using System;

using MediatR;

using MediatR.Pipeline;

using System.Threading.Tasks;

using System.Threading;

using Microsoft.Extensions.DependencyInjection;

using Ardalis.Result;

using System.Collections.Generic;

using System.Reflection;

​

public class Program

{

    static async Task Main()

    {

        var services = new ServiceCollection();

​

        services.AddMediatR(cfg =>

        {

            cfg.RegisterServicesFromAssemblies(typeof(DisableLdapAccountCommand).Assembly);

        });

        services.AddTransient<IRequestHandler<DisableLdapAccountCommand, Result>, DisableLdapAccountHandler>();

        services.AddTransient<IRequestHandler<EnableLdapAccountCommand, Result>, EnableLdapAccountHandler>();

​

        // services.AddTransient<IRequestPreProcessor<IWorkflowCommand>, StepRecorderingRequestPreProcessor>();

​

        var provider = services.BuildServiceProvider();

​

        var mediator = provider.GetRequiredService<IMediator>();

​

        var correlationId = Guid.NewGuid().ToString();

        List<IWorkflowCommand> steps = new List<IWorkflowCommand>();

        // LdapService used by handler throws exception

        steps.Add(new DisableLdapAccountCommand

        {

            SAMAccountName = "tory.berra",

            CorrelationId = correlationId,

        });

        steps.Add(new EnableLdapAccountCommand

        {

            SAMAccountName = "tory.berra",

            CorrelationId = correlationId,

        });     

​

        var results = new List<IResult>();

        foreach (var step in steps)

        {

            try

            {

                var response = await mediator.Send(step);

                results.Add((IResult)response);

            }

            catch (Exception e)

            {

                Console.WriteLine($"Global unhandled exception. {e.Message}");

            }

        }

​

        results.Dump();

    }

}

​

public interface IWorkflowCommand

{

    public string CorrelationId { get; set; }

    // Todo: Auditing stuff

}

​

public class DisableLdapAccountCommand : IRequest<Result>, IWorkflowCommand

{

    public string SAMAccountName { get; set; }

​

    public string CorrelationId { get; set; }

}

​

public class EnableLdapAccountCommand : IRequest<Result>, IWorkflowCommand

{

    public string SAMAccountName { get; set; }

​

    public string CorrelationId { get; set; }

}

​

public class DisableLdapAccountHandler : IRequestHandler<DisableLdapAccountCommand, Result>

{

    public Task<Result> Handle(DisableLdapAccountCommand request, CancellationToken cancellationToken)

    {

        // var ldapService = new LdapService();

        // ldapService.DisableLocalAccount(request.SAMAccountName);

        return Task.FromResult(Result.SuccessWithMessage("DisableLdapAccountHandler Worked"));

    }

}

​

public class EnableLdapAccountHandler : IRequestHandler<EnableLdapAccountCommand, Result>

{

    public Task<Result> Handle(EnableLdapAccountCommand request, CancellationToken cancellationToken)

    {

        // var ldapService = new LdapService();

        // ldapService.DisableLocalAccount(request.SAMAccountName);

        throw new Exception("Boom");

        return Task.FromResult(Result.SuccessWithMessage("EnableLdapAccountHandler Worked"));

    }

}

​

public class GenericRequestExceptionHandler<TRequest, TResponse, TException> : IRequestExceptionHandler<TRequest, TResponse, TException>

    where TRequest : IWorkflowCommand

    where TResponse : Result

    where TException : Exception

{

    public Task Handle(

        TRequest request,

        TException exception,

        RequestExceptionHandlerState<TResponse> state,

        CancellationToken cancellationToken = new CancellationToken())

    {

        Console.WriteLine("GenericRequestExceptionHandler translating exception to error.");

        var translatedResponse = Result.Error("Unhandled exception.");

        state.SetHandled((TResponse)translatedResponse); // ??? What is this error? There is a constraint that says TResponse is type of Result. So why does this mnot work?!?

        return Task.CompletedTask;

    }

}

​