import java.util.ArrayList;
import java.util.Scanner;

public class Main {

	 public static void main(String[] args) {
		    ArrayList<Student> students = new ArrayList<Student>();
		    Scanner in = new Scanner(System.in);

		    students.add(new Student("Dozie Anazia", 123123, 32, "Computer Science", "PS", "Senior", 4.0));


		    while (true) {
		      initialPrompt();

		      switch (in.nextLine()) {
		        case "0":
		          in.close();
		          System.exit(0);

		        case "1":
		          System.out.println("What's the student's name?");
		          String newName = in.nextLine();

		          System.out.println("What's the student's ID #?");
		          int newId = Integer.parseInt(in.nextLine());

		          System.out.println("What's the student's age?");
		          int newAge = Integer.parseInt(in.nextLine());

		          System.out.println("What's the student's major?");
		          String newMajor = in.nextLine();

		          System.out.println("What's the student's minor?");
		          String newMinor = in.nextLine();

		          System.out.println("What's the student's grade level?");
		          String newGradeLevel = in.nextLine();

		          System.out.println("What's the student's GPA?");
		          double newGpa = Double.parseDouble(in.nextLine());

		          students.add(new Student(newName, newId, newAge, newMajor, newMinor, newGradeLevel, newGpa));
		          break;

		        case "2":
		          System.out.println("1: View all students");
		          System.out.println("2: View all students with a specific major");

		          switch (in.nextLine()) {
		            case "1":
		              if (students.isEmpty()) {
		                System.out.println("You haven't entered any students yet!");
		                break;
		              }

		              for (Student s : students) {
		                System.out.println(s);
		              }
		              break;

		            case "2":
		              System.out.println("Which major would you like to view?");

		              if (students.isEmpty()) {
		                System.out.println("You haven't entered any students yet!");
		                break;
		              }

		              for (Student s : indexOfAllMajors(students, in.nextLine())) {
		                System.out.println(s);
		              }
		          }
		          break;

		        case "3":
              System.out.println("What's the name of the student you'd like to delete?");
		        	students.remove(getIndexByName(students, in.nextLine()));
		        	break;

            case "4":
              System.out.println("What's the name of the student you'd like to update?");

              int index = getIndexByName(students, in.nextLine());
              Student stud = students.get(index);

              updateLoop: while (true) {
                System.out.println("What would you like to update?");
                System.out.println("0: Done updating");
                System.out.println("1: Name");
                System.out.println("2: ID");
                System.out.println("3: Age");
                System.out.println("4: Major");
                System.out.println("5: Minor");
                System.out.println("6: Grade Level");
                System.out.println("7: GPA");

                switch (in.nextLine()) {
                  case "0":
                    break updateLoop;

                  case "1":
                    System.out.println("What's the new name?");
                    stud.setName(in.nextLine());
                    break;

                  case "2":
                    System.out.println("What's the new ID?");
                    stud.setId(Integer.parseInt(in.nextLine()));
                    break;

                  case "3":
                    System.out.println("What's the new Age?");
                    stud.setAge(Integer.parseInt(in.nextLine()));
                    break;

                  case "4":
                    System.out.println("What's the new Major?");
                    stud.setMajor(in.nextLine());
                    break;

                  case "5":
                    System.out.println("What's the new Minor?");
                    stud.setMinor(in.nextLine());
                    break;

                  case "6":
                    System.out.println("What's the new Grade Level?");
                    stud.setGradeLevel(in.nextLine());
                    break;

                  case "7":
                    System.out.println("What's the new GPA?");
                    stud.setGpa(Double.parseDouble(in.nextLine()));
                    break;
                }
              }

              students.set(index, stud);
              break;

            case "5":
              System.out.println("What's the name of the student you'd like to update?");

              int index_5 = getIndexByName(students, in.nextLine());
              Student stud_5 = new Student(students.get(index_5));
              stud_5.setName(stud_5.getName() + " (1)");

              students.add(stud_5);
              break;
		      }
		    }
		  }

		  private static void initialPrompt() {
		    System.out.println();
		    System.out.println("Hello, please enter an option from below:");
		    System.out.println("0: Exit");
		    System.out.println("1: Add a student");
		    System.out.println("2: View a student");
		    System.out.println("3: Delete a student");
		    System.out.println("4: Update a student");
        System.out.println("5: Copy a student");
		  }

		  private static int getIndexByName(ArrayList<Student> students, String key){

			  for (int i=0; i< students.size();i++) {
				  if(students.get(i).getName().equals(key)) {
					  return i;

				  }
			  }
			  return -1;
		  }

		  private static ArrayList<Student> indexOfAllMajors(ArrayList<Student> students, String major) {
		    final ArrayList<Student> studentsToReturn = new ArrayList<>();
		    for (Student s : students) {
		      if (s.getMajor().equals(major.trim())) {
		        studentsToReturn.add(s);
		      }
		    }
		    return studentsToReturn;
		  }

		  private static ArrayList<Student> findByName(ArrayList<Student> students, String key) {
		    final ArrayList<Student> studentsToReturn = new ArrayList<>();

		    for (Student s : students) {
		      if (s.getName().equals(key.trim())) {
		        studentsToReturn.add(s);
		      }
		    }

		    return studentsToReturn;
		  }
		  private static ArrayList<Student> findById(ArrayList<Student> students, int key) {
			    final ArrayList<Student> studentIdToReturn = new ArrayList<>();

			    for (Student s : students) {
			      if (s.getId()== key) {
			        studentIdToReturn.add(s);
			      }
			    }

			    return studentIdToReturn;
			  }
		}