/*

 * Copyright (c) 1999, 2017, 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 java.lang;

import java.io.PrintStream;

import java.util.Arrays;

import java.util.List;

import java.util.Optional;

class VersionProps {

    private static final String launcher_name =

        "@@LAUNCHER_NAME@@";

    private static final String java_version =

        "@@VERSION_SHORT@@";

    private static final String java_version_date =

        "@@VERSION_DATE@@";

    private static final String java_runtime_name =

        "@@RUNTIME_NAME@@";

    private static final String java_runtime_version =

        "@@VERSION_STRING@@";

    private static final String VERSION_NUMBER =

        "@@VERSION_NUMBER@@";

    private static final String VERSION_BUILD =

        "@@VERSION_BUILD@@";

    private static final String VERSION_PRE =

        "@@VERSION_PRE@@";

    private static final String VERSION_OPT =

        "@@VERSION_OPT@@";

    private static final boolean isLTS =

        "@@VERSION_OPT@@".startsWith("LTS");

    private static final String VENDOR_VERSION_STRING =

        "@@VENDOR_VERSION_STRING@@";

    private static final String vendor_version =

        (VENDOR_VERSION_STRING.length() > 0

         ? " " + VENDOR_VERSION_STRING : "");

    static {

        init();

    }

    public static void init() {

        System.setProperty("java.version", java_version);

        System.setProperty("java.version.date", java_version_date);

        System.setProperty("java.runtime.version", java_runtime_version);

        System.setProperty("java.runtime.name", java_runtime_name);

        if (VENDOR_VERSION_STRING.length() > 0)

            System.setProperty("java.vendor.version", VENDOR_VERSION_STRING);

    }

    private static int parseVersionNumber(String version, int prevIndex, int index) {

        if (index - prevIndex > 1 &&

            Character.digit(version.charAt(prevIndex), 10) <= 0)

            throw new IllegalArgumentException("Leading zeros not supported (" +

                    version.substring(prevIndex, index) + ")");

        return Integer.parseInt(version, prevIndex, index, 10);

    }

    // This method is reflectively used by regression tests.

    static List<Integer> parseVersionNumbers(String version) {

        // Let's find the size of an array required to hold $VNUM components

        int size = 0;

        int prevIndex = 0;

        do {

            prevIndex = version.indexOf('.', prevIndex) + 1;

            size++;

        } while (prevIndex > 0);

        Integer[] verNumbers = new Integer[size];

        // Fill in the array with $VNUM components

        int n = 0;

        prevIndex = 0;

        int index = version.indexOf('.');

        while (index > -1) {

            verNumbers[n] = parseVersionNumber(version, prevIndex, index);

            prevIndex = index + 1; // Skip the period

            index = version.indexOf('.', prevIndex);

            n++;

        }

        verNumbers[n] = parseVersionNumber(version, prevIndex, version.length());

        if (verNumbers[0] == 0 || verNumbers[n] == 0)

            throw new IllegalArgumentException("Leading/trailing zeros not allowed (" +

                    Arrays.toString(verNumbers) + ")");

        return List.of(verNumbers);

    }

    static List<Integer> versionNumbers() {

        return parseVersionNumbers(VERSION_NUMBER);

    }

    static Optional<String> pre() {

        return optionalOf(VERSION_PRE);

    }

    static Optional<Integer> build() {

        return VERSION_BUILD.isEmpty() ?

                Optional.empty() :

                Optional.of(Integer.parseInt(VERSION_BUILD));

    }

    static Optional<String> optional() {

        return optionalOf(VERSION_OPT);

    }

    // Treat empty strings as value not being present

    private static Optional<String> optionalOf(String value) {

        if (!value.isEmpty()) {

            return Optional.of(value);

        } else {

            return Optional.empty();

        }

    }

    /**

     * In case you were wondering this method is called by java -version.

     */

    public static void print(boolean err) {

        print(err, false);

    }

    /**

     * This is the same as print except that it adds an extra line-feed

     * at the end, typically used by the -showversion in the launcher

     */

    public static void println(boolean err) {

        print(err, true);

    }

    /**

     * Print version info.

     */

    private static void print(boolean err, boolean newln) {

        PrintStream ps = err ? System.err : System.out;

        /* First line: platform version. */

        if (err) {

            ps.println(launcher_name + " version \"" + java_version + "\""

                       + " " + java_version_date

                       + (isLTS ? " LTS" : ""));

        } else {

            /* Use a format more in line with GNU conventions */

            ps.println(launcher_name + " " + java_version

                       + " " + java_version_date

                       + (isLTS ? " LTS" : ""));

        }

        /* Second line: runtime version (ie, libraries). */

        String jdk_debug_level = System.getProperty("jdk.debug", "release");

        if ("release".equals(jdk_debug_level)) {

           /* Do not show debug level "release" builds */

            jdk_debug_level = "";

        } else {

            jdk_debug_level = jdk_debug_level + " ";

        }

        ps.println(java_runtime_name + vendor_version

                   + " (" + jdk_debug_level + "build " + java_runtime_version + ")");

        /* Third line: JVM information. */

        String java_vm_name    = System.getProperty("java.vm.name");

        String java_vm_version = System.getProperty("java.vm.version");

        String java_vm_info    = System.getProperty("java.vm.info");

        ps.println(java_vm_name + vendor_version

                   + " (" + jdk_debug_level + "build " + java_vm_version + ", "

                            + java_vm_info + ")");

    }

}