import java.util.Scanner; //library for user input
import java.lang.Math; //library for random numbers
public class Menu {
    // Instance Variables
    public final String DEFAULT = "\u001B[0m";  // Default Terminal Color
    public final String[][] COLORS = { // 2D Array of ANSI Terminal Colors
        {"Default",DEFAULT},
        {"Red", "\u001B[31m"},
        {"Green", "\u001B[32m"},
        {"Yellow", "\u001B[33m"},
        {"Blue", "\u001B[34m"},
        {"Purple", "\u001B[35m"},
        {"Cyan", "\u001B[36m"},
        {"White", "\u001B[37m"},
    };
    // 2D column location for data
    public final int NAME = 0;
    public final int ANSI = 1;  // ANSI is the "standard" for terminal codes
    // Constructor on this Object takes control of menu events and actions
    public Menu() {
        Scanner sc = new Scanner(System.in);  // using Java Scanner Object
        this.print();  // print Menu
        boolean quit = false;
        while (!quit) {
            try {  // scan for Input
                int choice = sc.nextInt();  // using method from Java Scanner Object
                System.out.print("" + choice + ": ");
                quit = this.action(choice);  // take action
            } catch (Exception e) {
                sc.nextLine(); // error: clear buffer
                System.out.println(e + ": Not a number, try again.");
            }
        }
        sc.close();
    }
    // Print the menu options to Terminal
    private void print() {
        //System.out.println commands below is used to present a Menu to the user.
        System.out.println("__________________________\n");
        System.out.println("Choose from these choices:");
        System.out.println("__________________________\n");
        System.out.println("1 - Say Hello");
        System.out.println("2 - Output colors");
        System.out.println("3 - Loading in color");
        System.out.println("4 - Factorial Calculator");
        System.out.println("5 - Degrees to Radians");
        System.out.println("6 - Grade Calculator");
        System.out.println("0 - Quit");
        System.out.println("__________________________\n");
    }
    // Private method to perform action and return true if action is to quit/exit
    private boolean action(int selection) {
        boolean quit = false;
        switch (selection) {  // Switch or Switch/Case is Control Flow statement and is used to evaluate the user selection
            case 0:
                System.out.print("Goodbye, World!");
                quit = true;
                break;
            case 1:
                System.out.print("Hello, World!");
                break;
            case 2:
                for(int i = 0; i < COLORS.length; i++)  // loop through COLORS array
                    System.out.print(COLORS[i][ANSI] + COLORS[i][NAME]);
                break;
            case 3:
                System.out.print("Loading...");
                for (int i = 0; i < 10; i++) {  // fixed length loading bar
                    int random = (int) (Math.random() * COLORS.length);  // random logic
                    try {
                        Thread.sleep(100);  // delay for loading
                    } catch (Exception e) {
                        System.out.println(e);
                    }
                    System.out.print(COLORS[random][ANSI] + "Hey! ");
                }
                break;
            case 4:
                System.out.print("Enter an Integer:");
                Scanner myObj = new Scanner(System.in);
                int number = myObj.nextInt();
                int i,fact=1;
                for(i=1;i<=number;i++){
                    fact=fact*i;
                }
                System.out.println("\nFactorial of "+number+" is: "+fact);
                break;
            case 5:
                System.out.print("Enter a Degree Value:");
                Scanner myObj2 = new Scanner(System.in);
                double number2 = myObj2.nextDouble();
                double radians = Math.toRadians(number2);
                System.out.println("\nValue in Radians = " + String.format("%.2f", radians));
                break;
            case 6:
                /* This program assumes that the student has 6 subjects,
                * thats why I have created the array of size 6. You can
                * change this as per the requirement.
                */
                int marks[] = new int[5];
                float total=0, avg;
                Scanner scanner = new Scanner(System.in);
                                    
                for(i=0; i<5; i++) { 
                    System.out.print("Enter Grade for Period "+(i+1)+": ");
                    int test = scanner.nextInt();
                    marks[i] = test;
                    
                    System.out.println(test);
                    System.out.println(marks[i]);
                    total = total + marks[i];
                }
                scanner.close();
                //Calculating average here
                avg = total/5;
                System.out.println("The student Grade is: ");
                if(avg>=80) {
                   System.out.println("A " + avg);
                }
                else if(avg>=60 && avg<80){
                    System.out.println("B " + avg);
                } 
                else if(avg>=40 && avg<60){
                    System.out.println("C " + avg);
                }
                else{
                    System.out.println("D " + avg);
                }
                
                break;
            default:
                //Prints error message from console
                System.out.print("Unexpected choice, try again.");
        }
        System.out.println(DEFAULT);  // make sure to reset color and provide new line
        return quit;
    }
    // Static driver/tester method
    static public void main(String[] args)  {
        new Menu(); // starting Menu object
    }
}
Menu.main(null);