using McMaster.Extensions.CommandLineUtils;

using Microsoft.Extensions.Hosting;

using Microsoft.Extensions.DependencyInjection;

using Microsoft.Extensions.FileProviders;

using System;

using System.Collections.Generic;

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(List1ProcessCommand))]

[Subcommand(typeof(List2ProcessCommand))]

class ProcessCommand : CLICommandBase

{

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

      app.ShowHelp();

      return 0;

    }

}

​

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

​

[Command(Name = "list1", UnrecognizedArgumentHandling = UnrecognizedArgumentHandling.CollectAndContinue, OptionsComparison = StringComparison.InvariantCultureIgnoreCase)]

class List1ProcessCommand : CLICommandBase

{

    private readonly ICommandHandler _handler;

    private readonly IFactory<IFileProvider, string> _fileProviderFactory;

    public List1ProcessCommand(ICommandHandler handler, IFactory<IFileProvider, string> fpFactory) {

      _handler = handler;

      _fileProviderFactory = fpFactory;

    }

​

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

    public string InputFolder { get; }

​

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

    {

      Console.WriteLine($"Executing list1 in {InputFolder}");

      var fileProvider = _fileProviderFactory.Create(InputFolder);

      var fileInfos = fileProvider.GetDirectoryContents("");

      foreach(var finfo in fileInfos) 

        _handler.Execute(finfo);

      return 0;

    }

}

​

[Command(Name = "list2", UnrecognizedArgumentHandling = UnrecognizedArgumentHandling.CollectAndContinue, OptionsComparison = StringComparison.InvariantCultureIgnoreCase)]

class List2ProcessCommand : CLICommandBase

{

    private readonly ICommandHandler _handler;

    private readonly IFileSystem _fileSystem;

    public List2ProcessCommand(ICommandHandler handler, IFileSystem fileSystem) {

      _handler = handler;

      _fileSystem = fileSystem;

    }

​

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

    public string InputFolder { get; }

​

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

    {

      Console.WriteLine($"Executing list2 in {InputFolder}");

      var fileInfos = _fileSystem.GetDirectoryContents(InputFolder, "");

      foreach(var finfo in fileInfos) 

        _handler.Execute(finfo);

      return 0;

    }

}

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

​

// To Factory or not?

​

public interface IFactory<TInterface, TOptions>

{

   TInterface Create(TOptions options);

}

​

public class DefaultFileProviderFactory : IFactory<IFileProvider, string>

{

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

}

​

// Using an Adaptor/Facade/Proxy to hide Factory

​

public interface IFileSystem 

{

    IEnumerable<IFileInfo> GetDirectoryContents(string baseFolder, string path);

}

​

public class DefaultFileSystem : IFileSystem

{

    private readonly IFactory<IFileProvider, string> _fileProviderFactory;

    public DefaultFileSystem(IFactory<IFileProvider, string> fpFactory) {

        _fileProviderFactory = fpFactory;

    }

    public IEnumerable<IFileInfo> GetDirectoryContents(string baseFolder, string path)

    {

      var fileProvider = _fileProviderFactory.Create(baseFolder);

      return fileProvider.GetDirectoryContents(path);

    }

}

​

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

//

// Services

​

public interface ICommandHandler {

   public void Execute(IFileInfo fileInfo);

}

​

public class ListFullPathFileHandler : ICommandHandler {

   public void Execute(IFileInfo fileInfo) {

      Console.WriteLine($"ListFullPath {fileInfo.PhysicalPath}");

   }

}

public class ListNameFileHandler : ICommandHandler {

   public void Execute(IFileInfo fileInfo) {

      Console.WriteLine($"ListName {fileInfo.Name}");

   }

}

​

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

​

public class Program

{

    private static async Task<int> Main()

    {

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

        try

        {

            string[] args = new string[] { "process", "list2", "--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>, DefaultFileProviderFactory>();

        services.AddSingleton<IFileSystem, DefaultFileSystem>();

        services.AddTransient<ICommandHandler, ListFullPathFileHandler>();

        services.AddTransient<ICommandHandler, ListNameFileHandler>();

    }

}