/*

  *   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 java.util.logging.Level;

 import javax.mail.Header;

 import javax.mail.Message;

 import javax.mail.MessagingException;

 import javax.mail.internet.InternetHeaders;

 import org.sonews.config.Config;

 import org.sonews.util.Log;

 /**

  * 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) {

 			Log.get().log(Level.WARNING, ex.getLocalizedMessage(), ex);

 			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) {

 			Log.get().log(Level.WARNING, ex.getLocalizedMessage(), ex);

 		}

 	}

 	/**

 	 * 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();

 			StringBuilder hexString = new StringBuilder();

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

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

 			}

 			randomString = hexString.toString();

 		} catch (NoSuchAlgorithmException ex) {

 			Log.get().log(Level.WARNING, ex.getLocalizedMessage(), ex);

 			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) {

 			Log.get().log(Level.WARNING, ex.getLocalizedMessage(), ex);

 			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();

 	}

 }