using System;
using System.IO;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using xCommons.Extensions;
using xCommons.Models;

namespace xCommons.Middlewares {
    public partial class XRequestLogger {

        private readonly ILogger logger;
        private readonly RequestDelegate next;

        public XRequestLogger (
            RequestDelegate next,
            ILoggerFactory loggerFactory
        ) {
            //
            this.next = next;
            this.logger = loggerFactory
                .CreateLogger<XRequestLogger> ();
        }

        public async Task InvokeAsync (HttpContext context) {
            //
            var logModel = new XLoggerModel ();

            //
            logModel.Path = context.Request.Path;
            logModel.Schema = context.Request.Scheme;
            logModel.Method = context.Request.Method;
            logModel.Headers = context.Request.Headers;
            logModel.Host = context.Request.Host.ToString ();
            logModel.QueryString = context.Request.QueryString.ToString ();
            logModel.UserID = context.User.Identity.IsAuthenticated ? context.User.Identity.Name : "Not Authenticated";

            //
            logModel.Connection = new XLoggerHttpConnection {
                Id = context.Connection.Id,
                RemoteIpAddress = context.Connection.RemoteIpAddress.ToString (),
                RemotePort = context.Connection.RemotePort.ToString (),
                LocalIpAddress = context.Connection.LocalIpAddress.ToString (),
                LocalPort = context.Connection.LocalPort.ToString (),
            };

            //
            // Check if a request is a Post Call so read data from Body ...
            if (context.Request.Method.ToNormalString () == "post") {
                //
                context.Request.EnableBuffering ();
                var request = await new StreamReader (context.Request.Body)
                    .ReadToEndAsync ();

                //
                context.Request.Body.Position = 0;
                logModel.Request = request;
            }

            //
            logModel.RequestedOn = DateTime.UtcNow;

            //
            // Do Request ...
            await next.Invoke (context);

            //
            using (Stream originalRequest = context.Response.Body) {
                try {
                    using (var memStream = new MemoryStream ()) {
                        //
                        context.Response.Body = memStream;

                        //
                        // All the Request processing as described above 
                        // happens from here.
                        // Response handling starts from here
                        // set the pointer to the beginning of the 
                        // memory stream to read
                        memStream.Position = 0;

                        //
                        // read the memory stream till the end
                        var response = await new StreamReader (memStream)
                            .ReadToEndAsync ();

                        //
                        logModel.Response = response;
                        logModel.RespondedOn = DateTime.UtcNow;
                        logModel.StatusCode = context.Response.StatusCode;
                        logModel.IsSucceed = context.Response.StatusCode >= 200 && context.Response.StatusCode <= 299;

                        //
                        // since we have read till the end of the stream, 
                        // reset it onto the first position
                        memStream.Position = 0;

                        //
                        // now copy the content of the temporary memory 
                        // stream we have passed to the actual response body 
                        // which will carry the response out.
                        await memStream.CopyToAsync (originalRequest);
                    }
                } catch (Exception ex) {
                    //
                    // Log Exception ...
                    logger.LogError ($"Error on Logging Request/Response ... {ex.ToJSON()}");
                } finally {
                    //
                    // assign the response body to the actual context
                    context.Response.Body = originalRequest;
                }
            }

            //
            // Log Response ...
            logger.LogCritical ($"Http Response/Response Information:{Environment.NewLine}" +
                $"Schema:{logModel.Schema} " + Environment.NewLine +
                $"Host: {logModel.Host} " + Environment.NewLine +
                $"Path: {logModel.Path} " + Environment.NewLine +
                $"Method: {logModel.Method} " + Environment.NewLine +
                $"UserID: {logModel.UserID} " + Environment.NewLine +
                $"QueryString: {context.Request.QueryString} " + Environment.NewLine +
                $"Headers: {logModel.Headers.ToJSON()}" + Environment.NewLine +
                $"" + Environment.NewLine +
                $"Http Connection: " + Environment.NewLine +
                $"Id: {logModel.Connection.Id}" + Environment.NewLine +
                $"RemoteIpAddress: {logModel.Connection.RemoteIpAddress}" + Environment.NewLine +
                $"RemotePort: {logModel.Connection.RemotePort}" + Environment.NewLine +
                $"LocalIpAddress: {logModel.Connection.LocalIpAddress}" + Environment.NewLine +
                $"LocalPort: {logModel.Connection.LocalPort}" + Environment.NewLine +
                $"" + Environment.NewLine +
                $"Request Body: {logModel.Request}" + Environment.NewLine +
                $"RequestedOn: {logModel.RequestedOn}" + Environment.NewLine +
                $"" + Environment.NewLine +
                $"IsSucceed: {logModel.IsSucceed}" + Environment.NewLine +
                $"StatucCode: {logModel.StatusCode}" + Environment.NewLine +
                $"Response Body: {logModel.Response}" + Environment.NewLine +
                $"RespondedOn: {logModel.RespondedOn}" + Environment.NewLine +
                $"" + Environment.NewLine
            );
        }
    }
}