/*
 * Copyright (C) 2005-2010 Alfresco Software Limited.
 *
 * This file is part of Alfresco
 *
 * Alfresco is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Alfresco is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with Alfresco. If not, see <http://www.gnu.org/licenses/>.
 */
package org.alfresco.repo.content.metadata;

import java.io.IOException;
import java.io.InputStream;
import java.io.Serializable;
import java.io.UnsupportedEncodingException;
import java.util.Arrays;
import java.util.Date;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import javax.mail.Header;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeUtility;
import javax.mail.internet.MimeMessage.RecipientType;

import org.alfresco.repo.content.MimetypeMap;
import org.alfresco.service.cmr.repository.ContentReader;
import org.alfresco.service.namespace.QName;

/**
 * Metadata extractor for RFC822 mime emails.
 * 
 * Default configuration:   (see RFC822MetadataExtractor.properties)
 * 
 * <pre>
 *   <b>messageFrom:</b>              --      imap:messageFrom, cm:originator
 *   <b>messageTo:</b>                --      imap:messageTo
 *   <b>messageCc:</b>                --      imap:messageCc
 *   <b>messageSubject:</b>           --      imap:messageSubject, cm:title, cm:description, cm:subjectline
 *   <b>messageSent:</b>              --      imap:dateSent, cm:sentdate
 *   <b>messageReceived:</b>          --      imap:dateReceived
 *   <b>All <code>{@link Header#getName() header names}:</b>
 *      <b>Thread-Index:</b>          --      imap:threadIndex
 *      <b>Message-ID:</b>            --      imap:messageId
 * </pre>
 * 
 * @author Derek Hulley
 * @since 3.2
 */
public class RFC822MetadataExtracter extends AbstractMappingMetadataExtracter
{

    protected static final String KEY_MESSAGE_FROM = "messageFrom";
    protected static final String KEY_MESSAGE_TO = "messageTo";
    protected static final String KEY_MESSAGE_CC = "messageCc";
    protected static final String KEY_MESSAGE_SUBJECT = "messageSubject";
    protected static final String KEY_MESSAGE_SENT = "messageSent";
    protected static final String KEY_MESSAGE_RECEIVED = "messageReceived";

    public static String[] SUPPORTED_MIMETYPES = new String[] { MimetypeMap.MIMETYPE_RFC822 };

    public RFC822MetadataExtracter()
    {
        super(new HashSet<String>(Arrays.asList(SUPPORTED_MIMETYPES)));
    }

    @Override
    protected Map<String, Serializable> extractRaw(ContentReader reader) throws Throwable
    {
        Map<String, Serializable> rawProperties = newRawMap();

        InputStream is = null;
        try
        {
            is = reader.getContentInputStream();
            MimeMessage mimeMessage = new MimeMessage(null, is);

            if (mimeMessage != null)
            {
                /**
                 * Extract RFC822 values that doesn't match to headers and need to be encoded.
                 * Or those special fields that require some code to extract data 
                 */
                putRawValue(KEY_MESSAGE_FROM, InternetAddress.toString(mimeMessage.getFrom()), rawProperties);
                putRawValue(KEY_MESSAGE_TO, InternetAddress.toString(mimeMessage.getRecipients(RecipientType.TO)), rawProperties);
                putRawValue(KEY_MESSAGE_CC, InternetAddress.toString(mimeMessage.getRecipients(RecipientType.CC)), rawProperties);
                putRawValue(KEY_MESSAGE_SENT, mimeMessage.getSentDate(), rawProperties); 
                
                /**
                 * Received field from RFC 822
                 * 
                 * "Received"    ":"        ; one per relay
                 *   ["from" domain]        ; sending host
                 *   ["by"   domain]        ; receiving host
                 *   ["via"  atom]          ; physical path
                 *  ("with" atom)           ; link/mail protocol
                 *   ["id"   msg-id]        ; receiver msg id
                 *   ["for"  addr-spec]     ; initial form
                 * ";"    date-time         ; time received
                 */
                Date rxDate = mimeMessage.getReceivedDate();
              
                if(rxDate != null)
                {
                    // The email implementation extracted the received date for us.
                    putRawValue(KEY_MESSAGE_RECEIVED, rxDate, rawProperties); 
                }
                else
                {
                    // the email implementation did not parse the received date for us.
                    String[] rx = mimeMessage.getHeader("received");
                    if(rx != null && rx.length > 0)
                    {
                        String lastReceived = rx[0];    
                        int x = lastReceived.indexOf(';');
                        if(x > 0)
                        {
                            String dateStr = lastReceived.substring(x + 1).trim();
                            putRawValue(KEY_MESSAGE_RECEIVED, dateStr, rawProperties); 
                        }
                    }
                }
                
                String[] subj = mimeMessage.getHeader("Subject");
                if (subj != null && subj.length > 0)
                {
                    String decodedSubject = subj[0];
                    try
                    {
                        decodedSubject = MimeUtility.decodeText(decodedSubject);
                    }
                    catch (UnsupportedEncodingException e)
                    {
                        logger.warn(e.toString());
                    }
                    putRawValue(KEY_MESSAGE_SUBJECT, decodedSubject, rawProperties);
                }
                
                /*
                 * Extract values from all header fields, including extension fields "X-"
                 */
                Set<String> keys = getMapping().keySet();
                Enumeration<Header> headers = mimeMessage.getAllHeaders();
                while (headers.hasMoreElements())
                {
                    Header header = (Header) headers.nextElement();
                    if (keys.contains(header.getName()))
                    {
                        header.getValue();
                        putRawValue(header.getName(), header.getValue(), rawProperties);
                    }
                }
                
            }
        }
        finally
        {
            if (is != null)
            {
                try
                {
                    is.close();
                }
                catch (IOException e)
                {
                }
            }
        }
        // Done
        return rawProperties;
    }
    
   /**
     * Back door for RM
     * @return
     */
    public final Map<String, Set<QName>> getCurrentMapping()
    {
         return super.getMapping();
    }
}