using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Diagnostics;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using System.Net;

namespace Syc.Abp.Application.Contracts
{
    public static class SycAbpContractsExtensions
    {
        /// <summary>
        /// 规范化异常处理
        /// </summary>
        /// <param name="app"></param>
        public static void UseSpecificationException(this IApplicationBuilder app)
        {
            app.UseExceptionHandler(configure =>
            {
                configure.Run(HandleExceptionAsync);
            });
        }

        internal async static Task HandleExceptionAsync(HttpContext httpContext)
        {
            var feature = httpContext.Features.Get<IExceptionHandlerPathFeature>();
            var error = FindFriendlyException(feature.Error);
            httpContext.RequestServices.GetService<ILogger<Exception>>().LogError(error, "An exception occurred: {exceptionMessage}");
            var result = feature.Error.ExceptionConvertResponse();
            httpContext.Response.ContentType = "application/json";
            httpContext.Response.StatusCode = (int)HttpStatusCode.OK;
            await httpContext.Response.WriteAsJsonAsync(result);
        }

        /// <summary>
        /// 生成异常响应
        /// </summary>
        /// <param name="exception"></param>
        /// <returns></returns>
        internal static Response ExceptionConvertResponse(this Exception exception)
        {
            int errorCode = -1;
            exception = FindFriendlyException(exception);
            string message = exception.Message;
            if (exception is FriendlyException)
                errorCode = (exception as FriendlyException).Code;
            else
                errorCode = 500;
            return Response.Error(errorCode,message); 
        }

        /// <summary>
        /// 递归查找友好异常
        /// </summary>
        /// <param name="exception"></param>
        /// <returns></returns>
        internal static Exception FindFriendlyException(Exception exception)
        {
            if (exception is FriendlyException || exception.InnerException is null)
                return exception;
            else return FindFriendlyException(exception.InnerException);
        }
    }
}