import com.darwinsys.util.Debug;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import java.util.*;

/** Simple Graphing program.
 */
public class Grapher extends JPanel {
    /** Multiplier for range to allow room for a border */
    public final static float BORDERFACTOR = 1.1f;

    /* Small inner class to hold x, y. Called Apoint to differentiate
     * from java.awt.Point.
     */
    class Apoint {
        float x;
        float y;
        public String toString(  ) {
            return "Apoint("+x+","+y+")";
        }
    }

    /** The list of Apoint points. */
    protected Vector data;

    /** The minimum and maximum X values */
    protected float minx = Integer.MAX_VALUE, maxx = Integer.MIN_VALUE;
    /** The minimum and maximum Y values */
    protected float miny = Integer.MAX_VALUE, maxy = Integer.MIN_VALUE;
    /** The number of data points */
    protected int n;
    /** The range of X and Y values */
    protected float xrange, yrange;


    public Grapher(  ) {
        data = new Vector(  );
    }

    /** Read the data file named. Each line has an x and a y coordinate. */
    public void read(String fname) {
        LineNumberReader is = null;
        try {
            is = new LineNumberReader(new FileReader(fname));

            String txt;
            // Read the file a line at a time, parse it, save the data.
            while ((txt = is.readLine(  )) != null) {
                StringTokenizer st = new StringTokenizer(txt);
                try {
                    Apoint d = new Apoint(  );
                    d.x = Float.parseFloat(st.nextToken(  ));
                    d.y = Float.parseFloat(st.nextToken(  ));
                    data.add(d);
                } catch(NumberFormatException nfe) {
                    System.err.println("Invalid number on line " +
                        is.getLineNumber(  ));
                } // XXX catch out of range exception
            }
        } catch (FileNotFoundException e) {
            System.err.println("File " + fname + " unreadable: " + e);
        } catch (IOException e) {
            System.err.println("I/O error on line " + is.getLineNumber(  ));
        }
        n = data.size(  );
        if (n < 2) {
            System.err.println("Not enough data points!");
            return;
        }

        // find min & max
        for (int i=0 ; i < n; i++) {
            Apoint d = (Apoint)data.elementAt(i);
            if (d.x < minx) minx = d.x;
            if (d.x > maxx) maxx = d.x;
            if (d.y < miny) miny = d.y;
            if (d.y > maxy) maxy = d.y;
        }

        // Compute ranges
        xrange = (maxx - minx) * BORDERFACTOR;
        yrange = (maxy - miny) * BORDERFACTOR;
        Debug.println("range", "minx,x,r = " + minx +' '+ maxx +' '+ xrange);
        Debug.println("range", "miny,y,r = " + miny +' '+ maxy +' '+ yrange);
    }

    /** Called when the window needs painting.
     * Computes X and Y range, scales.
     */
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Dimension s = getSize(  );
        if (n < 2) {
            g.drawString("Insufficient data", 10, 40);
            return;
        }

        // Compute scale factors
        float xfact =  s.width  / xrange;
        float yfact =  s.height / yrange;

        // Scale and plot the data
        for (int i=0 ; i < n; i++) {
            Apoint d = (Apoint)data.elementAt(i);
            float x = (d.x-minx) * xfact;
            float y = (d.y-miny) * yfact;
            Debug.println("point", "AT " + i + " " + d + "; " +
                "x = " + x + "; y = " + y);
            // Draw a 5-pixel rectangle centered, so -2 both x and y.
            // AWT numbers Y from 0 down, so invert:
            g.drawRect(((int)x)-2, s.height-2-(int)y, 5, 5);
        }
    }

    public Dimension getPreferredSize(  ) {
        return new Dimension(150, 150);
    }

    public static void main(String[] rgs) {
        final JFrame f = new JFrame("Grapher");
        f.addWindowListener(new WindowAdapter(  ) {
            public void windowClosing(WindowEvent e) {
                f.setVisible(false);
                f.dispose(  );
                System.exit(0);
            }
        });
        Grapher g = new Grapher(  );
        f.setContentPane(g);
        f.setLocation(100, 100);
        f.pack(  );
        if (rgs.length == 0)
            g.read("Grapher.dat");
        else
            g.read(rgs[0]);
        f.setVisible(true);
    }
}