package rebelsky.list;

/**
 * An implementation of lists using linked nodes.  Based closely
 * on the
 *
 * @author CSC152 2004F
 * @version 1.0 of October 2004.
 */
public class SimpleLinkedList
	implements SimpleList
{
// +--------+--------------------------------------------------
// | Fields |
// +--------+

	/** The "first" thing. */
	Node front;
	

// +--------------+--------------------------------------------
// | Constructors |
// +--------------+
	
	public SimpleLinkedList()
	{
		this.front = null;
	} // LinkedList()

	
// +---------+-------------------------------------------------
// | Methods |
// +---------+

	public void add(Object addMe)
	{
		// Add it to the front of the list.
		this.front = new Node(addMe, this.front);
	} // put(Object)

	/**
	 * Get a new cursor for the list.
	 */
	public SimpleCursor getSimpleCursor()
	{
		return new SimpleNodeCursor(this);
	} // getSimpleCursor()

	/**
	 * Get a new cursor for the list.
	 */
	public Cursor getCursor()
	{
		// STUB
		return null;
	} // getCursor()

	/**
	 * Remove the object last returned by cursor c.
	 *
	 * @pre
	 *    where is a cursor for this list.
	 *    where.next() has been called.
	 */
	public void remove(SimpleCursor where)
	{
		// Cast where to the right kind of simple cursor
		SimpleNodeCursor here = (SimpleNodeCursor) where;
		// If it's the first node, just remove the first one.
		if (here.pos == this.front) {
			System.err.println("DELETING THE FIRST ELEMENT");
			this.front = this.front.next;
			return;
		}
		System.err.println("DELETING SOME OTHER ELEMENT");
		// Find the previous item
		Node prev = this.front;
		while (prev.next != here.pos)
			prev = prev.next;
		// Make the previous item link to the next item
		prev.next = here.pos.next;
	} // remove(SimpleCursor)

	/**
	 * Convert this list to a string for ease of printing.
	 */
	public String toString()
	{
		String result = "[";
		Node tmp = this.front;
		while (tmp != null) {
			result = result + tmp.data + " ";
			tmp = tmp.next;
		} // while
		result = result + "]";
		return result;
	} // toString()
} // class SimpleLinkedList