using System;

using System.Collections.Generic;

using System.Text;

using System.Collections.ObjectModel;

namespace Aga.Controls.Tree

{

	/// <summary>

	/// Provides a simple ready to use implementation of <see cref="ITreeModel"/>. Warning: this class is not optimized 

	/// to work with big amount of data. In this case create you own implementation of <c>ITreeModel</c>, and pay attention

	/// on GetChildren and IsLeaf methods.

	/// </summary>

	public class TreeModel : ITreeModel

	{

		private Node _root;

		public Node Root

		{

			get { return _root; }

		}

		public Collection<Node> Nodes

		{

			get { return _root.Nodes; }

		}

		public TreeModel()

		{

			_root = new Node();

			_root.Model = this;

		}

		public TreePath GetPath(Node node)

		{

			if (node == _root)

				return TreePath.Empty;

			else

			{

				Stack<object> stack = new Stack<object>();

				while (node != _root)

				{

					stack.Push(node);

					node = node.Parent;

				}

				return new TreePath(stack.ToArray());

			}

		}

		public Node FindNode(TreePath path)

		{

			if (path.IsEmpty())

				return _root;

			else

				return FindNode(_root, path, 0);

		}

		private Node FindNode(Node root, TreePath path, int level)

		{

			foreach (Node node in root.Nodes)

				if (node == path.FullPath[level])

				{

					if (level == path.FullPath.Length - 1)

						return node;

					else

						return FindNode(node, path, level + 1);

				}

			return null;

		}

		#region ITreeModel Members

		public System.Collections.IEnumerable GetChildren(TreePath treePath)

		{

			Node node = FindNode(treePath);

			if (node != null)

				foreach (Node n in node.Nodes)

					yield return n;

			else

				yield break;

		}

		public bool IsLeaf(TreePath treePath)

		{

			Node node = FindNode(treePath);

			if (node != null)

				return node.IsLeaf;

			else

				throw new ArgumentException("treePath");

		}

		public event EventHandler<TreeModelEventArgs> NodesChanged;

		internal void OnNodesChanged(TreeModelEventArgs args)

		{

			if (NodesChanged != null)

				NodesChanged(this, args);

		}

		public event EventHandler<TreePathEventArgs> StructureChanged;

		public void OnStructureChanged(TreePathEventArgs args)

		{

			if (StructureChanged != null)

				StructureChanged(this, args);

		}

		public event EventHandler<TreeModelEventArgs> NodesInserted;

		internal void OnNodeInserted(Node parent, int index, Node node)

		{

			if (NodesInserted != null)

			{

				TreeModelEventArgs args = new TreeModelEventArgs(GetPath(parent), new int[] { index }, new object[] { node });

				NodesInserted(this, args);

			}

		}

		public event EventHandler<TreeModelEventArgs> NodesRemoved;

		internal void OnNodeRemoved(Node parent, int index, Node node)

		{

			if (NodesRemoved != null)

			{

				TreeModelEventArgs args = new TreeModelEventArgs(GetPath(parent), new int[] { index }, new object[] { node });

				NodesRemoved(this, args);

			}

		}

		#endregion

	}

}