import java.io.*;
import java.util.ArrayList;

public class Iterator implements Serializable
{
    private StudentNode head, tail;
    
    public Iterator(StudentNode head_)
    {
        head = head_;
        findTail();
    }
    
    private void findTail()
    {
        StudentNode cur = head;
        
        while(cur != null)
        {
            tail = cur;
            cur = cur.getNext();
        }
    }

    private void print(double minGPA, String searchFor, boolean reverse)
    {
        if(searchFor != null)
         System.out.println("Search: " + searchFor);
        
        if(minGPA > 0.0)
         System.out.println("Dean's List");
        
        StudentNode cur = head;
        
        if(reverse)
         cur = tail;
         
       while(cur != null)
       {
           if((cur.firstName().equals(searchFor) || cur.lastName().equals(searchFor) 
              || searchFor == null) && cur.gpa() >= minGPA)
               System.out.println("\n" + cur.toString() + "\n");
           if(reverse)
            cur = cur.getPrevious();
             else
              cur = cur.getNext();
       }
     }
     
     public void printAlphaOrder()
     {
         print(0.0, null, false);
     }
     
     public void printReverseAlphaOrder()
     {
         print(0.0, null, true);
     }
     
     public void printDeansList(double minGPA)
     {
         print(minGPA, null, false);
     }
     
     public void search(String searchFor)
     {
         print(0.0, searchFor, false);
     }
     
     public void add(StudentNode student)
     {
         if(head == null)
         {
             head = student;
             tail = student;
             return;
         }
         
         StudentNode cur = head;        
         while(cur != null && cur.lastName().compareTo(student.lastName()) > 0)
         {
             cur = cur.getNext();
         }
         
         if(cur == head)
         {
         	head = student;
         	head.setNext(cur);
         	return;
         }
         
         if(cur == null)
         {
         	tail.setNext(student);
         	student.setPrevious(tail);
         	return;
         }
         
         student.setNext(cur);
         student.setPrevious(cur.getPrevious());
         cur.getPrevious().setNext(student);
         cur.setPrevious(student);
         
         findTail();
         
     }
     
     public void removeStudent(String name)
     {
         StudentNode cur = head;
         while(cur != null && !cur.lastName().equals(name) && !cur.firstName().equals(name))
         {
             cur = cur.getNext();
         }
         if(cur == null)
         {
             System.out.println("The specified student could not be removed because the student could not be found.");
             return;
         }
         if(cur == head)
         {
             head = head.getNext();
         }
         if(cur.getPrevious() != null)
         {
             cur.getPrevious().setNext(cur.getNext());
         }
         if(cur.getNext() != null)
         {
              cur.getNext().setPrevious(cur.getPrevious());
         }
     }
     
     public ArrayList packageNodes()
     {
         ArrayList ret = new ArrayList();
         ret.add(this);
         
         StudentNode cur = head;
         
         while(cur != null)
         {
             ret.add(cur);
             cur = cur.getNext();
         }
         
         return ret;
     }
}