using Microsoft.AspNetCore.Http;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Internal;
using Microsoft.Extensions.Options;
using System;

namespace Example
{

    public class ApiExceptionMiddleware
    {
        private readonly RequestDelegate _next;
        private readonly ILogger _logger;
        
        private readonly ObjectResultExecutor _oex;

        public ApiExceptionMiddleware(RequestDelegate next, ILoggerFactory loggerFactory, ObjectResultExecutor oex)
        {
            _next = next;
            _logger = loggerFactory.CreateLogger<ApiExceptionMiddleware>();
            _oex = oex;
        }

        public async Task Invoke(HttpContext context)
        {
            try {
                await _next.Invoke(context);
            } catch (Exception e) {
                if (context.Response.HasStarted) {
                    _logger.LogWarning("The response has already started, the api exception middleware will not be executed");
                    throw;
                }
                context.Response.StatusCode = 500;
                context.Response.Clear();
                await _oex.ExecuteAsync(new ActionContext() { HttpContext = context }, new ObjectResult(new {
                    Error = "Exception",
                    Exception = e
                }));
           }
        }
    }
}