/*
 * TransformerFactoryImpl.java
 * Copyright (C) 2004 The Free Software Foundation
 * 
 * This file is part of GNU JAXP, a library.
 *
 * GNU JAXP is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * GNU JAXP 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Linking this library statically or dynamically with other modules is
 * making a combined work based on this library.  Thus, the terms and
 * conditions of the GNU General Public License cover the whole
 * combination.
 *
 * As a special exception, the copyright holders of this library give you
 * permission to link this library with independent modules to produce an
 * executable, regardless of the license terms of these independent
 * modules, and to copy and distribute the resulting executable under
 * terms of your choice, provided that you also meet, for each linked
 * independent module, the terms and conditions of the license of that
 * module.  An independent module is a module which is not derived from
 * or based on this library.  If you modify this library, you may extend
 * this exception to your version of the library, but you are not
 * obliged to do so.  If you do not wish to do so, delete this
 * exception statement from your version. 
 */

package gnu.xml.transform;

import java.io.IOException;
import java.net.URL;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.Map;
import java.util.Properties;
import javax.xml.transform.ErrorListener;
import javax.xml.transform.Source;
import javax.xml.transform.Templates;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.URIResolver;
import javax.xml.transform.dom.DOMResult;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.sax.SAXResult;
import javax.xml.transform.sax.SAXSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import gnu.xml.dom.DomDocument;

/**
 * GNU transformer factory implementation.
 *
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 */
public class TransformerFactoryImpl
  extends TransformerFactory
{

  final XPathFactory xpathFactory;
	final XSLURIResolver resolver;
  ErrorListener userListener;
  URIResolver userResolver;

  public TransformerFactoryImpl()
  {
    xpathFactory = new gnu.xml.xpath.XPathFactoryImpl();
    resolver = new XSLURIResolver();
  }

  public Transformer newTransformer(Source source)
    throws TransformerConfigurationException
  {
    Stylesheet stylesheet = newStylesheet(source, 0, null);
    Properties outputProperties =
      new TransformerOutputProperties(stylesheet);
    TransformerImpl transformer =
      new TransformerImpl(this, stylesheet, outputProperties);
    stylesheet.transformer = transformer;
    return transformer;
  }

  public Transformer newTransformer()
    throws TransformerConfigurationException
  {
    return new TransformerImpl(this, null, new Properties());
  }

  public Templates newTemplates(Source source)
    throws TransformerConfigurationException
  {
    Stylesheet stylesheet = newStylesheet(source, 0, null);
    return new TemplatesImpl(this, stylesheet);
  }

  Stylesheet newStylesheet(Source source, int precedence, Stylesheet parent)
    throws TransformerConfigurationException
  {
    Document doc = null;
    String systemId = null;
    if (source != null)
      {
        try
          {
            DOMSource ds;
            synchronized (resolver)
              {
                resolver.setUserResolver(userResolver);
                resolver.setUserListener(userListener);
                ds = resolver.resolveDOM(source, null, null);
              }
            Node node = ds.getNode();
            if (node == null)
              {
                throw new TransformerConfigurationException("no source document");
              }
            doc = (node instanceof Document) ? (Document) node :
              node.getOwnerDocument();
            systemId = ds.getSystemId();
          }
        catch (TransformerException e)
          {
            throw new TransformerConfigurationException(e);
          }
      }
    return new Stylesheet(this, parent, doc, systemId, precedence);
  }
  
  public Source getAssociatedStylesheet(Source source,
                                        String media,
                                        String title,
                                        String charset)
    throws TransformerConfigurationException
  {
    try
      {
        DOMSource ds;
        synchronized (resolver)
          {
            resolver.setUserResolver(userResolver);
            resolver.setUserListener(userListener);
            ds = resolver.resolveDOM(source, null, null);
          }
        Node node = ds.getNode();
        if (node == null)
          {
            throw new TransformerConfigurationException("no source document");
          }
        Document doc = (node instanceof Document) ? (Document) node :
          node.getOwnerDocument();
        LinkedList matches = new LinkedList();
        for (node = doc.getFirstChild();
             node != null;
             node = node.getNextSibling())
          {
            if (node.getNodeType() == Node.PROCESSING_INSTRUCTION_NODE &&
                "xml-stylesheet".equals(node.getNodeName()))
              {
                Map params = parseParameters(node.getNodeValue());
                if (media != null && !media.equals(params.get("media")))
                  {
                    continue;
                  }
                if (title != null && !title.equals(params.get("title")))
                  {
                    continue;
                  }
                if (charset != null && !charset.equals(params.get("charset")))
                  {
                    continue;
                  }
                String href = (String) params.get("href");
                URL url = resolver.resolveURL(null, node.getBaseURI(), href);
                matches.add(url);
              }
          }
        switch (matches.size())
          {
          case 0:
            return null;
          case 1:
            return new StreamSource(((URL) matches.getFirst()).toString());
          default:
            // Create a source representing a stylesheet with a list of
            // imports
            DomDocument ssDoc = new DomDocument();
            ssDoc.setBuilding(true);
            // Create document element
            Node root =
              ssDoc.createElementNS(Stylesheet.XSL_NS, "stylesheet");
            Node version =
              ssDoc.createAttributeNS(null, "version");
            version.setNodeValue("1.0");
            root.getAttributes().setNamedItemNS(version);
            ssDoc.appendChild(root);
            // Create xsl:import for each URL
            for (Iterator i = matches.iterator(); i.hasNext(); )
              {
                URL url = (URL) i.next();
                Node imp =
                  ssDoc.createElementNS(Stylesheet.XSL_NS, "import");
                Node href =
                  ssDoc.createAttributeNS(null, "href");
                href.setNodeValue(url.toString());
                imp.getAttributes().setNamedItemNS(href);
                root.appendChild(imp);
              }
            ssDoc.setBuilding(false);
            return new DOMSource(ssDoc);
          }
      }
    catch (IOException e)
      {
        throw new TransformerConfigurationException(e);
      }
    catch (TransformerException e)
      {
        throw new TransformerConfigurationException(e);
      }
  }

  Map parseParameters(String data)
  {
    Map ret = new LinkedHashMap();
    int len = data.length();
    String key = null;
    int start = 0;
    char quoteChar = '\u0000';
    for (int i = 0; i < len; i++)
      {
        char c = data.charAt(i);
        if (quoteChar == '\u0000' && c == ' ')
          {
            if (key == null && start < i)
              {
                key = data.substring(start, i);
              }
            else
              {
                String val = unquote(data.substring(start, i).trim());
                ret.put(key, val);
                key = null;
              }
            start = i + 1;
          }
        else if (c == '"')
          {
            quoteChar = (quoteChar == c) ? '\u0000' : c;
          }
        else if (c == '\'')
          {
            quoteChar = (quoteChar == c) ? '\u0000' : c;
          }
      }
    if (start < len && key != null)
      {
        String val = unquote(data.substring(start, len).trim());
        ret.put(key, val);
      }
    return ret;
  }

  String unquote(String text)
  {
    int end = text.length() - 1;
    if (text.charAt(0) == '\'' && text.charAt(end) == '\'')
      {
        return text.substring(1, end);
      }
    if (text.charAt(0) == '"' && text.charAt(end) == '"')
      {
        return text.substring(1, end);
      }
    return text;
  }

  public void setURIResolver(URIResolver resolver)
  {
    userResolver = resolver;
  }

  public URIResolver getURIResolver()
  {
    return userResolver;
  }

  public void setFeature(String name, boolean value)
    throws TransformerConfigurationException
  {
    throw new TransformerConfigurationException("not supported");
  }

  public boolean getFeature(String name)
  {
    if (SAXSource.FEATURE.equals(name) ||
        SAXResult.FEATURE.equals(name) ||
        StreamSource.FEATURE.equals(name) ||
        StreamResult.FEATURE.equals(name) ||
        DOMSource.FEATURE.equals(name) ||
        DOMResult.FEATURE.equals(name))
      {
        return true;
      }
    return false;
  }

  public void setAttribute(String name, Object value)
    throws IllegalArgumentException
  {
    throw new IllegalArgumentException("not supported");
  }

  public Object getAttribute(String name)
    throws IllegalArgumentException
  {
    throw new IllegalArgumentException("not supported");
  }

  public void setErrorListener(ErrorListener listener)
    throws IllegalArgumentException
  {
    userListener = listener;
  }

  public ErrorListener getErrorListener()
  {
    return userListener;
  }
  
}
