// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics;
using System.IO;
using System.Runtime.CompilerServices;
using System.Threading;
using System.Threading.Tasks;

namespace System.Net
{
    internal sealed class RequestStream : Stream
    {
        private bool _disposed;
        private readonly TaskCompletionSource _completeTcs;
        private readonly Stream _internalStream;

        public RequestStream(Stream internalStream, TaskCompletionSource completeTcs)
        {
            _internalStream = internalStream;
            _completeTcs = completeTcs;
        }

        public override bool CanRead
        {
            get
            {
                return false;
            }
        }

        public override bool CanSeek
        {
            get
            {
                return false;
            }
        }

        public override bool CanWrite
        {
            get
            {
                return true;
            }
        }

        public override void Flush()
        {
            ThrowIfDisposed();
            _internalStream.Flush();
        }

        public override Task FlushAsync(CancellationToken cancellationToken)
        {
            ThrowIfDisposed();
            return _internalStream.FlushAsync(cancellationToken);
        }

        public override long Length
        {
            get
            {
                throw new NotSupportedException();
            }
        }

        public override long Position
        {
            get
            {
                throw new NotSupportedException();
            }
            set
            {
                throw new NotSupportedException();
            }
        }

        public override int Read(byte[] buffer, int offset, int count)
        {
            throw new NotSupportedException();
        }

        public override long Seek(long offset, SeekOrigin origin)
        {
            throw new NotSupportedException();
        }

        public override void SetLength(long value)
        {
            throw new NotSupportedException();
        }

        public override void Write(byte[] buffer, int offset, int count)
        {
            ThrowIfDisposed();
            ValidateBufferArguments(buffer, offset, count);
            _internalStream.Write(new(buffer, offset, count));
        }

        public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
        {
            ThrowIfDisposed();
            ValidateBufferArguments(buffer, offset, count);
            return _internalStream.WriteAsync(buffer.AsMemory(offset, count), cancellationToken).AsTask();
        }

        public override ValueTask WriteAsync(ReadOnlyMemory<byte> buffer, CancellationToken cancellationToken = default)
        {
            ThrowIfDisposed();
            return _internalStream.WriteAsync(buffer, cancellationToken);
        }

        public override IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback? asyncCallback, object? asyncState)
        {
            ThrowIfDisposed();
            ValidateBufferArguments(buffer, offset, count);
            return _internalStream.BeginWrite(buffer, offset, count, asyncCallback, asyncState);
        }

        public void Complete()
        {
            _completeTcs.TrySetResult();
        }

        public override void EndWrite(IAsyncResult asyncResult)
        {
            ThrowIfDisposed();
            _internalStream.EndWrite(asyncResult);
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing && !_disposed)
            {
                _disposed = true;
            }
            _internalStream.Flush();
            Complete();
            base.Dispose(disposing);
        }

        public override async ValueTask DisposeAsync()
        {
            if (!_disposed)
            {
                _disposed = true;
            }
            await _internalStream.FlushAsync().ConfigureAwait(false);
            Complete();
            await base.DisposeAsync().ConfigureAwait(false);
        }

        private void ThrowIfDisposed()
        {
            ObjectDisposedException.ThrowIf(_disposed, this);
        }
    }
}