// JNA JARS

// https://github.com/twall/jna#readme

// you need 2 jars : jna-3.5.1.jar and platform-3.5.1.jar



// from : http://ochafik.com/blog/?p=98 , thanks to the author

// see the comments in the  original article for MACOS, Linux implementation



import java.text.DateFormat;

import java.text.SimpleDateFormat;

import java.util.Arrays;

import java.util.Date;

import java.util.List;



import com.sun.jna.*;

import com.sun.jna.win32.*;



/**

  * Utility method to retrieve the idle time on Windows and sample code to test it.

  * JNA shall be present in your classpath for this to work (and compile).

  * @author ochafik

  */

public class Win32IdleTime {

     public interface Kernel32 extends StdCallLibrary {

         Kernel32 INSTANCE = (Kernel32)Native.loadLibrary("kernel32", Kernel32.class);



         /**

          * Retrieves the number of milliseconds that have elapsed since the system was started.

          * @see http://msdn2.microsoft.com/en-us/library/ms724408.aspx

          * @return number of milliseconds that have elapsed since the system was started.

          */

         public int GetTickCount();

     };



     public interface User32 extends StdCallLibrary {

         User32 INSTANCE = (User32)Native.loadLibrary("user32", User32.class);

         /**

          * Contains the time of the last input.

          * @see http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui/windowsuserinterface/userinput/keyboardinput/keyboardinputreference/keyboardinputstructures/lastinputinfo.asp

          */

         public static class LASTINPUTINFO extends Structure {

             public int cbSize = 8;



             /// Tick count of when the last input event was received.

             public int dwTime;



            @SuppressWarnings("rawtypes")

            @Override

            protected List getFieldOrder() {

                return Arrays.asList(new String[] { "cbSize", "dwTime" });

            }

         }

         /**

          * Retrieves the time of the last input event.

          * @see http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui/windowsuserinterface/userinput/keyboardinput/keyboardinputreference/keyboardinputfunctions/getlastinputinfo.asp

          * @return time of the last input event, in milliseconds

          */

         public boolean GetLastInputInfo(LASTINPUTINFO result);

     };



     /**

      * Get the amount of milliseconds that have elapsed since the last input event

      * (mouse or keyboard)

      * @return idle time in milliseconds

      */

     public static int getIdleTimeMillisWin32() {

         User32.LASTINPUTINFO lastInputInfo = new User32.LASTINPUTINFO();

         User32.INSTANCE.GetLastInputInfo(lastInputInfo);

         return Kernel32.INSTANCE.GetTickCount() - lastInputInfo.dwTime;

     }



     enum State {

         UNKNOWN, ONLINE, IDLE, AWAY

     };







     // TEST

     public static void main(String[] args) throws Exception {

         if (!System.getProperty("os.name").contains("Windows")) {

             System.err.println("ERROR: Only implemented on Windows");

             System.exit(1);

         }

         State state = State.UNKNOWN;

         DateFormat dateFormat = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss");



         for (;;) {

             int idleSec = getIdleTimeMillisWin32() / 1000;



             State newState =

                 idleSec < 30 ? State.ONLINE :

                 idleSec > 5 * 60 ? State.AWAY : State.IDLE;



             if (newState != state) {

                 state = newState;

                 System.out.println(dateFormat.format(new Date()) + " # " + state);

                 //

                 // just for fun, if the state is AWAY (screensaver is coming!)

                 // we move the mouse wheel using java.awt.Robot just a little bit to change

                 // the state and prevent the screen saver execution.

                 //

                 if (state == State.AWAY) {

                     System.out.println("Activate the mouse wheel to change state!");

                     java.awt.Robot robot = new java.awt.Robot();

                     robot.mouseWheel(-1);

                     robot.mouseWheel(1);

                 }

             }

             try { Thread.sleep(1000); } catch (Exception ex) {}

         }

     }

}