using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Configs;
using BenchmarkDotNet.Running;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.ObjectPool;
using System;
using System.Linq;
using System.Security.Cryptography;
using System.Threading.Tasks;

[MemoryDiagnoser]
public class ObjectPoolBenchmarks
{
    private ObjectPool<ReusableBuffer> _bufferPool;
    private readonly string _sampleText = "The Test Text...";

    [GlobalSetup]
    public void Setup()
    {
        var services = new ServiceCollection();
        services.AddSingleton<ObjectPoolProvider, DefaultObjectPoolProvider>();
        services.AddSingleton<ObjectPool<ReusableBuffer>>(serviceProvider =>
        {
            var provider = serviceProvider.GetRequiredService<ObjectPoolProvider>();
            var policy = new DefaultPooledObjectPolicy<ReusableBuffer>();
            return provider.Create(policy);
        });

        var serviceProvider = services.BuildServiceProvider();
        _bufferPool = serviceProvider.GetRequiredService<ObjectPool<ReusableBuffer>>();
    }

    [Benchmark]
    public string ComputeHashWithoutPooling()
    {
        var buffer = new byte[1024 * 1024]; // 1 MB
        for (var i = 0; i < _sampleText.Length; i++)
        {
            buffer[i] = (byte)_sampleText[i];
        }

        Span<byte> hash = stackalloc byte[32];
        SHA256.HashData(buffer.AsSpan(0, _sampleText.Length), hash);
        return Convert.ToHexString(hash);
    }

    [Benchmark]
    public string ComputeHashWithPooling()
    {
        var buffer = _bufferPool.Get();
        try
        {
            for (var i = 0; i < _sampleText.Length; i++)
            {
                buffer.Data[i] = (byte)_sampleText[i];
            }

            Span<byte> hash = stackalloc byte[32];
            SHA256.HashData(buffer.Data.AsSpan(0, _sampleText.Length), hash);
            return Convert.ToHexString(hash);
        }
        finally
        {
            _bufferPool.Return(buffer);
        }
    }
}

public class ReusableBuffer : IResettable
{
    public byte[] Data { get; } = new byte[1024 * 1024];

    public bool TryReset()
    {
        Array.Clear(Data);
        return true;
    }
}

public class Program
{
    public static void Main(string[] args)
    {
        var summary = BenchmarkRunner.Run<ObjectPoolBenchmarks>();
    }
}

// .NET 8 Lowered C# Code unavailable due to errors:
error CS0234: The type or namespace name 'ObjectPool' does not exist in the namespace 'Microsoft.Extensions' (are you missing an assembly reference?)
error CS0246: The type or namespace name 'IResettable' could not be found (are you missing a using directive or an assembly reference?)
error CS0246: The type or namespace name 'ObjectPool<>' could not be found (are you missing a using directive or an assembly reference?)
error CS0246: The type or namespace name 'ObjectPoolProvider' could not be found (are you missing a using directive or an assembly reference?)
error CS0246: The type or namespace name 'DefaultObjectPoolProvider' could not be found (are you missing a using directive or an assembly reference?)
error CS0246: The type or namespace name 'DefaultPooledObjectPolicy<>' could not be found (are you missing a using directive or an assembly reference?)
error CS1061: 'ServiceCollection' does not contain a definition for 'BuildServiceProvider' and no accessible extension method 'BuildServiceProvider' accepting a first argument of type 'ServiceCollection' could be found (are you missing a using directive or an assembly reference?)

// .NET 8 IL Code unavailable due to errors:
error CS0234: The type or namespace name 'ObjectPool' does not exist in the namespace 'Microsoft.Extensions' (are you missing an assembly reference?)
error CS0246: The type or namespace name 'ObjectPool<>' could not be found (are you missing a using directive or an assembly reference?)
error CS0246: The type or namespace name 'IResettable' could not be found (are you missing a using directive or an assembly reference?)
error CS0246: The type or namespace name 'ObjectPoolProvider' could not be found (are you missing a using directive or an assembly reference?)
error CS0246: The type or namespace name 'DefaultObjectPoolProvider' could not be found (are you missing a using directive or an assembly reference?)
error CS0246: The type or namespace name 'DefaultPooledObjectPolicy<>' could not be found (are you missing a using directive or an assembly reference?)
error CS1061: 'ServiceCollection' does not contain a definition for 'BuildServiceProvider' and no accessible extension method 'BuildServiceProvider' accepting a first argument of type 'ServiceCollection' could be found (are you missing a using directive or an assembly reference?)