/*
 * File: ShowFile.java
 *
 * 
 * This Java applet divides the applet area into two parts:  an area
 * with controls such as buttons and choices, called controlPanelNorth,
 * and an area called dataPanel which has a TextArea to display
 * data from a file.  The dataPanel is a separate class.
 * 
 * The data points are read from a file which has the following format:
 *    an integer which is the number of items in the file
 *    items:  each item has an integer id no., a name, and a floating
 * 		point price
 * 
 * The data is read once from the file into a set of arrays.  Then the
 * data can be displayed in different ways depending on the controls.
 * 
 */

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;

public class ShowFile extends java.applet.Applet
			implements ItemListener, ActionListener
{
  Font f = new Font("TimesRoman", Font.ITALIC, 18);

  DisplayPanel dataPanel;	// the display panel, from the class below
  String inname;		// name of the data file

  Choice dataChoice;		//  control for type of data
  Button showfile;              //  display the data under current controls
  Label title;			//  label of the display

  public void init()
  { InputStream instream = null;
    Panel controlPanelNorth = new Panel();

    setLayout(new BorderLayout());
    
    // initialize the input stream and data panel
    try
      { inname = getParameter("inputfile");
        instream = new URL(getDocumentBase(), inname).openStream();
	dataPanel = new DisplayPanel(instream);
       }
    catch (IOException e)
      { System.err.println
	  ("I/O Exception:  probably bad filename or bad connection."
	         + e.getMessage());
      }

  // make the control panel
  controlPanelNorth.setLayout(new FlowLayout(FlowLayout.LEFT, 5, 5));

  title = new Label("Grocery Items");
  title.setFont(f);

  dataChoice = new Choice();
  dataChoice.setFont(f);
  dataChoice.addItem("Fruits");
  dataChoice.addItem("Veggies");
  dataChoice.addItemListener(this);

  showfile = new Button("Show Items");
  showfile.setFont(f);
  showfile.addActionListener(this);

  controlPanelNorth.add(title);
  controlPanelNorth.add(dataChoice);
  controlPanelNorth.add(showfile);


  // add the two components to the applet area
  add(controlPanelNorth, BorderLayout.NORTH);
  add(dataPanel, BorderLayout.CENTER);
  }

  public void itemStateChanged(ItemEvent e)
  {
    if (e.getSource() == dataChoice)
      { 
	dataPanel.settype (dataChoice.getSelectedItem());
      }
  }

  public void actionPerformed(ActionEvent e)
  {
    if (e.getSource() == showfile)
      {
	dataPanel.displayfile();
      }
  }
}

class DisplayPanel extends Panel
{
  String datatype = "Fruits";	// either "Fruits" or "Veggies"
  StringBuffer buff;
  Font f = new Font("Monospaced", Font.ITALIC, 18);
  TextArea ta;
  
  // variables to hold the data from the file 
  int numdata;
  int itemnumbers[];
  String itemnames[];
  double itemprices[];
  int maxlength;

  InputStreamReader isr;

  public DisplayPanel(InputStream instream)
  { 
    setLayout(new BorderLayout());
    ta = new TextArea("Grocery Item Display Area . . .", 20, 30);
    add( ta, BorderLayout.CENTER );
 
    try
    {
      isr = new InputStreamReader(instream);
      StreamTokenizer intokens = new StreamTokenizer(isr);
      intokens.parseNumbers();  intokens.slashSlashComments(true);
      
      /* read the number of data points and allocate data arrays */    
      int tok = intokens.nextToken();  
      numdata = (int) intokens.nval;
      
      itemnumbers = new int[numdata];
      itemnames = new String[numdata];
      itemprices = new double[numdata];

      // read data items 
      maxlength = 0;
      for (int i=0; i<numdata; i++)
      { tok = intokens.nextToken();  itemnumbers[i] = (int)intokens.nval;
        tok = intokens.nextToken();  itemnames[i] = intokens.sval;
        tok = intokens.nextToken();  itemprices[i] = intokens.nval;
	maxlength = Math.max(maxlength, itemnames[i].length());
      }

   /* for debugging
      for (int i=0; i<numdata; i++)
      { System.out.println(itemnumbers[i]);
        System.out.println(itemnames[i]);
        System.out.println(itemprices[i]);
      }
   */
    }
    catch (IOException e)
      { System.err.println
	  ("I/O Exception:  Reading data from file"
	         + e.getMessage());
      }
  }

  public void settype (String s)
  { datatype = s;
  }

  public void displayfile()
  { 
    buff = new StringBuffer();
    ta.setFont (f);
    Color fruitcolor = new Color(127, 0, 0);
    Color vegcolor = new Color(0, 127, 127);

    for (int i=0; i<numdata; i++)
      { if (datatype.equals("Fruits") && itemnumbers[i]<=1000)
	  appendtext(fruitcolor, itemnumbers[i], itemnames[i], itemprices[i]);
        if (datatype.equals("Veggies") && itemnumbers[i]>1000)
	  appendtext(vegcolor, itemnumbers[i], itemnames[i], itemprices[i]);
      }
    ta.setText(buff.toString());
  }

  public void appendtext (Color c, int n, String s, double d)
  {
    ta.setForeground (c);
    int diff = maxlength - s.length();

    buff.append( n + "      " + s);
    for (int i=0; i<diff; i++) buff.append(" ");
    buff.append( "  $" + d + "\n");
  }
}