import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.util.Calendar;

import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSpinner;
import javax.swing.JTextField;
import javax.swing.SpinnerListModel;
import javax.swing.SpinnerNumberModel;
import javax.swing.SwingConstants;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.LineBorder;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

public class Main {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Swing Calender");
//      frame.setSize(400,600);
        frame.add(new SwingCalendar());
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }
}


class SwingCalendar extends JPanel {
    private JSpinner  monthChooser = new JSpinner();
    private JSpinner  yearChooser = new JSpinner();

    private JLabel[]    weekLabels = new JLabel[7];
    private JLabel[][]  dayLabels = new JLabel[6][7];

    private static final Color WEEK_BG = new Color(240,240,255);
    private static final LineBorder WEEK_BORDER = new LineBorder(new Color(160,160,230), 2, false);

    private static final Color DAY_BG = new Color(250,250,255);
    private static final Color DAY_FG = Color.BLACK;
    private static final LineBorder DAY_BORDER = new LineBorder(new Color(40,40,40), 2, false);

    private static final Color TODAY_BG = new Color(255, 240, 240);
    private static final Color TODAY_FG = new Color(105,50,50);
    private static final LineBorder TODAY_BORDER = new LineBorder(new Color(175,50,50), 2, false);


    private static final Dimension DAY_LABEL_SIZE = new Dimension(50,50);
    private static final String[] WEEK_NAMES = new String[] {"SUN", "MON", "TUE", "WED", "THU", "FRI", "SAT"};
    private static final String[] MONTH_NAMES = new String[] {"JAN", "FEB", "MAR", "APR", "MAY", "JUNE", "JULY", "AUG", "SEP", "OCT", "NOV", "DEC"};

    public SwingCalendar() {
        try {
            UIManager.setLookAndFeel(
                "javax.swing.plaf.nimbus.NimbusLookAndFeel"
            );
        } catch (ClassNotFoundException | InstantiationException
                | IllegalAccessException | UnsupportedLookAndFeelException e) {
            e.printStackTrace();
        }

        /* MONTH CHOOSER */
        monthChooser.setModel(new SpinnerListModel(MONTH_NAMES));
        JTextField tm = ((JSpinner.DefaultEditor)monthChooser.getEditor()).getTextField();
        tm.setHorizontalAlignment(JTextField.CENTER);

        ChangeListener monthYearListener = new ChangeListener(){
            public void stateChanged(ChangeEvent e) {
                String value = (String) monthChooser.getValue();

                int month = 0;
                for( int i=0; i<MONTH_NAMES.length; i++ ){
                    if( value.equals(MONTH_NAMES[i]) ){
                        month = i;
                        break;
                    }
                }

                refreshDayLabels((int) yearChooser.getValue(), month);
            }
        };

        monthChooser.addChangeListener(monthYearListener);

        Dimension dm = monthChooser.getPreferredSize();
        dm.width += 10; //dm.height += 1;
        monthChooser.setPreferredSize(dm);

        /* YEAR CHOOSER */
        yearChooser.setModel(new SpinnerNumberModel(2012, 0, 5000,1 ));
        JSpinner.NumberEditor editor = new JSpinner.NumberEditor(yearChooser, "#");
        yearChooser.setEditor(editor);
        yearChooser.addChangeListener(monthYearListener);

        Dimension dy = yearChooser.getPreferredSize();
        dy.width += 10; //dy.height += 1;
        yearChooser.setPreferredSize(dy);

        /* DAY PANEL */
        JPanel dayPanel = new JPanel();
        GridLayout layout = new GridLayout(7, 7);
        layout.setHgap(3);
        layout.setVgap(3);
        dayPanel.setLayout(layout);

        for( int i=0; i<7; i++) {
            weekLabels[i] = new JLabel(WEEK_NAMES[i]);
            weekLabels[i].setHorizontalAlignment(SwingConstants.CENTER);
            weekLabels[i].setVerticalAlignment(SwingConstants.CENTER);
            weekLabels[i].setPreferredSize(DAY_LABEL_SIZE);
            weekLabels[i].setOpaque(true);
            weekLabels[i].setBackground(WEEK_BG);
            weekLabels[i].setBorder(WEEK_BORDER);
            if( i == 0 ) {
                weekLabels[i].setForeground(Color.RED);
            } else if ( i == 6 ) {
                weekLabels[i].setForeground(Color.BLUE);
            }

            dayPanel.add(weekLabels[i]);
        }

        for( int i=0; i<6; i++) {
            for( int j=0; j<7; j++) {
                dayLabels[i][j] = new JLabel();
                dayLabels[i][j].setHorizontalAlignment(SwingConstants.CENTER);
                dayLabels[i][j].setVerticalAlignment(SwingConstants.CENTER);
                dayLabels[i][j].setOpaque(true);
                dayLabels[i][j].setBackground(DAY_BG);
                dayLabels[i][j].setPreferredSize(DAY_LABEL_SIZE);
                dayLabels[i][j].setBorder(new LineBorder(Color.DARK_GRAY, 2, false));
                dayPanel.add(dayLabels[i][j]);
            }
        }

        setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
        JPanel chooserPanel = new JPanel();
        GridLayout l = new GridLayout(1,2);
        l.setHgap(10); l.setVgap(10);
        chooserPanel.add(yearChooser);
        chooserPanel.add(monthChooser);

        add(chooserPanel);
        add(dayPanel);

        Calendar cal = Calendar.getInstance();
        monthChooser.setValue(MONTH_NAMES[cal.get(Calendar.MONTH)]);
        yearChooser.setValue(cal.get(Calendar.YEAR));
        refreshDayLabels(cal, true);
    }

    private void refreshDayLabels(int year, int month) {
        Calendar cal = Calendar.getInstance();
        if( month == cal.get(Calendar.MONTH) && year == cal.get(Calendar.YEAR)) {
            refreshDayLabels( cal, true);
        } else {
            cal.set(year, month, 1);
            refreshDayLabels(cal, false);
        }
    }

    private void refreshDayLabels(Calendar calendar, boolean currentMonth) {
        int maxDate = calendar.getActualMaximum(Calendar.DATE);
        int today = calendar.get(Calendar.DATE);

        calendar.set(Calendar.DATE, 1);
        int firstDayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);

        for( JLabel[] ll : dayLabels) {
            for( JLabel l : ll ) {
                l.setText("");
            }
        }

        for( int day=1; day<=maxDate; day++ ) {
            getDayLabel( day, firstDayOfWeek ).setText(Integer.toString(day));
        }

        for( int i=0; i<dayLabels.length; i++) {
            for( int j=0; j<dayLabels[i].length; j++) {
                JLabel l = dayLabels[i][j];
                l.setBackground(DAY_BG);
                l.setForeground(DAY_FG);
                l.setBorder(DAY_BORDER);

                if( l.getText().length() != 0 ) {
                    l.setVisible(true);
                } else {
                    l.setVisible(false);
                }
            }
        }

        if( currentMonth ) {
            JLabel l = getDayLabel( today, firstDayOfWeek );
            l.setBackground(TODAY_BG);
            l.setForeground(TODAY_FG);
            l.setBorder(TODAY_BORDER);
        }
    }

    private JLabel getDayLabel( int day , int firstDayOfWeek ) {
        return dayLabels[(day + firstDayOfWeek - 2)/7][(day + firstDayOfWeek - 2)%7];
    }
}