CQRSDemoPart1

using System;
using System.Collections.Generic;
using System.ComponentModel.Design;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace CQRSDemo
{
    class Program
    {
        private static readonly CommandDispatcher Dispatcher = new CommandDispatcher();

        static void Main(string[] args)
        { 
            Console.WriteLine("Welcome to this simple CQRS demo");
            string commandText = "";
            while (!string.IsNullOrEmpty((commandText = Console.ReadLine())))
            {
                var command = ParseCommand(commandText);
                Dispatcher.HandleCommand(command);
            }
        }

        private static ICommand ParseCommand(string commandText)
        {
            return new CreateSkjema(commandText);
        }
    }

    public class CommandDispatcher
    {
        private Dictionary<Type, Action<object>> _commandHandlers = new Dictionary<Type, Action<object>>();
        public CommandDispatcher()
        {
            var skjemaHandler = new SkjemaHandler();
            Register<CreateSkjema>(skjemaHandler.Handle);
        }

        private void Register<TCommand>(Action<TCommand> handle) where TCommand : class
        {
            _commandHandlers.Add(typeof (TCommand), (y) => handle(y as TCommand));
        }

        public void HandleCommand(ICommand command)
        {
            var type = command.GetType();
            if (_commandHandlers.ContainsKey(type))
            {
                _commandHandlers[type](command);
            }
            else
            {
                throw new MissingHandlerException(command);
            }
        }
    }

    public class MissingHandlerException : Exception
    {
        public MissingHandlerException(ICommand command): base("Missing handler for command: " + command.GetType())
        {
        }
    }

    public interface ICommand
    {
    }

    public class CreateSkjema : ICommand
    {
        public CreateSkjema(string commandText)
        {
            Navn = commandText;
        }

        public string Navn { get; private set; }
    }

    public class SkjemaHandler : IHandle<CreateSkjema>
    {
        public void Handle(CreateSkjema command)
        {
            Console.WriteLine("Skjema created");
        }
    }

    public interface IConsume<TEvent> where TEvent : IEvent
    {
        void Handle(TEvent command);        
    }
    public interface IEvent
    {

    }

    public interface IHandle<TCommand> where TCommand : ICommand
    {
        void Handle(TCommand command);
    }
}