// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System.Buffers;
using System.IO;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Abstractions;
using Microsoft.AspNetCore.Mvc.Formatters;
using Microsoft.AspNetCore.Mvc.Infrastructure;
using Microsoft.AspNetCore.Mvc.Internal;
using Microsoft.AspNetCore.Routing;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;
using Newtonsoft.Json;
using Xunit;

namespace System.Web.Http
{
    public class ExceptionResultTest
    {
        [Fact]
        public async Task ExceptionResult_SetsStatusCode()
        {
            // Arrange
            var httpContext = new DefaultHttpContext();
            httpContext.RequestServices = CreateServices();

            var stream = new MemoryStream();
            httpContext.Response.Body = stream;

            var context = new ActionContext(httpContext, new RouteData(), new ActionDescriptor());
            var result = new ExceptionResult(new Exception("hello, world!"), includeErrorDetail: false);

            // Act
            await result.ExecuteResultAsync(context);

            // Assert
            Assert.Equal(StatusCodes.Status500InternalServerError, context.HttpContext.Response.StatusCode);
        }

        [Fact]
        public async Task ExceptionResult_WritesHttpError()
        {
            // Arrange
            var httpContext = new DefaultHttpContext();
            httpContext.RequestServices = CreateServices();

            var stream = new MemoryStream();
            httpContext.Response.Body = stream;

            var context = new ActionContext(httpContext, new RouteData(), new ActionDescriptor());
            var result = new ExceptionResult(new Exception("hello, world!"), includeErrorDetail: false);

            // Act
            await result.ExecuteResultAsync(context);

            // Assert
            using (var reader = new StreamReader(stream))
            {
                stream.Seek(0, SeekOrigin.Begin);
                var content = reader.ReadToEnd();
                Assert.Equal("{\"Message\":\"An error has occurred.\"}", content);
            }
        }

        private static IServiceProvider CreateServices()
        {
            var options = Options.Create(new MvcOptions());
            options.Value.OutputFormatters.Add(new StringOutputFormatter());
            options.Value.OutputFormatters.Add(new JsonOutputFormatter(
                new JsonSerializerSettings(),
                ArrayPool<char>.Shared));

            var services = new ServiceCollection();
            services.AddSingleton<IActionResultExecutor<ObjectResult>>(new ObjectResultExecutor(
                new DefaultOutputFormatterSelector(options, NullLoggerFactory.Instance),
                new TestHttpResponseStreamWriterFactory(),
                NullLoggerFactory.Instance));

            return services.BuildServiceProvider();
        }
    }
}