/*
 * $Id: ModuleMetaData.java 5820 2009-07-06 21:37:34Z uckelman $
 *
 * Copyright (c) 2008 by Brent Easton and Joel Uckelman
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License (LGPL) as published by the Free Software Foundation.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, copies are available
 * at http://www.opensource.org.
 */
package VASSAL.build.module.metadata;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import VASSAL.build.GameModule;
import VASSAL.tools.io.IOUtils;
import VASSAL.tools.logging.Logger;

/**
 * 
 * Class representing the metadata for a Module or an Extension. Modules
 * and extensions can't be differentiated until either the metadata or the
 * buildfile is parsed, so they share the same metadata structure.
 * 
 * @author Brent Easton
 * @since 3.1.0
 *
 */
public class ModuleMetaData extends AbstractMetaData {

  public static final String ZIP_ENTRY_NAME = "moduledata";
  public static final String DATA_VERSION = "1";
    
  protected Attribute nameAttr;

  public ModuleMetaData(ZipFile zip) {
    read(zip);
  }
  
  public ModuleMetaData(GameModule module) {
    super();
    nameAttr = new Attribute(module, GameModule.MODULE_NAME);
    setDescription(new Attribute(module, GameModule.DESCRIPTION));
    setVersion(module.getGameVersion());
  }

  public ModuleMetaData(String name, String version) {
    super();
    nameAttr = new Attribute(GameModule.MODULE_NAME, name);
    setVersion(version);
  }

  public String getName() {
    return nameAttr == null ? "" : nameAttr.getValue();
  }
  
  public String getLocalizedName() {
    return nameAttr == null ? "" : nameAttr.getLocalizedValue();
  }

  public String getZipEntryName() {
    return ZIP_ENTRY_NAME;
  }
  
  public String getMetaDataVersion() {
    return DATA_VERSION;
  }
  
  /**
   * Add elements specific to a ModuleMetaData 
   * 
   * @param doc Document
   * @param root Root element
   */
  protected void addElements(Document doc, Element root) {
    nameAttr.generateXML(doc, root, NAME_ELEMENT);
  }

  /**
   * Read and validate a Module file.
   *  - Check it has a Zip Entry named buildfile
   *  - If it has a metadata file, read and parse it.
   *  
   * @param file Module File
   */
  public void read(ZipFile zip) {
    version = "";

    try {
      // Try to parse the metadata. Failure is not catastrophic, we can
      // treat it like an old-style module with no metadata and parse
      // the first lines of the buildFile
      DefaultHandler handler = null;

      ZipEntry data = zip.getEntry(ZIP_ENTRY_NAME);
      if (data == null) {
        data = zip.getEntry(GameModule.BUILDFILE);
        if (data == null) return;
        
        handler = new ModuleBuildFileXMLHandler();
      }
      else {
        handler = new MetadataXMLHandler();
      }
      
      BufferedInputStream in = null;
      try {
        in = new BufferedInputStream(zip.getInputStream(data));

        synchronized (parser) {
          parser.setContentHandler(handler);
          parser.setDTDHandler(handler);
          parser.setEntityResolver(handler);
          parser.setErrorHandler(handler);
          parser.parse(new InputSource(in));
        }

        in.close(); 
      }
      finally {
        IOUtils.closeQuietly(in);
      }
 
      zip.close();
    }
    catch (IOException e) {
      Logger.log(e);
    }
    catch (SAXEndException e) {
      // Indicates End of module/extension parsing. not an error.
    }
    catch (SAXException e) {
      Logger.log(e);
    }
    finally {
      IOUtils.closeQuietly(zip);
    }
  }

  /**
   * XML Handler for parsing a Module/Extension metadata file
   */
  private class MetadataXMLHandler extends XMLHandler {

    @Override
    public void endElement(String uri, String localName, String qName) {
      // handle all of the elements which have CDATA here
      if (NAME_ELEMENT.equals(qName)) {
        if (nameAttr == null) {
          nameAttr = new Attribute(NAME_ELEMENT, accumulator.toString().trim());
        }
        else {
          nameAttr.addTranslation(language, accumulator.toString().trim());
        }
      }
      else {
        super.endElement(uri, localName, qName);
      }
    }
  }
  
  /**
   * XML Handle for parsing a Module buildFile. Used to read minimal data from
   * modules saved prior to 3.1.0. 
   */
  private class ModuleBuildFileXMLHandler extends BuildFileXMLHandler {

    @Override
    public void startElement(String uri, String localName,
                             String qName, Attributes attrs) 
        throws SAXEndException {
      super.startElement(uri, localName, qName, attrs);

      // handle element attributes we care about
      if (BUILDFILE_MODULE_ELEMENT1.equals(qName) ||
          BUILDFILE_MODULE_ELEMENT2.equals(qName)) {
        nameAttr = new Attribute (NAME_ELEMENT, getAttr(attrs, NAME_ATTR));
        setVersion(getAttr(attrs, VERSION_ATTR));
        setVassalVersion(getAttr(attrs, VASSAL_VERSION_ATTR));
        setDescription(getAttr(attrs, DESCRIPTION_ATTR));
        throw new SAXEndException();
      }
    }
  }
}
