/*

 * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

import java.io.BufferedReader;

import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.PrintStream;

import java.util.ArrayList;

import java.util.List;

public final class WindowsRegistry {

    private WindowsRegistry() {}

    /**

     * Reads the registry value for DisableRealtimeMonitoring.

     * @return true if DisableRealtimeMonitoring is set to 0x1,

     *         false otherwise.

     */

    public static final boolean readDisableRealtimeMonitoring() {

        boolean result = false;

        final String key = "HKEY_LOCAL_MACHINE\\Software\\Microsoft\\"

                  + "Windows Defender\\Real-Time Protection";

        final String subkey = "DisableRealtimeMonitoring";

        String value = readRegistry(key, subkey);

        if (!value.isEmpty()) {

            // This code could be written better but this works. It validates

            // that the result of readRegistry returned what we expect and then

            // checks for a 0x0 or 0x1. 0x0 means real time monitoring is

            // on, 0x1 means it is off. So this function returns true if

            // real-time-monitoring is disabled.

            int index = value.indexOf(subkey);

            value = value.substring(index + subkey.length());

            String reg = "REG_DWORD";

            index = value.indexOf(reg);

            value = value.substring(index + reg.length());

            String hex = "0x";

            index = value.indexOf(hex);

            value = value.substring(index + hex.length());

            if (value.equals("1")) {

                result = true;

            }

        }

        return result;

    }

    public static final List<String> readExclusionsPaths() {

        List<String> result = new ArrayList<String>();

        final String key = "HKEY_LOCAL_MACHINE\\Software\\Microsoft\\"

                + "Windows Defender\\Exclusions\\Paths";

        String value = readRegistry(key, "");

        if (!value.isEmpty()) {

            final String reg = "REG_DWORD";

            final String hex = "0x0";

            int index = value.indexOf(key);

            if (index == 0) {

                value = value.substring(index + key.length());

                while (value.length() > 0) {

                    index = value.indexOf(reg);

                    String name = value.substring(0, index);

                    value = value.substring(index + reg.length());

                    index = value.indexOf(hex);

                    value = value.substring(index + hex.length());

                    if (index > 0) {

                        name = name.trim();

                        result.add(name);

                    }

                }

            }

        }

        return result;

    }

    /**

     * @param key in the registry

     * @param subkey in the registry key

     * @return registry value or null if not found

     */

    public static final String readRegistry(String key, String subkey){

        String result = "";

        try {

            List<String> buildOptions = new ArrayList<>();

            buildOptions.add("reg");

            buildOptions.add("query");

            buildOptions.add("\"" + key + "\"");

            if (!subkey.isEmpty()) {

                buildOptions.add("/v");

                buildOptions.add(subkey);

            }

            try (ByteArrayOutputStream baos = new ByteArrayOutputStream();

                    PrintStream ps = new PrintStream(baos)) {

                ProcessBuilder security = new ProcessBuilder(buildOptions);

                exec(security, false, false, ps);

                BufferedReader bfReader = new BufferedReader(

                        new InputStreamReader(

                        new ByteArrayInputStream(baos.toByteArray())));

                String line = null;

                while((line = bfReader.readLine()) != null){

                    result += line;

                }

            }

            catch (IOException e) {

            }

        }

        catch (Exception e) {

        }

        return result;

    }

}