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

using System.Threading;
using System.Threading.Tasks;

namespace System.IO.Compression
{
    internal sealed class PositionPreservingWriteOnlyStreamWrapper : Stream
    {
        private readonly Stream _stream;
        private long _position;

        /// <summary>
        /// Creates a wrapper for write-only (non-readable, non-seekable) streams that keeps track of <see cref="Position"/> and allows it to be read.
        /// </summary>
        /// <param name="stream">The underlying stream, which handles all actual writes.</param>
        public PositionPreservingWriteOnlyStreamWrapper(Stream stream)
        {
            _stream = stream;
        }

        public override bool CanRead => false;
        public override bool CanSeek => false;
        public override bool CanWrite => true;

        public override long Position
        {
            get { return _position; }
            set { throw new NotSupportedException(SR.NotSupported); }
        }
        public override void Write(byte[] buffer, int offset, int count)
        {
            _position += count;
            _stream.Write(buffer, offset, count);
        }

        public override void Write(ReadOnlySpan<byte> buffer)
        {
            _position += buffer.Length;
            _stream.Write(buffer);
        }

        public override IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback? callback, object? state)
        {
            _position += count;
            return _stream.BeginWrite(buffer, offset, count, callback, state);
        }

        public override void EndWrite(IAsyncResult asyncResult) => _stream.EndWrite(asyncResult);

        public override void WriteByte(byte value)
        {
            _position += 1;
            _stream.WriteByte(value);
        }

        public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
        {
            _position += count;
            return _stream.WriteAsync(buffer, offset, count, cancellationToken);
        }

        public override ValueTask WriteAsync(ReadOnlyMemory<byte> buffer, CancellationToken cancellationToken = default(CancellationToken))
        {
            _position += buffer.Length;
            return _stream.WriteAsync(buffer, cancellationToken);
        }

        public override bool CanTimeout => _stream.CanTimeout;
        public override int ReadTimeout
        {
            get { return _stream.ReadTimeout; }
            set { _stream.ReadTimeout = value; }
        }
        public override int WriteTimeout
        {
            get { return _stream.WriteTimeout; }
            set { _stream.WriteTimeout = value; }
        }

        public override void Flush() => _stream.Flush();
        public override Task FlushAsync(CancellationToken cancellationToken) => _stream.FlushAsync(cancellationToken);

        public override void Close()
        {
            _stream.Close();
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
                _stream.Dispose();
        }

        public override ValueTask DisposeAsync() => _stream.DisposeAsync();

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

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

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

        public override int Read(byte[] buffer, int offset, int count) => throw new NotSupportedException(SR.NotSupported);

        public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken) => throw new NotSupportedException(SR.NotSupported);

        public override ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = default) => throw new NotSupportedException(SR.NotSupported);
    }
}