namespace Ploeh.AutoFixture
{
	using Kernel;
	using System;

	public class PostProcessWhereIsACustomization<T> : ICustomization
		where T : class
	{
		readonly PostProcessSpecimensBehavior _behavior;

		public PostProcessWhereIsACustomization( Action<T> action )
		{
			_behavior = new PostProcessSpecimensBehavior( action );
		}

		void ICustomization.Customize( IFixture fixture )
		{
			fixture.Behaviors.Add( _behavior );
		}

		class PostProcessSpecimensBehavior : ISpecimenBuilderTransformation
		{
			readonly Action<object> _applyActionIfSpecimenIsOfTypeT;

			public PostProcessSpecimensBehavior( Action<T> action )
			{
				_applyActionIfSpecimenIsOfTypeT = x =>
				{
					var asT = x as T;
					if ( asT != null )
						action( asT );
				};
			}

			ISpecimenBuilder ISpecimenBuilderTransformation.Transform( ISpecimenBuilder builder )
			{
				return new SpecimenBuilderPostProcessor( builder, _applyActionIfSpecimenIsOfTypeT );
			}

			class SpecimenBuilderPostProcessor : ISpecimenBuilderNode
			{
				readonly ISpecimenBuilder _builder;
				readonly Action<object> _postProcess;

				public SpecimenBuilderPostProcessor( ISpecimenBuilder builder, Action<object> initializationAction )
				{
					_postProcess = initializationAction;
					_builder = builder;
				}

				 object ISpecimenBuilder.Create( object request, ISpecimenContext context )
				 {
					 var specimen = _builder.Create( request, context );
					 _postProcess( specimen );
					 return specimen;
				 }

				 ISpecimenBuilderNode ISpecimenBuilderNode.Compose( System.Collections.Generic.IEnumerable<ISpecimenBuilder> builders )
				 {
					 return new SpecimenBuilderPostProcessor( new CompositeSpecimenBuilder( builders ), _postProcess );
				 }

				 System.Collections.Generic.IEnumerator<ISpecimenBuilder> System.Collections.Generic.IEnumerable<ISpecimenBuilder>.GetEnumerator()
				 {
					 yield return _builder;
				 }

				 System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
				 {
					 yield return _builder;
				 }
			}
		}
	}
}