using HuanMeng.DotNetCore.AttributeExtend;
using HuanMeng.DotNetCore.Base;
using HuanMeng.DotNetCore.Extensions;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc.Controllers;
using Microsoft.Extensions.DependencyInjection;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.IO;
using System.Reflection;
using System.Threading.Tasks;

namespace ChouBox.WebApi.Middleware
{
    /// <summary>
    /// 响应格式化中间件
    /// </summary>
    public class ResponseFormatterMiddleware
    {
        private readonly RequestDelegate _next;

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

        public async Task InvokeAsync(HttpContext context)
        {
            // 保存原始响应流
            var originalBodyStream = context.Response.Body;

            try
            {
                // 使用内存流替代响应流
                using var memoryStream = new MemoryStream();
                context.Response.Body = memoryStream;

                // 继续处理请求
                await _next(context);

                // 获取可能存在的动态消息（从HTTP头部）
                string customMessage = context.GetDynamicMessage();
                
                // 如果没有动态消息，则检查MessageAttribute
                if (string.IsNullOrEmpty(customMessage))
                {
                    var endpoint = context.GetEndpoint();
                    if (endpoint != null)
                    {
                        if (endpoint.Metadata.GetMetadata<ControllerActionDescriptor>() is ControllerActionDescriptor actionDescriptor)
                        {
                            var messageAttribute = actionDescriptor.MethodInfo.GetCustomAttribute<MessageAttribute>();
                            if (messageAttribute != null)
                            {
                                customMessage = messageAttribute.Message;
                            }
                        }
                    }
                }

                // 如果是API接口请求并且内容类型是JSON
                if (context.Request.Path.StartsWithSegments("/api") && 
                    context.Response.ContentType != null && 
                    context.Response.ContentType.Contains("application/json"))
                {
                    memoryStream.Seek(0, SeekOrigin.Begin);
                    string responseBody = await new StreamReader(memoryStream).ReadToEndAsync();

                    // 如果响应内容是简单字符串(不是JSON格式)，将其包装成BaseResponse
                    if (!string.IsNullOrEmpty(responseBody) && 
                        !responseBody.StartsWith("{") && 
                        !responseBody.StartsWith("["))
                    {
                        var response = new BaseResponse<string>
                        {
                            Status = 1,
                            Msg = customMessage,
                            Data = responseBody.Trim('"') // 去除JSON序列化添加的引号
                        };

                        // 重置流
                        memoryStream.SetLength(0);
                        
                        // 写入格式化后的响应
                        using var writer = new StreamWriter(memoryStream, leaveOpen: true);
                        await writer.WriteAsync(response.ToString());
                        await writer.FlushAsync();
                        
                        // 更新Content-Length
                        context.Response.ContentLength = memoryStream.Length;
                    }
                }

                // 将内存流复制回原始响应流
                memoryStream.Seek(0, SeekOrigin.Begin);
                await memoryStream.CopyToAsync(originalBodyStream);
            }
            finally
            {
                // 恢复原始响应流
                context.Response.Body = originalBodyStream;
            }
        }
    }

    /// <summary>
    /// 中间件扩展方法
    /// </summary>
    public static class ResponseFormatterMiddlewareExtensions
    {
        public static IApplicationBuilder UseResponseFormatter(this IApplicationBuilder builder)
        {
            return builder.UseMiddleware<ResponseFormatterMiddleware>();
        }
    }
}