using Microsoft.AspNetCore.Http;

using Newtonsoft.Json;

using System;

using System.Collections.Generic;

using System.IO;

using System.Linq;

using System.Net;

using System.Threading.Tasks;

using System.Xml.Serialization;

using UFX.Mall.EntityModel;

using UFX.Tools;

namespace UFX.Mall.WebApi

{

    public class ExceptionHandlerMiddleWare

    {

        private readonly RequestDelegate next;

        public ExceptionHandlerMiddleWare(RequestDelegate next)

        {

            this.next = next;

        }

        public async Task Invoke(HttpContext context)

        {

            try

            {

                await next(context);

            }

            catch (Exception ex)

            {

                await HandleExceptionAsync(context, ex);

            }

        }

        private static async Task HandleExceptionAsync(HttpContext context, Exception exception)

        {

            if (exception == null) return;

            await WriteExceptionAsync(context, exception).ConfigureAwait(false);

        }

        private static async Task WriteExceptionAsync(HttpContext context, Exception exception)

        {

            //记录日志

            LogHelper.Error(exception.GetBaseException().ToString());

            //返回友好的提示

            var response = context.Response;

            //状态码

            if (exception is UnauthorizedAccessException)

                response.StatusCode = (int)HttpStatusCode.Unauthorized;

            else if (exception is Exception)

                response.StatusCode = (int)HttpStatusCode.BadRequest;

            response.ContentType = context.Request.Headers["Accept"];

            if (response.ContentType.ToLower() == "application/xml")

            {

                await response.WriteAsync(Object2XmlString(ResultMsg.Failure(exception.GetBaseException().Message))).ConfigureAwait(false);

            }

            else

            {

                response.ContentType = "application/json";

                await response.WriteAsync(JsonConvert.SerializeObject(ResultMsg.Failure(exception.GetBaseException().Message))).ConfigureAwait(false);

            }

        }

        /// <summary>

        /// 对象转为Xml

        /// </summary>

        /// <param name="o"></param>

        /// <returns></returns>

        private static string Object2XmlString(object o)

        {

            StringWriter sw = new StringWriter();

            try

            {

                XmlSerializer serializer = new XmlSerializer(o.GetType());

                serializer.Serialize(sw, o);

            }

            catch

            {

                //Handle Exception Code

            }

            finally

            {

                sw.Dispose();

            }

            return sw.ToString();

        }

    }

}

// This method gets called by the runtime. Use this method to configure the HTTP request pipeline

        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)

        {

            loggerFactory.AddConsole(Configuration.GetSection("Logging"));

            loggerFactory.AddDebug();

            //配置NLog

            loggerFactory.AddNLog();

            env.ConfigureNLog("nlog.config");

            app.UseApplicationInsightsRequestTelemetry();

            app.UseApplicationInsightsExceptionTelemetry();

            //异常处理中间件

            app.UseMiddleware(typeof(ExceptionHandlerMiddleWare));

            app.UseMvc(); ;

        }