dotwhat/Program.cs

using DotWhat.Contracts;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Threading.Tasks;
using Cocona;

namespace DotWhat
{
    class Program
    {
        private static readonly IEnumerable<What> Whats =
            Assembly.GetExecutingAssembly()
                .GetTypes()
                .Where(type => type.BaseType == typeof(What))
                .Select(what => (What)Activator.CreateInstance(what));

        private static async Task<int> Main(string[] args)
        {
            await CoconaLiteApp.RunAsync<Program>(args);

            return 0;
        }

        public async Task StartAsync([Argument] string name = default)
        {
            if (string.IsNullOrEmpty(name))
            {
                Console.WriteLine("No what passed. Current available whats are:");
                PrintWhats();
                return;
            }

            var command = Whats.FirstOrDefault(what => what.Name.Equals(name, StringComparison.OrdinalIgnoreCase));

            if (command is null)
            {
                Console.WriteLine("Invalid what passed. Current available whats are:");
                PrintWhats();
                return;
            }

            await command.RunAsync();

            static void PrintWhats()
                => Whats.ToList().ForEach(what => Console.WriteLine(what.Name.ToLower()));
        }
    }
}