package school;

import java.util.Scanner;

import java.util.ArrayList;

public class StudentInfo {

	static public Student[] students = new Student[0];

	static public Scanner scanner = new Scanner(System.in);

	static private String[] letterGrades = new String[] { "F", "D", "C", "B", "A"};

	public static void main(String[] args) {


		boolean Exit = false;
		while(!Exit) {

			int selection = printMenu();
			switch(selection) {
			case 1: names(); break;
			case 2: students(); break;
			case 3: search(); break;
			case 4: searchGrade(); break;
			case 5: failing(); break;
			case 7: highest(); break;
			case 6: lowest(); break;
			case 8: average(); break;
			case 9: Exit = true; break;
			default:System.out.println("Uh oh, an error occured!"); break;
			}
		}
	}

	public static int printMenu() {


		System.out.println("Please choose an option. Start by adding the students' names.");
		System.out.println("1. Add students");
		System.out.println("2. Display students");
		System.out.println("3. Search for student by name");
		System.out.println("4. Find students by letter grade");
		System.out.println("5. Shows the failing students");
		System.out.println("6. Shows the student with the highest grade");
		System.out.println("7. Shows the with the lowest grade");
		System.out.println("8. Displays the class average");
		System.out.println("9. Exit");

		return scanner.nextInt();
	}

	public static void names() {
		boolean Exit = false;
		while(!Exit) {
			System.out.println();
			System.out.println("Enter name");
			String name = scanner.next();
			System.out.println("Enter a grade out of 100%");
			int grade = scanner.nextInt();

			addStudent(new Student(name, grade));

			System.out.println("Would you like to continue? Y or N");
			String choice = scanner.next();
			if (choice.equalsIgnoreCase("N"))Exit = true;
		}
	}

	public static void addStudent(Student student) {

		Student[] newStudents = new Student[students.length + 1];
		System.arraycopy(students, 0, newStudents, 0, students.length);

		newStudents[newStudents.length - 1] = student;

		students = newStudents;
	}
	public static void highest() {

		Student highestStudent = students[0];
		for (Student student : students) {
			if (highestStudent.grade < student.grade) highestStudent = student;
		}

		printStudent(highestStudent);
	}
	public static void search() {

		System.out.println();
		System.out.println("What is the name you're looking for?");

		scanner.nextLine();
		String name = scanner.nextLine();

		for (Student student : students) {
			if (!student.name.equals(name)) continue;
			printStudent(student);
		}
	}

	public static void students() {
		for (Student student : students) printStudent(student);
	}

	public static void average() {
		int grades = 0;
		for (Student student : students) {
			grades += student.grade;
		}
		System.out.println("The class average is " + grades / students.length);
	}


	public static void lowest() {
		Student lowestStudent = students[0];
		for (Student student : students) {
			if (lowestStudent.grade > student.grade) lowestStudent = student;
		}

		printStudent(lowestStudent);
	}

	public static void failing() {

		for (Student student : students) if (student.searchGrade.equals("F")) printStudent(student);
	}

	public static void printStudent(Student student) {

		System.out.println(student.name + " Grade: " + student.grade + " Letter Grade: " + student.searchGrade);
	}

	public static void searchGrade() {

		System.out.println();
		System.out.println("Enter the letter grade you would like to use");
		String searchGrade;
		while (true) {

			boolean canExit = false;
			searchGrade = scanner.nextLine();

			for (String letter : letterGrades) {

				if (searchGrade.equals(letter)) canExit = true;
			}

			if (!canExit) System.out.println("Please enter a letter grade");
			else break;
		}

		for (Student student : students) {

			if (!student.searchGrade.equals(searchGrade)) continue;
			printStudent(student);
		}
	}
}

class Student {
	public String name;
	public int grade;
	public String searchGrade;

	static private int[] searchGradeGrades = new int[]{ 49, 59, 69, 79, Integer.MAX_VALUE };
	static private String[] letterGrades = new String[] { "F", "D", "C", "B", "A"};

	Student(String name, int grade) {

		this.name = name;

		this.grade = grade;

		for (int i = 0; i < letterGrades.length; ++i) {
			if (grade <= searchGradeGrades[i]) {
				this.searchGrade = letterGrades[i];
				break;


			}
		}
	}
}