/*!
 * This program is free software; you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
 * Foundation.
 *
 * You should have received a copy of the GNU Lesser General Public License along with this
 * program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
 * or from the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * 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 Lesser General Public License for more details.
 *
 * Copyright (c) 2002-2013 Pentaho Corporation..  All rights reserved.
 */

package org.pentaho.platform.util;

import org.pentaho.platform.api.engine.IDocumentResourceLoader;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamSource;
import java.io.IOException;
import java.io.InputStream;

public class JarEntityResolver implements IDocumentResourceLoader {

  private static JarEntityResolver instance;

  public static JarEntityResolver getInstance() {
    if ( JarEntityResolver.instance == null ) {
      JarEntityResolver.instance = new JarEntityResolver();
    }
    return JarEntityResolver.instance;
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.xml.sax.EntityResolver#resolveEntity(java.lang.String, java.lang.String)
   */
  public InputSource resolveEntity( final String publicId, final String systemId ) throws SAXException, IOException {

    int idx = systemId.lastIndexOf( '/' );
    String dtdName = systemId.substring( idx + 1 );

    try {
      InputStream xslIS = getClass().getClassLoader().getResourceAsStream( "system/dtd/" + dtdName ); //$NON-NLS-1$
      if ( xslIS != null ) {
        InputSource source = new InputSource( xslIS );
        return source;
      }
    } catch ( Exception e ) {
      //ignored
    }
    return null;
  }

  public Source resolve( final String href, final String base ) {
    try {
      InputStream xslIS = getClass().getClassLoader().getResourceAsStream( href );
      StreamSource xslSrc = new StreamSource( xslIS );
      return xslSrc;
    } catch ( Exception e ) {
      //ignored
    }
    return null;

  }

  public InputStream loadXsl( final String name ) {

    try {
      InputStream xslIS = getClass().getClassLoader().getResourceAsStream( name );
      return xslIS;
    } catch ( Exception e ) {
      //ignored
    }
    return null;
  }

}