using BMA.EHR.Domain.Common;
using BMA.EHR.Domain.Shared;
using Microsoft.AspNetCore.Http;
using System.Net;
using System.Text.Json;

namespace BMA.EHR.Domain.Middlewares
{
    public class ErrorHandlerMiddleware
    {
        private readonly RequestDelegate _next;

        public ErrorHandlerMiddleware(RequestDelegate next)
        {
            _next = next;
        }

        public async Task Invoke(HttpContext context)
        {
            try
            {
                await _next(context);

                var response = context.Response;
                var statusCode = response.StatusCode;

                // ตรวจสอบว่า response ยังไม่ถูกส่งและเป็น status code ที่ต้องการจัดการ
                if (!response.HasStarted &&
                    (statusCode == (int)HttpStatusCode.Unauthorized || statusCode == (int)HttpStatusCode.Forbidden))
                {
                    var responseModel = new ResponseObject
                    {
                        Status = statusCode,
                        Message = statusCode == (int)HttpStatusCode.Unauthorized
                            ? GlobalMessages.NotAuthorized
                            : GlobalMessages.ForbiddenAccess
                    };

                    response.ContentType = "application/json";
                    
                    // ใช้ JsonSerializer แทน WriteAsJsonAsync เพื่อความปลอดภัย
                    var jsonResponse = JsonSerializer.Serialize(responseModel);
                    await response.WriteAsync(jsonResponse);
                }
            }
            catch (Exception error)
            {
                await HandleExceptionAsync(context, error);
            }
        }

        private static async Task HandleExceptionAsync(HttpContext context, Exception error)
        {
            var response = context.Response;

            // ตรวจสอบว่า response ยังไม่ถูกส่งไป
            if (response.HasStarted)
            {
                // ถ้า response เริ่มแล้ว ไม่สามารถแก้ไขได้ แค่ log
                Console.WriteLine("Cannot write error response, stream already started.");
                Console.WriteLine($"Error: {error}");
                return;
            }

            try
            {
                // Clear response เฉพาะเมื่อยังไม่ได้เริ่มส่ง
                response.Clear();
                response.ContentType = "application/json";
                response.StatusCode = (int)HttpStatusCode.InternalServerError;

                // สร้าง error message
                var msg = error.Message;
                var inner = error.InnerException;
                while (inner != null)
                {
                    msg += $" {inner.Message}\r\n";
                    inner = inner.InnerException;
                }

                var responseModel = new ResponseObject
                {
                    Status = response.StatusCode,
                    Message = GlobalMessages.ExceptionOccured,
                    Result = msg
                };

                // ใช้ JsonSerializer และ WriteAsync เพื่อหลีกเลี่ยงปัญหา stream
                var jsonResponse = JsonSerializer.Serialize(responseModel);
                await response.WriteAsync(jsonResponse);
            }
            catch (Exception writeError)
            {
                // ถ้าเขียน response ไม่ได้ ให้ log error
                Console.WriteLine("Failed to write error response:");
                Console.WriteLine($"Original Error: {error}");
                Console.WriteLine($"Write Error: {writeError}");
            }
        }
    }
}


// using BMA.EHR.Domain.Common;
// using BMA.EHR.Domain.Shared;
// using Microsoft.AspNetCore.Http;
// using System.Net;
//
// namespace BMA.EHR.Domain.Middlewares
// {
//     public class ErrorHandlerMiddleware
//     {
//         private readonly RequestDelegate _next;
//
//         public ErrorHandlerMiddleware(RequestDelegate next)
//         {
//             _next = next;
//         }
//
//         public async Task Invoke(HttpContext context)
//         {
//             try
//             {
//                 await _next(context);
//
//                 var response = context.Response;
//                 var statusCode = response.StatusCode;
//
//                 if (!response.HasStarted &&
//                     (statusCode == (int)HttpStatusCode.Unauthorized || statusCode == (int)HttpStatusCode.Forbidden))
//                 {
//                     var responseModel = new ResponseObject
//                     {
//                         Status = statusCode,
//                         Message = statusCode == (int)HttpStatusCode.Unauthorized
//                             ? GlobalMessages.NotAuthorized
//                             : GlobalMessages.ForbiddenAccess
//                     };
//
//                     response.ContentType = "application/json";
//                     await response.WriteAsJsonAsync(responseModel);
//                 }
//             }
//             catch (Exception error)
//             {
//                 var response = context.Response;
//
//                 if (!response.HasStarted)
//                 {
//                     response.Clear();
//                     response.ContentType = "application/json";
//                     response.StatusCode = (int)HttpStatusCode.InternalServerError;
//
//                     var msg = error.Message;
//                     var inner = error.InnerException;
//                     while (inner != null)
//                     {
//                         msg += $" {inner.Message}\r\n";
//                         inner = inner.InnerException;
//                     }
//
//                     var responseModel = new ResponseObject
//                     {
//                         Status = response.StatusCode,
//                         Message = GlobalMessages.ExceptionOccured,
//                         Result = msg
//                     };
//
//                     await response.WriteAsJsonAsync(responseModel);
//                 }
//                 else
//                 {
//                     // logging กรณีที่ response เริ่มถูกส่งแล้ว
//                     Console.WriteLine("Cannot write error response, stream already started.");
//                     Console.WriteLine(error);
//                 }
//             }
//         }
//     }
// }