import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

/**
Graphics interface for Student class.  Makes it possible to add grades, see averages, and see grade lists.  There is no file-handling mechanism.
@author Melvin Fitting
@version October, 2003, revised October, 2004
*/
public class StudentGui extends JFrame implements ActionListener
{
   private Student s;
   private JTextField instructions;
   private JComboBox choiceList;
   private JTextField average;
   private JTextField newGrade;
   private JTextArea gradeList;
   private JScrollPane gradeListScroll;

/**
@param inS Student object for which this is the GUI
*/
   public StudentGui(Student inS)
   {
      s = inS;
      setSize(400,480);
      setTitle(s.getFirst() + " " + s.getLast());
      setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
      setLayout(null);
      setBackground(Color.YELLOW);

      instructions = new JTextField("Select an item below.");
      instructions.setFont(new Font("SansSerif", Font.BOLD, 20));
      instructions.setSize(280,30);
      instructions.setLocation(30,50);
      instructions.setBackground(Color.YELLOW);
      instructions.setEditable(false);
      add(instructions);

      String[] choices = {"Select an item here", "Add a grade", 
      		"See the average",
			"See the list of grades", "Quit"};
      choiceList = new JComboBox(choices);
      choiceList.setSize(280,30);
      choiceList.setLocation(30,100);
      choiceList.addActionListener(this);
      add(choiceList);

      average = new JTextField("No grades entered yet");
      average.setSize(280,30);
      average.setLocation(30,150);
      average.setEditable(false);

      gradeList = new JTextArea("No grades entered yet");
      gradeList.setEditable(false);
      gradeList.setLineWrap(true);
      gradeListScroll = new JScrollPane(gradeList);
      gradeListScroll.setSize(280,200);
      gradeListScroll.setLocation(30,150);

      newGrade = new JTextField("Enter grade here");
      newGrade.setSize(280,30);
      newGrade.setLocation(30,150);
      newGrade.setEditable(true);
      newGrade.addActionListener(this);
   }

   public void actionPerformed(ActionEvent e)
   {
      if (e.getSource() == choiceList)
      {
         int choice = choiceList.getSelectedIndex();
         switch(choice)
         {
            case 1: addGrade();
            break;

            case 2: seeAverage();
            break;

            case 3: seeList();
            break;

            case 4: dispose();
         }
      }
      else if (e.getSource() == newGrade)
      {
         String input = newGrade.getText();
         input = input.trim();
         try
         {
            int grade = Integer.parseInt(input);
            s.addGrade(grade);
            newGrade.setText("Enter a grade here");
            remove(newGrade);
            repaint();
         }
         catch(NumberFormatException ex)
         {
            newGrade.setText("Please re-enter");
         }
      }
   }

   private void refresh()
   {
      remove(average);
      remove(gradeListScroll);
      remove(newGrade);
      choiceList.setSelectedIndex(0);
   }

   private void addGrade()
   {
      refresh();
      add(newGrade);
      repaint();
   }

   private void seeAverage()
   {
      refresh();
      if (!s.listEmpty())
         average.setText("Average is " + s.getAverage());
      add(average);
      repaint();
   }

   private void seeList()
   {
      refresh();
      if (!s.listEmpty())
         {
            Integer[] grades = s.getGradeList();
            StringBuffer textBuffer = new StringBuffer("" + grades[0]);
            for(int n = 1; n < grades.length; n++)
               textBuffer.append(", " + grades[n]);
            gradeList.setText(textBuffer.toString());
          }
      add(gradeListScroll);
      gradeListScroll.validate();
      repaint();
   }
}