/**
 * Write a description of class SingleLinkedList here.
 * 
 * @author John Paxton
 * @version 1.0
 */

public class SingleLinkedList implements MyListInterface
{
    public void print() 
    {
        Node current = dummyHeader.getNext();
        
        System.out.println("--------- print forward --------------");
        
        while (current != dummyTrailer)
        {
            System.out.println(current.getData());
            current = current.getNext();
        }
        
        System.out.println("--------------------------------------");
    }
    
    /**
     * To be completed as part of in lab 5.
     * pre: The list is set up correctly.
     * post: The list is printed from back to front, omitting any dummy nodes.
     */
    
    public void printReverse()
    {
        System.out.println("--------- print backwards -------------");
        System.out.println("---------------------------------------");
    }
    
    /**
     * To be completed as part of in lab 5.
     * pre: The list is in ascending sorted order.
     * post: The list is still in ascending sorted order, "data" is added.
     */
    
    public void insert (Object data)
    {
        System.out.println("Attempting to insert " + data + 
            " into a sorted list");
    }
    
    public boolean insert (Object data, int position) 
    {
        System.out.println("Attempting to insert " + 
            data + " at position " + position);
            
        if ((position < 0) || (position > size))
        {
            return false;
        }
        else
        {
            Node before = dummyHeader;
            Node after = before.getNext();
            int count = 0;
            
            Node toInsert = new Node();
            toInsert.setData(data);
            
            while (count < position)
            {
                before = after;
                after = after.getNext();
                count++;
            }
            
            before.setNext(toInsert);
            toInsert.setNext(after);
            size++;
            
            return true;
        }
    }
    
    public Object remove (int position) 
    {
        System.out.println("Attempting to remove at position: " + position);
        
        if ((position < 0) || (position >= size))
        {
            return null;
        }
        else
        {
            Node trailer = dummyHeader;
            Node current = trailer.getNext();
            int count = 0;
            while (position != count)
            {
                trailer = current;
                current = current.getNext();
                count++;
            }
            size--;
            trailer.setNext(current.getNext());
            return current.getData();
        }
    }
    
    public void makeEmpty() 
    {
        dummyHeader = new Node();
        dummyTrailer = new Node();
        
        dummyHeader.setNext(dummyTrailer);
        dummyTrailer.setNext(null);
        
        size = 0;
    }
    
    private Node dummyHeader;
    private Node dummyTrailer;
    private int size;
}