// Copyright 2004 by Richard Mansfield Kandarian
// This program is licensed under the GPL. The GPL text is available at
// http://www.opensource.org/licenses/gpl-license.php

import java.awt.*;
import java.awt.geom.GeneralPath;
import java.awt.event.*;
import java.awt.image.*;
import java.net.*;
import java.applet.*;
import java.lang.*;
import java.text.*;
import java.util.*;

class RouteTime extends Object{

  double total;
  double bttotal;
  double num, den;
  double dt, btc, nbtc;
  int bt;

  public void init(int i){
    num = i+1; den = i+2;
    total = 1 + 2*num/den;
    bttotal = total;
    bt=2;
    if(i > 0){
      btc=1;
      dt = 1/num + 1/den;
      while(true){
	if((nbtc = dt*(bt-1)+1/(double)bt) < btc){
	  btc = nbtc;
	  bt++;
	  continue;
	}else{
	  break;
	}
      }
      bttotal = total - (1 - btc);
    }
  }

  double total(){
    return total;
  }

  double bttotal(){
    return bttotal;
  }

  int backTrack(){
    return bt-2;
  }
}

class GridSpeed extends Component{
  Font labelFont;
  int fontHeight = 10;
  int lineHeight = fontHeight+2;
  int lm = 5*fontHeight;
  int tm = lineHeight;
  int rm = lm;
  int bm = 4*lineHeight;
  int pbm = 3*lineHeight;
  float lx = fontHeight/2;
  Graphics2D grid;
  int Size = 6;
  boolean initialized = false;

  int getGSize(){
    return Size;
  }

  void setGSize(int size){
    Size = size;
  }

  public void init(){
      initialized = true;
  }

  final static float MARGIN = 10F/100F;
  final static float PLOT = 1F/3F;

  public void drawRoute(Graphics g1){
    if(!initialized){
      init();
    }
    DecimalFormat lform = new DecimalFormat("#0.00");
    RouteTime routeTime = new RouteTime();
    Dimension d = getSize();
    float side = d.width - lm - rm;
    if((tm + side + bm + side/4F + pbm) > d.height){
      side = (float)(d.height - tm - bm - pbm)/(float)(1+1/4F);
    }
    float gw = lm + side + rm;
    float gh = tm + side + bm;
    labelFont = new Font("Helvetica", Font.PLAIN, fontHeight);
    Graphics2D g = (Graphics2D)g1;
    grid = g;
    g.setFont(labelFont);
    /*
    g.setColor(Color.darkGray);
    g.setColor(Color.white);
    */
    g.setColor(Color.gray);
    g.fillRect(0, 0, (int)gw, (int)gh);
    float dx = side/(Size - 1);
    boolean noxlabel = false;
    if(dx < lm/2){
      noxlabel = true;
    }
    boolean noylabel = false;
    if(dx < lineHeight){
      noylabel = true;
    }
    boolean toobig = false;
    if(dx < 3){
      toobig = true;
    }
    float xzero = lm;
    float yzero = tm + side;
    float plh = side/4F;
    float pyzero =  gh + plh;
    GeneralPath plscale = new GeneralPath();
    plscale.moveTo(xzero, (int)gh);
    plscale.lineTo(xzero, pyzero);
    plscale.lineTo(xzero+(int)side, pyzero);
    GeneralPath s1plot = new GeneralPath();
    GeneralPath s2plot = new GeneralPath();
    g.setColor(Color.white);
    g.fillRect(0, (int)gh, (int)gw, (int)(plh) + pbm);
    g.setColor(Color.black);
    g.drawString(lform.format(2.0), lx, pyzero + fontHeight/2);
    g.drawString(lform.format(3.0), lx, pyzero - plh + fontHeight);
    GeneralPath grid = new GeneralPath();
    grid.moveTo(xzero, yzero);
    grid.lineTo(xzero, yzero-side);
    grid.lineTo(xzero+side, yzero-side);
    grid.lineTo(xzero+side, yzero);
    grid.closePath();
    double sum1 = 0;
    double sum2 = 0;
    int ybt;
    GeneralPath route = new GeneralPath();
    GeneralPath btroutex = new GeneralPath();
    GeneralPath btroutey = new GeneralPath();
    route.moveTo(xzero, yzero);
    s1plot.moveTo(xzero, pyzero);
    s2plot.moveTo(xzero, pyzero);
    if(toobig){
      btroutex.moveTo(xzero, yzero);
      btroutey.moveTo(xzero, yzero);
    }
    float xinner = 0; float xouter = 0; float yinner = 0; float youter = 0;
    for(int i=0; i<Size-1; i++){
      routeTime.init(i);
      sum1 += routeTime.total();
      sum2 += routeTime.bttotal();
      xinner = xzero+i*dx;
      xouter = xzero+(i+1)*dx;
      yinner = yzero-i*dx;
      youter = yzero-(i+1)*dx;
      s1plot.lineTo(xouter, (float)(pyzero-((sum1/(float)(i+1)-2)/1.*plh)));
      s2plot.lineTo(xouter, (float)(pyzero-((sum2/(float)(i+1)-2)/1.*plh)));
      if(!toobig){
	grid.moveTo(xouter, yzero); grid.lineTo(xouter, yzero-side);
	grid.moveTo(xzero, youter); grid.lineTo(xzero+side, youter);
      }
      if(!toobig){
	if(i%2 == 0){
	  route.lineTo(xouter, yzero);
	  route.lineTo(xouter, youter);
	  route.lineTo(xzero, youter);
	  if((ybt = routeTime.backTrack()) > 0){
	    btroutex.moveTo(xinner, yzero);
	    btroutex.lineTo(xinner, yzero - ybt*dx);
	    btroutex.lineTo(xouter, yzero - ybt*dx);
	    btroutex.lineTo(xouter, yzero);
	  }
	  if(!noylabel){
	    g.drawString(lform.format(sum1), lx, youter);
	    g.drawString(lform.format(sum2), lx, youter + lineHeight);
	  }
	}else{
	  route.lineTo(xzero, youter);
	  route.lineTo(xouter, youter);
	  route.lineTo(xouter, yzero);
	  if((ybt = routeTime.backTrack()) > 0){
	    btroutey.moveTo(xzero, yinner);
	    btroutey.lineTo(xzero + ybt*dx, yinner);
	    btroutey.lineTo(xzero + ybt*dx, youter);
	    btroutey.lineTo(xzero, youter);
	  }
	  if(!noxlabel){
	    g.drawString(lform.format(sum1), xouter, yzero+2*lineHeight);
	    g.drawString(lform.format(sum2), xouter, yzero+3*lineHeight);
	  }
	}
      }else{
	ybt = routeTime.backTrack();
	if(i%2 == 0){
	  btroutex.lineTo(xinner, yzero - ybt*dx);
	  btroutex.lineTo(xouter, yzero - ybt*dx);
	}else{
	  btroutey.lineTo(xzero + ybt*dx, yinner);
	  btroutey.lineTo(xzero + ybt*dx, youter);
	}
      }
      g.fillRect((int)xinner, (int)(gh-5), (int)(dx>1?dx+1:1), 3);
    }
    if(noylabel){
      g.drawString(lform.format(sum1), lx, youter);
      g.drawString(lform.format(sum2), lx, youter + lineHeight);
    }
    BasicStroke gridstroke = new BasicStroke(dx/10, BasicStroke.CAP_BUTT,
      BasicStroke.JOIN_ROUND);
    BasicStroke routestroke = new BasicStroke(dx/20, BasicStroke.CAP_ROUND,
      BasicStroke.JOIN_ROUND);
    BasicStroke btroutestroke = new BasicStroke(dx/40, BasicStroke.CAP_ROUND,
      BasicStroke.JOIN_ROUND);
    BasicStroke plscalestroke = new BasicStroke(1, BasicStroke.CAP_ROUND,
      BasicStroke.JOIN_ROUND);
    BasicStroke s1plotstroke = new BasicStroke(1, BasicStroke.CAP_ROUND,
      BasicStroke.JOIN_ROUND);
    BasicStroke s2plotstroke = new BasicStroke(1, BasicStroke.CAP_ROUND,
      BasicStroke.JOIN_ROUND);
    /* g.setColor(Color.black); */
    g.setColor(Color.lightGray);
    g.setStroke(gridstroke);
    g.draw(grid);
    g.setColor(Color.red);
    g.setStroke(routestroke);
    g.draw(route);
    g.setColor(Color.blue);
    g.setStroke(btroutestroke);
    g.draw(btroutex);
    g.draw(btroutey);
    g.setColor(Color.black);
    g.setStroke(plscalestroke);
    g.draw(plscale);
    g.setColor(Color.blue);
    g.setStroke(s2plotstroke);
    g.draw(s2plot);
    g.setColor(Color.red);
    g.setStroke(s1plotstroke);
    g.draw(s1plot);
  }

  public void paint(Graphics g1){
    drawRoute(g1);
  }
}

public
class GridSpeedApplet extends Applet implements ActionListener {
  
  GridSpeed gridSpeed;
  TextField sf;

  public void init(){
    String param = getParameter("SIZE");
    if(param != null){
      gridSpeed.setGSize(Integer.parseInt(param));
      sf.setText(param);
    }else{
      gridSpeed.setGSize(6);
      sf.setText("6");
    }
    sf.selectAll();
  }

  public GridSpeedApplet(){
    setLayout(new BorderLayout());
    add("Center", gridSpeed = new GridSpeed());
    Panel p = new Panel();
    p.setLayout(new FlowLayout());
    add ("South", p);
    p.add("West", new Label("Enter grid size, >1 and <=100000:"));
    sf = new TextField(6);
    sf.addActionListener(this);
    p.add("West", sf);
  }

  public void itemStateChanged(ItemEvent e){
    String item = (String)(e.getItem());
  }

  public void actionPerformed(ActionEvent e){
    String sizetext = e.getActionCommand();
    int size = gridSpeed.getGSize();
    boolean valid = false;
    try{
      size = Integer.parseInt(sizetext);
      if(size > 1 && size <= 100000){
	gridSpeed.setGSize(size);
	gridSpeed.repaint();
      }
    }catch(NumberFormatException nfe){}
    sf.selectAll();
  }

  public static void main(String args[]){
    Frame f = new Frame("Grid Speed");
    GridSpeedApplet gridSpeedApplet = new GridSpeedApplet();
    f.add("Center", gridSpeedApplet);
    f.pack();
    f.setVisible(true);
    gridSpeedApplet.init();
    gridSpeedApplet.start();
  }
}