using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Ocelot.Configuration.File;
using Shouldly;
using TestStack.BDDfy;
using Xunit;

namespace Ocelot.AcceptanceTests
{
    public class GzipTests : IDisposable
    {
        private IWebHost _builder;
        private readonly Steps _steps;

        public GzipTests()
        {
            _steps = new Steps();
        }

        [Fact]
        public void should_return_response_200_with_simple_url()
        {
            var configuration = new FileConfiguration
            {
                ReRoutes = new List<FileReRoute>
                    {
                        new FileReRoute
                        {
                            DownstreamPathTemplate = "/",
                            DownstreamScheme = "http",
                            DownstreamHostAndPorts = new List<FileHostAndPort>
                            {
                                new FileHostAndPort
                                {
                                    Host = "localhost",
                                    Port = 51879,
                                }
                            },
                            UpstreamPathTemplate = "/",
                            UpstreamHttpMethod = new List<string> { "Post" },
                        }
                    }
            };

            var input = "people";
            
            this.Given(x => x.GivenThereIsAServiceRunningOn("http://localhost:51879", "/", 200, "Hello from Laura", "\"people\""))
                .And(x => _steps.GivenThereIsAConfiguration(configuration))
                .And(x => _steps.GivenOcelotIsRunning())
                .And(x => _steps.GivenThePostHasGzipContent(input))
                .When(x => _steps.WhenIPostUrlOnTheApiGateway("/"))
                .Then(x => _steps.ThenTheStatusCodeShouldBe(HttpStatusCode.OK))
                .And(x => _steps.ThenTheResponseBodyShouldBe("Hello from Laura"))
                .BDDfy();
        }

        private void GivenThereIsAServiceRunningOn(string baseUrl, string basePath, int statusCode, string responseBody, string expected)
        {
            _builder = new WebHostBuilder()
                .UseUrls(baseUrl)
                .UseKestrel()
                .UseContentRoot(Directory.GetCurrentDirectory())
                .UseIISIntegration()
                .Configure(app =>
                {
                    app.UsePathBase(basePath);
                    app.Run(async context =>
                    {   
                        if(context.Request.Headers.TryGetValue("Content-Encoding", out var contentEncoding))
                        {
                            contentEncoding.First().ShouldBe("gzip");
                            
                            string text = null;
                            using (var decompress = new GZipStream(context.Request.Body, CompressionMode.Decompress))
                            {
                                using (var sr = new StreamReader(decompress)) {
                                    text = sr.ReadToEnd();
                                }
                            }

                            if(text != expected)
                            {
                                throw new Exception("not gzipped");
                            }
                            
                            context.Response.StatusCode = statusCode;
                            await context.Response.WriteAsync(responseBody);
                        }
                        else
                        {
                            context.Response.StatusCode = statusCode;
                            await context.Response.WriteAsync("downstream path didnt match base path");
                        }
                    });
                })
                .Build();

            _builder.Start();
        }

        public void Dispose()
        {
            _builder?.Dispose();
            _steps.Dispose();
        }
    }
}