/*

   Copyright 2001,2003  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.batik.svggen;

import java.util.Vector;

import org.w3c.dom.Attr;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

/**
 * This utility class converts a standard SVG document that uses
 * attribute into one that uses the CSS style attribute instead
 *
 * @author <a href="mailto:vincent.hardy@eng.sun.com">Vincent Hardy</a>
 * @version $Id: SVGCSSStyler.java,v 1.9 2004/08/18 07:14:59 vhardy Exp $
 */
public class SVGCSSStyler implements SVGSyntax{
    private static final String CSS_PROPERTY_VALUE_SEPARATOR = ":";
    private static final String CSS_RULE_SEPARATOR = ";";
    private static final String SPACE = " ";

    /**
     * Invoking this method removes all the styling attributes
     * (such as 'fill' or 'fill-opacity') from the input element
     * and its descendant and replaces them with their CSS2
     * property counterparts.
     * @param node SVG Node to be converted to use style
     *
     */
    public static void style(final Node node){
        final NamedNodeMap attributes = node.getAttributes();
        if (attributes != null){
            // Has to be an Element, as it has attributes
            // According to spec.
            final Element element = (Element)node;
            final StringBuffer styleAttrBuffer = new StringBuffer();
            final int nAttr = attributes.getLength();
            final Vector toBeRemoved = new Vector();
            for(int i=0; i<nAttr; i++){
                final Attr attr = (Attr)attributes.item(i);
                if(SVGStylingAttributes.set.contains(attr.getName())){
                    // System.out.println("Found new style attribute");
                    styleAttrBuffer.append(attr.getName());
                    styleAttrBuffer.append(CSS_PROPERTY_VALUE_SEPARATOR);
                    styleAttrBuffer.append(attr.getValue());
                    styleAttrBuffer.append(CSS_RULE_SEPARATOR);
                    styleAttrBuffer.append(SPACE);
                    toBeRemoved.addElement(attr.getName());
                }
            }

            if(styleAttrBuffer.length() > 0){
                                // System.out.println("Setting style attribute on node: " + styleAttrBuffer.toString().trim());
                                // There were some styling attributes
                element.setAttributeNS(null,
                                       SVG_STYLE_ATTRIBUTE,
                                       styleAttrBuffer.toString().trim());

                final int n = toBeRemoved.size();
                for(int i=0; i<n; i++)
                    element.removeAttribute((String)toBeRemoved.elementAt(i));
            }
            // else
            // System.out.println("NO STYLE PROPERTIES");
        }

        // Now, process child elements
        final NodeList children = node.getChildNodes();
        final int nChildren = children.getLength();
        for(int i=0; i<nChildren; i++){
            final Node child = children.item(i);
            style(child);
        }

    }
}
