/**

  * Free Telco Dictionary

  * Copyright © 2013 František Kučera (frantovo.cz)

  *

  * 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 cz.frantovo.telco.dictionary;

 import static cz.frantovo.telco.dictionary.Xmlns.*;

 import static cz.frantovo.telco.dictionary.Functions.*;

 import java.io.BufferedWriter;

 import java.io.ByteArrayOutputStream;

 import java.io.DataOutputStream;

 import java.io.File;

 import java.io.FileOutputStream;

 import java.io.FileWriter;

 import java.io.IOException;

 import java.nio.ByteBuffer;

 import java.nio.charset.Charset;

 import java.util.ArrayList;

 import java.util.List;

 import java.util.logging.Level;

 import java.util.logging.Logger;

 import javax.xml.parsers.DocumentBuilder;

 import javax.xml.parsers.DocumentBuilderFactory;

 import javax.xml.parsers.ParserConfigurationException;

 import javax.xml.transform.Transformer;

 import javax.xml.transform.TransformerConfigurationException;

 import javax.xml.transform.TransformerException;

 import javax.xml.transform.TransformerFactory;

 import javax.xml.transform.dom.DOMSource;

 import javax.xml.transform.stream.StreamResult;

 import javax.xml.transform.stream.StreamSource;

 import javax.xml.xpath.XPath;

 import javax.xml.xpath.XPathConstants;

 import javax.xml.xpath.XPathExpression;

 import javax.xml.xpath.XPathExpressionException;

 import javax.xml.xpath.XPathFactory;

 import org.w3c.dom.Document;

 import org.w3c.dom.Node;

 import org.w3c.dom.NodeList;

 import org.xml.sax.SAXException;

 /**

  * <p>

  * Generates dictionary files in StarDict format from source in our XML format.

  * </p>

  *

  * <p>

  * Number format should be: 32-bits unsigned number in network byte order

  * </p>

  *

  * @author Ing. František Kučera (frantovo.cz)

  */

 public class Generator {

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

 	private static final String EMAIL_TOKEN = "ixumhht68";

 	private final DocumentBuilderFactory documentBuilderFactory;

 	private final DocumentBuilder documentBuilder;

 	private final XPathFactory xpathFactory;

 	private final XPath xpath;

 	private final TransformerFactory xslFactory;

 	private final Transformer xsl;

 	private final Charset utf8;

 	public Generator() throws ParserConfigurationException, TransformerConfigurationException {

 		utf8 = Charset.forName("UTF-8");

 		documentBuilderFactory = DocumentBuilderFactory.newInstance();

 		documentBuilderFactory.setNamespaceAware(true);

 		documentBuilder = documentBuilderFactory.newDocumentBuilder();

 		xslFactory = TransformerFactory.newInstance();

 		xsl = xslFactory.newTransformer(new StreamSource("concept.xsl"));

 		xpathFactory = XPathFactory.newInstance();

 		xpath = xpathFactory.newXPath();

 		xpath.setNamespaceContext(getNamespaceContext());

 	}

 	private void generate(File folder, String filePrefix) {

 		File infoFile = new File(folder, filePrefix + ".ifo");

 		File dictFile = new File(folder, filePrefix + ".dict");

 		File indexFile = new File(folder, filePrefix + ".idx");

 		File synonymFile = new File(folder, filePrefix + ".syn");

 		FileOutputStream dictOutputStream = null;

 		DataOutputStream synonymOutputStream = null;

 		DataOutputStream indexOutputStream = null;

 		BufferedWriter infoWriter = null;

 		try {

 			dictOutputStream = new FileOutputStream(dictFile);

 			synonymOutputStream = new DataOutputStream(new FileOutputStream(synonymFile));

 			indexOutputStream = new DataOutputStream(new FileOutputStream(indexFile));

 			infoWriter = new BufferedWriter(new FileWriter(infoFile));

 			Document sourceDocument = documentBuilder.parse("../../data/dictionary.xml");

 			XPathExpression termsXPath = xpath.compile("d:term/@completeForm|d:term/@abbreviation");

 			// TODO: tags - labels/descriptions

 			xsl.setParameter("tags", sourceDocument.getElementsByTagNameNS(DICTIONARY, "tags").item(0));

 			/**

 			 * TODO: sorting

 			 */

 			long offset = 0;

 			long conceptIndex = 0;

 			long synonymCount = 0;

 			for (Node conceptNode : nodeIterable(sourceDocument.getElementsByTagNameNS(DICTIONARY, "concept"))) {

 				ByteArrayOutputStream conceptXhtml = new ByteArrayOutputStream();

 				xsl.transform(new DOMSource(conceptNode), new StreamResult(conceptXhtml));

 				int length = conceptXhtml.size();

 				dictOutputStream.write(conceptXhtml.toByteArray());

 				NodeList nameNodes = (NodeList) termsXPath.evaluate(conceptNode, XPathConstants.NODESET);

 				List<String> names = new ArrayList<>();

 				for (Node nameNode : nodeIterable(nameNodes)) {

 					String name = nameNode.getTextContent().trim();

 					if (!name.isEmpty()) {

 						names.add(name);

 					}

 				}

 				synonymCount = +writeSynonyms(synonymOutputStream, names, conceptIndex);

 				writeIndex(indexOutputStream, names.get(0), offset, length);

 				offset = offset + length;

 				conceptIndex++;

 			}

 			indexOutputStream.flush();

 			writeInfo(infoWriter, sourceDocument, conceptIndex + 1, synonymCount, indexFile.length());

 		} catch (SAXException | IOException | TransformerException | XPathExpressionException e) {

 			log.log(Level.SEVERE, "unable to generate", e);

 		} finally {

 			close(dictOutputStream);

 			close(synonymOutputStream);

 			close(indexOutputStream);

 			close(infoWriter);

 		}

 	}

 	private void writeIndex(DataOutputStream indexOutputStream, String name, long offset, long length) throws IOException {

 		indexOutputStream.write(name.getBytes(utf8));

 		indexOutputStream.write(0);

 		indexOutputStream.writeInt((int) offset); // unsigned int 32

 		indexOutputStream.writeInt((int) length); // unsigned int 32

 	}

 	private int writeSynonyms(DataOutputStream synonymOutputStream, List<String> names, long baseIndex) throws IOException {

 		if (names.size() > 1) {

 			for (int i = 1; i < names.size(); i++) {

 				String name = names.get(i);

 				synonymOutputStream.write(name.getBytes(utf8));

 				synonymOutputStream.write(0);

 				synonymOutputStream.writeInt((int) baseIndex); // unsigned int 32

 			}

 			return names.size() - 1;

 		} else {

 			return 0;

 		}

 	}

 	private void writeInfo(BufferedWriter infoWriter, Document sourceDocument, long wordcount, long synwourdcount, long idxfilesize) throws IOException {

 		// TODO: values from document metadata

 		infoWriter.write("StarDict's dict ifo file\n");

 		infoWriter.write("version=2.4.2\n");

 		infoWriter.write("bookname=Free Telco Dictionary\n");

 		infoWriter.write("wordcount=" + wordcount + "\n");

 		infoWriter.write("synwordcount=" + synwourdcount + "\n");

 		infoWriter.write("idxfilesize=" + idxfilesize + "\n");

 		infoWriter.write("idxoffsetbits=32\n");

 		infoWriter.write("author=František Kučera\n");

 		infoWriter.write("email=telco-dictionary." + EMAIL_TOKEN + "@" + "frantovo.cz\n");

 		infoWriter.write("website=https://telco.frantovo.cz\n");

 		infoWriter.write("description=A dictionary for telecommunications licensed under GNU FDL\n");

 		infoWriter.write("date=2013.07.09\n");

 		infoWriter.write("sametypesequence=h\n");

 	}

 	public static void main(String[] args) {

 		File outputFolder = new File("../../delivery/free-telco-dictionary");

 		outputFolder.mkdir();

 		try {

 			Generator g = new Generator();

 			g.generate(outputFolder, "telco");

 		} catch (ParserConfigurationException | TransformerConfigurationException e) {

 			log.log(Level.SEVERE, "error during initialization", e);

 		}

 	}

 }