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

namespace Xtremegaida.DataStructures;

public class DataQueueWriteStream : Stream
{
	private readonly IDataQueueWriter owner;
	private readonly bool keepWriterOpen;

	public override bool CanRead => false;
	public override bool CanSeek => false;
	public override bool CanWrite => true;
	public override long Length => owner.TotalBytesWritten;
	public override long Position { get => owner.TotalBytesWritten; set => throw new NotSupportedException(); }

	public DataQueueWriteStream(IDataQueueWriter owner, bool keepWriterOpen = false)
	{
		this.owner = owner;
		this.keepWriterOpen = keepWriterOpen;
	}

	public override void Flush() { }
	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)
	{
		var task = owner.WriteAsync(new ReadOnlyMemory<byte>(buffer, offset, count));
		if (task.IsCompletedSuccessfully) { return; }
		task.AsTask().Wait();
	}

	public override void WriteByte(byte value)
	{
		var task = owner.WriteByteAsync(value);
		if (task.IsCompletedSuccessfully) { return; }
		task.AsTask().Wait();
	}

	public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
	{
		var task = owner.WriteAsync(new ReadOnlyMemory<byte>(buffer, offset, count), cancellationToken);
		if (task.IsCompletedSuccessfully) { return Task.CompletedTask; }
		return task.AsTask();
	}

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

	public override void Close()
	{
		if (!keepWriterOpen) { owner.CloseWrite(); }
	}
}