/*
*  The URLMenu class -(c) Suresh Kumar Nalluru
*/

/*
*  Assumptions:
*   1.  The 3 images are of the same size.
*   2.  There are atmost 50 URL's per applet.
*   3.  There is atleast one URL per applet.
*   4.  No check is made if the whole string is displayable
*           or not. In such cases it just chops off the string
*           and displays whatever is visible.
*   5.  If the Font cant be loaded, then some default font is used
*           instead of giving the error messages,
*   6.  If a image cant be loaded, it silently goes to no-image mode
*           instead of complaining.
*   7.  If statustext is given then it is tried to display these strings
*           and in case , the number of strings are not equal to the
*           number of text, then the default method is used.
*
*   8. Showstatus:
*           0 : No status text
*           1 : Text in applet: URL format
*           2 : Statustext is displayed
*/   
import java.applet.*;
import java.awt.*;
import java.net.*;

public class URLMenu extends Applet implements Runnable
{
    /*
    *  butCnt           No. of buttons
    *  images           Display images?
    *  horiStyle        Horizontal style?
    *  activeIndex      Which of the buttons is active
    *  n_URLMenu         The thread of the applet
    *  n_Graphics       The raphics context of the thread
    *  n_Images         The array of the loaded images
    *  n_fAllLoaded     Are all the images loaded?
    *  mouse_down       Is mouse pressed down?
    *  NUM_IMAGES       The number of images in the images array
    *  n_nImgWidth      The width of each of the image
    *  n_nImgHeight     The height of each of the image
    *  w,h              Width and Height of each of active region
    *  fontsize         The fontsize
    */  

        private int butCnt = 0; 
        private boolean images = true;
        private int showstatus = 1;
        private boolean horiStyle = false;    
        private int activeIndex = -1;
        private Thread   n_URLMenu = null;
        private Graphics n_Graphics;
        private Image    n_Images[];
        private boolean  n_fAllLoaded = false;
        private boolean  mouse_down = false;
        private final int NUM_IMAGES = 3;
        private int      n_nImgWidth  = 0;
        private int      n_nImgHeight = 0;
        private int w , h;
        private int fontsize = 12;

        // assume atmost 50 URl's
        private String n_url[] = new String[50];
        private String n_text[] = new String[50];
        private String n_statustext[] = new String[50];
        private String n_frame[] = new String[50];
        
        // default foreground and background colors
        private Color n_fgColor = new Color(255,255,40);
        private Color n_bkColor2 = new Color(42,42,140);
        private Color n_bkColor1 = new Color(58,185,224);

        // strings to get the parameters
        private final String param_url = "url";
        private final String param_frame = "frame";
        private final String param_text = "text";
        private final String param_showstatus = "showstatus";
        private final String param_statustext = "statustext";
        private final String param_bkColor1 = "bkColor1";
        private final String param_bkColor2 = "bkColor2";
        private final String param_fgColor = "fgColor";
        private final String param_font = "font";
        private final String param_fontsize = "fontsize";
        private final String param_style = "style";
        private final String param_images = "images";

        private final String DEFAULT_font = "Helvetica";

        public String getAppletInfo()
        {
                return "Name: URLMenu\r\n" +
                       "Author: Suresh Kumar Nalluru\r\n" ;
        }

        /*
        *  Given a string it will parse it by commas. If will
        *  fill the destination array with the sub strings
        *  and will return the number of sub strings that are
        *  extracted from the Main string
        */  
        private int parse(String dst[], String src)
        {
            int i=0,x=0;
            while(true)
            {
                int n = src.indexOf(',', x);
                if(n==-1)
                {
                    dst[i] = src.substring(x);
                    break;
                }
                else
                        dst[i] = src.substring(x, n);
                dst[i] = dst[i].trim();
                x = n+1;
                i++;
            }
            return i+1;
        }

        /*
        *  It will initialise the various varibles from the
        *  parameters passed to the applet. Note the initialisation
        *  of h,w by dividing the applet size with the number or URLs
        */  
        public void init()
        {
            String param;
            String col[] = new String[3];
            int i;
            Color c;

            param = getParameter(param_url);
            if (param != null)
                    parse(n_url, param);

            try {

            param = getParameter(param_bkColor1);
            if (param != null)
            {
                i=parse(col,param);
                // is in the format R,G,B ??
                if(i==3)
				{
                    c = new Color(Integer.parseInt(col[0]),
                                            Integer.parseInt(col[1]),
                                            Integer.parseInt(col[2]));
                    // Only when there is no error
					if(c!=null)
						n_bkColor1 = c;
				}
            }

            param = getParameter(param_bkColor2);
            if (param != null)
            {
                i=parse(col,param);
                if(i==3)
				{
                    c = new Color(Integer.parseInt(col[0]),
                                            Integer.parseInt(col[1]),
                                            Integer.parseInt(col[2]));
					if(c!=null)
						n_bkColor2 = c;
				}
            }

            param = getParameter(param_fgColor);
            if (param != null)
            {
                i=parse(col,param);
                if(i==3)
				{
                    c = new Color(Integer.parseInt(col[0]),
                                            Integer.parseInt(col[1]),
                                            Integer.parseInt(col[2]));
					if(c!=null)
						n_fgColor = c;
				}
            }
            }
            catch(Exception e)
            {
            };

            param = getParameter(param_text);
            if (param != null)
                    butCnt = parse(n_text, param);

            param = getParameter(param_showstatus);
            if (param != null)
                    showstatus = Integer.parseInt(param);


            param = getParameter(param_statustext);
            if (param != null)
            {
                    i = parse(n_statustext, param);
                    if(i!= butCnt && showstatus==2)
                        showstatus = 1;
            }
            else if(showstatus ==2)
                showstatus = 1;


            param = getParameter(param_frame);
            if (param != null)
                    parse(n_frame, param);

            param = getParameter(param_fontsize);
            if (param != null)
                    fontsize = Integer.parseInt(param);

            param = getParameter(param_font);
            if (param != null)
                    setFont(new Font(param,Font.PLAIN,fontsize));
            else
                setFont(new Font(DEFAULT_font,Font.PLAIN,fontsize));

            param = getParameter(param_images);
            if (param != null)
                    images = (Integer.parseInt(param)==1);

            param = getParameter(param_style);
            if (param != null)
                    horiStyle = (Integer.parseInt(param)==1);

            Dimension d=size();
            if(horiStyle)
            {
                w=(d.width+1)/butCnt;
                h=d.height;
            }
            else
            {
                w= d.width;
                h=(d.height+1)/butCnt;
            };

        }

        /*
        *  this routine draws one region. n specifies the active region
        *  to be drawn. Style is the style with which it is drawn.
        *
        *  style:
        *  0: Default
        *  1: Mouse on an URL
        *  2: Selected URL ,by mouse click
        */  
        private void draw1(Graphics g, int n,int stage)
        {
            // for boundary conditions
            if(n>=butCnt)
                return;
            if(n<0)
                return;

            // the rectangle to be painted
            Rectangle r;
            if(horiStyle)
                    r = new Rectangle(w*n,0,w,h);
            else
                    r = new Rectangle(0,n*h,w,h);

            if(r==null)
                    return;

            // Only when all images are loaded , then do the 
            // fashion things
            if ((!images) || n_fAllLoaded)
            {
                // draw the appropriate background color
                if(stage==0)
                {
                    g.setColor(n_bkColor1);
                    g.fill3DRect(r.x, r.y, r.width, r.height,false);
                }
                else
                {
                    g.setColor(n_bkColor2);
                    g.fill3DRect(r.x, r.y, r.width, r.height,true);
                }

                // draw the image
                if(images)
                {

                    if(horiStyle)
                        g.drawImage(n_Images[stage], w*n+5,
                            (h - n_nImgHeight) / 2, null);
                    else
                        g.drawImage(n_Images[stage],
                            5, n*h+(h - n_nImgHeight) / 2, null);
                }
            }
            // draw the string
            g.setColor(n_fgColor);
            g.drawString(n_text[n], r.x+10+n_nImgWidth, r.y+r.height/2 +
                    g.getFontMetrics().getAscent()/2);

            if(activeIndex>=0)
            {
                if (showstatus==1)
                    showStatus(n_text[n]+" : " + n_url[n]);
                else if(showstatus ==2)
                    showStatus(n_statustext[n]);

            }
                
        }

        public void paint(Graphics g)
        {
            for(int i=0; i<butCnt; i++)
                draw1(g, i,0);
        }

        public void start()
        {
            if (n_URLMenu == null)
            {
                n_URLMenu = new Thread(this);
                n_URLMenu.start();
            }
        }

        public void stop()
        {
            if (n_URLMenu != null)
            {
                n_URLMenu.stop();
                n_URLMenu = null;
            }

        }

        public void run()
        {
            // if first time
            if (!n_fAllLoaded)
            {
                // Load all the images to the images array
                n_Graphics = getGraphics();
                repaint();

                if(images)
                {

                n_Images   = new Image[NUM_IMAGES];

                MediaTracker tracker = new MediaTracker(this);
                String strImage;

                for (int i = 1; i <= NUM_IMAGES; i++)
                {
                    strImage = "stage" + i + ".gif";
                    n_Images[i-1] = getImage(getCodeBase(), strImage);
                    tracker.addImage(n_Images[i-1], i);
                }
                try
                {
                    // wait till all the images are loaded
                    tracker.waitForAll();
                    n_fAllLoaded = !(tracker.isErrorAny());
                }
                catch (InterruptedException e)
                {
                };
                        

                if (!n_fAllLoaded)
                    images=false;
                else
                {
                // initialise to size of the iamges.
                    n_nImgWidth  = n_Images[0].getWidth(this);
                    n_nImgHeight = n_Images[0].getHeight(this);
                }

                }

            }
            repaint();
        }

        // converts (x,y) coordinate to Active Index 
        private int xy2ai(int x, int y)
        {
            if(x<0 || y<0)
                return -1;
            else
                return horiStyle? x/w:y/h;
        }

        private void validateAI(int x, int y)
        {
            if(xy2ai(x,y) != activeIndex && ((!images) ||n_fAllLoaded))
            {
                if(activeIndex!=-1)
                {
                    // turn off previous button indicator
                    draw1(n_Graphics, activeIndex, 0);
                }
                        // hilight new one
                activeIndex = xy2ai(x,y);
                draw1(n_Graphics, activeIndex, 1);
            }
        }

        public boolean mouseDown(Event evt, int x, int y)
        {
            mouse_down=true;
            if((!images) || n_fAllLoaded)
            {
                validateAI(x, y);
                draw1(n_Graphics, xy2ai(x,y), 2);
            }
            return true;
        }

        public boolean mouseUp(Event evt, int x, int y)
        {
            mouse_down=false;
            // if mouse raised outside the applet region
            if(activeIndex==-1)
                return true;

            validateAI(x, y);
            draw1(n_Graphics, xy2ai(x,y), 2);

            // jump through hyperlink
            URL theUrl;
            try {
                theUrl = new URL(getDocumentBase(), n_url[activeIndex]);
                getAppletContext().showDocument(theUrl,
                    (n_frame[activeIndex]==null)? "_self":
                        n_frame[activeIndex]);
                }
                catch (MalformedURLException e)
                {
                }

            return true;
        }

        public boolean mouseEnter(Event evt, int x, int y)
        {
            if((!images) || n_fAllLoaded)
            {
                activeIndex = xy2ai(x,y);
                if(mouse_down)
                    draw1(n_Graphics, activeIndex, 2);
                else
                    draw1(n_Graphics, activeIndex, 1);
            }
            return true;
        }

        public boolean mouseDrag(Event evt, int x, int y)
        {
            int temp;

            if(horiStyle)
            {
                if (y<0 || y>=h)
                {
                    activeIndex = -1;
                    return true;
                }
            }
            else
            {
                if(x<0 || x>= w)
                {
                    activeIndex = -1;
                    return true;
                }
            };

            temp=xy2ai(x,y);
            if(temp != activeIndex && ((!images) || n_fAllLoaded))
            {
                if(activeIndex!=-1)
                    draw1(n_Graphics, activeIndex, 0);
                activeIndex = temp;
                draw1(n_Graphics, activeIndex, 2);
            }
            return true;
        }

        public boolean mouseMove(Event evt, int x, int y)
        {
            validateAI(x,y);
            return true;
        }

        public boolean mouseExit(Event evt, int x, int y)
        {
            if((!images) || n_fAllLoaded)
            {
                draw1(n_Graphics, activeIndex, 0);
                activeIndex = -1;
            }
            return true;
        }
}