/**
 * Applet used for drawing an image.
 *
 * @author  Ruedi Hofer
 */
import java.applet.*;
import java.awt.*;
import java.util.*;
//import netscape.javascript.*;

public class AppletPaint extends Applet
{
  Graphics zeichenbereich;
  Button clearButton;
  Button undoButton;
  Button undo10Button;
  Choice colorChooser;
  CheckboxGroup cbMode;
  Checkbox cbDel,cbDraw;
  private boolean drawMode=true;
  private Color zeichenfarbe=Color.black;
  private int last_x=0;
  private int last_y=0;
  private Vector vector = new Vector();
  private final int appletWidth=400;
  private final int appletHeight=400;
  private final int drawAreaStartY=35;
  private final int drawAreaStartX=0;
  public String out="asdfasdf";

  /**
   * Initializes the applet and sets up the widgets.
   *
   * @param     void
   * @return    void
   * @exception none
   */
  public void init()
  {
    setBackground (Color.white);
    setForeground (Color.black);
    initDrawArea();
    // CheckboxGroup mode
    cbMode=new CheckboxGroup();
    cbDel=new Checkbox("Delete",cbMode,false);
    cbDraw=new Checkbox("Draw",cbMode,true);
    add(cbDel);
    add(cbDraw);
    // clear button
    clearButton=new Button("Clear");
    add(clearButton);
    // undo button
    undoButton=new Button("Undo");
    add(undoButton);
    // undo10 button
    undo10Button=new Button("Undo10");
    add(undo10Button);
    // color chooser
    colorChooser=new Choice();
    colorChooser.addItem("black");
    colorChooser.addItem("white");
    colorChooser.addItem("blue");
    colorChooser.addItem("cyan");
    colorChooser.addItem("green");
    colorChooser.addItem("yellow");
    colorChooser.addItem("orange");
    colorChooser.addItem("magenta");
    colorChooser.addItem("pink");
    colorChooser.addItem("red");
    add(colorChooser);
  }

  public boolean mouseDown(Event theEvent, int x, int y)
  {
    if (drawMode)
    {
      // End of line
      ArrayListElement aleend=new ArrayListElement();
      aleend.setElement(-1,-1,zeichenfarbe);
      vector.addElement(aleend);
      // start new line
      ArrayListElement alenew=new ArrayListElement();
      alenew.setElement(x,y,zeichenfarbe);
      vector.addElement(alenew);

      last_x=x;
      last_y=y;
    }
    else
    {
      // delete mode
      ArrayListElement ale=new ArrayListElement();
      ale.setElement(x,y,zeichenfarbe);

      int i=vector.indexOf(ale);
      if (i!=-1)
      {
        // found an element to be removed
        vector.removeElementAt(i);
        // add an end of line element
        ArrayListElement aleend=new ArrayListElement();
        aleend.setElement(-1,-1,zeichenfarbe);
        vector.insertElementAt(aleend, i);
        // System.out.println("Element "+i+" removed");
        repaint();
      }
    }
    return true;
  }

  public boolean mouseDrag(Event theEvent, int x, int y)
  {
    if (drawMode)
    {
      if (y>drawAreaStartY && y<appletHeight-1 &&
          x>drawAreaStartX && x<appletWidth-1)
      {
        // put element to vector
        ArrayListElement ale=new ArrayListElement();
        ale.setElement(x,y,zeichenfarbe);
        vector.addElement(ale);
        // draw the line
        zeichenbereich=getGraphics();
        zeichenbereich.setColor(zeichenfarbe);
        zeichenbereich.drawLine(last_x,last_y,x,y);
        last_x=x;
        last_y=y;
      }
    }
    return true;
  }

  public void initDrawArea()
  {
    Graphics g=this.getGraphics();
    g.setColor(Color.black);
    g.drawRect(drawAreaStartX,drawAreaStartY,
               appletWidth-drawAreaStartX-1,appletHeight-drawAreaStartY-1);
  }

  public void paint (Graphics g)
  {
    initDrawArea();

    int lx=-1,ly=-1;

    for (int i=0; i<vector.size(); i++)
    {
       ArrayListElement ale=( ArrayListElement) vector.elementAt(i);
       //System.out.println(ale.toString());
       g.setColor(ale.getColor());

       int x=ale.getX();
       int y=ale.getY();

       if (lx!=-1 && x!=-1)
       {
         g.drawLine(lx,ly,x,y);
       }

       lx=x;
       ly=y;
    }
  }

  public boolean action(Event evt, Object arg)
  {
    if (evt.target instanceof Button)
    {
      String button=arg.toString();
      if (button=="Clear")
      {
        Graphics g=this.getGraphics();
        g.setColor(Color.white);
        g.fillRect(0,0,appletWidth,appletHeight);
        vector.removeAllElements();
        initDrawArea();
      }
      if (button=="Undo")
      {
        if (!vector.isEmpty())
          vector.removeElementAt(vector.size()-1);
        repaint();
      }
      if (button=="Undo10")
      {

        for (int i=0; i<10 && !vector.isEmpty(); i++)
          vector.removeElementAt(vector.size()-1);
        repaint();
      }
    }
    if (evt.target instanceof Choice)
    {
      String entry=arg.toString();
      if (entry=="black") zeichenfarbe=Color.black;
      if (entry=="blue") zeichenfarbe=Color.blue;
      if (entry=="red") zeichenfarbe=Color.red;
      if (entry=="yellow") zeichenfarbe=Color.yellow;
      if (entry=="green") zeichenfarbe=Color.green;
      if (entry=="white") zeichenfarbe=Color.white;
      if (entry=="magenta") zeichenfarbe=Color.magenta;
      if (entry=="orange") zeichenfarbe=Color.orange;
      if (entry=="pink") zeichenfarbe=Color.pink;
      if (entry=="cyan") zeichenfarbe=Color.cyan;
    }
    if (evt.target instanceof Checkbox)
    {
      Checkbox mode=cbMode.getSelectedCheckbox();
      String selected=mode.toString();
      if (selected.indexOf("Delete")!=-1)
      {
        drawMode=false;
      }
      if (selected.indexOf("Draw")!=-1)
      {
        drawMode=true;
      }
    }
    return false;
  }

}