/*

  *   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.BufferedReader;

 import java.io.ByteArrayOutputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.InputStreamReader;

 import java.io.PrintStream;

 import java.io.StringReader;

 import java.io.StringWriter;

 import java.io.UnsupportedEncodingException;

 import java.sql.ResultSet;

 import java.sql.SQLException;

 import java.util.ArrayList;

 import java.util.Date;

 import java.util.Enumeration;

 import java.util.logging.Level;

 import java.util.logging.Logger;

 import javax.mail.Header;

 import javax.mail.MessagingException;

 import javax.mail.Multipart;

 import javax.mail.Session;

 import javax.mail.internet.InternetAddress;

 import javax.mail.internet.MimeBodyPart;

 import javax.mail.internet.MimeMessage;

 import javax.mail.internet.MimeMultipart;

 import javax.xml.transform.Transformer;

 import javax.xml.transform.TransformerFactory;

 import javax.xml.transform.stream.StreamResult;

 import javax.xml.transform.stream.StreamSource;

 import org.sonews.util.io.Resource;

 /**

  * This is MimeMessage which enables custom Message-ID header

  * (this header will not be overwritten by the default one like in MimeMessage).

  * 

  * Also add header and body separate serialization.

  * 

  * And can be deserialized from SQL ResultSet

  * 

  * @author František Kučera (frantovo.cz)

  */

 public class DrupalMessage extends MimeMessage {

 	private static final Logger log = Logger.getLogger(DrupalMessage.class.getName());

 	private static final String MESSAGE_ID_HEADER = "Message-ID";

 	private static final String CRLF = "\r\n";

 	public static final String CHARSET = "UTF-8";

 	private static final String XHTML_CONTENT_TYPE = "text/html; charset=" + CHARSET;

 	private String messageID;

 	/**

 	 * Constructs MIME message from SQL result.

 	 * @param rs ResultSet containing message data. No {@link ResultSet#next()} will be called, just values from current row will be read.

 	 * @param constructBody true if whole message should be constructed | false if we need only message headers (body will be dummy).

 	 */

 	public DrupalMessage(ResultSet rs, String myDomain, boolean constructBody) throws SQLException, UnsupportedEncodingException, MessagingException {

 		super(Session.getDefaultInstance(System.getProperties()));

 		addHeader("Message-id", constructMessageId(rs.getInt("id"), rs.getInt("group_id"), rs.getString("group_name"), myDomain));

 		addHeader("Newsgroups", rs.getString("group_name"));

 		setFrom(new InternetAddress(rs.getString("sender_email"), rs.getString("sender_name")));

 		setSubject(rs.getString("subject"));

 		setSentDate(new Date(rs.getLong("created")));

 		int parentID = rs.getInt("parent_id");

 		if (parentID > 0) {

 			String parentMessageID = constructMessageId(parentID, rs.getInt("group_id"), rs.getString("group_name"), myDomain);

 			addHeader("In-Reply-To", parentMessageID);

 			addHeader("References", parentMessageID);

 		}

 		if (constructBody) {

 			Multipart multipart = new MimeMultipart("alternative");

 			setContent(multipart);

 			/** XHTML part */

 			MimeBodyPart htmlPart = new MimeBodyPart();

 			String xhtmlText = readXhtmlText(rs);

 			htmlPart.setContent(xhtmlText, XHTML_CONTENT_TYPE);

 			/** Plain text part */

 			MimeBodyPart textPart = new MimeBodyPart();

 			textPart.setText(readPlainText(rs, xhtmlText));

 			/**

 			 * Thunderbirdu záleží, v jakém pořadí části jsou 

 			 * (když je prostý text druhý, html se nezobrazí),

 			 * KNode zobrazuje HTML správně, i když je na prvním místě.

 			 */

 			multipart.addBodyPart(textPart);

 			multipart.addBodyPart(htmlPart);

 		} else {

 			/** empty body, just headers */

 			setText("");

 		}

 	}

 	private String readPlainText(ResultSet rs, String xhtmlText) {

 		/**

 		 * TODO: převést na prostý text

 		 */

 		return "TODO: obyčejný text\n(zatím čtěte XHTML verzi)";

 	}

 	private String readXhtmlText(ResultSet rs) {

 		/**

 		 * TODO: 

 		 *		- znovupoužívat XSL transformér

 		 *		- používat cache, ukládat si vygenerované články

 		 */

 		try {

 			String inputText = makeSimpleXHTML(rs.getString("text"));

 			TransformerFactory tf = TransformerFactory.newInstance();

 			Transformer paragraphTransformer = tf.newTransformer(new StreamSource(Resource.getAsStream("helpers/mimeXhtmlPart-make-paragraphs.xsl")));

 			String paragraphedText;

 			boolean tidyWasUsed = false;

 			try {

 				StringReader input = new StringReader(inputText);

 				StringWriter output = new StringWriter(2 * inputText.length());

 				paragraphTransformer.transform(new StreamSource(input), new StreamResult(output));

 				paragraphedText = output.toString();

 			} catch (Exception e) {

 				log.log(Level.FINER, "HTML input was shitty – Tidy had to be called.", e);

 				StringReader input = new StringReader(tidyXhtml(inputText));

 				StringWriter output = new StringWriter(2 * inputText.length());

 				paragraphTransformer.transform(new StreamSource(input), new StreamResult(output));

 				paragraphedText = output.toString();

 				tidyWasUsed = true;

 			}

 			Transformer xhtmlTransformer = tf.newTransformer(new StreamSource(Resource.getAsStream("helpers/mimeXhtmlPart.xsl")));

 			xhtmlTransformer.setParameter("isRoot", (rs.getInt("parent_id") == 0));

 			xhtmlTransformer.setParameter("title", rs.getString("subject"));

 			xhtmlTransformer.setParameter("urlBase", rs.getString("urlBase"));

 			xhtmlTransformer.setParameter("wwwRead", rs.getString("wwwRead"));

 			xhtmlTransformer.setParameter("wwwPost", rs.getString("wwwPost"));

 			xhtmlTransformer.setParameter("headComment", String.format("Drupal-NNTP bridge. Transformed: %1$tc. Tidy had to be used: %2$b", new Date(), tidyWasUsed));

 			StringReader input = new StringReader(paragraphedText);

 			StringWriter output = new StringWriter(2 * paragraphedText.length());

 			xhtmlTransformer.transform(new StreamSource(input), new StreamResult(output));

 			return output.toString();

 		} catch (Exception e) {

 			/**

 			 * TODO: lepší ošetření chyby

 			 */

 			log.log(Level.WARNING, "Error while transforming article to XHTML", e);

 			return makeSimpleXHTML("<p>Při transformaci příspěvku bohužel došlo k chybě.</p>");

 		}

 	}

 	private static String makeSimpleXHTML(String body) {

 		return "<html xmlns=\"http://www.w3.org/1999/xhtml\"><body>" + body + "</body></html>";

 	}

 	/**

 	 * TODO: refaktorovat, přesunout

 	 */

 	private static String tidyXhtml(String inputText) throws IOException {

 		// https://sourceforge.net/tracker/index.php?func=detail&aid=3424437&group_id=27659&atid=390966

 		inputText = inputText.replaceAll("\\n", "◆\n");

 		Runtime r = Runtime.getRuntime();

 		Process p = r.exec(new String[]{"tidy", // http://tidy.sourceforge.net

 					"-asxml", // well formed XHTML

 					"-numeric", // číselné entity

 					"-utf8", // kódování

 					"--show-warnings", "false", // žádná varování nás nezajímají

 					"--show-errors", "0", // ani chyby

 					"--doctype", "omit", // doctype nepotřebujeme (doplníme si případně vlastní v XSLT)

 					"--logical-emphasis", "true", // em a strong místo i a b

 					"--literal-attributes", "true", // zachovat mezery a konce řádků v atributech

 					"--force-output", "true" // neznámé značky zahodíme, vložíme jen jejich obsah

 				});

 		PrintStream vstupProcesu = new PrintStream(p.getOutputStream());

 		vstupProcesu.print(inputText);

 		vstupProcesu.close();

 		String outputText = streamToString(p.getInputStream());

 		outputText = outputText.replaceAll("◆\\n", "\n");

 		outputText = outputText.replaceAll("◆", "\n");

 		return outputText;

 	}

 	/**

 	 * TODO: refaktorovat, přesunout

 	 */

 	private static String streamToString(InputStream proud) throws IOException {

 		StringBuilder výsledek = new StringBuilder();

 		BufferedReader buf = new BufferedReader(new InputStreamReader(proud));

 		while (true) {

 			String radek = buf.readLine();

 			if (radek == null) {

 				break;

 			} else {

 				výsledek.append(radek);

 				výsledek.append("\n");

 			}

 		}

 		return výsledek.toString();

 	}

 	private static String constructMessageId(int articleID, int groupID, String groupName, String domainName) {

 		StringBuilder sb = new StringBuilder();

 		sb.append("<");

 		sb.append(articleID);

 		sb.append("-");

 		sb.append(groupID);

 		sb.append("-");

 		sb.append(groupName);

 		sb.append("@");

 		sb.append(domainName);

 		sb.append(">");

 		return sb.toString();

 	}

 	@Override

 	public void setHeader(String name, String value) throws MessagingException {

 		super.setHeader(name, value);

 		if (MESSAGE_ID_HEADER.equalsIgnoreCase(name)) {

 			messageID = value;

 		}

 	}

 	@Override

 	public final void addHeader(String name, String value) throws MessagingException {

 		super.addHeader(name, value);

 		if (MESSAGE_ID_HEADER.equalsIgnoreCase(name)) {

 			messageID = value;

 		}

 	}

 	@Override

 	public void removeHeader(String name) throws MessagingException {

 		super.removeHeader(name);

 		if (MESSAGE_ID_HEADER.equalsIgnoreCase(name)) {

 			messageID = null;

 		}

 	}

 	public void setMessageID(String messageID) {

 		this.messageID = messageID;

 	}

 	@Override

 	protected void updateMessageID() throws MessagingException {

 		if (messageID == null) {

 			super.updateMessageID();

 		} else {

 			setHeader(MESSAGE_ID_HEADER, messageID);

 		}

 	}

 	/**

 	 * Call {@link #saveChanges()} before this method, if you want all headers including such ones like:

 	 * 

 	 * <pre>MIME-Version: 1.0

 	 *Content-Type: multipart/alternative;</pre>

 	 * 

 	 * @return serialized headers

 	 * @throws MessagingException if getAllHeaders() fails

 	 */

 	public String getHeaders() throws MessagingException {

 		StringBuilder sb = new StringBuilder();

 		for (Enumeration eh = getAllHeaderLines(); eh.hasMoreElements();) {

 			sb.append(eh.nextElement());

 			sb.append(CRLF);

 		}

 		return sb.toString();

 	}

 	public byte[] getBody() throws IOException, MessagingException {

 		saveChanges();

 		ArrayList<String> skipHeaders = new ArrayList<String>();

 		for (Enumeration eh = getAllHeaders(); eh.hasMoreElements();) {

 			Header h = (Header) eh.nextElement();

 			skipHeaders.add(h.getName());

 		}

 		ByteArrayOutputStream baos = new ByteArrayOutputStream(1024);

 		writeTo(baos, skipHeaders.toArray(new String[skipHeaders.size()]));

 		return baos.toByteArray();

 	}

 }