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    * 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   *
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   *   http://www.apache.org/licenses/LICENSE-2.0                 *
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   * 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.james.jms.builder;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Random;
  
  import javax.mail.MessagingException;
  import javax.mail.internet.ParseException;
  
  import org.apache.commons.io.IOUtils;
  import org.apache.james.api.jms.MailBuilder;
  import org.apache.james.core.MailImpl;
  import org.apache.james.mime4j.field.ParsedField;
  import org.apache.james.mime4j.field.AddressListField;
  import org.apache.james.mime4j.field.DefaultFieldParser;
  import org.apache.james.mime4j.field.MailboxListField;
  import org.apache.james.mime4j.field.address.Mailbox;
  import org.apache.james.mime4j.field.address.MailboxList;
  import org.apache.james.services.MailServer;
  import org.apache.mailet.Mail;
  import org.apache.mailet.MailAddress;
  
  /**
   * <p>Basic implementation that builds {@link Mail} 
   * from basic non-mime <code>ASCII</code> mail.
   * Naively uses the <code>to</code> header
   * to determine the recipent and <code>from</code>
   * to determine the sender.
   * </p><p>
   * <strong>Note</strong> this implementation is too
   * simple to cope well with wild emails. It may be useful
   * when dealing with generated ASCII emails.
   * </p>
   */
  public class SimpleMailBuilder implements MailBuilder {
      
      private static final String US_ASCII = "US-ASCII";
  
      private final IdGenerator generator;
      
      public SimpleMailBuilder() {
          this(new IdGenerator() {
              private final Random random = new Random();
              public String getId() {
                  return "SimpleMailBuilder#" + random.nextLong();
              }
          });
      }
      
      public SimpleMailBuilder(final IdGenerator generator) {
          this.generator = generator;
      }
      
      public Mail build(String text) throws MessagingException {
          final Collection recipients = new ArrayList();
          MailAddress sender = null;
          final int length = text.length();
          int position = 0;
          while (position < length) {
              position = text.indexOf('\n', position);
              if (position == -1) {
                  position = length;
              }
              final char nextChar = text.charAt(++position);
              
              switch (nextChar) {
                  case '\r':
                      // end of headers
                      position = length;
                      break;
                  case 'F':
                  case 'f':
                      // from header?
                      sender = parseFrom(text, sender, length, position);
                      break; 
                  case 'T':
                  case 't':
                      parseTo(text, recipients, length, position);
                   break; 
               default:
                   break;
           }
       }
       final String key = generator.getId();
       final InputStream input = toInputStream(text);
       final Mail result = new MailImpl(key, sender, recipients, input);
       return result;
   }
 
   private MailAddress parseFrom(final String text, final MailAddress defaultAddress, final int length, int position) throws ParseException {
       MailAddress result = defaultAddress;
       int eol = text.indexOf('\r', position);
       if (eol == -1) {
           eol = length;
       }
         int nameEnds = text.indexOf(':', position);
         if (nameEnds == -1) {
           nameEnds = length;
         }
       final String name = text.substring(position, nameEnds);
         final String body = text.substring(nameEnds+1, eol);
       final ParsedField parsedField = new DefaultFieldParser().parse(name, body, null);
       if ("from".equalsIgnoreCase(parsedField.getName())) {
           if (parsedField instanceof AddressListField) {
               final AddressListField field = (AddressListField) parsedField; 
               final MailboxList mailboxes = field.getAddressList().flatten();
               result = firstMailAddress(mailboxes);
           } else if (parsedField instanceof MailboxListField) {
               final MailboxListField field = (MailboxListField) parsedField;
               final MailboxList mailboxes = field.getMailboxList();
               result = firstMailAddress(mailboxes);
           }
       }
       return result;
   }
   
   private void parseTo(final String text, Collection addresses, final int length, int position) throws ParseException {
       int eol = text.indexOf('\r', position);
       if (eol == -1) {
           eol = length;
       }
         int nameEnds = text.indexOf(':', position);
         if (nameEnds == -1) {
           nameEnds = length;
         }
         final String name = text.substring(position, nameEnds);
         final String body = text.substring(nameEnds+1, eol);
         final ParsedField parsedField = new DefaultFieldParser().parse(name, body, null);
       if ("to".equalsIgnoreCase(parsedField.getName())) {
           if (parsedField instanceof AddressListField) {
               final AddressListField field = (AddressListField) parsedField; 
               final MailboxList mailboxes = field.getAddressList().flatten();
               addMailAddresses(addresses, mailboxes);
           } else if (parsedField instanceof MailboxListField) {
               final MailboxListField field = (MailboxListField) parsedField;
               final MailboxList mailboxes = field.getMailboxList();
               addMailAddresses(addresses, mailboxes);
           }
       }
   }
 
   private void addMailAddresses(Collection addresses, final MailboxList mailboxes) throws ParseException {
       int size = mailboxes.size();
       for (int i=0;i< size;i++) {
           final MailAddress address = toMailAddress(mailboxes.get(i));
           addresses.add(address);
       }
   }
 
   private MailAddress firstMailAddress(final MailboxList mailboxes) throws ParseException {
       MailAddress result = null;
       if (mailboxes.size() > 0) {
           final Mailbox first = mailboxes.get(0);
           result = toMailAddress(first);
       }
       return result;
   }
 
   private MailAddress toMailAddress(final Mailbox mailbox) throws ParseException {
       MailAddress result;
       final String domain = mailbox.getDomain();
       final String local = mailbox.getLocalPart();
       result = new MailAddress(local, domain);
       return result;
   }
 
   private InputStream toInputStream(String text) throws MessagingException {
       try {
           final InputStream result = IOUtils.toInputStream(text, US_ASCII);
           return result;
       } catch (IOException e) {
           throw new MessagingException("Conversion to ASCII stream failed.", e);
       }
   }
 
   
   
   public interface IdGenerator {
       
       /**
         * Generate a new identifier/name for a mail being processed by this server.
         *
         * @return the new identifier
         */
       String getId();
   }
   
   public final static class JamesIdGenerator implements IdGenerator {
       private final MailServer mailServer;
       
       public JamesIdGenerator(final MailServer mailServer) {
           super();
           this.mailServer = mailServer;
       }
 
       public String getId() {
           return mailServer.getId();
       }
 
       /**
         * Renders suitably for logging.
         * @return a <code>String</code> representation 
         * of this object.
         */
       public String toString()
       {
           final String TAB = " ";
           final String retValue = "JamesIdGenerator ( "
               + "mailServer = " + this.mailServer + TAB
               + " )";     
           return retValue;
       }
       
       
   }
 
   /**
     * Renders suitably for logging.
     * @return a <code>String</code> representation 
     * of this object.
     */
   public String toString()
   {
       final String TAB = " ";
       
       final String retValue = "SimpleMailBuilder ( "
           + "generator = " + this.generator + TAB
           + " )";
   
       return retValue;
   }
   
   
 }