/*

 * Copyright (c) 2018, 2021, 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.

 */

package jdk.internal.util;

import java.lang.annotation.Native;

import java.util.HashMap;

import java.util.Map;

/**

 * System Property initialization for internal use only

 * Retrieves the platform, JVM, and command line properties,

 * applies initial defaults and returns the Properties instance

 * that becomes the System.getProperties instance.

 */

public final class SystemProps {

    // no instances

    private SystemProps() {}

    /**

     * Create and initialize the system properties from the native properties

     * and command line properties.

     * Note:  Build-defined properties such as versions and vendor information

     * are initialized by VersionProps.java-template.

     *

     * @return a Properties instance initialized with all of the properties

     */

    public static Map<String, String> initProperties() {

        // Initially, cmdProperties only includes -D and props from the VM

        Raw raw = new Raw();

        HashMap<String, String> props = raw.cmdProperties();

        String javaHome = props.get("java.home");

        assert javaHome != null : "java.home not set";

        putIfAbsent(props, "user.home", raw.propDefault(Raw._user_home_NDX));

        putIfAbsent(props, "user.dir", raw.propDefault(Raw._user_dir_NDX));

        putIfAbsent(props, "user.name", raw.propDefault(Raw._user_name_NDX));

        // Platform defined encoding cannot be overridden on the command line

        put(props, "sun.jnu.encoding", raw.propDefault(Raw._sun_jnu_encoding_NDX));

        var nativeEncoding = ((raw.propDefault(Raw._file_encoding_NDX) == null)

                ? raw.propDefault(Raw._sun_jnu_encoding_NDX)

                : raw.propDefault(Raw._file_encoding_NDX));

        put(props, "native.encoding", nativeEncoding);

        // Add properties that have not been overridden on the cmdline

        putIfAbsent(props, "file.encoding", nativeEncoding);

        // Use platform values if not overridden by a commandline -Dkey=value

        // In no particular order

        putIfAbsent(props, "os.name", raw.propDefault(Raw._os_name_NDX));

        putIfAbsent(props, "os.arch", raw.propDefault(Raw._os_arch_NDX));

        putIfAbsent(props, "os.version", raw.propDefault(Raw._os_version_NDX));

        putIfAbsent(props, "line.separator", raw.propDefault(Raw._line_separator_NDX));

        putIfAbsent(props, "file.separator", raw.propDefault(Raw._file_separator_NDX));

        putIfAbsent(props, "path.separator", raw.propDefault(Raw._path_separator_NDX));

        putIfAbsent(props, "java.io.tmpdir", raw.propDefault(Raw._java_io_tmpdir_NDX));

        putIfAbsent(props, "http.proxyHost", raw.propDefault(Raw._http_proxyHost_NDX));

        putIfAbsent(props, "http.proxyPort", raw.propDefault(Raw._http_proxyPort_NDX));

        putIfAbsent(props, "https.proxyHost", raw.propDefault(Raw._https_proxyHost_NDX));

        putIfAbsent(props, "https.proxyPort", raw.propDefault(Raw._https_proxyPort_NDX));

        putIfAbsent(props, "ftp.proxyHost", raw.propDefault(Raw._ftp_proxyHost_NDX));

        putIfAbsent(props, "ftp.proxyPort", raw.propDefault(Raw._ftp_proxyPort_NDX));

        putIfAbsent(props, "socksProxyHost", raw.propDefault(Raw._socksProxyHost_NDX));

        putIfAbsent(props, "socksProxyPort", raw.propDefault(Raw._socksProxyPort_NDX));

        putIfAbsent(props, "http.nonProxyHosts", raw.propDefault(Raw._http_nonProxyHosts_NDX));

        putIfAbsent(props, "ftp.nonProxyHosts", raw.propDefault(Raw._ftp_nonProxyHosts_NDX));

        putIfAbsent(props, "socksNonProxyHosts", raw.propDefault(Raw._socksNonProxyHosts_NDX));

        putIfAbsent(props, "sun.arch.abi", raw.propDefault(Raw._sun_arch_abi_NDX));

        putIfAbsent(props, "sun.arch.data.model", raw.propDefault(Raw._sun_arch_data_model_NDX));

        putIfAbsent(props, "sun.os.patch.level", raw.propDefault(Raw._sun_os_patch_level_NDX));

        putIfAbsent(props, "sun.stdout.encoding", raw.propDefault(Raw._sun_stdout_encoding_NDX));

        putIfAbsent(props, "sun.stderr.encoding", raw.propDefault(Raw._sun_stderr_encoding_NDX));

        putIfAbsent(props, "sun.io.unicode.encoding", raw.propDefault(Raw._sun_io_unicode_encoding_NDX));

        putIfAbsent(props, "sun.cpu.isalist", raw.propDefault(Raw._sun_cpu_isalist_NDX));

        putIfAbsent(props, "sun.cpu.endian", raw.propDefault(Raw._sun_cpu_endian_NDX));

        /* Construct i18n related options */

        fillI18nProps(props,"user.language", raw.propDefault(Raw._display_language_NDX),

                raw.propDefault(Raw._format_language_NDX));

        fillI18nProps(props,"user.script",   raw.propDefault(Raw._display_script_NDX),

                raw.propDefault(Raw._format_script_NDX));

        fillI18nProps(props,"user.country",  raw.propDefault(Raw._display_country_NDX),

                raw.propDefault(Raw._format_country_NDX));

        fillI18nProps(props,"user.variant",  raw.propDefault(Raw._display_variant_NDX),

                raw.propDefault(Raw._format_variant_NDX));

        return props;

    }

    /**

     * Puts the property if it is non-null

     * @param props the Properties

     * @param key the key

     * @param value the value

     */

    private static void put(HashMap<String, String> props, String key, String value) {

        if (value != null) {

            props.put(key, value);

        }

    }

    /**

     * Puts the property if it is non-null and is not already in the Properties.

     * @param props the Properties

     * @param key the key

     * @param value the value

     */

    private static void putIfAbsent(HashMap<String, String> props, String key, String value) {

        if (value != null) {

            props.putIfAbsent(key, value);

        }

    }

    /**

     * For internationalization options, compute the values for

     * display and format properties

     * MUST NOT override command line defined values.

     *

     * @param base the base property name

     * @param display the display value for the base

     * @param format the format value for the base

     */

    private static void fillI18nProps(HashMap<String, String> cmdProps,

                                      String base,

                                      String display,

                                      String format) {

        // Do not override command line setting

        String baseValue = cmdProps.get(base);

        if (baseValue != null) {

            return;     // Do not override value from the command line

        }

        // Not overridden on the command line; define the properties if there are platform defined values

        if (display != null) {

            cmdProps.put(base, display);

            baseValue = display;

        }

        /* user.xxx.display property */

        String disp = base.concat(".display");

        String dispValue = cmdProps.get(disp);

        if (dispValue == null && display != null && !display.equals(baseValue)) {

            // Create the property only if different from the base property

            cmdProps.put(disp, display);

        }

        /* user.xxx.format property */

        String fmt = base.concat(".format");

        String fmtValue = cmdProps.get(fmt);

        if (fmtValue == null && format != null && !format.equals(baseValue)) {

            // Create the property only if different than the base property

            cmdProps.put(fmt, format);

        }

    }

    /**

     * Read the raw properties from native System.c.

     */

    public static class Raw {

        // Array indices written by native vmProperties()

        // The order is arbitrary (but alphabetic for convenience)

        @Native private static final int _display_country_NDX = 0;

        @Native private static final int _display_language_NDX = 1 + _display_country_NDX;

        @Native private static final int _display_script_NDX = 1 + _display_language_NDX;

        @Native private static final int _display_variant_NDX = 1 + _display_script_NDX;

        @Native private static final int _file_encoding_NDX = 1 + _display_variant_NDX;

        @Native private static final int _file_separator_NDX = 1 + _file_encoding_NDX;

        @Native private static final int _format_country_NDX = 1 + _file_separator_NDX;

        @Native private static final int _format_language_NDX = 1 + _format_country_NDX;

        @Native private static final int _format_script_NDX = 1 + _format_language_NDX;

        @Native private static final int _format_variant_NDX = 1 + _format_script_NDX;

        @Native private static final int _ftp_nonProxyHosts_NDX = 1 + _format_variant_NDX;

        @Native private static final int _ftp_proxyHost_NDX = 1 + _ftp_nonProxyHosts_NDX;

        @Native private static final int _ftp_proxyPort_NDX = 1 + _ftp_proxyHost_NDX;

        @Native private static final int _http_nonProxyHosts_NDX = 1 + _ftp_proxyPort_NDX;

        @Native private static final int _http_proxyHost_NDX = 1 + _http_nonProxyHosts_NDX;

        @Native private static final int _http_proxyPort_NDX = 1 + _http_proxyHost_NDX;

        @Native private static final int _https_proxyHost_NDX = 1 + _http_proxyPort_NDX;

        @Native private static final int _https_proxyPort_NDX = 1 + _https_proxyHost_NDX;

        @Native private static final int _java_io_tmpdir_NDX = 1 + _https_proxyPort_NDX;

        @Native private static final int _line_separator_NDX = 1 + _java_io_tmpdir_NDX;

        @Native private static final int _os_arch_NDX = 1 + _line_separator_NDX;

        @Native private static final int _os_name_NDX = 1 + _os_arch_NDX;

        @Native private static final int _os_version_NDX = 1 + _os_name_NDX;

        @Native private static final int _path_separator_NDX = 1 + _os_version_NDX;

        @Native private static final int _socksNonProxyHosts_NDX = 1 + _path_separator_NDX;

        @Native private static final int _socksProxyHost_NDX = 1 + _socksNonProxyHosts_NDX;

        @Native private static final int _socksProxyPort_NDX = 1 + _socksProxyHost_NDX;

        @Native private static final int _sun_arch_abi_NDX = 1 + _socksProxyPort_NDX;

        @Native private static final int _sun_arch_data_model_NDX = 1 + _sun_arch_abi_NDX;

        @Native private static final int _sun_cpu_endian_NDX = 1 + _sun_arch_data_model_NDX;

        @Native private static final int _sun_cpu_isalist_NDX = 1 + _sun_cpu_endian_NDX;

        @Native private static final int _sun_io_unicode_encoding_NDX = 1 + _sun_cpu_isalist_NDX;

        @Native private static final int _sun_jnu_encoding_NDX = 1 + _sun_io_unicode_encoding_NDX;

        @Native private static final int _sun_os_patch_level_NDX = 1 + _sun_jnu_encoding_NDX;

        @Native private static final int _sun_stderr_encoding_NDX = 1 + _sun_os_patch_level_NDX;

        @Native private static final int _sun_stdout_encoding_NDX = 1 + _sun_stderr_encoding_NDX;

        @Native private static final int _user_dir_NDX = 1 + _sun_stdout_encoding_NDX;

        @Native private static final int _user_home_NDX = 1 + _user_dir_NDX;

        @Native private static final int _user_name_NDX = 1 + _user_home_NDX;

        @Native private static final int FIXED_LENGTH = 1 + _user_name_NDX;

        // Array of Strings returned from the VM and Command line properties

        // The array is not used after initialization is complete.

        private final String[] platformProps;

        private Raw() {

            platformProps = platformProperties();

        }

        /**

         * Return the value for a well known default from native.

         * @param index the index of the known property

         * @return the value

         */

        String propDefault(int index) {

            return platformProps[index];

        }

        /**

         * Return a Properties instance of the command line and VM options

         * defined by name and value.

         * The Properties instance is sized to include the fixed properties.

         *

         * @return return a Properties instance of the command line and VM options

         */

        private HashMap<String, String> cmdProperties() {

            String[] vmProps = vmProperties();

            // While optimal initialCapacity here would be the exact number of properties

            // divided by LOAD_FACTOR, a large portion of the properties in Raw are

            // usually not set, so for typical cases the chosen capacity avoids resizing

            var cmdProps = new HashMap<String, String>((vmProps.length / 2) + Raw.FIXED_LENGTH);

            for (int i = 0; i < vmProps.length;) {

                String k = vmProps[i++];

                if (k != null) {

                    String v = vmProps[i++];

                    cmdProps.put(k, v != null ? v : "");

                } else {

                    // no more key/value pairs

                    break;

                }

            }

            return cmdProps;

        }

        /**

         * Returns the available VM and Command Line Properties.

         * The VM supplies some key/value pairs and processes the command line

         * to extract key/value pairs from the {@code "-Dkey=value"} arguments.

         *

         * @return an array of strings, with alternating key and value strings.

         *      Either keys or values may be null, the array may not be full.

         *      The first null key indicates there are no more key, value pairs.

         */

        private static native String[] vmProperties();

        /**

         * Returns the platform specific property values identified

         * by {@code "_xxx_NDX"} indexes.

         * The indexes are strictly private, to be shared only with the native code.

         *

         * @return a array of strings, the properties are indexed by the {@code _xxx_NDX}

         * indexes.  The values are Strings and may be null.

         */

        private static native String[] platformProperties();

    }

}