/*

 *   SONEWS News Server

 *   see AUTHORS for the list of contributors

 *

 *   This program is free software: you can redistribute it and/or modify

 *   it under the terms of the GNU General Public License as published by

 *   the Free Software Foundation, either version 3 of the License, or

 *   (at your option) any later version.

 *

 *   This program 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 General Public License for more details.

 *

 *   You should have received a copy of the GNU General Public License

 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */

package org.sonews.storage;

import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.IOException;

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

import java.util.UUID;

import java.util.ArrayList;

import java.util.Enumeration;

import java.util.List;

import javax.mail.Header;

import javax.mail.Message;

import javax.mail.MessagingException;

import javax.mail.internet.InternetHeaders;

import org.sonews.config.Config;

/**

 * Represents a newsgroup article.

 * @author Christian Lins

 * @author Denis Schwerdel

 * @since n3tpd/0.1

 */

public class Article extends ArticleHead

{

  /**

   * Loads the Article identified by the given ID from the JDBCDatabase.

   * @param messageID

   * @return null if Article is not found or if an error occurred.

   */

  public static Article getByMessageID(final String messageID)

  {

    try

    {

      return StorageManager.current().getArticle(messageID);

    }

    catch(StorageBackendException ex)

    {

      ex.printStackTrace();

      return null;

    }

  }

  private byte[] body       = new byte[0];

  /**

   * Default constructor.

   */

  public Article()

  {

  }

  /**

   * Creates a new Article object using the date from the given

   * raw data.

   */

  public Article(String headers, byte[] body)

  {

    try

    {

      this.body  = body;

      // Parse the header

      this.headers = new InternetHeaders(

        new ByteArrayInputStream(headers.getBytes()));

      this.headerSrc = headers;

    }

    catch(MessagingException ex)

    {

      ex.printStackTrace();

    }

  }

  /**

   * Creates an Article instance using the data from the javax.mail.Message

   * object. This constructor is called by the Mailinglist gateway.

   * @see javax.mail.Message

   * @param msg

   * @throws IOException

   * @throws MessagingException

   */

  public Article(final Message msg)

    throws IOException, MessagingException

  {

    this.headers = new InternetHeaders();

    for(Enumeration e = msg.getAllHeaders() ; e.hasMoreElements();) 

    {

      final Header header = (Header)e.nextElement();

      this.headers.addHeader(header.getName(), header.getValue());

    }

	// Reads the raw byte body using Message.writeTo(OutputStream out)

	this.body = readContent(msg);

    // Validate headers

    validateHeaders();

  }

  /**

   * Reads from the given Message into a byte array.

   * @param in

   * @return

   * @throws IOException

   */

  private byte[] readContent(Message in)

    throws IOException, MessagingException

  {

    ByteArrayOutputStream out = new ByteArrayOutputStream();

    in.writeTo(out);

    return out.toByteArray();

  }

  /**

   * Removes the header identified by the given key.

   * @param headerKey

   */

  public void removeHeader(final String headerKey)

  {

    this.headers.removeHeader(headerKey);

    this.headerSrc = null;

  }

  /**

   * Generates a message id for this article and sets it into

   * the header object. You have to update the JDBCDatabase manually to make this

   * change persistent.

   * Note: a Message-ID should never be changed and only generated once.

   */

  private String generateMessageID()

  {

    String randomString;

    MessageDigest md5;

    try

    {

      md5 = MessageDigest.getInstance("MD5");

      md5.reset();

      md5.update(getBody());

      md5.update(getHeader(Headers.SUBJECT)[0].getBytes());

      md5.update(getHeader(Headers.FROM)[0].getBytes());

      byte[] result = md5.digest();

      StringBuffer hexString = new StringBuffer();

      for (int i = 0; i < result.length; i++)

      {

        hexString.append(Integer.toHexString(0xFF & result[i]));

      }

      randomString = hexString.toString();

    }

    catch (NoSuchAlgorithmException e)

    {

      e.printStackTrace();

      randomString = UUID.randomUUID().toString();

    }

    String msgID = "<" + randomString + "@"

        + Config.inst().get(Config.HOSTNAME, "localhost") + ">";

    this.headers.setHeader(Headers.MESSAGE_ID, msgID);

    return msgID;

  }

  /**

   * Returns the body string.

   */

  public byte[] getBody()

  {

    return body;

  }

  /**

   * @return Numerical IDs of the newsgroups this Article belongs to.

   */

  public List<Group> getGroups()

  {

    String[]         groupnames = getHeader(Headers.NEWSGROUPS)[0].split(",");

    ArrayList<Group> groups     = new ArrayList<Group>();

    try

    {

      for(String newsgroup : groupnames)

      {

        newsgroup = newsgroup.trim();

        Group group = StorageManager.current().getGroup(newsgroup);

        if(group != null &&         // If the server does not provide the group, ignore it

          !groups.contains(group))  // Yes, there may be duplicates

        {

          groups.add(group);

        }

      }

    }

    catch(StorageBackendException ex)

    {

      ex.printStackTrace();

      return null;

    }

    return groups;

  }

  public void setBody(byte[] body)

  {

    this.body = body;

  }

  /**

   * 

   * @param groupname Name(s) of newsgroups

   */

  public void setGroup(String groupname)

  {

    this.headers.setHeader(Headers.NEWSGROUPS, groupname);

  }

  /**

   * Returns the Message-ID of this Article. If the appropriate header

   * is empty, a new Message-ID is created.

   * @return Message-ID of this Article.

   */

  public String getMessageID()

  {

    String[] msgID = getHeader(Headers.MESSAGE_ID);

    return msgID[0].equals("") ? generateMessageID() : msgID[0];

  }

  /**

   * @return String containing the Message-ID.

   */

  @Override

  public String toString()

  {

    return getMessageID();

  }

}