// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Text;
using BenchmarkDotNet.Attributes;
using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;

namespace Microsoft.AspNetCore.Server.Kestrel.Performance
{
    public class KnownStringsBenchmark
    {
        static byte[] _methodConnect = Encoding.ASCII.GetBytes("CONNECT ");
        static byte[] _methodDelete = Encoding.ASCII.GetBytes("DELETE \0");
        static byte[] _methodGet = Encoding.ASCII.GetBytes("GET ");
        static byte[] _methodHead = Encoding.ASCII.GetBytes("HEAD \0\0\0");
        static byte[] _methodPatch = Encoding.ASCII.GetBytes("PATCH \0\0");
        static byte[] _methodPost = Encoding.ASCII.GetBytes("POST \0\0\0");
        static byte[] _methodPut = Encoding.ASCII.GetBytes("PUT \0\0\0\0");
        static byte[] _methodOptions = Encoding.ASCII.GetBytes("OPTIONS ");
        static byte[] _methodTrace = Encoding.ASCII.GetBytes("TRACE \0\0");

        static byte[] _version = Encoding.UTF8.GetBytes("HTTP/1.1\r\n");
        const int loops = 1000;

        [Benchmark(OperationsPerInvoke = loops * 10)]
        public int GetKnownMethod_GET()
        {
            Span<byte> data = _methodGet;

            return GetKnownMethod(data);
        }

        [Benchmark(OperationsPerInvoke = loops * 10)]
        public int GetKnownMethod_CONNECT()
        {
            Span<byte> data = _methodConnect;

            return GetKnownMethod(data);
        }

        [Benchmark(OperationsPerInvoke = loops * 10)]
        public int GetKnownMethod_DELETE()
        {
            Span<byte> data = _methodDelete;

            return GetKnownMethod(data);
        }
        [Benchmark(OperationsPerInvoke = loops * 10)]
        public int GetKnownMethod_HEAD()
        {
            Span<byte> data = _methodHead;

            return GetKnownMethod(data);
        }

        [Benchmark(OperationsPerInvoke = loops * 10)]
        public int GetKnownMethod_PATCH()
        {
            Span<byte> data = _methodPatch;

            return GetKnownMethod(data);
        }
        [Benchmark(OperationsPerInvoke = loops * 10)]
        public int GetKnownMethod_POST()
        {
            Span<byte> data = _methodPost;

            return GetKnownMethod(data);
        }
        [Benchmark(OperationsPerInvoke = loops * 10)]
        public int GetKnownMethod_PUT()
        {
            Span<byte> data = _methodPut;

            return GetKnownMethod(data);
        }

        [Benchmark(OperationsPerInvoke = loops * 10)]
        public int GetKnownMethod_OPTIONS()
        {
            Span<byte> data = _methodOptions;

            return GetKnownMethod(data);
        }

        [Benchmark(OperationsPerInvoke = loops * 10)]
        public int GetKnownMethod_TRACE()
        {
            Span<byte> data = _methodTrace;

            return GetKnownMethod(data);
        }

        private int GetKnownMethod(Span<byte> data)
        {
            int len = 0;
            HttpMethod method;

            for (int i = 0; i < loops; i++)
            {
                data.GetKnownMethod(out method, out var length);
                len += length;
                data.GetKnownMethod(out method, out length);
                len += length;
                data.GetKnownMethod(out method, out length);
                len += length;
                data.GetKnownMethod(out method, out length);
                len += length;
                data.GetKnownMethod(out method, out length);
                len += length;
                data.GetKnownMethod(out method, out length);
                len += length;
                data.GetKnownMethod(out method, out length);
                len += length;
                data.GetKnownMethod(out method, out length);
                len += length;
                data.GetKnownMethod(out method, out length);
                len += length;
                data.GetKnownMethod(out method, out length);
                len += length;
            }
            return len;
        }

        [Benchmark(OperationsPerInvoke = loops * 10)]
        public int GetKnownVersion_HTTP1_1()
        {
            int len = 0;
            HttpVersion version;
            Span<byte> data = _version;
            for (int i = 0; i < loops; i++)
            {
                data.GetKnownVersion(out version, out var length);
                len += length;
                data.GetKnownVersion(out version, out length);
                len += length;
                data.GetKnownVersion(out version, out length);
                len += length;
                data.GetKnownVersion(out version, out length);
                len += length;
                data.GetKnownVersion(out version, out length);
                len += length;
                data.GetKnownVersion(out version, out length);
                len += length;
                data.GetKnownVersion(out version, out length);
                len += length;
                data.GetKnownVersion(out version, out length);
                len += length;
                data.GetKnownVersion(out version, out length);
                len += length;
                data.GetKnownVersion(out version, out length);
                len += length;
            }
            return len;
        }
    }
}