using System;

using System.Collections.Generic;

using System.Text;

using System.Collections.ObjectModel;

using System.Windows.Forms;

using System.Drawing;

namespace Aga.Controls.Tree

{

	public class Node

	{

		#region NodeCollection

		private class NodeCollection : Collection<Node>

		{

			private Node _owner;

			public NodeCollection(Node owner)

			{

				_owner = owner;

			}

			protected override void ClearItems()

			{

				while (this.Count != 0)

					this.RemoveAt(this.Count - 1);

			}

			protected override void InsertItem(int index, Node item)

			{

				if (item == null)

					throw new ArgumentNullException("item");

				if (item.Parent != _owner)

				{

					if (item.Parent != null)

						item.Parent.Nodes.Remove(item);

					item._parent = _owner;

					item._index = index;

					for (int i = index; i < Count; i++)

						this[i]._index++;

					base.InsertItem(index, item);

					TreeModel model = _owner.FindModel();

					if (model != null)

						model.OnNodeInserted(_owner, index, item);

				}

			}

			protected override void RemoveItem(int index)

			{

				Node item = this[index];

				item._parent = null;

				item._index = -1;

				for (int i = index + 1; i < Count; i++)

					this[i]._index--;

				base.RemoveItem(index);

				TreeModel model = _owner.FindModel();

				if (model != null)

					model.OnNodeRemoved(_owner, index, item);

			}

			protected override void SetItem(int index, Node item)

			{

				if (item == null)

					throw new ArgumentNullException("item");

				RemoveAt(index);

				InsertItem(index, item);

			}

		}

		#endregion

		#region Properties

		private TreeModel _model;

		internal TreeModel Model

		{

			get { return _model; }

			set { _model = value; }

		}

		private NodeCollection _nodes;

		public Collection<Node> Nodes

		{

			get { return _nodes; }

		}

		private Node _parent;

		public Node Parent

		{

			get { return _parent; }

			set 

			{

				if (value != _parent)

				{

					if (_parent != null)

						_parent.Nodes.Remove(this);

					if (value != null)

						value.Nodes.Add(this);

				}

			}

		}

		private int _index = -1;

		public int Index

		{

			get

			{

				return _index;

			}

		}

		public Node PreviousNode

		{

			get

			{

				int index = Index;

				if (index > 0)

					return _parent.Nodes[index - 1];

				else

					return null;

			}

		}

		public Node NextNode

		{

			get

			{

				int index = Index;

				if (index >= 0 && index < _parent.Nodes.Count - 1)

					return _parent.Nodes[index + 1];

				else

					return null;

			}

		}

		private string _text;

		public virtual string Text

		{

			get { return _text; }

			set 

			{

				if (_text != value)

				{

					_text = value;

					NotifyModel();

				}

			}

		}

		private CheckState _checkState;

		public virtual CheckState CheckState

		{

			get { return _checkState; }

			set 

			{

				if (_checkState != value)

				{

					_checkState = value;

					NotifyModel();

				}

			}

		}

		private Image _image;

		public Image Image

		{

			get { return _image; }

			set 

			{

				if (_image != value)

				{

					_image = value;

					NotifyModel();

				}

			}

		}

		private object _tag;

		public object Tag

		{

			get { return _tag; }

			set { _tag = value; }

		}

		public bool IsChecked

		{

			get 

			{ 

				return CheckState != CheckState.Unchecked;

			}

			set 

			{

				if (value)

					CheckState = CheckState.Checked;

				else

					CheckState = CheckState.Unchecked;

			}

		}

		public virtual bool IsLeaf

		{

			get

			{

				return false;

			}

		}

		#endregion

		public Node()

			: this(string.Empty)

		{

		}

		public Node(string text)

		{

			_text = text;

			_nodes = new NodeCollection(this);

		}

		public override string ToString()

		{

			return Text;

		}

		private TreeModel FindModel()

		{

			Node node = this;

			while (node != null)

			{

				if (node.Model != null)

					return node.Model;

				node = node.Parent;

			}

			return null;

		}

		protected void NotifyModel()

		{

			TreeModel model = FindModel();

			if (model != null && Parent != null)

			{

				TreePath path = model.GetPath(Parent);

				if (path != null)

				{

					TreeModelEventArgs args = new TreeModelEventArgs(path, new int[] { Index }, new object[] { this });

					model.OnNodesChanged(args);

				}

			}

		}

	}

}