/*
    * 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.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.net.URI;
  import java.net.URISyntaxException;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Enumeration;
  import java.util.Iterator;
  import java.util.List;
  import javax.activation.DataHandler;
  import javax.activation.DataSource;
  import javax.mail.Address;
  import javax.mail.Header;
  import javax.mail.Message;
  import javax.mail.MessagingException;
  import javax.mail.Session;
  import javax.mail.Transport;
  import javax.mail.URLName;
  import javax.mail.internet.InternetAddress;
  
  import org.springframework.util.Assert;
  import org.springframework.util.ObjectUtils;
  import org.springframework.ws.WebServiceMessage;
  import org.springframework.ws.transport.AbstractReceiverConnection;
  import org.springframework.ws.transport.TransportConstants;
  import org.springframework.ws.transport.WebServiceConnection;
  import org.springframework.ws.transport.mail.support.MailTransportUtils;
  
  /**
   * Implementation of {@link WebServiceConnection} that is used for server-side Mail access. Exposes a {@link Message}
   * request and response message.
   *
   * @author Arjen Poutsma
   * @since 1.5.0
   */
  public class MailReceiverConnection extends AbstractReceiverConnection {
  
      private final Message requestMessage;
  
      private final Session session;
  
      private Message responseMessage;
  
      private ByteArrayOutputStream responseBuffer;
  
      private String responseContentType;
  
      private URLName transportUri;
  
      private InternetAddress from;
  
      /** Constructs a new Mail connection with the given parameters. */
      protected MailReceiverConnection(Message requestMessage, Session session) {
          Assert.notNull(requestMessage, "'requestMessage' must not be null");
          Assert.notNull(session, "'session' must not be null");
          this.requestMessage = requestMessage;
          this.session = session;
      }
  
      /** Returns the request message for this connection. */
      public Message getRequestMessage() {
          return requestMessage;
      }
  
      /** Returns the response message, if any, for this connection. */
      public Message getResponseMessage() {
          return responseMessage;
      }
  
      /*
       * Package-friendly setters
       */
      void setTransportUri(URLName transportUri) {
          this.transportUri = transportUri;
      }
  
      void setFrom(InternetAddress from) {
          this.from = from;
     }
 
     /*
      * URI
      */
 
     public URI getUri() throws URISyntaxException {
         try {
             Address[] recipients = requestMessage.getRecipients(Message.RecipientType.TO);
             if (!ObjectUtils.isEmpty(recipients) && recipients[0] instanceof InternetAddress) {
                 return MailTransportUtils.toUri((InternetAddress) recipients[0], requestMessage.getSubject());
             }
             else {
                 throw new URISyntaxException("", "Could not determine To header");
             }
         }
         catch (MessagingException ex) {
             throw new URISyntaxException("", ex.getMessage());
         }
     }
 /*
      * Errors
      */
 
     public String getErrorMessage() throws IOException {
         return null;
     }
 
     public boolean hasError() throws IOException {
         return false;
     }
 
     /*
     * Receiving
     */
 
     @Override
     protected Iterator<String> getRequestHeaderNames() throws IOException {
         try {
             List<String> headers = new ArrayList<String>();
             Enumeration<?> enumeration = requestMessage.getAllHeaders();
             while (enumeration.hasMoreElements()) {
                 Header header = (Header) enumeration.nextElement();
                 headers.add(header.getName());
             }
             return headers.iterator();
         }
         catch (MessagingException ex) {
             throw new IOException(ex.getMessage());
         }
     }
 
     @Override
     protected Iterator<String> getRequestHeaders(String name) throws IOException {
         try {
             String[] headers = requestMessage.getHeader(name);
             return Arrays.asList(headers).iterator();
         }
         catch (MessagingException ex) {
             throw new MailTransportException(ex);
         }
     }
 
     @Override
     protected InputStream getRequestInputStream() throws IOException {
         try {
             return requestMessage.getInputStream();
         }
         catch (MessagingException ex) {
             throw new MailTransportException(ex);
         }
     }
 
     @Override
     protected void addResponseHeader(String name, String value) throws IOException {
         try {
             responseMessage.addHeader(name, value);
             if (TransportConstants.HEADER_CONTENT_TYPE.equals(name)) {
                 responseContentType = value;
             }
         }
         catch (MessagingException ex) {
             throw new MailTransportException(ex);
         }
     }
 
     @Override
     protected OutputStream getResponseOutputStream() throws IOException {
         return responseBuffer;
     }
 
     /*
      * Sending
      */
 
     @Override
     protected void onSendBeforeWrite(WebServiceMessage message) throws IOException {
         try {
             responseMessage = requestMessage.reply(false);
             responseMessage.setFrom(from);
 
             responseBuffer = new ByteArrayOutputStream();
         }
         catch (MessagingException ex) {
             throw new MailTransportException(ex);
         }
     }
 
     @Override
     protected void onSendAfterWrite(WebServiceMessage message) throws IOException {
         Transport transport = null;
         try {
             responseMessage.setDataHandler(
                     new DataHandler(new ByteArrayDataSource(responseContentType, responseBuffer.toByteArray())));
             transport = session.getTransport(transportUri);
             transport.connect();
             responseMessage.saveChanges();
             transport.sendMessage(responseMessage, responseMessage.getAllRecipients());
         }
         catch (MessagingException ex) {
             throw new MailTransportException(ex);
         }
         finally {
             MailTransportUtils.closeService(transport);
         }
     }
 
     private class ByteArrayDataSource implements DataSource {
 
         private byte[] data;
 
         private String contentType;
 
         public ByteArrayDataSource(String contentType, byte[] data) {
             this.data = data;
             this.contentType = contentType;
         }
 
         public String getContentType() {
             return contentType;
         }
 
         public InputStream getInputStream() throws IOException {
             return new ByteArrayInputStream(data);
         }
 
         public String getName() {
             return "ByteArrayDataSource";
         }
 
         public OutputStream getOutputStream() throws IOException {
             throw new UnsupportedOperationException();
         }
     }
 }