/*
 * [Population.java]
 *
 * Summary: Simple World Population Clock Applet.
 *
 * Copyright: (c) 2012-2017 Roedy Green, Canadian Mind Products, http://mindprod.com
 *
 * Licence: This software may be copied and used freely for any purpose but military.
 *          http://mindprod.com/contact/nonmil.html
 *
 * Requires: JDK 1.8+
 *
 * Created with: JetBrains IntelliJ IDEA IDE http://www.jetbrains.com/idea/
 *
 * Version History:
 *  1.0 2012-03-07 initial version
 *  1.1 2012-12-24 add more population data
 *  1.2 2013-01-30 revised population estimates.
 */
package com.mindprod.population;

import com.mindprod.common18.BigDate;
import com.mindprod.common18.Build;
import com.mindprod.common18.CMPAboutJBox;
import com.mindprod.common18.Common18;
import com.mindprod.common18.FontFactory;
import com.mindprod.common18.HybridJ;
import com.mindprod.common18.JEButton;
import com.mindprod.common18.VersionCheck;

import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.Timer;
import java.awt.Color;
import java.awt.Container;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.TimeZone;

import static java.lang.System.*;

/**
 * Simple World Population Clock Applet.
 * <p/>
 * It works by interpolating monthly populations projections from http://www.census.gov/population/popclockworld.html
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 1.2 2013-01-30 revised population estimates.
 * @since 2012-03-07
 */
public final class Population extends JApplet implements ActionListener
    {
    /**
     * true if debugging, and want extra output
     */
    private static final boolean DEBUGGING = false;

    /**
     * height of Applet box in pixels. Does not include surrounding frame.
     */
    private static final int APPLET_HEIGHT = 150;

    /**
     * Width of Applet box in pixels.
     */
    private static final int APPLET_WIDTH = 340;

    private static final int FIRST_COPYRIGHT_YEAR = 2012;

    /**
     * how ofter to update the world population clock in milliseconds.
     */
    private static final int FREQUENCY = 400;

    /**
     * undisplayed copyright notice
     */
    private static final String EMBEDDED_COPYRIGHT =
            "Copyright: (c) 2012-2017 Roedy Green, Canadian Mind Products, http://mindprod.com";

    private static final String RELEASE_DATE = "2013-01-30";

    private static final String TITLE_STRING = "World Population Clock";

    /**
     * embedded version string.
     */
    private static final String VERSION_STRING = "1.2";

    /**
     * raw time data from  http://www.census.gov/population/international/data/idb/informationGateway.php
     * http://en.wikipedia.org/wiki/World_population_estimates
     */
    private static final String[] timestampStrings = {      // last checked  2014-03-23
            "2012-03-01",     // 6_997_564_595
            "2012-04-01",     // 7_004_110_246
            "2012-05-01",     // 7_010_444_747
            "2012-06-01",     // 7_016_990_398
            "2012-07-01",     // 7_017_543_964
            "2012-08-01",     // 7_024_140_935
            "2012-09-01",     // 7_030_737_906
            "2012-10-01",     // 7_037_122_072
            "2012-11-01",     // 7_043_719_043
            "2012-12-01",     // 7_050_103_209
            "2013-01-01",     // 7_056_700_180
            "2013-02-01",     // 7_063_297_151
            "2013-03-01",     // 7_069_255_706
            "2013-04-01",     // 7_075_852_677
            "2013-05-01",     // 7_082_236_843
            "2013-06-01",     // 7_088_833_814
            "2013-07-01",     // 7_095_217_980
            "2014-07-01",     // 7_172_800_105
            "2015-01-01",     // 7_200_008_584
            "2015-07-01",     // 7_250_104_524
            "2020-01-01",     // 7_557_514_266
            "2025-01-01",     // 7_892_758_722
            "2025-07-01",     // 7_986_584_000
            "2030-01-01",     // 8_202_205_367
            "2035-01-01",     // 8_487_066_951
            "2040-01-01",     // 8_748_743_446
            "2045-01-01",     // 8_987_418_540
            "2050-01-01",     // 9_202_458_484
    };

    /**
     * background colour for window.
     */
    private static final Color BACKGROUND_FOR_APP = Build.BACKGROUND_FOR_BLENDING;

    /**
     * for final result
     */
    private static final Color BACKGROUND_FOR_POPULATION = Color.WHITE;

    /**
     * for final result
     */
    private static final Color BACKGROUND_FOR_TIME = Color.WHITE;

    /**
     * foreground colour for window text
     */
    private static final Color FOREGROUND_FOR_APP = Color.BLACK;

    /**
     * for final result
     */
    private static final Color FOREGROUND_FOR_POPULATION = new Color( 0xff7f24 );

    /**
     * for final result
     */
    private static final Color FOREGROUND_FOR_TIME = new Color( 0x8b2500 );

    /**
     * for titles
     */
    private static final Color FOREGROUND_FOR_TITLE = new Color( 0xdc143c );

    /**
     * population value formatter.
     */
    private static final DecimalFormat FPOPULATION = new DecimalFormat( "0,000" );

    /**
     * for final result
     */
    private static final Font FONT_FOR_POPULATION;

    /**
     * for final result
     */
    private static final Font FONT_FOR_TIME;

    /**
     * for for titles and About buttons
     */
    private static final Font FONT_FOR_TITLE;

    /**
     * Local date formatter.
     */
    private static final SimpleDateFormat FLOCAL = new SimpleDateFormat( "EEEE yyyy-MM-dd  hh:mm:ss aa" );

    /**
     * monthly populations estimate, data must be kept current from http://www.census.gov/population/international/data/idb/informationGateway.php
     */
    private static final long[] populations = {
            6_997_564_595L,  // 2012-03-01
            7_004_110_246L,  // 2012-04-01
            7_010_444_747L,  // 2012-05-01
            7_016_990_398L,  // 2012-06-01
            7_017_543_964L,  // 2012-07-01
            7_024_140_935L,  // 2012-08-01
            7_030_737_906L,  // 2012-09-01
            7_037_122_072L,  // 2012-10-01
            7_043_719_043L,  // 2012-11-01
            7_050_103_209L,  // 2012-12-01
            7_056_700_180L,  // 2013-01-01
            7_063_297_151L,  // 2013-02-01
            7_069_255_706L,  // 2013-03-01
            7_075_852_677L,  // 2013-04-01
            7_082_236_843L,  // 2013-05-01
            7_088_833_814L,  // 2013-06-01
            7_095_217_980L,  // 2013-07-01
            7_172_800_105L,  // 2014-07-01
            7_200_008_584L,  // 2015-01-01
            7_250_104_524L,  // 2015-07-01
            7_557_514_266L,  // 2020-01-01
            7_892_758_722L,  // 2025-01-01
            7_986_584_000L,  // 2025-07-01
            8_202_205_367L,  // 2030-01-01
            8_487_066_951L,  // 2035-01-01
            8_748_743_446L,  // 2040-01-01
            8_987_418_540L,  // 2045-01-01
            9_202_458_484L,  // 2050-01-01
    };

    /**
     * timestamp (millis since 1970 UTC)  when corresponding populations estimate is valid,
     */
    private static final long[] timestamps;

    static
        {
        FONT_FOR_POPULATION = FontFactory.build( "Dialog", Font.BOLD, 30 );
        FONT_FOR_TIME = FontFactory.build( "Dialog", Font.PLAIN, 16 );
        FONT_FOR_TITLE = FontFactory.build( "Dialog", Font.BOLD, 17 );
        }

    static
        {
        /* get long timestamps from date strings. */
        if ( timestampStrings.length != populations.length )
            {
            throw new IllegalArgumentException( "program bug: mismatch in timestamps and population estimates" );
            }
        final TimeZone utc = TimeZone.getTimeZone( "UTC" );
        timestamps = new long[ timestampStrings.length ];
        for ( int i = 0; i < timestamps.length; i++ )
            {
            final BigDate d = new BigDate( timestampStrings[ i ] );
            timestamps[ i ] = d.getTimeStamp( utc );
            }
        }

    /**
     * about
     */
    private JButton about;

    /**
     * first line of result as a sentence.
     */
    private JLabel localTime;

    /**
     * title of applet
     */
    private JLabel title;

    /**
     * annual growth in consumption as a percent
     */
    private JLabel worldPopulation;

    /**
     * timer to keep population stats up to date
     */
    private Timer splashTimer;

    /**
     * constructor
     */
    public Population()
        {
        }

    /**
     * Calculate current world populations. -1 means cannot compute because tables are obsolete.
     *
     * @return current world populations
     */
    private static long calcCurrentPopulation()
        {
        final long now = System.currentTimeMillis();
        if ( DEBUGGING )
            {
            out.println( now + " " + FLOCAL.format( now ) );
            for ( long t : timestamps )
                {
                out.println( t + " " + FLOCAL.format( t ) );
                }
            }
        final int where = Arrays.binarySearch( timestamps, now );
        int thisMonthIndex;
        int nextMonthIndex;
        if ( where >= 0 )
            {
            thisMonthIndex = where;
            nextMonthIndex = where + 1;
            }
        else
            {
            final int insertionPoint = -( where + 1 );
            thisMonthIndex = insertionPoint - 1;
            nextMonthIndex = insertionPoint;
            }
        if ( DEBUGGING )
            {
            out.println( thisMonthIndex + " " + nextMonthIndex );
            }
        if ( thisMonthIndex < 0 || nextMonthIndex >= timestamps.length )
            {
            return -1;
            }
        // interpolate
        final double startPop = populations[ thisMonthIndex ];
        final double endPop = populations[ nextMonthIndex ];
        final double popIncrease = endPop - startPop;
        final double start = timestamps[ thisMonthIndex ];
        final double end = timestamps[ nextMonthIndex ];
        final double fraction = ( now - start ) / ( end - start );
        final double popIncreaseSoFar = popIncrease * fraction;
        final double popNow = popIncreaseSoFar + startPop;
        return ( long ) ( popNow + .5 );
        }

    /**
     * create gui components
     */
    private void createComponents()
        {
        title = new JLabel( TITLE_STRING + " " + VERSION_STRING );
        title.setFont( FONT_FOR_TITLE );
        title.setForeground( FOREGROUND_FOR_TITLE );
        // leave background app background
        about = new JEButton( "About" );
        about.setToolTipText( "About " + TITLE_STRING + " " + VERSION_STRING );
        worldPopulation = new JLabel( "", JLabel.CENTER );
        worldPopulation.setFont( FONT_FOR_POPULATION );
        worldPopulation.setBackground( BACKGROUND_FOR_POPULATION );
        worldPopulation.setForeground( FOREGROUND_FOR_POPULATION );
        localTime = new JLabel( "", JLabel.CENTER );
        localTime.setFont( FONT_FOR_TIME );
        localTime.setBackground( BACKGROUND_FOR_TIME );
        localTime.setForeground( FOREGROUND_FOR_TIME );
        }

    /**
     * hook up the listeners
     */
    private void hookListeners()
        {
        // engage the listeners
        about.addActionListener( new ActionListener()
            {
            public void actionPerformed( ActionEvent e )
                {
                // open about box frame
                new CMPAboutJBox( TITLE_STRING,
                        VERSION_STRING,
                        "Displays current running estimate of world populations",
                        "from U.S. Census bureau information.",
                        "freeware",
                        RELEASE_DATE,
                        FIRST_COPYRIGHT_YEAR,
                        "Roedy Green",
                        "POPULATION",
                        "1.8" );
                }
            } );
        }

    /**
     * layout the components
     *
     * @param contentPane where to add components
     */
    private void layoutGridBag( Container contentPane )
        {
        // basic layout:
        // 0-----0------------------------------------ 1-------
        // 0 -----------TITLE------------------------ ----about
        // 1 ----------world population----------------------
        // 2 ----------local time-----------------------------
        // x y w h wtx wty anchor fill T L B R padx pady
        contentPane.add( title,
                new GridBagConstraints( 0,
                        0,
                        1,
                        1,
                        1.0,
                        1.0,
                        GridBagConstraints.WEST,
                        GridBagConstraints.NONE,
                        new Insets( 10, 10, 5, 5 ),
                        0,
                        0 )
        );
        // x y w h wtx wty anchor fill T L B R padx pady
        contentPane.add( about,
                new GridBagConstraints( 1,
                        0,
                        1,
                        1,
                        0.0,
                        0.0,
                        GridBagConstraints.EAST,
                        GridBagConstraints.NONE,
                        new Insets( 10, 5, 5, 10 ),
                        10,
                        2 )
        );
        // x y w h wtx wty anchor fill T L B R padx pady
        contentPane.add( worldPopulation,
                new GridBagConstraints( 0,
                        1,
                        2,
                        1,
                        1.0,
                        1.0,
                        GridBagConstraints.CENTER,
                        GridBagConstraints.NONE,
                        new Insets( 0, 10, 5, 10 ),
                        0,
                        0 )
        );
        // x y w h wtx wty anchor fill T L B R padx pady
        contentPane.add( localTime,
                new GridBagConstraints( 0,
                        2,
                        2,
                        1,
                        1.0,
                        1.0,
                        GridBagConstraints.CENTER,
                        GridBagConstraints.BOTH,
                        new Insets( 0, 10, 10, 10 ),
                        0,
                        0 )
        );
        }

    /**
     * Allow this Applet to run as as application as well.
     *
     * @param args command line arguments ignored.
     */
    public static void main( String args[] )
        {
        HybridJ.fireup( new Population(),
                TITLE_STRING + " " + VERSION_STRING,
                APPLET_WIDTH,
                APPLET_HEIGHT );
        } // end main

    /**
     * invoked whenever Timer ticks over
     *
     * @param e event not used.
     */
    public void actionPerformed( ActionEvent e )
        {
        final long now = System.currentTimeMillis();
        // FLOCAL.setTimeZone( TimeZone.getDefault() );  local tz happens by default.
        localTime.setText( FLOCAL.format( now ) );
        final long population = calcCurrentPopulation();
        if ( population < 0 )
            {
            worldPopulation.setText( "To function, the program needs fresh US Census data." );
            }
        else
            {
            worldPopulation.setText( FPOPULATION.format( population ) );
            }
        }

    /**
     * Called by the browser or Applet viewer to inform
     * this Applet that it is being reclaimed and that it should destroy
     * any resources that it has allocated.
     */
    @Override
    public void destroy()
        {
        about = null;
        worldPopulation = null;
        localTime = null;
        title = null;
        if ( splashTimer != null )
            {
            splashTimer.stop();
            splashTimer = null;
            }
        }

    /**
     * Called by the browser or Applet viewer to inform
     * this Applet that it has been loaded into the system.
     */
    @Override
    public void init()
        {
        if ( !VersionCheck.isJavaVersionOK( 1, 8, 0, this ) )
            {
            return;
            }
        Common18.setLaf();
        Container contentPane = this.getContentPane();
        contentPane.setBackground( BACKGROUND_FOR_APP );
        contentPane.setForeground( FOREGROUND_FOR_APP );
        contentPane.setLayout( new GridBagLayout() );
        createComponents();
        layoutGridBag( contentPane );
        hookListeners();
        this.validate();
        this.setVisible( true );
        } // end init

    /**
     * usual Applet start
     */
    public void start()
        {
        // use a Swing timer to keep updating the time and the population.
        splashTimer = new Timer( FREQUENCY, this );
        splashTimer.setRepeats( true );
        splashTimer.start();
        }

    /**
     * usual Applet stop
     */
    @Override
    public void stop()
        {
        if ( splashTimer != null )
            {
            splashTimer.stop();
            }
        }
    }