/*

 * 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.

 */

package com.sun.org.apache.xml.internal.security;

import java.io.InputStream;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.security.PrivilegedActionException;

import java.security.PrivilegedExceptionAction;

import java.util.ArrayList;

import java.util.List;

import javax.xml.parsers.DocumentBuilder;

import com.sun.org.apache.xml.internal.security.algorithms.JCEMapper;

import com.sun.org.apache.xml.internal.security.algorithms.SignatureAlgorithm;

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

import com.sun.org.apache.xml.internal.security.exceptions.XMLSecurityException;

import com.sun.org.apache.xml.internal.security.keys.keyresolver.KeyResolver;

import com.sun.org.apache.xml.internal.security.transforms.Transform;

import com.sun.org.apache.xml.internal.security.utils.ElementProxy;

import com.sun.org.apache.xml.internal.security.utils.I18n;

import com.sun.org.apache.xml.internal.security.utils.XMLUtils;

import com.sun.org.apache.xml.internal.security.utils.resolver.ResourceResolver;

import org.w3c.dom.Attr;

import org.w3c.dom.Document;

import org.w3c.dom.Element;

import org.w3c.dom.Node;

/**

 * This class does the configuration of the library. This includes creating

 * the mapping of Canonicalization and Transform algorithms. Initialization is

 * done by calling {@link Init#init} which should be done in any static block

 * of the files of this library. We ensure that this call is only executed once.

 */

public class Init {

    /** The namespace for CONF file **/

    public static final String CONF_NS = "http://www.xmlsecurity.org/NS/#configuration";

    private static final com.sun.org.slf4j.internal.Logger LOG =

        com.sun.org.slf4j.internal.LoggerFactory.getLogger(Init.class);

    /** Field alreadyInitialized */

    private static boolean alreadyInitialized = false;

    /**

     * Method isInitialized

     * @return true if the library is already initialized.

     */

    public static final synchronized boolean isInitialized() {

        return Init.alreadyInitialized;

    }

    /**

     * Method init

     *

     */

    public static synchronized void init() {

        if (alreadyInitialized) {

            return;

        }

        InputStream is =

            AccessController.doPrivileged(

                (PrivilegedAction<InputStream>)

                    () -> {

                        String cfile =

                            System.getProperty("com.sun.org.apache.xml.internal.security.resource.config");

                        if (cfile == null) {

                            return null;

                        }

                        return Init.class.getResourceAsStream(cfile);

                    }

                );

        if (is == null) {

            dynamicInit();

        } else {

            fileInit(is);

        }

        alreadyInitialized = true;

    }

    /**

     * Dynamically initialise the library by registering the default algorithms/implementations

     */

    private static void dynamicInit() {

        //

        // Load the Resource Bundle - the default is the English resource bundle.

        // To load another resource bundle, call I18n.init(...) before calling this

        // method.

        //

        I18n.init("en", "US");

        LOG.debug("Registering default algorithms");

        try {

            AccessController.doPrivileged(new PrivilegedExceptionAction<Void>(){

                @Override public Void run() throws XMLSecurityException {

                    //

                    // Bind the default prefixes

                    //

                    ElementProxy.registerDefaultPrefixes();

                    //

                    // Set the default Transforms

                    //

                    Transform.registerDefaultAlgorithms();

                    //

                    // Set the default signature algorithms

                    //

                    SignatureAlgorithm.registerDefaultAlgorithms();

                    //

                    // Set the default JCE algorithms

                    //

                    JCEMapper.registerDefaultAlgorithms();

                    //

                    // Set the default c14n algorithms

                    //

                    Canonicalizer.registerDefaultAlgorithms();

                    //

                    // Register the default resolvers

                    //

                    ResourceResolver.registerDefaultResolvers();

                    //

                    // Register the default key resolvers

                    //

                    KeyResolver.registerDefaultResolvers();

                    return null;

                }

            });

        } catch (PrivilegedActionException ex) {

            XMLSecurityException xse = (XMLSecurityException)ex.getException();

            LOG.error(xse.getMessage(), xse);

            xse.printStackTrace();

        }

    }

    /**

     * Initialise the library from a configuration file

     */

    private static void fileInit(InputStream is) {

        try {

            /* read library configuration file */

            DocumentBuilder db = XMLUtils.createDocumentBuilder(false);

            Document doc = db.parse(is);

            Node config = doc.getFirstChild();

            for (; config != null; config = config.getNextSibling()) {

                if ("Configuration".equals(config.getLocalName())) {

                    break;

                }

            }

            if (config == null) {

                LOG.error("Error in reading configuration file - Configuration element not found");

                return;

            }

            for (Node el = config.getFirstChild(); el != null; el = el.getNextSibling()) {

                if (Node.ELEMENT_NODE != el.getNodeType()) {

                    continue;

                }

                String tag = el.getLocalName();

                if ("ResourceBundles".equals(tag)) {

                    Element resource = (Element)el;

                    /* configure internationalization */

                    Attr langAttr = resource.getAttributeNodeNS(null, "defaultLanguageCode");

                    Attr countryAttr = resource.getAttributeNodeNS(null, "defaultCountryCode");

                    String languageCode =

                        (langAttr == null) ? null : langAttr.getNodeValue();

                    String countryCode =

                        (countryAttr == null) ? null : countryAttr.getNodeValue();

                    I18n.init(languageCode, countryCode);

                }

                if ("CanonicalizationMethods".equals(tag)) {

                    Element[] list =

                        XMLUtils.selectNodes(el.getFirstChild(), CONF_NS, "CanonicalizationMethod");

                    for (Element element : list) {

                        String uri = element.getAttributeNS(null, "URI");

                        String javaClass =

                            element.getAttributeNS(null, "JAVACLASS");

                        try {

                            Canonicalizer.register(uri, javaClass);

                            LOG.debug("Canonicalizer.register({}, {})", uri, javaClass);

                        } catch (ClassNotFoundException e) {

                            Object exArgs[] = { uri, javaClass };

                            LOG.error(I18n.translate("algorithm.classDoesNotExist", exArgs));

                        }

                    }

                }

                if ("TransformAlgorithms".equals(tag)) {

                    Element[] tranElem =

                        XMLUtils.selectNodes(el.getFirstChild(), CONF_NS, "TransformAlgorithm");

                    for (Element element : tranElem) {

                        String uri = element.getAttributeNS(null, "URI");

                        String javaClass =

                            element.getAttributeNS(null, "JAVACLASS");

                        try {

                            Transform.register(uri, javaClass);

                            LOG.debug("Transform.register({}, {})", uri, javaClass);

                        } catch (ClassNotFoundException e) {

                            Object exArgs[] = { uri, javaClass };

                            LOG.error(I18n.translate("algorithm.classDoesNotExist", exArgs));

                        } catch (NoClassDefFoundError ex) {

                            LOG.warn("Not able to found dependencies for algorithm, I'll keep working.");

                        }

                    }

                }

                if ("JCEAlgorithmMappings".equals(tag)) {

                    Node algorithmsNode = ((Element)el).getElementsByTagName("Algorithms").item(0);

                    if (algorithmsNode != null) {

                        Element[] algorithms =

                            XMLUtils.selectNodes(algorithmsNode.getFirstChild(), CONF_NS, "Algorithm");

                        for (Element element : algorithms) {

                            String id = element.getAttributeNS(null, "URI");

                            JCEMapper.register(id, new JCEMapper.Algorithm(element));

                        }

                    }

                }

                if ("SignatureAlgorithms".equals(tag)) {

                    Element[] sigElems =

                        XMLUtils.selectNodes(el.getFirstChild(), CONF_NS, "SignatureAlgorithm");

                    for (Element sigElem : sigElems) {

                        String uri = sigElem.getAttributeNS(null, "URI");

                        String javaClass =

                            sigElem.getAttributeNS(null, "JAVACLASS");

                        /** $todo$ handle registering */

                        try {

                            SignatureAlgorithm.register(uri, javaClass);

                            LOG.debug("SignatureAlgorithm.register({}, {})", uri, javaClass);

                        } catch (ClassNotFoundException e) {

                            Object exArgs[] = { uri, javaClass };

                            LOG.error(I18n.translate("algorithm.classDoesNotExist", exArgs));

                        }

                    }

                }

                if ("ResourceResolvers".equals(tag)) {

                    Element[] resolverElem =

                        XMLUtils.selectNodes(el.getFirstChild(), CONF_NS, "Resolver");

                    for (Element element : resolverElem) {

                        String javaClass =

                            element.getAttributeNS(null, "JAVACLASS");

                        String description =

                            element.getAttributeNS(null, "DESCRIPTION");

                        if (description != null && description.length() > 0) {

                            LOG.debug("Register Resolver: {}: {}", javaClass, description);

                        } else {

                            LOG.debug("Register Resolver: {}: For unknown purposes", javaClass);

                        }

                        try {

                            ResourceResolver.register(javaClass);

                        } catch (Throwable e) {

                            LOG.warn(

                                 "Cannot register:" + javaClass

                                 + " perhaps some needed jars are not installed",

                                 e

                             );

                        }

                    }

                }

                if ("KeyResolver".equals(tag)){

                    Element[] resolverElem =

                        XMLUtils.selectNodes(el.getFirstChild(), CONF_NS, "Resolver");

                    List<String> classNames = new ArrayList<>(resolverElem.length);

                    for (Element element : resolverElem) {

                        String javaClass =

                            element.getAttributeNS(null, "JAVACLASS");

                        String description =

                            element.getAttributeNS(null, "DESCRIPTION");

                        if (description != null && description.length() > 0) {

                            LOG.debug("Register Resolver: {}: {}", javaClass, description);

                        } else {

                            LOG.debug("Register Resolver: {}: For unknown purposes", javaClass);

                        }

                        classNames.add(javaClass);

                    }

                    KeyResolver.registerClassNames(classNames);

                }

                if ("PrefixMappings".equals(tag)){

                    LOG.debug("Now I try to bind prefixes:");

                    Element[] nl =

                        XMLUtils.selectNodes(el.getFirstChild(), CONF_NS, "PrefixMapping");

                    for (Element element : nl) {

                        String namespace = element.getAttributeNS(null, "namespace");

                        String prefix = element.getAttributeNS(null, "prefix");

                        LOG.debug("Now I try to bind {} to {}", prefix, namespace);

                        ElementProxy.setDefaultPrefix(namespace, prefix);

                    }

                }

            }

        } catch (Exception e) {

            LOG.error("Bad: ", e);

        }

    }

}