// 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.Buffers;
using System.IO.Pipelines;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Connections.Features;
using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http3;
using Moq;
using Xunit;
 
namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests;
 
public class Http3FrameWriterTests
{
    private readonly MemoryPool<byte> _dirtyMemoryPool;
 
    public Http3FrameWriterTests()
    {
        var memoryBlock = new Mock<IMemoryOwner<byte>>();
        memoryBlock.Setup(block => block.Memory).Returns(() =>
        {
            var blockArray = new byte[4096];
            for (int i = 0; i < 4096; i++)
            {
                blockArray[i] = 0xff;
            }
            return new Memory<byte>(blockArray);
        });
 
        var dirtyMemoryPool = new Mock<MemoryPool<byte>>();
        dirtyMemoryPool.Setup(pool => pool.Rent(It.IsAny<int>())).Returns(memoryBlock.Object);
        _dirtyMemoryPool = dirtyMemoryPool.Object;
    }
 
    [Fact]
    public async Task WriteSettings_NoSettingsWrittenWithProtocolDefault()
    {
        var pipe = new Pipe(new PipeOptions(_dirtyMemoryPool, PipeScheduler.Inline, PipeScheduler.Inline));
        var frameWriter = CreateFrameWriter(pipe);
 
        var settings = new Http3PeerSettings();
        await frameWriter.WriteSettingsAsync(settings.GetNonProtocolDefaults());
 
        var payload = await pipe.Reader.ReadForLengthAsync(2);
 
        Assert.Equal(new byte[] { 0x04, 0x00 }, payload.ToArray());
    }
 
    [Fact]
    public async Task WriteSettings_OneSettingsWrittenWithKestrelDefaults()
    {
        var pipe = new Pipe(new PipeOptions(_dirtyMemoryPool, PipeScheduler.Inline, PipeScheduler.Inline));
        var frameWriter = CreateFrameWriter(pipe);
 
        var kestrelLimits = new KestrelServerLimits();
        var settings = new Http3PeerSettings();
        settings.HeaderTableSize = (uint)kestrelLimits.Http3.HeaderTableSize;
        settings.MaxRequestHeaderFieldSectionSize = (uint)kestrelLimits.MaxRequestHeadersTotalSize;
 
        await frameWriter.WriteSettingsAsync(settings.GetNonProtocolDefaults());
 
        // variable length ints make it so the results isn't know without knowing the values
        var payload = await pipe.Reader.ReadForLengthAsync(5);
 
        Assert.Equal(new byte[] { 0x04, 0x05, 0x06, 0x80, 0x00 }, payload.ToArray());
    }
 
    [Fact]
    public async Task WriteSettings_TwoSettingsWritten()
    {
        var pipe = new Pipe(new PipeOptions(_dirtyMemoryPool, PipeScheduler.Inline, PipeScheduler.Inline));
        var frameWriter = CreateFrameWriter(pipe);
 
        var settings = new Http3PeerSettings();
        settings.HeaderTableSize = 1234;
        settings.MaxRequestHeaderFieldSectionSize = 567890;
 
        await frameWriter.WriteSettingsAsync(settings.GetNonProtocolDefaults());
 
        // variable length ints make it so the results isn't know without knowing the values
        var payload = await pipe.Reader.ReadForLengthAsync(10);
 
        Assert.Equal(new byte[] { 0x04, 0x08, 0x01, 0x44, 0xD2, 0x06, 0x80, 0x08, 0xAA, 0x52 }, payload.ToArray());
    }
 
    private Http3FrameWriter CreateFrameWriter(Pipe pipe)
    {
        var frameWriter = new Http3FrameWriter(null, null, null, _dirtyMemoryPool, null, Mock.Of<IStreamIdFeature>(), new Http3PeerSettings(), null);
        frameWriter.Reset(pipe.Writer, null);
 
        return frameWriter;
    }
}