/*
 * reserved comment block
 * DO NOT REMOVE OR ALTER!
 */
/*
 * Copyright 2005 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 (c) 2005, 2008, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * $Id: DOMExcC14NMethod.java,v 1.2 2008/07/24 15:20:32 mullan Exp $
 */
package org.jcp.xml.dsig.internal.dom;

import javax.xml.crypto.*;
import javax.xml.crypto.dsig.*;
import javax.xml.crypto.dsig.spec.C14NMethodParameterSpec;
import javax.xml.crypto.dsig.spec.ExcC14NParameterSpec;
import javax.xml.crypto.dsig.spec.TransformParameterSpec;

import java.security.InvalidAlgorithmParameterException;
import java.security.spec.AlgorithmParameterSpec;
import java.util.*;
import org.w3c.dom.Element;

import com.sun.org.apache.xml.internal.security.c14n.Canonicalizer;
import com.sun.org.apache.xml.internal.security.c14n.InvalidCanonicalizerException;

/**
 * DOM-based implementation of CanonicalizationMethod for Exclusive
 * Canonical XML algorithm (with or without comments).
 * Uses Apache XML-Sec Canonicalizer.
 *
 * @author Sean Mullan
 */
public final class DOMExcC14NMethod extends ApacheCanonicalizer {

    public void init(TransformParameterSpec params)
        throws InvalidAlgorithmParameterException {
        if (params != null) {
            if (!(params instanceof ExcC14NParameterSpec)) {
                throw new InvalidAlgorithmParameterException
                    ("params must be of type ExcC14NParameterSpec");
            }
            this.params = (C14NMethodParameterSpec) params;
        }
    }

    public void init(XMLStructure parent, XMLCryptoContext context)
        throws InvalidAlgorithmParameterException {
        super.init(parent, context);
        Element paramsElem = DOMUtils.getFirstChildElement(transformElem);
        if (paramsElem == null) {
            this.params = null;
            this.inclusiveNamespaces = null;
            return;
        }
        unmarshalParams(paramsElem);
    }

    private void unmarshalParams(Element paramsElem) {
        String prefixListAttr = paramsElem.getAttributeNS(null, "PrefixList");
        this.inclusiveNamespaces = prefixListAttr;
        int begin = 0;
        int end = prefixListAttr.indexOf(' ');
        List prefixList = new ArrayList();
        while (end != -1) {
            prefixList.add(prefixListAttr.substring(begin, end));
            begin = end + 1;
            end = prefixListAttr.indexOf(' ', begin);
        }
        if (begin <= prefixListAttr.length()) {
            prefixList.add(prefixListAttr.substring(begin));
        }
        this.params = new ExcC14NParameterSpec(prefixList);
    }

    public void marshalParams(XMLStructure parent, XMLCryptoContext context)
        throws MarshalException {

        super.marshalParams(parent, context);
        AlgorithmParameterSpec spec = getParameterSpec();
        if (spec == null) {
            return;
        }

        String prefix =
            DOMUtils.getNSPrefix(context, CanonicalizationMethod.EXCLUSIVE);
        Element excElem = DOMUtils.createElement
            (ownerDoc, "InclusiveNamespaces",
             CanonicalizationMethod.EXCLUSIVE, prefix);
        if (prefix == null || prefix.length() == 0) {
            excElem.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns",
                CanonicalizationMethod.EXCLUSIVE);
        } else {
            excElem.setAttributeNS("http://www.w3.org/2000/xmlns/",
                "xmlns:" + prefix, CanonicalizationMethod.EXCLUSIVE);
        }

        ExcC14NParameterSpec params = (ExcC14NParameterSpec) spec;
        StringBuffer prefixListAttr = new StringBuffer("");
        List prefixList = params.getPrefixList();
        for (int i = 0, size = prefixList.size(); i < size; i++) {
            prefixListAttr.append((String) prefixList.get(i));
            if (i < size - 1) {
                prefixListAttr.append(" ");
            }
        }
        DOMUtils.setAttribute(excElem, "PrefixList", prefixListAttr.toString());
        this.inclusiveNamespaces = prefixListAttr.toString();
        transformElem.appendChild(excElem);
    }

    public String getParamsNSURI() {
        return CanonicalizationMethod.EXCLUSIVE;
    }

    public Data transform(Data data, XMLCryptoContext xc)
        throws TransformException {

        // ignore comments if dereferencing same-document URI that require
        // you to omit comments, even if the Transform says otherwise -
        // this is to be compliant with section 4.3.3.3 of W3C Rec.
        if (data instanceof DOMSubTreeData) {
            DOMSubTreeData subTree = (DOMSubTreeData) data;
            if (subTree.excludeComments()) {
                try {
                    apacheCanonicalizer = Canonicalizer.getInstance
                        (CanonicalizationMethod.EXCLUSIVE);
                } catch (InvalidCanonicalizerException ice) {
                    throw new TransformException
                        ("Couldn't find Canonicalizer for: " +
                         CanonicalizationMethod.EXCLUSIVE + ": " +
                         ice.getMessage(), ice);
                }
            }
        }

        return canonicalize(data, xc);
    }
}