using System;
using System.Collections.Generic;

namespace IocContainer
{
    public class Program 
    {
        public static void Main()
        {
            var containerBuilder = new ContainerBuilder();
            containerBuilder.For<ILogger>().Use<FileLogger>();
            var container = containerBuilder
                                    .Build();
									
            
            
            var logger = container.Resolve<ILogger>();
			logger.Log();
            
        }
    }

    public class Container
    {
        public Dictionary<Type, Type> serviceRegistration;
		
		public Container()
		{
			serviceRegistration = new Dictionary<Type,Type>();
		}
        
        public T Resolve<T>()
        {
            if(serviceRegistration.ContainsKey(typeof(T)))
            {
                var implementation = serviceRegistration[typeof(T)];
                return (T) Activator.CreateInstance(implementation);
            }
            else 
            {
                throw new InvalidOperationException("${typeof(T).Name} service is not registered to the container");
            }
        }
    }

    public class ContainerBuilder 
    {
        private Container _container;
        private Type serviceType; 
		
		public ContainerBuilder()
		{
			_container = new Container();
		}
		
        public ContainerBuilder For<T>()
        {
             serviceType = typeof(T);
             return this;
        }
            
        public ContainerBuilder Use<T>()
        {
            _container.serviceRegistration.Add(serviceType, typeof(T));
            return this;
        }

        public Container Build()
        {
            return _container;
        }
    }
    
    public interface ILogger
    {
        void Log();
    }

    public class SQLServerLogger : ILogger
    {
        public void Log()
        {
            Console.WriteLine("SQL Server logging...");
        }
    }
	
    public class FileLogger : ILogger
    {
        public void Log()
        {
            Console.WriteLine("File Logging...");
        }
    }
}