/*

 * 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

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

 *

 * 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.

 *

 */

package sun.awt;

import java.security.PrivilegedAction;

import java.util.HashMap;

import java.util.Map;

import static sun.awt.OSInfo.OSType.*;

/**

 * @author Pavel Porvatov

 */

public class OSInfo {

    public static enum OSType {

        WINDOWS,

        LINUX,

        SOLARIS,

        UNKNOWN

    }

    /*

       The map windowsVersionMap must contain all windows version constants except WINDOWS_UNKNOWN,

       and so the method getWindowsVersion() will return the constant for known OS.

       It allows compare objects by "==" instead of "equals".

     */

    public static final WindowsVersion WINDOWS_UNKNOWN = new WindowsVersion(-1, -1);

    public static final WindowsVersion WINDOWS_95 = new WindowsVersion(4, 0);

    public static final WindowsVersion WINDOWS_98 = new WindowsVersion(4, 10);

    public static final WindowsVersion WINDOWS_ME = new WindowsVersion(4, 90);

    public static final WindowsVersion WINDOWS_2000 = new WindowsVersion(5, 0);

    public static final WindowsVersion WINDOWS_XP = new WindowsVersion(5, 1);

    public static final WindowsVersion WINDOWS_2003 = new WindowsVersion(5, 2);

    public static final WindowsVersion WINDOWS_VISTA = new WindowsVersion(6, 0);

    private static final String OS_NAME = "os.name";

    private static final String OS_VERSION = "os.version";

    private final static Map<String, WindowsVersion> windowsVersionMap = new HashMap<String, OSInfo.WindowsVersion>();

    static {

        windowsVersionMap.put(WINDOWS_95.toString(), WINDOWS_95);

        windowsVersionMap.put(WINDOWS_98.toString(), WINDOWS_98);

        windowsVersionMap.put(WINDOWS_ME.toString(), WINDOWS_ME);

        windowsVersionMap.put(WINDOWS_2000.toString(), WINDOWS_2000);

        windowsVersionMap.put(WINDOWS_XP.toString(), WINDOWS_XP);

        windowsVersionMap.put(WINDOWS_2003.toString(), WINDOWS_2003);

        windowsVersionMap.put(WINDOWS_VISTA.toString(), WINDOWS_VISTA);

    }

    private static final PrivilegedAction<OSType> osTypeAction = new PrivilegedAction<OSType>() {

        public OSType run() {

            return getOSType();

        }

    };

    private OSInfo() {

        // Don't allow to create instances

    }

    /**

     * Returns type of operating system.

     */

    public static OSType getOSType() throws SecurityException {

        String osName = System.getProperty(OS_NAME);

        if (osName != null) {

            if (osName.contains("Windows")) {

                return WINDOWS;

            }

            if (osName.contains("Linux")) {

                return LINUX;

            }

            if (osName.contains("Solaris") || osName.contains("SunOS")) {

                return SOLARIS;

            }

            // determine another OS here

        }

        return UNKNOWN;

    }

    public static PrivilegedAction<OSType> getOSTypeAction() {

        return osTypeAction;

    }

    public static WindowsVersion getWindowsVersion() throws SecurityException {

        String osVersion = System.getProperty(OS_VERSION);

        if (osVersion == null) {

            return WINDOWS_UNKNOWN;

        }

        synchronized (windowsVersionMap) {

            WindowsVersion result = windowsVersionMap.get(osVersion);

            if (result == null) {

                // Try parse version and put object into windowsVersionMap

                String[] arr = osVersion.split("\\.");

                if (arr.length == 2) {

                    try {

                        result = new WindowsVersion(Integer.parseInt(arr[0]), Integer.parseInt(arr[1]));

                    } catch (NumberFormatException e) {

                        return WINDOWS_UNKNOWN;

                    }

                } else {

                    return WINDOWS_UNKNOWN;

                }

                windowsVersionMap.put(osVersion, result);

            }

            return result;

        }

    }

    public static class WindowsVersion implements Comparable<WindowsVersion> {

        private final int major;

        private final int minor;

        private WindowsVersion(int major, int minor) {

            this.major = major;

            this.minor = minor;

        }

        public int getMajor() {

            return major;

        }

        public int getMinor() {

            return minor;

        }

        public int compareTo(WindowsVersion o) {

            int result = major - o.getMajor();

            if (result == 0) {

                result = minor - o.getMinor();

            }

            return result;

        }

        public boolean equals(Object obj) {

            return obj instanceof WindowsVersion && compareTo((WindowsVersion) obj) == 0;

        }

        public int hashCode() {

            return 31 * major + minor;

        }

        public String toString() {

            return major + "." + minor;

        }

    }

}