import javax.swing.JOptionPane;
class Grades3{
	static final double ENGLISH_MIDTERM_PERCENTAGE = .25;
	static final double ENGLISH_FINALEXAM_PERCENTAGE = .25;
	static final double ENGLISH_RESEARCH_PERCENTAGE = .30;
	static final double ENGLISH_PRESENTATION_PERCENTAGE = .20;
		
	static final double MATH_MIDTERM_PERCENTAGE = .50;
	static	final double MATH_FINALEXAM_PERCENTAGE = .50;
		
	static	final double SCIENCE_MIDTERM_PERCENTAGE = .40;
	static	final double SCIENCE_FINALEXAM_PERCENTAGE = .40;
	static	final double SCIENCE_RESEARCH_PERCENTAGE = .20;
		
	static	int midterm = 0;
	static	int research = 0;
	static	int finalExam = 0;
	static	int presentation = 0;
		
	static	double finalNumericGrade = 0;
	static	String finalLetterGrade = "";
	
	public static void main(String[] args){
		
		String response;
		String moreGrades;
		
		moreGrades = JOptionPane.showInputDialog("Do you want to calculate a grade(Y/N)?");
		moreGrades = moreGrades.toUpperCase();
		
		while (moreGrades.equals("Y")){
		//what type of student are we calculating?	
		
		response = whatKindOfStudent();
		
		switch(Integer.parseInt(response)){
			case 1:
						calculateEnglishGrade();
						displayGrade(midterm,finalExam,research,presentation,finalNumericGrade,finalLetterGrade);
						break;
						
			case 2:
						calculateMathGrade();
						displayGrade(midterm,finalExam,finalNumericGrade,finalLetterGrade);
						break;
						
			case 3:
						calculateScienceGrade();
						displayGrade(midterm,finalExam,research,finalNumericGrade,finalLetterGrade);
						break;
			
			default:
						JOptionPane.showMessageDialog(null,response+"-is not a valid student type!");
						System.exit(0);
		}
		
		
			
			moreGrades = JOptionPane.showInputDialog("Do you want to calculate another one(Y/N)?");
			moreGrades = moreGrades.toUpperCase();
			
		}
		
		JOptionPane.showMessageDialog(null,"Thank you for using this Grades Calculate programm!");
		System.exit(0);		
	}
	
	public static String whatKindOfStudent(){
		String response;
		response = JOptionPane.showInputDialog("Enter student type(1=English;2=Math;3=Science)");	
		
		if(response == null)
		{
			JOptionPane.showMessageDialog(null,"You have clicked the cancle button!");
			System.exit(0);	
		}
		else
		if(response.equals(""))
		{
			JOptionPane.showMessageDialog(null,"You must make a choice in the input box!");
			System.exit(0);
		}
		else
		if(Integer.parseInt(response)<1 | Integer.parseInt(response)>3 )
		{
			JOptionPane.showMessageDialog(null,response+"-is not a valid entry!");
			System.exit(0);
		}
		
		return response;
	}
	
	public static void calculateEnglishGrade(){
		midterm = Integer.parseInt(JOptionPane.showInputDialog("Enter the Midterm grade:"));
		finalExam = Integer.parseInt(JOptionPane.showInputDialog("Enter the final exam grade:"));
		research = Integer.parseInt(JOptionPane.showInputDialog("Enter the research grade:"));
		presentation = Integer.parseInt(JOptionPane.showInputDialog("Enter the presentation grade:"));
		
		finalNumericGrade = (midterm*ENGLISH_MIDTERM_PERCENTAGE)+
																	(finalExam*ENGLISH_FINALEXAM_PERCENTAGE)+
																	(research*ENGLISH_RESEARCH_PERCENTAGE)+
																	(presentation*ENGLISH_PRESENTATION_PERCENTAGE);
		if(finalNumericGrade >= 93)
			finalLetterGrade = "A";
		else if((finalNumericGrade >= 85)&(finalNumericGrade < 93))
			finalLetterGrade = "B";
		else if((finalNumericGrade >= 78)&(finalNumericGrade < 85))
			finalLetterGrade = "C";
		else if((finalNumericGrade >= 70)&(finalNumericGrade < 78))
			finalLetterGrade = "D";
		else
			finalLetterGrade = "F";							
		
	}
	
	public static void calculateMathGrade(){
		midterm = Integer.parseInt(JOptionPane.showInputDialog("Enter the midterm grade:"));										
		finalExam = Integer.parseInt(JOptionPane.showInputDialog("Enter the final exam grade:"));
								
		finalNumericGrade = (midterm*MATH_MIDTERM_PERCENTAGE)+(finalExam*MATH_FINALEXAM_PERCENTAGE);
								
		if(finalNumericGrade > 90)
			finalLetterGrade = "A";
		else if((finalNumericGrade >= 83)&(finalNumericGrade < 90))
			finalLetterGrade = "B";
		else if((finalNumericGrade >= 76)&(finalNumericGrade < 83))
		  finalLetterGrade = "C";
		else if((finalNumericGrade >= 65)&(finalNumericGrade < 76))
			finalLetterGrade = "D";
		else 
			finalLetterGrade = "F";	
	}
	
	public static void calculateScienceGrade(){
		midterm = Integer.parseInt(JOptionPane.showInputDialog("Enter the midterm grade:"));
		finalExam = Integer.parseInt(JOptionPane.showInputDialog("Enter the final exam grade:"));
		research = Integer.parseInt(JOptionPane.showInputDialog("Enter the research grade:"));
								
		finalNumericGrade = (midterm*SCIENCE_MIDTERM_PERCENTAGE)+(finalExam*SCIENCE_FINALEXAM_PERCENTAGE)+
																		(research*SCIENCE_RESEARCH_PERCENTAGE);
								
		if (finalNumericGrade >= 90)
			finalLetterGrade = "A";
		else
		if((finalNumericGrade >=80)&(finalNumericGrade < 90))
			finalLetterGrade = "B";
		else
		if((finalNumericGrade >=70) & (finalNumericGrade < 80))
			finalLetterGrade = "C";
		else
		if((finalNumericGrade >= 60)&(finalNumericGrade < 70))
			finalLetterGrade = "D";
		else
			finalLetterGrade = "F";
	}
	
	public static void displayGrade(int midterm,int finalExam,int research,int presentation,
																	double finalNumericGrade,String finalLetterGrade){
			JOptionPane.showMessageDialog(null,"***ENGLISH STUDENT***\n\n"+
								"Midterm grade is:"+midterm+"\n"+
								"Final Exam grade is:"+finalExam+"\n"+
								"Research grade is:"+research+"\n"+
								"Presentation grade is:"+presentation+"\n\n"+
								"Final Numeric grade is:"+finalNumericGrade+"\n"+
								"Final Letter Grade is:"+finalLetterGrade);
	}
	
	public static void displayGrade(int midterm,int finalExam,double finalNumericGrade,String finalLetterGrade){
			JOptionPane.showMessageDialog(null,"***MATH STUDENT***\n\n"+
								"Midterm grade is:"+midterm+"\n"+
								"Final Exam grade is:"+finalExam+"\n"+								
								"Final Numeric grade is:"+finalNumericGrade+"\n"+
								"Final Letter Grade is:"+finalLetterGrade);
	}
	
	public static void displayGrade(int midterm,int finalExam,int research,
																	double finalNumericGrade,String finalLetterGrade){
			JOptionPane.showMessageDialog(null,"***SCIENCE STUDENT***\n\n"+
												"Midterm grade is:"+midterm+"\n"+
												"Final Exam is:"+finalExam+"\n"+
												"Research grade is:"+research+"\n\n"+
												"Final Numeric Grade is:"+finalNumericGrade+"\n"+
												"Final Letter Grade is:"+finalLetterGrade);
	}
	
}