// cal.java, V1.0
// Sunday, Nov. 19, 2000, by Yamin Li, yamin@k.hosei.ac.jp
// Uptated Monday, June 28, 2005: add Buttons.
// Free to use, modify, and distribute.

import javax.swing.*;
import javax.swing.text.*;
import javax.swing.event.*;

import java.awt.*;
import java.applet.Applet;
import java.awt.event.*;
import java.util.Calendar;

public class cal extends JApplet implements ActionListener{
    private Button b_prev, b_next;
    private TextField inputYear;

    private int daysPerMonth[]={
        31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
    private int year;
    private String month[]={
        " January ", "February ", "  March  ", "  April  ",
        "   May   ", "  June   ", "  July   ", " August  ",
        "September", " October ", "November ", "December "};
    private String day[]={"Su", "Mo", "Tu", "We", "Th", "Fr", "Sa"};
    private int[][][] date;

    private Image displayBuffer;
    private Graphics drawingBuffer;

    public void init(){
        date=new int[12][7][6];
        Calendar calendar=Calendar.getInstance();
        year=calendar.get(Calendar.YEAR);

        inputYear=new TextField(Integer.toString(year));
        inputYear.addActionListener(this);

        b_prev=new Button( "                  Previous year                  " );
        b_prev.addActionListener(this);

        b_next=new Button( "                    Next year                    " );
        b_next.addActionListener(this);

        Panel yearPanel=new Panel();
        yearPanel.setLayout(new BorderLayout());
	yearPanel.add(b_prev, BorderLayout.WEST);
        yearPanel.add(inputYear, BorderLayout.CENTER);
	yearPanel.add(b_next, BorderLayout.EAST);

        displayBuffer=createImage(600, 400);
        drawingBuffer=displayBuffer.getGraphics();

	getContentPane().add("North",yearPanel);

        execute();
    }

    public void paint(Graphics g){
        drawingBuffer.setColor(new Color(0x1f, 0xbf, 0xaf));
        drawingBuffer.fill3DRect(0, 0, 600, 400, true);
        if ((year<=0)||(year>9999)){
            drawingBuffer.setFont(new Font("Sansserif", Font.BOLD, 60));
            drawingBuffer.setColor(Color.red);
            drawingBuffer.drawString("use 1-9999", 20, 100);
            g.drawImage(displayBuffer, 0, 0, this);
            return;
        }
        drawingBuffer.setFont(new Font("Monospaced", Font.PLAIN, 12));
        for (int i=0; i<12; i++){
            drawingBuffer.setColor(Color.blue);
            drawingBuffer.drawString(month[i], (i%4)*150+50, (i/4)*120+50);
            for (int j=0; j<7; j++){
                drawingBuffer.setColor(j==0?Color.red:Color.orange);
                drawingBuffer.drawString(day[j], (i%4)*150+j*20+10, (i/4)*120+70);
                for (int k=0; k<6; k++){
                    drawingBuffer.setColor(j==0?Color.red:Color.black);
                    drawingBuffer.drawString(intToString(date[i][j][k]),
                    (i%4)*150+j*20+10, (i/4)*120+90+k*12);
                }
            }
        }
        g.drawImage(displayBuffer, 0, 0, this);
    }

    public void update(Graphics g){
        paint(g);
    }

    public String intToString(int value){
        if (value==0) return("  ");
        String v=Integer.toString(value);
        if (value>9) return(v);
        else return(" "+v);
    }

    public void execute(){
        int[] firstDay=new int[12];
        for (int i=0; i<12; i++){
            for (int j=0; j<7; j++){
                for (int k=0; k<6; k++){
                    date[i][j][k]=0;
                }
            }
        }
        if (year>1752){
            daysPerMonth[1]=(((year%4)==0 && (year%100)!=0)||((year%400)==0))?29:28;
            firstDay[0]=((year-1)+(int)((year-1)/4)-(int)((year-1)/100)+(int)((year-1)/400)+1)%7;
        }else{
            daysPerMonth[1]=((year%4)==0)?29:28;
            firstDay[0]=((year-1)+(int)((year-1)/4)+6)%7;
        }
        daysPerMonth[8]=year==1752?19:30;
        for (int i=1; i<12; i++)
            firstDay[i]=(firstDay[i-1]+daysPerMonth[i-1])%7;
        for (int i=0; i<12; i++){
            for (int j=1; j<=daysPerMonth[i]; j++){
                if ((year==1752)&&(i==8)&&(j>2))
                     date[i][(j-1+firstDay[i])%7][(j-1+firstDay[i])/7]=j+11;
                else date[i][(j-1+firstDay[i])%7][(j-1+firstDay[i])/7]=j;
            }
        }
        repaint();
    }

    public void actionPerformed(ActionEvent e){
        if (e.getSource() == inputYear){
            year=Integer.parseInt(inputYear.getText());
            execute();
        } else {
	    if (e.getSource() == b_next){
		year++;
		inputYear.setText(Integer.toString(year));
		execute();
	    } else {
		if (e.getSource() == b_prev){
		    --year;
		    inputYear.setText(Integer.toString(year));
		    execute();
		}
	    }
	}
    }
}