#region License

// Copyright (c) 2010, Jasper Yeh.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, 
// are permitted provided that the following conditions are met:
//
//    * Redistributions of source code must retain the above copyright notice, 
//      this list of conditions and the following disclaimer.
//    * Redistributions in binary form must reproduce the above copyright notice, 
//      this list of conditions and the following disclaimer in the documentation 
//      and/or other materials provided with the distribution.
//    * Neither the name of ClearCanvas Inc. nor the names of its contributors 
//      may be used to endorse or promote products derived from this software without 
//      specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 
// OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE 
// GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
// ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
// OF SUCH DAMAGE.

#endregion

using System;
using System.Windows;
using ClearCanvas.Common;
using ClearCanvas.Common.Utilities;
using ClearCanvas.Desktop;
using Application=System.Windows.Application;

namespace Nullstack.ClearCanvasEx.DesktopEx.View.WpfAdapter
{
	/// <summary>
	/// The WPF implementation of the <see cref="IGuiToolkit"/>.
	/// </summary>
	[ExtensionOf(typeof (GuiToolkitExtensionPoint))]
	public class WpfGuiToolkit : IGuiToolkit
	{
		/// <summary>
		/// The ID of this GUI toolkit, which is "WPF".
		/// </summary>
		public const string GuiToolkitId = "WPF";

		private readonly object _syncLock = new object();
		private event EventHandler _started;
		private Application _wpfApplication;

		/// <summary>
		/// Gets the toolkit ID, which is <see cref="GuiToolkitId"/>.
		/// </summary>
		public string ToolkitId
		{
			get { return GuiToolkitId; }
		}

		/// <summary>
		/// Gets the toolkit ID, which is <see cref="GuiToolkitId"/>.
		/// </summary>
		string IGuiToolkit.ToolkitID
		{
			get { return ToolkitId; }
		}

		/// <summary>
		/// Fired when the application has started.
		/// </summary>
		public event EventHandler Started
		{
			add { _started += value; }
			remove { _started -= value; }
		}

		/// <summary>
		/// Starts as a WPF application on this thread.
		/// </summary>
		public void Run()
		{
			if (_wpfApplication != null)
				throw new InvalidOperationException("The application has already started.");

			lock (_syncLock)
			{
				if (_wpfApplication == null)
				{
					_wpfApplication = new Application();
					_wpfApplication.Startup += OnWpfApplicationStartup;
					_wpfApplication.Run();
				}
			}
		}

		/// <summary>
		/// Terminates the WPF application running on this thread.
		/// </summary>
		public void Terminate()
		{
			if (_wpfApplication == null)
				throw new InvalidOperationException("The application has not yet started.");

			lock (_syncLock)
			{
				if (_wpfApplication != null)
				{
					_wpfApplication.Shutdown();
					_wpfApplication.Startup -= OnWpfApplicationStartup;
					_wpfApplication = null;
				}
			}
		}

		private void OnWpfApplicationStartup(object sender, StartupEventArgs e)
		{
			EventsHelper.Fire(_started, this, EventArgs.Empty);
		}
	}
}