using System.Net;
using GerstITS.Web.Api.ExceptionHandling;
using Microsoft.AspNetCore.Diagnostics;
using Microsoft.AspNetCore.Http.Features;

namespace GerstITS.Examples.Api.ExceptionHandling;

internal static class WebApplicationExtensions
{
    internal static WebApplication UseGlobalExceptionHandling(this WebApplication app)
    {
        app.UseExceptionHandler(exceptionHandlerApp =>
        {
            exceptionHandlerApp.Run(async context =>
            {
                var exceptionFeature = context.Features.Get<IExceptionHandlerFeature>();
                if (exceptionFeature is null) return;

                var exception = exceptionFeature.Error;
                var ticketId = Guid.NewGuid().ToString();

                context.RequestServices
                       .GetRequiredService<ILoggerFactory>()
                       .CreateLogger("GlobalExceptionHandler")
                       .LogError($"Global exception occurs (TicketId {ticketId}).{Environment.NewLine}{exception}");

                var transformation = context.RequestServices
                                            .GetServices<IExceptionTransformation>()
                                            .FirstOrDefault(x => x.CanTransform(exception));

                var info = transformation?.Transform(exception, ticketId) ?? new ExceptionTransformationInfo
                {
                    StatusCode = HttpStatusCode.InternalServerError,
                    ReasonPhrase = "Internal Server Error.",
                    Details = $"An internal error occurs. Please contact support with ticket id '{ticketId}'."
                };

                context.Response.StatusCode = (int)info.StatusCode;
                context.Features.Get<IHttpResponseFeature>().ReasonPhrase = info.ReasonPhrase;
                await context.Response.WriteAsync(info.Details ?? string.Empty);
            });
        });

        return app;
    }
}