/** 
* GPACalc
* by Jay Tomlin, 1/19/97
* http://ezinfo.ucs.indiana.edu/~ltomlin/GPA.html
* A configurable GPA calculator applet (^_^)
*/

import java.applet.*;
import java.awt.*;
 
public class GPACalc extends Applet implements Runnable {
 
//
// Declare the class variables
//
 
Thread calculationThread;  // a background thread for updating the GPA \\
Panel Priors, Calc, Controls, Master, ConfigPanel, Config, ConfigButtons;
GridLayout grid, configGrid;
GridBagLayout gridbag;
CardLayout card;
  
	// For the Calc panel: \\

TextField Hours1, Hours2, Hours3, Hours4, Hours5, Hours6, Hours7;
TextField Grade1, Grade2, Grade3, Grade4, Grade5, Grade6, Grade7;
TextField NumGrade1, NumGrade2, NumGrade3, NumGrade4, NumGrade5,
	NumGrade6, NumGrade7;
 
	// For the Priors panel: \\

TextField PriorGPA, PriorHours;
 
	// For the Controls panel: \\

TextField SemesterHours, SemesterGPA, CumulativeHours, CumulativeGPA;
Button  Clear, anotherSemester, Configure;

	// For the Config panel: \\

Panel instructionsPanel;
GridLayout instGrid;
TextArea instructions;
TextField APlusValue, AValue, AMinusValue, BPlusValue, BValue, BMinusValue,
		CPlusValue, CValue, CMinusValue, DPlusValue, DValue, DMinusValue, FValue;
Button Return, RestoreDefaults;
double aplus, a, aminus, bplus, b, bminus, cplus, c, cminus, dplus, d, dminus, f;
double points = 0;
			    
			    
public void init() {

	// get the GridBag started
	
	gridbag = new GridBagLayout();
	
	//
	// Create the component Panels and add their widgets:
	//
	
// Priors, a panel where the user enters prior GPA and credit hours: \\
	
	Priors = new Panel();
	Priors.setLayout(gridbag);
	PriorHours = new TextField(3);
	PriorGPA = new TextField(4);
	
	
	addComponent(Priors, new Label("Prior Credit Hours:"), 1, 0, 1, 1, GridBagConstraints.SOUTHEAST, GridBagConstraints.NONE);
	addComponent(Priors, PriorHours, 2, 0, 1, 1, GridBagConstraints.SOUTHWEST, GridBagConstraints.NONE);
	addComponent(Priors, new Label("Prior GPA:"), 1, 1, 1, 1, GridBagConstraints.NORTHEAST, GridBagConstraints.NONE);
	addComponent(Priors, PriorGPA, 2, 1, 1, 1, GridBagConstraints.NORTHWEST, GridBagConstraints.NONE);
	
	
	PriorHours.setText("0"); PriorGPA.setText("0.00");
	
	
	
	// Calc, a Panel where the user enters current-semester grades \\
	
	Calc = new Panel();
	grid = new GridLayout(9, 3, 5, 5); // a 9x3 grid for entering course & grade info \\	
	Calc.setLayout(grid);
 	
	Hours1 = new TextField(1);
	Hours2 = new TextField(1);
	Hours3 = new TextField(1);
	Hours4 = new TextField(1);
	Hours5 = new TextField(1);
	Hours6 = new TextField(1);
	Hours7 = new TextField(1);
 
	Grade1 = new TextField(2);
	Grade2 = new TextField(2);
	Grade3 = new TextField(2);
	Grade4 = new TextField(2);
	Grade5 = new TextField(2);
	Grade6 = new TextField(2);
	Grade7 = new TextField(2);
	
	NumGrade1 = new TextField(4); NumGrade1.setEditable(false);
	NumGrade2 = new TextField(4); NumGrade2.setEditable(false);
	NumGrade3 = new TextField(4); NumGrade3.setEditable(false);
	NumGrade4 = new TextField(4); NumGrade4.setEditable(false);
	NumGrade5 = new TextField(4); NumGrade5.setEditable(false);
	NumGrade6 = new TextField(4); NumGrade6.setEditable(false);
	NumGrade7 = new TextField(4); NumGrade7.setEditable(false);
	
	Calc.add(new Label("Hours")); Calc.add(new Label("Grade")); Calc.add(new Label("Points"));
	Calc.add(Hours1); Calc.add(Grade1); Calc.add(NumGrade1);
	Calc.add(Hours2); Calc.add(Grade2); Calc.add(NumGrade2);
	Calc.add(Hours3); Calc.add(Grade3); Calc.add(NumGrade3);
	Calc.add(Hours4); Calc.add(Grade4); Calc.add(NumGrade4);
	Calc.add(Hours5); Calc.add(Grade5); Calc.add(NumGrade5);
	Calc.add(Hours6); Calc.add(Grade6); Calc.add(NumGrade6);
	Calc.add(Hours7); Calc.add(Grade7); Calc.add(NumGrade7);
	
	
	// Controls, a panel for the bottom row of buttons and fields \\
	
	Controls = new Panel();
	Controls.setLayout(gridbag);
 
	SemesterHours = new TextField(3);
	SemesterGPA = new TextField(8);
	CumulativeHours = new TextField(3);
	CumulativeGPA = new TextField(8);
	
	
	Clear = new Button("Clear");
	anotherSemester = new Button("Do Another Semester");
	Configure = new Button("Configure...");
	
	addComponent(Controls, new Label("Total Hours"), 1, 0, 1, 1, GridBagConstraints.SOUTH, GridBagConstraints.NONE);
	addComponent(Controls, new Label("GPA"), 2, 0, 1, 1, GridBagConstraints.SOUTH, GridBagConstraints.NONE);
	addComponent(Controls, new Label("This Semester: "), 0, 1, 1, 1, GridBagConstraints.EAST, GridBagConstraints.NONE);
	addComponent(Controls, new Label("Cumulative: "), 0, 2, 1, 1, GridBagConstraints.EAST, GridBagConstraints.NONE);
	addComponent(Controls, SemesterHours, 1, 1, 1, 1);
	addComponent(Controls, SemesterGPA, 2, 1, 1, 1);
	addComponent(Controls, CumulativeHours, 1, 2, 1, 1);
	addComponent(Controls, CumulativeGPA, 2, 2, 1, 1);
	addComponent(Controls, SemesterHours, 1, 1, 1, 1);
	addComponent(Controls, Clear, 2, 3, 1, 1);
	addComponent(Controls, anotherSemester, 0, 3, 1, 1);
	addComponent(Controls, Configure, 1, 3, 1, 1);
	
	// Master, a Panel (Card) to hold everything so far

	Master = new Panel();
	Master.setLayout(gridbag);
	addComponent(Master, Priors, 0, 0, 1, 1, GridBagConstraints.NORTH, GridBagConstraints.NONE);
	addComponent(Master, Calc, 0, 1, 1, 1, GridBagConstraints.NORTH, GridBagConstraints.NONE);
	addComponent(Master, Controls, 0, 2, 1, 1, GridBagConstraints.SOUTH, GridBagConstraints.NONE);
	
	// ConfigPanel, a Panel (Card) to hold the instructions and configurations
	
	ConfigPanel = new Panel();
	
	instructions = new TextArea(10, 35);
	instructions.setEditable(false);
	instructions.setText("GPACalc\nby Jay Tomlin\nhttp://ezinfo.ucs.indiana.edu/~ltomlin\n\n");
	instructions.appendText("Enter the number equivalents for each \nletter grade listed below. ");
	instructions.appendText("To restore\nthe original equivalents, click the\n\"Restore Defaults\" button.\n");
	instructionsPanel = new Panel();
	instGrid = new GridLayout(1,1); // necessary so the text area resizes
	instructionsPanel.setLayout(instGrid);
	instructionsPanel.add(instructions);
	
	ConfigButtons = new Panel(); // we'll just let the default FlowLayout take this one
	Return = new Button("Return");
	RestoreDefaults = new Button("Restore Defaults");
	ConfigButtons.add(RestoreDefaults);
	ConfigButtons.add(Return);		
	
	// Config, a panel where the user sets the point value for each letter grade \\
	
	Config = new Panel();
	configGrid = new GridLayout(7, 4);   // a 7x4 grid for configuring grade values \\
	Config.setLayout(configGrid);	
 
 	APlusValue = new TextField(3); 
 	AValue = new TextField(3); 
 	AMinusValue = new TextField(3); 
	BPlusValue = new TextField(3); 
 	BValue = new TextField(3); 
 	BMinusValue = new TextField(3); 
 	CPlusValue = new TextField(3); 
 	CValue = new TextField(3); 
 	CMinusValue = new TextField(3); 
 	DPlusValue = new TextField(3); 
 	DValue = new TextField(3); 
 	DMinusValue = new TextField(3); 
 	FValue = new TextField(3); 
 	RestoreDefaults(); // defined below
	
 	Config.add(new Label("A+:")); Config.add(APlusValue);		 // four components \\
 		Config.add(new Label(" C: ")); Config.add(CValue);	//      per row     \\
 	Config.add(new Label("A:")); Config.add(AValue);
 		Config.add(new Label(" C-:")); Config.add(CMinusValue);
 	Config.add(new Label("A-:")); Config.add(AMinusValue);
 		Config.add(new Label(" D+:")); Config.add(DPlusValue);
 	Config.add(new Label("B+:")); Config.add(BPlusValue);
 		Config.add(new Label(" D:")); Config.add(DValue);
 	Config.add(new Label("B:")); Config.add(BValue);
 		Config.add(new Label(" D-:")); Config.add(DMinusValue);
 	Config.add(new Label("B-:")); Config.add(BMinusValue);
 		Config.add(new Label(" F: ")); Config.add(FValue);
 	Config.add(new Label("C+:")); Config.add(CPlusValue);
 	
 	// assemble the elements of the ConfigPanel in a GridBagLayout: \\
 			
	ConfigPanel.setLayout(gridbag);
	addComponent(ConfigPanel, instructionsPanel, 0, 0, 1, 1, GridBagConstraints.NORTH, GridBagConstraints.BOTH);
	addComponent(ConfigPanel, Config, 0, 1, 1, 1, GridBagConstraints.SOUTH, GridBagConstraints.NONE);
	addComponent(ConfigPanel, ConfigButtons, 0, 2, 1, 1, GridBagConstraints.SOUTH, GridBagConstraints.NONE);
		
	//
	// Finally, add all Panels to the Applet and show them
	//
	
	card = new CardLayout();
	this.setLayout(card);
	this.add("First", Master);
	this.add("Second", ConfigPanel);
	card.show(this, "First");
	this.show();
	
	}  // ends init() \\
	
 
 
public void start() {
	
	if (calculationThread == null) {
		
		calculationThread = new Thread(this);
		calculationThread.start(); // starts the run() method
	
		}
 
	
	} // ends start() \\
 
public void run() {
 		while (calculationThread != null) {
 		
 		try {Thread.sleep(3000);}  // sleep for 3 seconds at a time to reduce flicker
	 		catch (InterruptedException e) {}
 		
 		 // Get the number equivalences for each letter grade \\
 		//      from the fields on the Config panel:           \\
 		
		try {
			Double aplus_val = new Double(APlusValue.getText());
			 aplus = aplus_val.doubleValue();
		} catch (NumberFormatException e) {  aplus = 0;}

		try {
			Double a_val = new Double(AValue.getText());
			 a = a_val.doubleValue();
		} catch (NumberFormatException e) {  a = 0;}


		try {
			Double aminus_val = new Double(AMinusValue.getText());
			 aminus = aminus_val.doubleValue();
		} catch (NumberFormatException e) {  aminus = 0;}

		try {
			Double bplus_val = new Double(BPlusValue.getText());
			 bplus = bplus_val.doubleValue();
		} catch (NumberFormatException e) { bplus = 0;}

		try {
			Double b_val = new Double(BValue.getText());
			 b = b_val.doubleValue();
		} catch (NumberFormatException e) { b = 0;}

		try {
			Double bminus_val = new Double(BMinusValue.getText());
			 bminus = bminus_val.doubleValue();
		} catch (NumberFormatException e) { bminus = 0;}
		
		try {
			Double cplus_val = new Double(CPlusValue.getText());
			cplus = cplus_val.doubleValue();
		} catch (NumberFormatException e) { cplus = 0;}

		try {
			Double c_val = new Double(CValue.getText());
			c = c_val.doubleValue();
		} catch (NumberFormatException e) { c = 0;}

		try {
			Double cminus_val = new Double(CMinusValue.getText());
			cminus = cminus_val.doubleValue();
		} catch (NumberFormatException e) { cminus = 0;}

		try {
			Double dplus_val = new Double(DPlusValue.getText());
			dplus = dplus_val.doubleValue();
		} catch (NumberFormatException e) { dplus = 0;}

		try {
			Double d_val = new Double(DValue.getText());
			d = d_val.doubleValue();
		} catch (NumberFormatException e) { d = 0;}

		try {
			Double dminus_val = new Double(DMinusValue.getText());
			dminus = dminus_val.doubleValue();
		} catch (NumberFormatException e) { dminus = 0;}
		
		try {
			Double f_val = new Double(FValue.getText());
			f = f_val.doubleValue();
		} catch (NumberFormatException e) { f = 0;}

		// Now we have primitive doubles (not Doubles) in 
		// aplus, a, aminus, etc...  
		
		// multiply number values times Hours fields and put
		// the result in NumGrade fields:
		
		TextField[] HoursArray = {Hours1, Hours2, Hours3, Hours4, Hours5, Hours6, Hours7};
		TextField[] NumGradeArray = {NumGrade1, NumGrade2, NumGrade3, NumGrade4, NumGrade5, NumGrade6, NumGrade7};
		TextField[] GradeArray = {Grade1, Grade2, Grade3, Grade4, Grade5, Grade6, Grade7};
		 
		for (int i=0; i < 7; i++) {
			Double h = new Double(0);
			try {h = new Double(HoursArray[i].getText());}
				catch (NumberFormatException e) {h = new Double(0);}
			int hours = h.intValue();
			String grade = GradeArray[i].getText();
			if (grade.equals("A+")) { points = aplus * hours;}
			else if(grade.equals("A")) { points = a * hours;}
			else if(grade.equals("A-")) { points = aminus * hours;}
			else if(grade.equals("B+")) { points = bplus * hours;}
			else if(grade.equals("B")) { points = b * hours;}
			else if(grade.equals("B-")) { points = bminus * hours;}
			else if(grade.equals("C+")) { points = cplus * hours;}
			else if(grade.equals("C")) { points = c * hours;}
			else if(grade.equals("C-")) { points = cminus * hours;}
			else if(grade.equals("D+")) { points = dplus * hours;}
			else if(grade.equals("D")) { points = d * hours;}
			else if(grade.equals("D-")) { points = dminus * hours;}
			else if(grade.equals("F")) { points = f * hours;}
			else {points = 0;}
			
			Double Points = new Double(points);
			NumGradeArray[i].setText(Points.toString());		
			} //ends for loop
		
		double sum_hours = 0;
		double sum_points = 0;
		Double sem_hrs = new Double(0); 
		Double hrs = new Double(0);
		Double pnts = new Double(0);
		for(int i=0; i < 7; i++) {
			try { hrs = new Double(HoursArray[i].getText());} 
				catch (NumberFormatException e) {hrs = new Double(0);}
			sum_hours += hrs.doubleValue();
			
			try { pnts = new Double(NumGradeArray[i].getText()); }
				catch (NumberFormatException e) { pnts = new Double(0); }
			sum_points += pnts.doubleValue();
			
			} // ends for loop
		Double Total_Semester_Hours = new Double(sum_hours);
		SemesterHours.setText(Total_Semester_Hours.toString());

		double sem_gpa = 0;
		if (sum_hours != 0) {sem_gpa = sum_points / sum_hours;}
			else {sem_gpa = 0.0;}
		Double Sem_GPA = new Double(sem_gpa);
		SemesterGPA.setText(Sem_GPA.toString());
		
		// now calculate cumulatives
		
		double prior_hours, prior_gpa, prior_points, cum_hours, cum_gpa, cum_points;
		Double Prior_Hours, Prior_GPA, Cum_Hours, Cum_GPA;
		
		try { Prior_Hours = new Double(PriorHours.getText()); }
			catch (NumberFormatException e) {Prior_Hours = new Double(0);}
		prior_hours = Prior_Hours.doubleValue();
		
		try { Prior_GPA = new Double(PriorGPA.getText()); }
			catch (NumberFormatException e) {Prior_GPA = new Double(0);}
		prior_gpa = Prior_GPA.doubleValue();
		prior_points = prior_hours * prior_gpa;
		
		cum_hours = prior_hours + sum_hours;
		cum_points = prior_points + sum_points;
		if (cum_hours != 0) {cum_gpa = cum_points / cum_hours;}
			else {cum_gpa = 0.0;}
		
		Cum_Hours = new Double(cum_hours);
		Cum_GPA = new Double(cum_gpa);
		CumulativeHours.setText(Cum_Hours.toString());
		CumulativeGPA.setText(Cum_GPA.toString());

  		} // ends while thread == null
 		
 		
 
 
	} // ends run() \\
	
void addComponent(Container cont, Component comp, int grid_x, int grid_y,
					int grid_w, int grid_h) {
		
		GridBagConstraints c = new GridBagConstraints();
		
		c.gridx=grid_x; c.gridy=grid_y;
		c.gridwidth=grid_w; c.gridheight=grid_h;
		gridbag.setConstraints(comp, c);
		cont.add(comp);
		
		} //ends addComponent(cont, comp, x, y, w, h)
		
	
void addComponent(Container cont, Component comp, int grid_x, int grid_y,
					int grid_w, int grid_h, int anchor, int fill) {
		
		GridBagConstraints c = new GridBagConstraints();
		
		c.gridx=grid_x; c.gridy=grid_y;
		c.gridwidth=grid_w; c.gridheight=grid_h;
		c.anchor = anchor;
		c.fill = fill;
		
		gridbag.setConstraints(comp, c);
		cont.add(comp);
		
		} //ends addComponent(cont, comp, x, y, w, h, anchor, fill)
	
//	
// Handle user clicks.
//	

public boolean handleEvent(Event e) {
	switch(e.id) {
		case Event.ACTION_EVENT:
			if(e.target == Configure) {	card.show(this, "Second"); return true;}
			else if(e.target == Return) {card.show(this, "First"); return true;}
			else if(e.target == RestoreDefaults) {RestoreDefaults(); return true;}
			else if(e.target == Clear) {ClearFields(); return true;}
			else if(e.target == anotherSemester) {DoAnotherSemester(); return true;}
			else {return false;}				
		} //ends switch
		
		return false; // this way the super.handleEvent(e) is called
	
	} // ends handleEvent
	

	
//
// And now the function calls:
//

void RestoreDefaults() {

 	APlusValue.setText("4.0");
 	AValue.setText("4.0");
 	AMinusValue.setText("3.7");
	BPlusValue.setText("3.3");
 	BValue.setText("3.0");
 	BMinusValue.setText("2.7");
 	CPlusValue.setText("2.3");
 	CValue.setText("2.0");
 	CMinusValue.setText("1.7");
 	DPlusValue.setText("1.3");
 	DValue.setText("1.0");
 	DMinusValue.setText("0.7");
 	FValue.setText("0.0");
	} // ends restoreDefaults()
	
void ClearFields() {
	Hours1.setText(""); Grade1.setText("");
	Hours2.setText(""); Grade2.setText("");
	Hours3.setText(""); Grade3.setText("");
	Hours4.setText(""); Grade4.setText("");
	Hours5.setText(""); Grade5.setText("");
	Hours6.setText(""); Grade6.setText("");
	Hours7.setText(""); Grade7.setText("");
	
	

	} // ends ClearFields() 
	
void DoAnotherSemester() {
	PriorGPA.setText(CumulativeGPA.getText());
	PriorHours.setText(CumulativeHours.getText());
	ClearFields();	

	} // ends DoAnotherSemester()
 
} // ends class GPACalc