import java.applet.*;
import javax.swing.*;
import java.awt.geom.*;
import edu.jsu.leathrum.mathlets.shared.*;
import java.text.ParsePosition;
import java.awt.Font;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.FlowLayout;

public class Parabola extends AMathlet {

private class GraphCanvas extends ASimpleGraphCanvas {
  double a = 1.0;
  double b = 0.0;
  double c = 0.0;

  public GraphCanvas(int initialWidth, int initialHeight, int scale) {
    super(initialWidth, initialHeight, scale);
  }

  public void setValues(double newa, double newb, double newc) {
    a = newa;
    b = newb;
    c = newc;
  }

  private double f(double x) {
    return ((a*x*x)+(b*x)+c);
  }

  protected void drawFigure(Graphics2D g) {
    double p;
    GeneralPath par = new GeneralPath();

    p = trinv.transform(new Point2D.Double(0,0),null).getX();
    par.moveTo((float) p, (float) f(p));
    for (int x = 1; x < wd; x++) {
      p = trinv.transform(new Point2D.Double(x,0),null).getX();
      par.lineTo((float) p, (float) f(p));
    }
    g.setPaint(Color.blue);
    g.draw(tr.createTransformedShape(par));
  }

}

private class EqnSet extends JPanel {
  DblButtonSet aButtons = new DblButtonSet();
  DblButtonSet bButtons = new DblButtonSet();
  DblButtonSet cButtons = new DblButtonSet();

  FormattedLabel eqn = new FormattedLabel();

  Box b0, b1;

  public EqnSet () {
    b0 = new Box(BoxLayout.X_AXIS);
    b1 = new Box(BoxLayout.Y_AXIS);
    b0.add(Box.createHorizontalGlue());
    b0.add(eqn);
    b0.add(Box.createHorizontalGlue());
    b1.add(b0);
    
    b0 = new Box(BoxLayout.X_AXIS);
    b0.add(Box.createHorizontalGlue());
    b0.add(aButtons);
    b0.add(bButtons);
    b0.add(cButtons);
    b0.add(Box.createHorizontalGlue());
    b1.add(b0);
    add(b1);

    aButtons.setRepeat();
    bButtons.setRepeat();
    cButtons.setRepeat();
    setOpaque(false);
    eqn.setFontStyle(Font.BOLD);
    eqn.setFontSize(14);
  }

  public void setText(String text) {
    eqn.setText(text);
  }

  public double getaValue() {
    return aButtons.getValue();
  }

  public double getbValue() {
    return bButtons.getValue();
  }

  public double getcValue() {
    return cButtons.getValue();
  }

  public void setaValue(double newa) {
    aButtons.setValue(newa);
  }

  public void setbValue(double newb) {
    bButtons.setValue(newb);
  }

  public void setcValue(double newc) {
    cButtons.setValue(newc);
  }

  public void setValues(double a, double b, double c) {
    aButtons.setValue(a);
    bButtons.setValue(b);
    cButtons.setValue(c);
  }

  public void setNames(String a, String b, String c) {
    aButtons.setName(a);
    bButtons.setName(b);
    cButtons.setName(c);
  }

  public void setAction(ActionWrapper act) {
    aButtons.setButtonAction(act);
    bButtons.setButtonAction(act);
    cButtons.setButtonAction(act);
  }

  public void registerFields(String a, String b, String c) {
    setHandler(a, aButtons);
    setHandler(b, bButtons);
    setHandler(c, cButtons);
  }

  public void setToDefaults(double defa, double defb, double defc) {
    aButtons.setDefault(defa);
    aButtons.setToDefault();
    bButtons.setDefault(defb);
    bButtons.setToDefault();
    cButtons.setDefault(defc);
    cButtons.setToDefault();
  }
}

  GraphCanvas graph = new GraphCanvas(300,300,15);
  JPanel buttonPanel = new JPanel();

  EqnSet stdEqn = new EqnSet();
  EqnSet genEqn = new EqnSet();

  JButton clearButton = new JButton("clear");

  Box b0, b1;

  public Parabola() {
    this.getContentPane().setBackground(Color.white);
    this.getContentPane().setLayout(new FlowLayout());
    this.getContentPane().add(graph);
    b1 = new Box(BoxLayout.Y_AXIS);

    b1.add(stdEqn);

    class GenAction implements ActionWrapper {
      public void doThis() {
        genCompute();
        draw();
      }
    }

    stdEqn.setAction(new GenAction());

    b1.add(genEqn);

    class StdAction implements ActionWrapper {
      public void doThis() {
        stdCompute();
        draw();
      }
    }

    genEqn.setAction(new StdAction());

    b0 = new Box(BoxLayout.X_AXIS);
    b0.add(Box.createHorizontalGlue());
    b0.add(clearButton);
    b0.add(Box.createHorizontalGlue());
    b1.add(b0);

    this.getContentPane().add(b1);

    clearButton.setOpaque(false);
  }

  public void draw() {
    graph.setValues(genEqn.getaValue(), genEqn.getbValue(),
		      genEqn.getcValue());
    graph.repaint();
  }

  private void genCompute() {
    double a = stdEqn.getaValue();
    double h = stdEqn.getbValue();
    double k = stdEqn.getcValue();
    double b = -2*a*h; 
    double c = k+a*h*h;
    genEqn.setValues(a, b, c);
  }

  private void stdCompute() {
    double a = genEqn.getaValue();
    double b = genEqn.getbValue();
    double c = genEqn.getcValue();
    double h = -1*b/(2*a);
    double k = c-b*b/(4*a);
    stdEqn.setValues(a, h, k);
  }

  public void localinit() {
    AMathlet.getNumberFormat().setMaximumFractionDigits(1);
    stdEqn.setText(AMathlet.getProperty("Parabola.stdeqn"));
    genEqn.setText(AMathlet.getProperty("Parabola.geneqn"));
    stdEqn.setNames(AMathlet.getProperty("consta"), 
        AMathlet.getProperty("consth"), AMathlet.getProperty("constk"));
    stdEqn.registerFields("a1", "h", "k");
    stdEqn.setToDefaults(1.0, 0.0, 0.0);
    genEqn.setNames(AMathlet.getProperty("consta"),
        AMathlet.getProperty("constb"), AMathlet.getProperty("constc"));
    genEqn.registerFields("a2", "b", "c");
    genEqn.setToDefaults(1.0, 0.0, 0.0);
    graph.setValues(genEqn.getaValue(), genEqn.getbValue(),
		    genEqn.getcValue());
    registerClearButton(clearButton);
  }
}