/* ======================================================================
The Bodington System Software License, Version 1.0
  
Copyright (c) 2001 The University of Leeds.  All rights reserved.
  
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

1.  Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.

2.  Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.

3.  The end-user documentation included with the redistribution, if any,
must include the following acknowledgement:  "This product includes
software developed by the University of Leeds
(http://www.bodington.org/)."  Alternately, this acknowledgement may
appear in the software itself, if and wherever such third-party
acknowledgements normally appear.

4.  The names "Bodington", "Nathan Bodington", "Bodington System",
"Bodington Open Source Project", and "The University of Leeds" must not be
used to endorse or promote products derived from this software without
prior written permission. For written permission, please contact
d.gardner@leeds.ac.uk.

5.  The name "Bodington" may not appear in the name of products derived
from this software without prior written permission of the University of
Leeds.

THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO,  TITLE,  THE IMPLIED WARRANTIES 
OF QUALITY  AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO 
EVENT SHALL THE UNIVERSITY OF LEEDS OR ITS CONTRIBUTORS BE LIABLE FOR 
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE 
GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 
STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
POSSIBILITY OF SUCH DAMAGE.
=========================================================

This software was originally created by the University of Leeds and may contain voluntary 
contributions from others.  For more information on the Bodington Open Source Project, please 
see http://bodington.org/

====================================================================== */

package org.bodington.server.ims;

import java.io.*;
import java.util.Hashtable;
import org.xml.sax.*;

import javax.xml.parsers.ParserConfigurationException;  
import javax.xml.parsers.DocumentBuilderFactory;  
import javax.xml.parsers.FactoryConfigurationError;  
import javax.xml.parsers.DocumentBuilder;

/*
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.Element;
import org.w3c.dom.CharacterData;
import org.w3c.dom.NodeList;
import org.w3c.dom.DOMException;
*/

import org.xml.sax.ext.LexicalHandler;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.helpers.*;


import org.bodington.assessment.*;
import org.bodington.server.BuildingServerException;


public class PackageResourcesHandler extends DefaultHandler
    {
    private Hashtable resources=null;

    private boolean done=false;
    private boolean in_resources=false;
    private boolean in_resource=false;
    private boolean ref_file_found=false;

    private String resources_baseurl;
    private String resource_baseurl;
    private String file_baseurl;
    private String type, identifier, href, filehref;
    
    //===========================================================
    // SAX DocumentHandler methods
    //===========================================================
    public PackageResourcesHandler()
        {
        }

    public Hashtable getResources()
        {
        return resources;
        }

    public void startDocument ()
    throws SAXException
        {
        done=false;
        resources = null;
        in_resources=false;
        in_resource=false;
        }

    public void endDocument ()
    throws SAXException
        {
        if ( resources == null )
            throw new SAXException( "The package manifest lacked the compulsory resources element." );
        }

    public void startElement (  String uri, String localName, String name, Attributes attrs )
    throws SAXException
        {
        
        if ( done )
            return;
            
        if ( name.equals( "resources" ) )
            {
            in_resources=true;
            resources = new Hashtable();
            resources_baseurl = attrs.getValue( "xml:base" );
            return;
            }
            
        if ( !in_resources )
            return;
            
        if ( name.equals( "manifestref" ) )
            {
            throw new SAXException( "Nested packages are not yet supported." );
            }
            
        if ( name.equals( "xinclude:include" ) )
            {
            throw new SAXException( "External resources not supported" );
            }
            
        if ( name.equals( "resource" ) )
            {
            if ( in_resource )
                throw new SAXException( "A resource element is not allowed inside another resource element." );
            in_resource=true;
            type = attrs.getValue( "type" );
            if ( type==null || !type.equals( "webcontent" ) )
                throw new SAXException( "Type content other than 'webcontent' not supported." );
            
            resource_baseurl = attrs.getValue( "xml:base" );
            identifier = attrs.getValue( "identifier" );

            href = attrs.getValue( "href" );
            if ( href==null || href.length()==0 )
                throw new SAXException( "Resource element without href attribute not supported." );

            if ( resource_baseurl !=null && resource_baseurl.length()>0 )
                href = resource_baseurl + href;
            else if ( resources_baseurl !=null && resources_baseurl.length()>0 )
                href = resources_baseurl + href;
 

            ref_file_found=false;
            }
            
        if ( name.equals( "file" ) )
            {
            if ( !in_resource )
                throw new SAXException( "A file element must appear inside a resource element." );
            file_baseurl = attrs.getValue( "xml:base" );

            filehref = attrs.getValue( "href" );
            if ( file_baseurl !=null && file_baseurl.length()>0 )
                filehref = file_baseurl + filehref;
            else if ( resource_baseurl !=null && resource_baseurl.length()>0 )
                filehref = resource_baseurl + filehref;
            else if ( resources_baseurl !=null && resources_baseurl.length()>0 )
                filehref = resources_baseurl + filehref;

            if ( filehref.equals( href ) )
                ref_file_found=true;
            }
        }

    public void endElement (  String uri, String localName, String name)
        throws SAXException
        {
        if ( name.equals( "resources" ) )
            {
            in_resources=false;
            done=true;
            }
        if ( name.equals( "resource" ) )
            {
            if ( !ref_file_found )
                throw new SAXException( "A resource element specified an entry point href that doesn't exist as a file element." );
            resources.put( identifier, href );
            in_resource=false;
            }
        return;
        }


    public void characters (char buf [], int offset, int len)
        throws SAXException
        {
        return;
        }

    }