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.
/**
 *  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 org.apache.catalina.authenticator.jaspic;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.util.digester.Digester;
import org.apache.tomcat.util.res.StringManager;
import org.xml.sax.SAXException;

Utility class for the loading and saving of JASPIC persistent provider
registrations.
/**
 * Utility class for the loading and saving of JASPIC persistent provider
 * registrations.
 */
final class PersistentProviderRegistrations {

    private static final StringManager sm =
            StringManager.getManager(PersistentProviderRegistrations.class);


    private PersistentProviderRegistrations() {
        // Utility class. Hide default constructor
    }


    static Providers loadProviders(File configFile) {
        try (InputStream is = new FileInputStream(configFile)) {
            // Construct a digester to read the XML input file
            Digester digester = new Digester();

            try {
                digester.setFeature("http://apache.org/xml/features/allow-java-encodings", true);
                digester.setValidating(true);
                digester.setNamespaceAware(true);
            } catch (Exception e) {
                throw new SecurityException(e);
            }

            // Create an object to hold the parse results and put it on the top
            // of the digester's stack
            Providers result = new Providers();
            digester.push(result);

            // Configure the digester
            digester.addObjectCreate("jaspic-providers/provider", Provider.class.getName());
            digester.addSetProperties("jaspic-providers/provider");
            digester.addSetNext("jaspic-providers/provider", "addProvider", Provider.class.getName());

            digester.addObjectCreate("jaspic-providers/provider/property", Property.class.getName());
            digester.addSetProperties("jaspic-providers/provider/property");
            digester.addSetNext("jaspic-providers/provider/property", "addProperty", Property.class.getName());

            // Parse the input
            digester.parse(is);

            return result;
        } catch (IOException | SAXException e) {
            throw new SecurityException(e);
        }
    }


    static void writeProviders(Providers providers, File configFile) {
        File configFileOld = new File(configFile.getAbsolutePath() + ".old");
        File configFileNew = new File(configFile.getAbsolutePath() + ".new");

        // Remove left over temporary files if present
        if (configFileOld.exists()) {
            if (configFileOld.delete()) {
                throw new SecurityException(sm.getString(
                        "persistentProviderRegistrations.existsDeleteFail",
                        configFileOld.getAbsolutePath()));
            }
        }
        if (configFileNew.exists()) {
            if (configFileNew.delete()) {
                throw new SecurityException(sm.getString(
                        "persistentProviderRegistrations.existsDeleteFail",
                        configFileNew.getAbsolutePath()));
            }
        }

        // Write out the providers to the temporary new file
        try (OutputStream fos = new FileOutputStream(configFileNew);
                Writer writer = new OutputStreamWriter(fos, StandardCharsets.UTF_8)) {
            writer.write(
                    "<?xml version='1.0' encoding='utf-8'?>\n" +
                    "<jaspic-providers\n" +
                    "    xmlns=\"http://tomcat.apache.org/xml\"\n" +
                    "    xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n" +
                    "    xsi:schemaLocation=\"http://tomcat.apache.org/xml jaspic-providers.xsd\"\n" +
                    "    version=\"1.0\">\n");
            for (Provider provider : providers.providers) {
                writer.write("  <provider");
                writeOptional("className", provider.getClassName(), writer);
                writeOptional("layer", provider.getLayer(), writer);
                writeOptional("appContext", provider.getAppContext(), writer);
                writeOptional("description", provider.getDescription(), writer);
                writer.write(">\n");
                for (Entry<String,String> entry : provider.getProperties().entrySet()) {
                    writer.write("    <property name=\"");
                    writer.write(entry.getKey());
                    writer.write("\" value=\"");
                    writer.write(entry.getValue());
                    writer.write("\"/>\n");
                }
                writer.write("  </provider>\n");
            }
            writer.write("</jaspic-providers>\n");
        } catch (IOException e) {
            if (!configFileNew.delete()) {
                Log log = LogFactory.getLog(PersistentProviderRegistrations.class);
                log.warn(sm.getString("persistentProviderRegistrations.deleteFail",
                        configFileNew.getAbsolutePath()));
            }
            throw new SecurityException(e);
        }

        // Move the current file out of the way
        if (configFile.isFile()) {
            if (!configFile.renameTo(configFileOld)) {
                throw new SecurityException(sm.getString("persistentProviderRegistrations.moveFail",
                        configFile.getAbsolutePath(), configFileOld.getAbsolutePath()));
            }
        }

        // Move the new file into place
        if (!configFileNew.renameTo(configFile)) {
            throw new SecurityException(sm.getString("persistentProviderRegistrations.moveFail",
                    configFileNew.getAbsolutePath(), configFile.getAbsolutePath()));
        }

        // Remove the old file
        if (configFileOld.exists() && !configFileOld.delete()) {
            Log log = LogFactory.getLog(PersistentProviderRegistrations.class);
            log.warn(sm.getString("persistentProviderRegistrations.deleteFail",
                    configFileOld.getAbsolutePath()));
        }
    }


    private static void writeOptional(String name, String value, Writer writer) throws IOException {
        if (value != null) {
            writer.write(" " + name + "=\"");
            writer.write(value);
            writer.write("\"");
        }
    }


    public static class Providers {
        private final List<Provider> providers = new ArrayList<>();

        public void addProvider(Provider provider) {
            providers.add(provider);
        }

        public List<Provider> getProviders() {
            return providers;
        }
    }


    public static class Provider {
        private String className;
        private String layer;
        private String appContext;
        private String description;
        private final Map<String,String> properties = new HashMap<>();


        public String getClassName() {
            return className;
        }
        public void setClassName(String className) {
            this.className = className;
        }


        public String getLayer() {
            return layer;
        }
        public void setLayer(String layer) {
            this.layer = layer;
        }


        public String getAppContext() {
            return appContext;
        }
        public void setAppContext(String appContext) {
            this.appContext = appContext;
        }


        public String getDescription() {
            return description;
        }
        public void setDescription(String description) {
            this.description = description;
        }


        public void addProperty(Property property) {
            properties.put(property.getName(), property.getValue());
        }
        void addProperty(String name, String value) {
            properties.put(name, value);
        }
        public Map<String,String> getProperties() {
            return properties;
        }
    }


    public static class Property {
        private String name;
        private String value;


        public String getName() {
            return name;
        }
        public void setName(String name) {
            this.name = name;
        }


        public String getValue() {
            return value;
        }
        public void setValue(String value) {
            this.value = value;
        }
    }
}