package net.panonet;

import java.io.IOException;
import java.io.File;
import java.net.URL;
import java.util.Map;
import java.io.StringWriter;
import java.io.StringReader;

import javax.xml.transform.TransformerFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;

import com.ecyrd.jspwiki.WikiContext;
import com.ecyrd.jspwiki.WikiEngine;

import com.ecyrd.jspwiki.plugin.WikiPlugin;
import com.ecyrd.jspwiki.plugin.PluginException;

import com.ecyrd.jspwiki.attachment.AttachmentManager;
import com.ecyrd.jspwiki.attachment.Attachment;
import com.ecyrd.jspwiki.providers.ProviderException;
import com.ecyrd.jspwiki.providers.WikiPageProvider;
import com.ecyrd.jspwiki.providers.WikiAttachmentProvider;


/**
 * JSPWiki plugin for processing XML files into HTML in a Wiki page using XSLT.
 *
 * The plugin has two parameters from the perspective of the Wiki page:
 * 
 * xsl='<xslfile>'    Name of the XSLT file to use
 * xml='<xslfile>'    Name of the XML file to process
 *
 * 29.05.2004 Jan Wessely <info@jawe.net>: Relative paths are resolved to the wiki's base URL.
 * 12.01.2005 Joe Mocker <mock at misfit.dhs.org>: Added ability to use Wiki Attachments & Pages
 */
public class XSLTPlugin implements WikiPlugin
{
    /**
     * Main plugin entry point.
     *
     */
    public String execute(WikiContext context,
                          Map params)
        throws PluginException
    {
        // Get the names of the XML and XSL files to use
       StreamSource xml = getSource((String) params.get("xml"), context);
       StreamSource xsl = getSource((String) params.get("xsl"), context);
		
       String result = "";
       
       try {
	  // Create a Transformer
	  TransformerFactory transformerFactory
	     = TransformerFactory.newInstance();
	  Transformer transformer
	     = transformerFactory.newTransformer( xsl );
	  
	  // Transform the given XML file using the given XSL file, placing
	  // it in a String.
	  StringWriter resultWriter = new StringWriter();
	  
	  transformer.transform( xml,
				 new StreamResult( resultWriter ) );
	  
	  result = resultWriter.toString();
       }
       catch( Exception e ) {
	  e.printStackTrace();
	  throw new PluginException( "Exception performing transformation.", e);
       }
       
       return result;
    }
   
   private StreamSource getSource(String path, WikiContext context) 
      throws PluginException {
      
      WikiEngine engine = context.getEngine();
      StreamSource source = null;
      
      if (path.startsWith("http:")) {
	 source = new StreamSource(path);
      }
      else if (!path.startsWith("file:")) {
	 // first, see if the parameter is a WikiAttachment
	 try {
	    AttachmentManager mgr = engine.getAttachmentManager();
	    WikiAttachmentProvider provider = mgr.getCurrentProvider();
	    Attachment        att = mgr.getAttachmentInfo( context, path);
	    
	    if (att != null) {
	       // The jspwiki.baseURL property in jspwiki.properties 
	       // must be defined for this to work.
	       source =  new StreamSource(provider.getAttachmentData(att));
	    }
	 }
	 catch (ProviderException e) {
	    throw new PluginException( "Attachment info failed: "+e.getMessage() );
	 }
	 catch (IOException e) {
	    throw new PluginException( "Attachmeand read failed: " + e.getMessage() );
	 }
      
	 // next, see if this parameter is a WikiPage & not ourselves
	 if (source == null && engine.pageExists(path) && !path.equals(context.getPage().getName())) {
	    String contents = engine.getPureText(path, WikiPageProvider.LATEST_VERSION);
	    source = new StreamSource(new StringReader(contents));
	 }
	 
	 // last, assume the parameter is just a file on the webserver.
	 if (source == null) {
	    path = context.getEngine().getBaseURL() + path;
	    source = new StreamSource(path);
	 }
      } 
      else if (path.startsWith("file:")) {
	 throw new IllegalArgumentException("file: URLs are not allowed.");
      }

      return source;
   }
}