/*
 * Copyright 2006-2009 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.
 *
 */
/*
 * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
 */
package javax.xml.crypto.test.dsig;

import java.io.*;
import java.util.*;
import javax.xml.crypto.*;
import javax.xml.crypto.dsig.*;
import javax.xml.crypto.dsig.dom.DOMValidateContext;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.Element;
import org.w3c.dom.traversal.*;

/**
 * This is a class which performs xml signature validation upon request
 *
 * @author Sean Mullan
 * @author Valerie Peng
 */
public class SignatureValidator {

    private File dir;

    public SignatureValidator(File base) {
	dir = base;
    }

    public boolean validate(String fn, KeySelector ks) throws Exception {
	return validate(fn, ks, null);
    }

    public DOMValidateContext getValidateContext(String fn, KeySelector ks)
	throws Exception {
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        dbf.setNamespaceAware(true);
        dbf.setValidating(false);
        Document doc = dbf.newDocumentBuilder().parse(new File(dir, fn));
        Element sigElement = getSignatureElement(doc);
	if (sigElement == null) {
	    throw new Exception("Couldn't find signature Element");
	}
	DOMValidateContext vc = new DOMValidateContext(ks, sigElement);
	vc.setBaseURI(dir.toURI().toString());
	return vc;
    }

    public boolean validate(String fn, KeySelector ks, URIDereferencer ud)
	throws Exception {

	DOMValidateContext vc = getValidateContext(fn, ks);
	if (ud != null) {
	    vc.setURIDereferencer(ud);
	}

	return validate(vc);
    }

    public boolean validate(DOMValidateContext vc) throws Exception {

        XMLSignatureFactory factory = XMLSignatureFactory.getInstance
            ("DOM", new org.jcp.xml.dsig.internal.dom.XMLDSigRI());
    	XMLSignature signature = factory.unmarshalXMLSignature(vc);
    	boolean coreValidity = signature.validate(vc);
    
    	// Check core validation status
    	if (coreValidity == false) {
    	    // check the validation status of each Reference
    	    Iterator i = signature.getSignedInfo().getReferences().iterator();
    	    for (int j=0; i.hasNext(); j++) {
		Reference reference = (Reference) i.next();
		reference.validate(vc);
    	    }
    	}
        return coreValidity;
    }

    public static Element getSignatureElement(Document doc) {
        NodeIterator ni = ((DocumentTraversal)doc).createNodeIterator(
            doc.getDocumentElement(), NodeFilter.SHOW_ELEMENT, null, false);
        
        for(Node n = ni.nextNode(); n != null; n = ni.nextNode() ) {
            if("Signature".equals(n.getLocalName())) {
                return (Element) n;
            }
        }
        return null;
    }
}