using System;

using System.Collections.Generic;

using System.Text;

using System.Drawing;

using System.Threading;

using System.Windows.Forms;

namespace Aga.Controls.Tree.NodeControls

{

	/// <summary>

	/// Displays an animated icon for those nodes, who are in expanding state. 

	/// Parent TreeView must have AsyncExpanding property set to true.

	/// </summary>

	public class ExpandingIcon: NodeControl

	{

		private static GifDecoder _gif = ResourceHelper.LoadingIcon;

		private static int _index = 0;

		private static volatile Thread _animatingThread;

        private static object _lock = new object();

		public override Size MeasureSize(TreeNodeAdv node, DrawContext context)

		{

			return ResourceHelper.LoadingIcon.FrameSize;

		}

		protected override void OnIsVisibleValueNeeded(NodeControlValueEventArgs args)

		{

			args.Value = args.Node.IsExpandingNow;

			base.OnIsVisibleValueNeeded(args);

		}

		public override void Draw(TreeNodeAdv node, DrawContext context)

		{

			Rectangle rect = GetBounds(node, context);

			Image img = _gif.GetFrame(_index).Image;

			context.Graphics.DrawImage(img, rect.Location);

		}

		public static void Start()

		{

            lock (_lock)

            {

                if (_animatingThread == null)

                {

                    _index = 0;

                    _animatingThread = new Thread(new ThreadStart(IterateIcons));

                    _animatingThread.IsBackground = true;

                    _animatingThread.Priority = ThreadPriority.Lowest;

                    _animatingThread.Start();

                }

            }

		}

        public static void Stop()

        {

            lock (_lock)

            {

                _index = 0;

                _animatingThread = null;

            }

        }

		private static void IterateIcons()

		{

            while (_animatingThread != null)

			{

				if (_index < _gif.FrameCount - 1)

					_index++;

				else

					_index = 0;

				if (IconChanged != null)

					IconChanged(null, EventArgs.Empty);

				int delay = _gif.GetFrame(_index).Delay;

				Thread.Sleep(delay);

			}

            System.Diagnostics.Debug.WriteLine("IterateIcons Stopped");

		}

		public static event EventHandler IconChanged;

	}

}