The Time Machine

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Reflection;

namespace AssemblyService
{
    /// <summary>
    /// Works with asseblies
    /// </summary>
    public static class StaticExtensionAssemblyService
    {


        /// <summary>
        /// Gets first interface object
        /// </summary>
        /// <typeparam name="T">Type of interface</typeparam>
        /// <returns>First object</returns>
        public static T GetFirstInterfaceObjectFromBaseDirectory<T>() where T : class
        {
            return AppDomain.CurrentDomain.BaseDirectory.GetFirstInterfaceObject<T>();
        }
 


        /// <summary>
        /// Gets interfaces from base directory
        /// </summary>
        /// <typeparam name="T">Type</typeparam>
        /// <returns>Interfaces</returns>
        public static IEnumerable<T> GetInterfacesFromBaseDirectory<T>() where T : class
        {
            return AppDomain.CurrentDomain.BaseDirectory.GetInterfaces<T>();
        }


        /// <summary>
        /// Gets first interface object
        /// </summary>
        /// <typeparam name="T">Type of interface</typeparam>
        /// <param name="directory">Directory</param>
        /// <returns>First object</returns>
        public static T GetFirstInterfaceObject<T>(this string directory) where T : class
        {
            IEnumerable<T> en = directory.GetInterfaces<T>();
            foreach (T t in en)
            {
                return t;
            }
            return null;
        }

        /// <summary>
        /// Gets interfaces
        /// </summary>
        /// <typeparam name="T">Interface type</typeparam>
        /// <param name="directory">Directory</param>
        /// <returns>Interface objects</returns>
        public static IEnumerable<T> GetInterfaces<T>(this string directory) where T : class
        {
            string[] fn = Directory.GetFiles(directory, "*.dll");   // Dll files
            Assembly[] ass = AppDomain.CurrentDomain.GetAssemblies(); // Current domain assemblies
            List<string> l = new List<string>();
            foreach (Assembly a in ass) // Looking for objects in loaded assemblies
            {
                l.Add(a.Location);
                IEnumerable<T> en = a.GetInterfaces<T>();
                foreach (T t in en)
                {
                    yield return t;
                }

            }
            foreach (string f in fn) // Looking for objects in directory
            {
                if (!l.Contains(f))
                {
                   IEnumerable<T> en = Assembly.LoadFile(f).GetInterfaces<T>();
                   foreach (T t in en)
                   {
                       yield return t;
                   }
                }
            }
        }

        /// <summary>
        /// Gets interfaces from assembly (Serching of driver assembly)
        /// </summary>
        /// <typeparam name="T">Interface type</typeparam>
        /// <param name="assembly">Assembly</param>
        /// <returns>Interface objects</returns>
        public static IEnumerable<T> GetInterfaces<T>(this Assembly assembly) where T : class
        {
            Type[] types = assembly.GetTypes(); // Assembly types
            string st = typeof(T).FullName;     // Interface full name
            foreach (Type t in types)
            {
                Type ti = t.GetInterface(st);   // Gets interface
                if (ti == null)
                {
                    continue;
                }
                FieldInfo fi = t.GetField("Singleton"); // Gets Singleton field
                if (fi != null)
                {
                    yield return fi.GetValue(null) as T; // yeild Singleton
                }
            }
        }
    }
}