import java.util.*;

public class Activity2_MenuDriven {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);

        ArrayList<String> list = new ArrayList<String>();
        list.add("Abigail");
        list.add("Brian");
        list.add("Zachery");
        list.add("Christy");

        while (true) {
            System.out.println("-----------ENROLLMENT MENU-----------");
            System.out.println("1 - ENROLL");
            System.out.println("2 - UNENROLL");
            System.out.println("3 - PRINT STUDENTS");
            System.out.println("4 - SORT STUDENTS");
            System.out.println("5 - SEARCH STUDENTS");
            System.out.println("6 - REPLACE");
            System.out.println("7 - Exit");
            System.out.println("--------------------------------------");
            
            System.out.print("Enter choice: ");
            int choice = s.nextInt();
            s.nextLine(); // Consume newline

            switch (choice) {
                case 1:
                    Enroll(list, s);
                    break;
                case 2:
                    Unenroll(list, s);
                    break;
                case 3:
                    System.out.println("Updated enrolled students: ");
                    Print(list);
                    break;
                case 4:
                    System.out.println("Before sorted: ");
                    Print(list);
                    System.out.println("After sorted: ");
                    SortStuds(list);
                    break;
                case 5:
                    SearchStuds(list, s);
                    break;
                case 6:
                    Replace(list, s);
                    break;
                case 7:
                    System.out.print("You exited.");
                    System.exit(0);
                    break;
                default:
                    System.out.println("Use numbers between 1 - 6.");
                    System.out.println();
                    break;
            }
        }
    }

    public static void Enroll(ArrayList<String> list, Scanner s) {
        System.out.print("Enter how many Students you want to Enroll: ");
        int studCount = s.nextInt();
        s.nextLine(); // Consume newline
        
        System.out.println("Enter name(s) you want to Enroll: ");
        for (int i = 0; i < studCount; i++) {
            String students = s.nextLine();
            list.add(students);
        }

        System.out.println("You/They are now Enrolled!");
        System.out.println("Enrolled students: ");
        for (int i = 0; i < list.size(); i++) {
            System.out.println(i + 1 + "). " + list.get(i));
        }
        System.out.println();
    }

    public static void Unenroll(ArrayList<String> list, Scanner s) {
       Print(list);
       
       System.out.print("Enter how many Students you want to unenroll: ");
       int studCount = s.nextInt();
       s.nextLine(); // Consume newline
   
       int[] indices = new int[studCount];
       System.out.print("Specify which indices you want to unenroll: ");
       for (int i = 0; i < studCount; i++) {
           indices[i] = s.nextInt() - 1;
       }
       s.nextLine(); // Consume newline
   
       for (int i = studCount - 1; i >= 0; i--) {
           int indexToRemove = indices[i];
           if (indexToRemove >= 0 && indexToRemove < list.size()) {
               list.remove(indexToRemove);
           }
       }
   
       System.out.println("You/They are now Unenrolled!");
       System.out.println("Updated enrolled students: ");
       Print(list);
   }

    
    public static void Print(ArrayList<String> list) {
        for (int i = 0; i < list.size(); i++) {
            System.out.println(i + 1 + "). " + list.get(i));
        }
        System.out.println();
    }
    
    public static void SortStuds(ArrayList<String> list) {
        Collections.sort(list);
        Print(list);
        System.out.println();
    }
    
    public static void SearchStuds(ArrayList<String> list, Scanner s) {
       Collections.sort(list);
       System.out.println("Enrolled students: ");
       Print(list);
       System.out.print("Enter the name you want to search: ");
       String students = s.nextLine();
   
       if (list.contains(students)) {
           System.out.println(students + " exists!");
       } else {
           System.out.println(students + " does not exist!");
       }
   
       System.out.println();
   }
   
   public static void Replace(ArrayList<String> list, Scanner s) {
        Print(list);
         
        System.out.print("Enter how many Students you want to replace: ");
        int studCount = s.nextInt();
        s.nextLine(); // Consume newline

        int[] indices = new int[studCount];
        Print(list);
        System.out.print("Specify which indices you want to replace: ");
        for (int i = 0; i < studCount; i++) {
            indices[i] = s.nextInt() - 1;
        }
        s.nextLine(); // Consume newline

        System.out.println("Enter names you want to replace them with: ");
        for (int i = 0; i < studCount; i++) {
            String students = s.nextLine();
            list.set(indices[i], students);
        }

        System.out.println("\nThey are now replaced!");
        System.out.println("New students: ");
        Print(list);
    }

}