using System;

namespace System.Data
{
	/// <summary>
	/// Summary description for Node.
	/// </summary>
	public class Node
	{
		protected int _iBalance;    // currently, -2 means 'deleted'
		internal Node _nNext;       // node of next index (nNext==null || nNext.iId=iId+1)
		protected Node _nLeft;
		protected Node _nRight;
		protected Node _nParent;

		protected DataRow _row;
		
		public Node(DataRow row)
		{
			_row = row;
		}

		internal int GetBalance()
		{
			if (_iBalance == -2)
				throw new Exception ("Node is deleted.");

			return _iBalance;
		}

		internal void Delete()
		{
			_iBalance = -2;
			_nLeft = null;
			_nRight = null;
			_nParent = null;
		}


		internal DataRow Row
		{
			get {
				return _row;
			}
		}

		internal Node Left
		{
			get {
				if (_iBalance == -2)
					throw new Exception ("Node is deleted.");

				return _nLeft;
			}

			set {
				if (_iBalance == -2)
					throw new Exception ("Node is deleted.");

				_nLeft = value;
			}
		}

		internal Node Right
		{
			get {
				if (_iBalance == -2)
					throw new Exception ("Node is deleted.");
				return _nRight;
			}

			set {
				if (_iBalance == -2)
					throw new Exception ("Node is deleted.");

				_nRight = value;
			}
		}


		internal Node Parent
		{
			get {
				if (_iBalance == -2)
					throw new Exception ("Node is deleted.");

				return _nParent;
			}

			set {
				if (_iBalance == -2)
					throw new Exception ("Node is deleted.");
				_nParent = value;
			}
		}

		internal bool IsRoot()
		{
			return _nParent == null;
		}


		internal void SetBalance(int b)
		{

			if (_iBalance == -2)
				throw new Exception ("Node is deleted.");

			_iBalance = b;
		}

		internal bool From()
		{

			if (this.IsRoot()){
				return true;
			}

			if (_iBalance == -2)
				throw new Exception ("Node is deleted.");
			Node parent = Parent;

			return Equals(parent.Left);
		}

		internal Object[] GetData()
		{

			if (_iBalance == -2)
				throw new Exception ("Node is deleted.");
			return _row.ItemArray;
		}

		internal bool Equals(Node n)
		{

			if (_iBalance == -2)
				throw new Exception ("Node is deleted.");

			return n == this;
		}
	}
}