/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/**

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements. See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership. The ASF licenses this file

 * to you 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, Oracle and/or its affiliates. All rights reserved.

 */

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.

 *

 */

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<String> 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);

    }

    @SuppressWarnings("unchecked")

    public List<String> getParameterSpecPrefixList(ExcC14NParameterSpec paramSpec) {

        return paramSpec.getPrefixList();

    }

    @Override

    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 eElem = DOMUtils.createElement(ownerDoc,

                                               "InclusiveNamespaces",

                                               CanonicalizationMethod.EXCLUSIVE,

                                               prefix);

        if (prefix == null || prefix.length() == 0) {

            eElem.setAttributeNS("http://www.w3.org/2000/xmlns/", "xmlns",

                                 CanonicalizationMethod.EXCLUSIVE);

        } else {

            eElem.setAttributeNS("http://www.w3.org/2000/xmlns/",

                                   "xmlns:" + prefix,

                                   CanonicalizationMethod.EXCLUSIVE);

        }

        ExcC14NParameterSpec params = (ExcC14NParameterSpec)spec;

        StringBuilder prefixListAttr = new StringBuilder("");

        List<String> prefixList = getParameterSpecPrefixList(params);

        for (int i = 0, size = prefixList.size(); i < size; i++) {

            prefixListAttr.append(prefixList.get(i));

            if (i < size - 1) {

                prefixListAttr.append(' ');

            }

        }

        DOMUtils.setAttribute(eElem, "PrefixList", prefixListAttr.toString());

        this.inclusiveNamespaces = prefixListAttr.toString();

        transformElem.appendChild(eElem);

    }

    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 {

                    canonicalizer = Canonicalizer.getInstance

                        (CanonicalizationMethod.EXCLUSIVE);

                } catch (InvalidCanonicalizerException ice) {

                    throw new TransformException

                        ("Couldn't find Canonicalizer for: " +

                         CanonicalizationMethod.EXCLUSIVE + ": " +

                         ice.getMessage(), ice);

                }

            }

        }

        return canonicalize(data, xc);

    }

}