import javax.servlet.http.*;
import javax.servlet.*;
import java.io.*;
import java.awt.*;
import com.stevesoft.phreida.*;
import java.net.*;
import java.util.*;

// This is just a demo servlet
public class BarChartServlet extends HttpServlet {
  public void service(HttpServletRequest request,
                      HttpServletResponse response)
    throws ServletException, IOException
  {
    // If our product has a key, let's use it.
    ServletContext context = getServletContext();
    Key.registeredTo(context.getInitParameter("product-key"));

    response.setHeader("content-type","application/pdf");
    OutputStream out = response.getOutputStream();

    // Generate some data
    Random r = new Random();
    int[] data = new int[12];
    for(int i=0;i<data.length;i++)
      data[i] = r.nextInt(5)+1;
    int max = data[0], min = data[0];
    for(int i=1;i<data.length;i++) {
      if(data[i] > max) max = data[i];
      if(data[i] < min) min = data[i];
    }

    // Configuration
    Color[] colors = new Color[]{
      Color.red,
      Color.blue,
      Color.gray};
    int max_height = 200;
    int top_margin = 50;
    int left_margin = 50;
    int bar_width = 40;
    int bar_spacing = bar_width+5;
    int axis_overshoot=5;
    int gridy = 7;
    Color gridColor = Color.cyan;

    // Begin the drawing....
    PGraphics pdf = new PGraphics(out,0,0,700,300);
    pdf.drawString("Profitability by Month",10,20);
    pdf.setColor(gridColor);
    for(int i=0;i<gridy;i++) {
      int h = top_margin+max_height*i/gridy;
      pdf.drawLine(left_margin,h,
                   left_margin+bar_spacing*data.length,h);
    }
    for(int i=0;i<data.length;i++) {
      int h = max_height*data[i]/max;
      pdf.setColor(colors[i%colors.length]);
      pdf.fillRect(i*bar_spacing+left_margin,
                   top_margin+max_height,
		   bar_width,-h);
    }
    pdf.setColor(Color.black);

    pdf.drawLine(left_margin,top_margin-axis_overshoot,
                 left_margin,top_margin+max_height);
    pdf.drawLine(left_margin,top_margin+max_height,
                 left_margin+bar_spacing*data.length+axis_overshoot,
		 top_margin+max_height);

    pdf.dispose(); // We need to call this to finish the output
  }
}