReceiver;
  import org.springframework.ws.transport.mail.monitor.MonitoringStrategy;
  import org.springframework.ws.transport.mail.monitor.PollingMonitoringStrategy;
  import org.springframework.ws.transport.mail.monitor.Pop3PollingMonitoringStrategy;
  import org.springframework.ws.transport.mail.support.MailTransportUtils;
  import org.springframework.ws.transport.support.AbstractAsyncStandaloneMessageReceiver;
  
  /**
   * Server-side component for receiving email messages using JavaMail.  Requires a {@link #setTransportUri(String)
   * transport} URI, {@link #setStoreUri(String) store} URI, and {@link #setMonitoringStrategy(MonitoringStrategy)
   * monitoringStrategy} to be set, in addition to the {@link #setMessageFactory(WebServiceMessageFactory) messageFactory}
   * and {@link #setMessageReceiver(WebServiceMessageReceiver) messageReceiver} required by the base class.
   * <p/>
   * The {@link MonitoringStrategy} is used to detect new incoming email request. If the <code>monitoringStrategy</code>
   * is not explicitly set, this receiver will use the {@link Pop3PollingMonitoringStrategy} for POP3 servers, and the
   * {@link PollingMonitoringStrategy} for IMAP servers.
   *
   * @author Arjen Poutsma
   * @since 1.5.0
   */
  public class MailMessageReceiver extends AbstractAsyncStandaloneMessageReceiver {
  
      private Session session = Session.getInstance(new Properties(), null);
  
      private URLName storeUri;
  
      private URLName transportUri;
  
      private Folder folder;
  
      private Store store;
  
      private InternetAddress from;
  
      private MonitoringStrategy monitoringStrategy;
  
      /** Sets the from address to use when sending response messages. */
      public void setFrom(String from) throws AddressException {
          this.from = new InternetAddress(from);
      }
  
      /**
       * Set JavaMail properties for the {@link Session}.
       * <p/>
       * A new {@link Session} will be created with those properties. Use either this method or {@link #setSession}, but
       * not both.
       * <p/>
       * Non-default properties in this instance will override given JavaMail properties.
       */
      public void setJavaMailProperties(Properties javaMailProperties) {
          session = Session.getInstance(javaMailProperties, null);
      }
  
      /**
       * Set the JavaMail <code>Session</code>, possibly pulled from JNDI.
       * <p/>
       * Default is a new <code>Session</code> without defaults, that is completely configured via this instance's
       * properties.
       * <p/>
       * If using a pre-configured <code>Session</code>, non-default properties in this instance will override the
       * settings in the <code>Session</code>.
       *
       * @see #setJavaMailProperties
       */
      public void setSession(Session session) {
          Assert.notNull(session, "Session must not be null");
          this.session = session;
     }
 
     /**
      * Sets the JavaMail Store URI to be used for retrieving request messages. Typically takes the form of
      * <code>[imap|pop3]://user:password@host:port/INBOX</code>. Setting this property is required.
      * <p/>
      * For example, <code>imap://john:[email protected]/INBOX</code>
      *
      * @see Session#getStore(URLName)
      */
     public void setStoreUri(String storeUri) {
         this.storeUri = new URLName(storeUri);
     }
 
     /**
      * Sets the JavaMail Transport URI to be used for sending response messages. Typically takes the form of
      * <code>smtp://user:password@host:port</code>. Setting this property is required.
      * <p/>
      * For example, <code>smtp://john:[email protected]</code>
      *
      * @see Session#getTransport(URLName)
      */
     public void setTransportUri(String transportUri) {
         this.transportUri = new URLName(transportUri);
     }
 
     /**
      * Sets the monitoring strategy to use for retrieving new requests. Default is the {@link
      * PollingMonitoringStrategy}.
      */
     public void setMonitoringStrategy(MonitoringStrategy monitoringStrategy) {
         this.monitoringStrategy = monitoringStrategy;
     }
 
     @Override
     public void afterPropertiesSet() throws Exception {
         Assert.notNull(storeUri, "Property 'storeUri' is required");
         Assert.notNull(transportUri, "Property 'transportUri' is required");
         if (monitoringStrategy == null) {
             String protocol = storeUri.getProtocol();
             if ("pop3".equals(protocol)) {
                 monitoringStrategy = new Pop3PollingMonitoringStrategy();
             }
             else if ("imap".equals(protocol)) {
                 monitoringStrategy = new PollingMonitoringStrategy();
             }
             else {
                 throw new IllegalArgumentException("Cannot determine monitoring strategy for \"" + protocol + "\". " +
                         "Set the 'monitoringStrategy' explicitly.");
             }
         }
         super.afterPropertiesSet();
     }
 
     @Override
     protected void onActivate() throws MessagingException {
         openSession();
         openFolder();
     }
 
     @Override
     protected void onStart() {
         if (logger.isInfoEnabled()) {
             logger.info("Starting mail receiver [" + MailTransportUtils.toPasswordProtectedString(storeUri) + "]");
         }
         execute(new MonitoringRunnable());
     }
 
     @Override
     protected void onStop() {
         if (logger.isInfoEnabled()) {
             logger.info("Stopping mail receiver [" + MailTransportUtils.toPasswordProtectedString(storeUri) + "]");
         }
         closeFolder();
     }
 
     @Override
     protected void onShutdown() {
         if (logger.isInfoEnabled()) {
             logger.info("Shutting down mail receiver [" + MailTransportUtils.toPasswordProtectedString(storeUri) + "]");
         }
         closeFolder();
         closeSession();
     }
 
     private void openSession() throws MessagingException {
         store = session.getStore(storeUri);
         if (logger.isDebugEnabled()) {
             logger.debug("Connecting to store [" + MailTransportUtils.toPasswordProtectedString(storeUri) + "]");
         }
         store.connect();
     }
 
     private void openFolder() throws MessagingException {
         if (folder != null && folder.isOpen()) {
             return;
         }
         folder = store.getFolder(storeUri);
         if (folder == null || !folder.exists()) {
             throw new IllegalStateException("No default folder to receive from");
         }
         if (logger.isDebugEnabled()) {
             logger.debug("Opening folder [" + MailTransportUtils.toPasswordProtectedString(storeUri) + "]");
         }
         folder.open(monitoringStrategy.getFolderOpenMode());
     }
 
     private void closeFolder() {
         MailTransportUtils.closeFolder(folder, true);
     }
 
     private void closeSession() {
         MailTransportUtils.closeService(store);
     }
 
     private class MonitoringRunnable implements SchedulingAwareRunnable {
 
         public void run() {
             try {
                 openFolder();
                 while (isRunning()) {
                     try {
                         Message[] messages = monitoringStrategy.monitor(folder);
                         for (Message message : messages) {
                             MessageHandler handler = new MessageHandler(message);
                             execute(handler);
                         }
                     }
                     catch (FolderClosedException ex) {
                         logger.debug("Folder closed, reopening");
                         if (isRunning()) {
                             openFolder();
                         }
                     }
                     catch (MessagingException ex) {
                         logger.warn(ex);
                     }
                 }
             }
             catch (InterruptedException ex) {
                 // Restore the interrupted status
                 Thread.currentThread().interrupt();
             }
             catch (MessagingException ex) {
                 logger.error(ex);
             }
         }
 
         public boolean isLongLived() {
             return true;
         }
     }
 
     private class MessageHandler implements SchedulingAwareRunnable {
 
         private final Message message;
 
         public MessageHandler(Message message) {
             this.message = message;
         }
 
         public void run() {
             MailReceiverConnection connection = new MailReceiverConnection(message, session);
             connection.setTransportUri(transportUri);
             connection.setFrom(from);
             try {
                 handleConnection(connection);
             }
             catch (Exception ex) {
                 logger.error("Could not handle incoming mail connection", ex);
             }
         }
 
         public boolean isLongLived() {
             return false;
         }
     }
 
 }