RuntimeExtensionManagement

using System;
using System.Linq.Expressions;
using Pfz.ConversionManagement.Converters;

namespace Pfz.ConversionManagement.Searchers
{
	/// <summary>
	/// Contains the SearchingHandler to allow enums to be converter to their
	/// underlying types (that is, convert an enum to int, usually, but if the underlying
	/// type is different, it works too).
	/// </summary>
    public sealed class EnumToUnderlyingConverterSearcher:
        IConverterSearcher
    {
        private static readonly EnumToUnderlyingConverterSearcher _instance = new EnumToUnderlyingConverterSearcher();
        /// <summary>
        /// Gets the singleton instance of this class.
        /// </summary>
        public static EnumToUnderlyingConverterSearcher Instance
        {
            get
            {
                return _instance;
            }
        }

        private EnumToUnderlyingConverterSearcher()
        {
        }

        /// <summary>
        /// Returns 0.
        /// </summary>
        public int DefaultPriority
        {
            get
            {
                return 0;
            }
        }

        /// <summary>
        /// If the input type is an enum and the output type is its underlying type,
        /// it registers a conversion.
        /// </summary>
        public void Search(ConverterSearchArgs args)
        {
            var inputType = args.InputType;
            var outputType = args.OutputType;

            if (inputType.IsEnum && outputType == Enum.GetUnderlyingType(inputType))
            {
                var type = typeof(EnumToUnderlyingConverter<,>).MakeGenericType(inputType, outputType);
                var property = type.GetProperty("Instance");
                var converter = property.GetValue(null, null);
                args.SetConverter((IConverter)converter, false);
            }
        }
    }
}