/*
 * Copyright 2000-2004 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.jetspeed.portal.portlets;

//Element Construction Set
import org.apache.ecs.ConcreteElement;
import org.apache.ecs.StringElement;

//Jetspeed stuff
import org.apache.jetspeed.portal.PortletConfig;
import org.apache.jetspeed.portal.PortletException;
import org.apache.jetspeed.util.JetspeedClearElement;
import org.apache.jetspeed.util.MimeType;
import org.apache.jetspeed.cache.disk.JetspeedDiskCache;
import org.apache.jetspeed.services.logging.JetspeedLogFactoryService;
import org.apache.jetspeed.services.logging.JetspeedLogger;

//turbine
import org.apache.turbine.util.RunData;

//standard java stuff
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;


import org.xml.sax.AttributeList;
import org.xml.sax.HandlerBase;
import org.xml.sax.Parser;
import org.xml.sax.SAXParseException;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.ParserFactory;

/**
 * This portlet serves well-formed WML file content and strips
 * them of superfluous tags liks <wml>
 *
 * <strong>The strip capability has been temporarily disabled due to
 * class conflicts in Tomcat 3.2, so this portlet can only currently
 * serve fragments of WML documents, without the <wml> tag</strong>
 *
 * @author <a href="mailto:raphael@apache.org">Raphaël Luta</a>
 * @version $Id: WMLFilePortlet.java,v 1.11 2004/02/23 04:03:33 jford Exp $ 
 */
public class WMLFilePortlet extends FileWatchPortlet 
{
    /**
     * Static initialization of the logger for this class
     */    
    private static final JetspeedLogger logger = JetspeedLogFactoryService.getLogger(WMLFilePortlet.class.getName());
    
    private ConcreteElement content = new StringElement("Not available");
    
    /**
      * @see Portlet#supportsType
      */
    public boolean supportsType( MimeType type ) {
        return type.equals(MimeType.WML);
    }
 
    /** Initialize the content of the portlet
    */
    public void init() throws PortletException {

        PortletConfig config = this.getPortletConfig();
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
 
        try {
            // RL: disable the SAX filter due to a class path problem
            // with Tomcat 3.2
            /*
            String url = JetspeedDiskCache.getInstance().getEntry( config.getURL() ).getURL();

            WMLFilter myFilter = new WMLFilter(new PrintWriter(bos));
            myFilter.filter(url);
            content = new JetspeedClearElement( bos.toString() );
            */
            content = new JetspeedClearElement(
                JetspeedDiskCache.getInstance().getEntry( config.getURL() ).getData() );
        } catch (Exception e) {
            throw new PortletException( e.getMessage() );
        } finally {
            try {
                bos.close();
            } catch (IOException e) {}
        }
    }

    public ConcreteElement getContent( RunData data ) {
        return content;
    }
    
    class WMLFilter extends HandlerBase {
    
        private static final String DEFAULT_PARSER_NAME = "javax.xml.parsers.SAXParser";

        protected PrintWriter out=new PrintWriter(System.out);

        public WMLFilter(PrintWriter outPW) throws UnsupportedEncodingException {
            this.out=outPW;
        }

        public void filter(String uri) {

            try {
                HandlerBase handler = this;
    
                Parser parser = ParserFactory.makeParser(DEFAULT_PARSER_NAME);
                parser.setDocumentHandler(handler);
                parser.setErrorHandler(handler);
                parser.parse(uri);
            }
            catch (Exception e) {
                logger.error("Exception",  e);
            }
        }

        public void processingInstruction(String target, String data) {        
            //filter all PIs
        }

        public void startElement(String name, AttributeList attrs) {

            // strip <wml>
            if (name.equals("wml")) return;

            // else output the element        
            out.print('<');
            out.print(name);
            if (attrs != null) {
                int len = attrs.getLength();
                for (int i = 0; i < len; i++) {
                    out.print(' ');
                    out.print(attrs.getName(i));
                    out.print("=\"");
                    out.print(normalize(attrs.getValue(i)));
                    out.print('"');
                }
            }
            out.print('>');    
        }

        public void characters(char ch[], int start, int length) {
            out.print(normalize(new String(ch, start, length)));
        }

        public void ignorableWhitespace(char ch[], int start, int length) {
            characters(ch, start, length);
        }

        public void endElement(String name) {
            //filter <wml>
            if (name.equals("wml")) return;
            
            // outpu anything else
            out.print("</");
            out.print(name);
            out.print('>');
        }

        public void endDocument() {
            out.flush();
        }

        public void warning(SAXParseException ex) {
            logger.info(getLocationString(ex)+": "+ex.getMessage());
        }

        public void error(SAXParseException ex) {
            logger.error(getLocationString(ex)+": "+ex, ex);
        }

        public void fatalError(SAXParseException ex) throws SAXException {
            logger.error(getLocationString(ex)+": "+ex, ex);
            throw ex;
        }

        /**
        Retrieves the error location in the input stream
        */
        private String getLocationString(SAXParseException ex) {
            StringBuffer str = new StringBuffer();
    
            String systemId = ex.getSystemId();
            if (systemId != null) {
                int index = systemId.lastIndexOf('/');
                if (index != -1)
                    systemId = systemId.substring(index + 1);
                str.append(systemId);
            }
            str.append(':');
            str.append(ex.getLineNumber());
            str.append(':');
            str.append(ex.getColumnNumber());
    
            return str.toString();
    
        }

        /**
        Escapes characters data
        */
        protected String normalize(String s) {
            StringBuffer str = new StringBuffer();
    
            int len = (s != null) ? s.length() : 0;
            for (int i = 0; i < len; i++) {
                char ch = s.charAt(i);
                switch (ch) {
                    case '<': {
                        str.append("&lt;");
                        break;
                    }
                    case '>': {
                        str.append("&gt;");
                        break;
                    }
                    case '&': {
                        str.append("&amp;");
                        break;
                    }
                    case '"': {
                        str.append("&quot;");
                        break;
                    }
                    default: {
                        str.append(ch);
                    }
                }
            }

            return str.toString();

        }
    }
}
