// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System;
using System.Net;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using BenchmarkDotNet.Attributes;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection.Extensions;
using Polly;
using Polly.Timeout;
 
namespace Microsoft.Extensions.Http.Resilience.PerformanceTests;
 
public class RetryBenchmark
{
    private static readonly Uri _uri = new(HttpClientFactory.PrimaryEndpoint);
 
    private HttpClient _v7 = null!;
    private HttpClient _v8 = null!;
    private CancellationToken _cancellationToken;
 
    private static HttpRequestMessage Request => new(HttpMethod.Post, _uri);
 
    [GlobalSetup]
    public void Prepare()
    {
        _cancellationToken = new CancellationTokenSource().Token;
 
        var services = new ServiceCollection();
 
        // The ResiliencePipelineBuilder added by Polly includes telemetry, which affects the results.
        // Since Polly v7 does not include telemetry either, let's disable the telemetry for v8 for fair results.
        services.TryAddTransient<ResiliencePipelineBuilder>();
 
        services
            .AddHttpClient("v8")
            .ConfigurePrimaryHttpMessageHandler(() => new NoRemoteCallHandler())
            .AddResilienceHandler("my-retries", builder => builder.AddRetry(new HttpRetryStrategyOptions
            {
                BackoffType = DelayBackoffType.Constant,
                Delay = TimeSpan.FromSeconds(1),
                MaxRetryAttempts = 3
            }));
 
        var builder = Policy.Handle<HttpRequestException>().Or<TimeoutRejectedException>().OrResult<HttpResponseMessage>(r =>
        {
            var statusCode = (int)r.StatusCode;
 
            return statusCode >= 500 ||
                r.StatusCode == HttpStatusCode.RequestTimeout ||
                statusCode == 429;
        });
 
        services
            .AddHttpClient("v7")
            .ConfigurePrimaryHttpMessageHandler(() => new NoRemoteCallHandler())
            .AddPolicyHandler(builder.WaitAndRetryAsync(3, _ => TimeSpan.FromSeconds(1)));
 
        var factory = services.BuildServiceProvider().GetRequiredService<IHttpClientFactory>();
 
        _v7 = factory.CreateClient("v7");
        _v8 = factory.CreateClient("v8");
    }
 
    [Benchmark(Baseline = true)]
    public Task<HttpResponseMessage> Retry_Polly_V7()
    {
        return _v7!.SendAsync(Request, _cancellationToken);
    }
 
    [Benchmark]
    public Task<HttpResponseMessage> Retry_Polly_V8()
    {
        return _v8!.SendAsync(Request, _cancellationToken);
    }
 
    [Benchmark]
    public HttpResponseMessage Retry_Polly_V8_Sync()
    {
        return _v8!.Send(Request, _cancellationToken);
    }
}