using McMaster.Extensions.CommandLineUtils;

using Microsoft.Extensions.Hosting;

using Microsoft.Extensions.DependencyInjection;

using Microsoft.Extensions.FileProviders;

using System;

using System.Threading.Tasks;

​

//////////////////////////////////////////////////////////////////////////////////////////////////////

​

[HelpOption("--help")]

abstract class CLICommandBase

{

    protected abstract Task<int> DoWorkAsync(CommandLineApplication app);

    protected Task<int> OnExecuteAsync(CommandLineApplication app) => DoWorkAsync(app);

}

​

[Command(Name = "process", UnrecognizedArgumentHandling = UnrecognizedArgumentHandling.CollectAndContinue, OptionsComparison = StringComparison.InvariantCultureIgnoreCase)]

[Subcommand(typeof(Sub1ProcessCommand))]

class ProcessCommand : CLICommandBase

{

    protected async override Task<int> DoWorkAsync(CommandLineApplication app) {

      app.ShowHelp();

      return 0;

    }

}

​

//////////////////////////////////////////////////////////////////////////////////////////////////////

​

[Command(Name = "sub1", UnrecognizedArgumentHandling = UnrecognizedArgumentHandling.CollectAndContinue, OptionsComparison = StringComparison.InvariantCultureIgnoreCase)]

class Sub1ProcessCommand : CLICommandBase

{

    private readonly IProcessor _processor;

    private readonly IFactory<IFileProvider, string> _fileProviderFactory;

    public Sub1ProcessCommand(IProcessor processor, IFactory<IFileProvider, string> fpFactory) {

      _processor = processor;

      _fileProviderFactory = fpFactory;

    }

​

    [Option(CommandOptionType.SingleValue, LongName = "folder")]

    public string InputFolder { get; }

​

    protected override async Task<int> DoWorkAsync(CommandLineApplication app) 

    {

      Console.WriteLine($"Executing sub1 in {InputFolder}");

      var fileProvider = _fileProviderFactory.Create(InputFolder);

      var fileInfos = fileProvider.GetDirectoryContents("");

      foreach(var finfo in fileInfos) 

          Console.WriteLine(finfo.PhysicalPath);

      _processor.Execute();

      return 0;

    }

}

​

[Command(Name = "sub2", UnrecognizedArgumentHandling = UnrecognizedArgumentHandling.CollectAndContinue, OptionsComparison = StringComparison.InvariantCultureIgnoreCase)]

class Sub2ProcessCommand : CLICommandBase

{

    private readonly IProcessor _processor;

    public Sub2ProcessCommand(IProcessor processor) {

      _processor = processor;

    }

​

    [Option(CommandOptionType.SingleValue, LongName = "folder")]

    public string InputFolder { get; }

​

    protected override async Task<int> DoWorkAsync(CommandLineApplication app) 

    {

      Console.WriteLine($"Executing sub2 in {InputFolder}");

      _processor.Execute();

      return 0;

    }

}

//////////////////////////////////////////////////////////////////////////////////////////////////////

​

// To Factory or not?

​

public interface IFactory<TInterface, TOptions>

{

   TInterface Create(TOptions options);

}

​

public class FileProviderFactory : IFactory<IFileProvider, string>

{

   public IFileProvider Create(string root) => new PhysicalFileProvider(root);

}

//////////////////////////////////////////////////////////////////////////////////////////////////////

//

// Services

​

public interface IProcessor {

   public void Execute();

}

​

public class DefaultProcessor : IProcessor {

   public void Execute() {

      Console.WriteLine("Coming from the Default Processor");

   }

}

​

//////////////////////////////////////////////////////////////////////////////////////////////////////

​

public class Program

{

    private static async Task<int> Main()

    {

        var builder = new HostBuilder().ConfigureServices(ConfigureApplicationServices);

        try

        {

            string[] args = new string[] { "process", "sub1", "--folder", "/" }; // Runtime information

            return await builder.RunCommandLineApplicationAsync<ProcessCommand>(args).ConfigureAwait(false);

        }

        catch (Exception ex)

        {

            Console.WriteLine(ex.Message);

            return 1;

        }

    }

    static void ConfigureApplicationServices(HostBuilderContext hostContext, IServiceCollection services)

    {

        services.AddSingleton<IFactory<IFileProvider, string>, FileProviderFactory>();

        services.AddTransient<IProcessor, DefaultProcessor>();

    }

}