import java.io.FileNotFoundException;
import java.io.FileReader;
import java.util.LinkedList;
import java.util.ListIterator;
import java.util.Scanner;

public class RegistrationActions
{

	public LinkedList<Student> Registration()
	{

		LinkedList<Student> students = Student.readStudents();
		try
		{
			Scanner actions = new Scanner(new FileReader("registration.txt"));
			String toDo;
			int stuNum;
			
			while (actions.hasNext())
			{
				ListIterator<Student> mark = students.listIterator();
				String hold = actions.next();
				Student stu = null;
				
				int test = Integer.parseInt(hold);
				while (mark.hasNext())
				{
					stu = mark.next();
					stuNum = stu.getStudentNumber();
					
					// if the student is found
					if (test == stuNum)
						break;
				}
					
						toDo = actions.next();
						if (toDo.equalsIgnoreCase("A"))
						{
							ListIterator<Offering> alreadyHave = RegistrationSystem
									.getAllOfferings().listIterator();
							boolean found = false;
							String holding = actions.next();
							short ref = Short.parseShort(holding);
							for (int i = 0; i < stu.getNumberCourses();i++)
							{
								Offering course = alreadyHave.next();
								short check = course.reference;

								if (check == ref)
								{
									found = true;
									stu.addCourse(course);
									break;
								}								
							}
							
							if (found == false)
							{
								Offering course = new Offering(ref);
								RegistrationSystem.getAllOfferings().addLast(
										course);
								stu.addCourse(course);
								System.out.println("Course added");
								// break;
							}
						} else if (toDo.equalsIgnoreCase("D"))
						{
							Offering course = new Offering();
							String holder = actions.next();
							short ref = Short.parseShort(holder);
							course.setReference(ref);
							stu.dropCourse(course);
							System.out.println("Course dropped");
							break;
						}
					
					}
					
				
			
			
			
		} catch (FileNotFoundException e)
		{
			System.out.println("Registration File not found.");
			System.exit(1);
		}
	return students;
	}

}