#region
/* -----------------------------------------------------------------------
 * <copyright file="IoC.cs" company="GRNet">
 * 
 * Copyright 2011-2012 GRNET S.A. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met:
 *
 *   1. Redistributions of source code must retain the above
 *      copyright notice, this list of conditions and the following
 *      disclaimer.
 *
 *   2. 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.
 *
 *
 * THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``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 GRNET S.A 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
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 * The views and conclusions contained in the software and
 * documentation are those of the authors and should not be
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 * or implied, of GRNET S.A.
 * </copyright>
 * -----------------------------------------------------------------------
 */
#endregion
namespace Pithos.ShellExtensions
{
    using System;
    using System.ComponentModel.Composition;
    using System.ComponentModel.Composition.Hosting;
    using System.Diagnostics;
    using System.Reflection;
    
    /// <summary>
    /// The IoC class initializes MEF DI and acts as a service locator.
    /// A singleton instance of IoC is provided by Instance
    /// </summary>
    public class IoC
    {
        private static readonly log4net.ILog Log = log4net.LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        /// <summary>
        /// The MEF Container
        /// </summary>
        public CompositionContainer Container;
        
        /// <summary>
        /// Layily initialized singleton instance of IoC
        /// </summary>
        static readonly Lazy<IoC> Instance=new Lazy<IoC>();

        /// <summary>
        /// Gets the singleton instance of IoC
        /// </summary>
        public static IoC Current
        {
            get { return Instance.Value; }
        }

        /// <summary>
        /// Initializes a new instance of the IoC from types exported from the executing assembly
        /// </summary>
        public IoC()
        {
            var catalog = new AggregateCatalog();
            catalog.Catalogs.Add(new AssemblyCatalog(Assembly.GetExecutingAssembly()));            
            
            Container=new CompositionContainer(catalog);
        }
        
        /// <summary>
        /// Initializes all imported properties of the target object
        /// </summary>
        /// <typeparam name="T">Type of the target object</typeparam>
        /// <param name="target">The target object</param>
        /// <returns>The object with all imported properties initialized</returns>
        public T Compose<T>(T target)
        {
            try
            {
                Container.ComposeParts(target);
                return target;
            }
            catch (Exception exc)
            {
                Log.ErrorFormat("Composition Error: {0}",exc);
                throw;
            }
        }
    }
}