using Microsoft.AspNetCore.Http.Extensions;
using Ocelot.RequestId;
using Serilog;
using System.Diagnostics;
using System.Text;
using Yitter.IdGenerator;

namespace HuiXin.Gateway.Ocelot.Middlewares
{
    public class AccessLoggingMiddleware
    {
        private readonly RequestDelegate _next;

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

        public async Task InvokeAsync(HttpContext context)
        {
            var traceIdKey = DefaultRequestIdKey.Value;
            var traceId = YitIdHelper.NextId().ToString();
            context.TraceIdentifier = traceId;
            context.Request.Headers[traceIdKey] = traceId;

            var sw = Stopwatch.StartNew();
            sw.Start();

            var sb = new StringBuilder();

            sb.AppendLine();
            sb.AppendLine("-------------------Request Start-------------------");
            sb.AppendLine(DateTime.Now.ToString());
            sb.AppendLine($"追踪id:{traceId}");
            sb.AppendLine($"地址:{context.Request.GetDisplayUrl()}");
            sb.AppendLine("请求头:");
            foreach (var header in context.Request.Headers)
            {
                sb.AppendLine($"{header.Key}:{header.Value}");
            }
            sb.AppendLine($"数据:{await GetRequestBody(context.Request)}");
            sb.AppendLine("===================Request End===================");

            Log.Information(sb.ToString());
            sb.Clear();

            //Copy a pointer to the original response body stream
            var originalBodyStream = context.Response.Body;

            //Create a new memory stream...
            using var responseBody = new MemoryStream();
            //...and use that for the temporary response body
            context.Response.Body = responseBody;

            //Continue down the Middleware pipeline, eventually returning to this class
            await _next(context);

            //Format the response from the server
            //var response = await FormatResponse(context.Response);
            sb.AppendLine();
            sb.AppendLine("-------------------Response Start-------------------");
            sb.AppendLine(DateTime.Now.ToString());
            sb.AppendLine($"追踪id:{traceId}");
            sb.AppendLine($"耗时:{sw.ElapsedMilliseconds}毫秒");
            sb.AppendLine($"状态码:{context.Response.StatusCode}");
            //sb.AppendLine("Headers: ");
            //foreach (var header in context.Response.Headers)
            //{
            //    sb.AppendLine($"{header.Key}:{header.Value}");
            //}
            sb.AppendLine($"数据:{await GetResponseBody(context.Response)}");
            sb.AppendLine("===================Response End===================");

            //Save log to chosen datastore
            Log.Information(sb.ToString());

            sb.Clear();

            //Copy the contents of the new memory stream (which contains the response) to the original stream, which is then returned to the client.
            await responseBody.CopyToAsync(originalBodyStream);
        }

        private static async Task<string> GetRequestBody(HttpRequest request)
        {
            request.EnableBuffering();
            // Leave the body open so the next middleware can read it.
            using var reader = new StreamReader(
                request.Body,
                encoding: Encoding.UTF8,
                detectEncodingFromByteOrderMarks: false,
                leaveOpen: true);
            var body = await reader.ReadToEndAsync();
            // Do some processing with body…

            //var formattedRequest = $"{request.Scheme} {request.Host}{request.Path} {request.QueryString} {body}";

            // Reset the request body stream position so the next middleware can read it
            request.Body.Position = 0;

            return body;
        }

        private static async Task<string> GetResponseBody(HttpResponse response)
        {
            //We need to read the response stream from the beginning...
            response.Body.Seek(0, SeekOrigin.Begin);

            //...and copy it into a string
            string text = await new StreamReader(response.Body).ReadToEndAsync();

            //We need to reset the reader for the response so that the client can read it.
            response.Body.Seek(0, SeekOrigin.Begin);

            //Return the string for the response, including the status code (e.g. 200, 404, 401, etc.)
            //return $"{response.StatusCode}: {text}";
            return text;
        }

        static AccessLoggingMiddleware()
        {
            // 创建 IdGeneratorOptions 对象，可在构造函数中输入 WorkerId：
            var options = new IdGeneratorOptions();
            // options.WorkerIdBitLength = 10; // 默认值6，限定 WorkerId 最大值为2^6-1，即默认最多支持64个节点。
            // options.SeqBitLength = 6; // 默认值6，限制每毫秒生成的ID个数。若生成速度超过5万个/秒，建议加大 SeqBitLength 到 10。
            // options.BaseTime = Your_Base_Time; // 如果要兼容老系统的雪花算法，此处应设置为老系统的BaseTime。
            // ...... 其它参数参考 IdGeneratorOptions 定义。

            // 保存参数（务必调用，否则参数设置不生效）：
            YitIdHelper.SetIdGenerator(options);
        }
    }
}