using System;

using System.IO;

using System.Threading;

using System.Threading.Tasks;

using Microsoft.AspNetCore.Http.Features;

namespace Blog.Core.Common.Https;

/// <summary>

/// 扩展 HttpResponseStream <br/>

/// 原始[HttpResponseStream]实际上只是个包装类,内部包装了[HttpResponsePipeWriter]来进行写入响应数据

/// </summary>

public class FluentHttpResponseStream : Stream

{

private readonly IHttpBodyControlFeature _bodyControl;

private readonly IHttpResponseBodyFeature _pipeWriter;

private readonly MemoryStream _stream = new();

public FluentHttpResponseStream(IHttpResponseBodyFeature pipeWriter, IHttpBodyControlFeature bodyControl)

{

_pipeWriter = pipeWriter;

_bodyControl = bodyControl;

}

public override bool CanRead => _stream.CanRead;

public override bool CanSeek => _stream.CanSeek;

public override bool CanWrite => _stream.CanWrite;

public override long Length => _stream.Length;

public override long Position { get => _stream.Position; set => _stream.Position = value; }

public override void Flush()

{

if (!_bodyControl.AllowSynchronousIO)

{

throw new InvalidOperationException("SynchronousWritesDisallowed ");

}

_stream.Flush();

}

public override int Read(byte[] buffer, int offset, int count)

{

return _stream.Read(buffer, offset, count);

}

public override long Seek(long offset, SeekOrigin origin)

{

return _stream.Seek(offset, origin);

}

public override void SetLength(long value)

{

_stream.SetLength(value);

}

public override void Write(byte[] buffer, int offset, int count)

{

WriteAsync(buffer, offset, count, default).GetAwaiter().GetResult();

}

public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)

{

_stream.Write(buffer, offset, count);

return _pipeWriter.Writer.WriteAsync(new ReadOnlyMemory<byte>(buffer, offset, count), cancellationToken).AsTask();

}

protected override void Dispose(bool disposing)

{

_stream.Dispose();

base.Dispose(disposing);

}

}