using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using System.Text;
using Microsoft.AspNetCore.Server.Kestrel.Internal.Http;
using Microsoft.AspNetCore.Server.Kestrel.Internal.Infrastructure;
using Xunit;

namespace Microsoft.AspNetCore.Server.KestrelTests
{
    public class KnownStringsTests
    {
        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");


        const int MagicNumer = 0x0600000C;
        static byte[] _invalidMethod1 = BitConverter.GetBytes((ulong)MagicNumer);
        static byte[] _invalidMethod2 = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
        static byte[] _invalidMethod3 = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
        static byte[] _invalidMethod4 = Encoding.ASCII.GetBytes("CONNECT ");
        static byte[] _invalidMethod5 = Encoding.ASCII.GetBytes("DELETE \0");
        static byte[] _invalidMethod6 = Encoding.ASCII.GetBytes("GET ");
        static byte[] _invalidMethod7 = Encoding.ASCII.GetBytes("HEAD \0\0\0");
        static byte[] _invalidMethod8 = Encoding.ASCII.GetBytes("PATCH \0\0");
        static byte[] _invalidMethod9 = Encoding.ASCII.GetBytes("POST \0\0\0");
        static byte[] _invalidMethod10 = Encoding.ASCII.GetBytes("PUT \0\0\0\0");
        static byte[] _invalidMethod11 = Encoding.ASCII.GetBytes("OPTIONS ");
        static byte[] _invalidMethod12 = Encoding.ASCII.GetBytes("TRACE \0\0");



        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private static object[] CreateTestDataEntry(byte[] methodData, HttpMethod expectedMethod, int expectedLength, bool expectedResult)
        {
            return new object[] { methodData, expectedMethod, expectedLength, expectedResult };
        }

        private static readonly List<object[]> _testData
            = new List<object[]>
            {
                CreateTestDataEntry(_methodGet, HttpMethod.Get, 3,true),
                CreateTestDataEntry(_methodPut, HttpMethod.Put, 3,true),
                CreateTestDataEntry(_methodPost, HttpMethod.Post, 4,true),
                CreateTestDataEntry(_methodHead, HttpMethod.Head, 4,true),
                CreateTestDataEntry(_methodTrace, HttpMethod.Trace, 5,true),
                CreateTestDataEntry(_methodPatch, HttpMethod.Patch, 5,true),
                CreateTestDataEntry(_methodDelete, HttpMethod.Delete, 6,true),
                CreateTestDataEntry(_methodConnect, HttpMethod.Connect, 7,true),
                CreateTestDataEntry(_methodOptions, HttpMethod.Options, 7,true),
                CreateTestDataEntry(_invalidMethod1, HttpMethod.Custom, 0,false),
                CreateTestDataEntry(_invalidMethod2, HttpMethod.Custom, 0,false),
                CreateTestDataEntry(_invalidMethod3, HttpMethod.Custom, 0,false),
                CreateTestDataEntry(_invalidMethod4, HttpMethod.Custom, 0,false),
                CreateTestDataEntry(_invalidMethod5, HttpMethod.Custom, 0,false),
                CreateTestDataEntry(_invalidMethod6, HttpMethod.Custom, 0,false),
                CreateTestDataEntry(_invalidMethod7, HttpMethod.Custom, 0,false),
                CreateTestDataEntry(_invalidMethod8, HttpMethod.Custom, 0,false),
                CreateTestDataEntry(_invalidMethod9, HttpMethod.Custom, 0,false),
                CreateTestDataEntry(_invalidMethod10, HttpMethod.Custom, 0,false),
                CreateTestDataEntry(_invalidMethod11, HttpMethod.Custom, 0,false),
                CreateTestDataEntry(_invalidMethod12, HttpMethod.Custom, 0,false),
            };

        public static IEnumerable<object[]> TestData => _testData;


        [Theory]
        [MemberData(nameof(TestData), MemberType = typeof(KnownStringsTests))]
        public void GetsKnownMethod(byte[] methodData, HttpMethod expectedMethod, int expectedLength, bool expectedResult)
        {
            var data = new Span<byte>(methodData);

            HttpMethod method;
            int length;

            bool result = data.GetKnownMethod(out method, out length);

            Assert.Equal(expectedResult, result);
            Assert.Equal(expectedMethod, method);
            Assert.Equal(expectedLength, length);

        }
    }
}