using System;
using System.Threading;
using System.Threading.Tasks;
using Xtremegaida.DataStructures;

namespace MediaContainers.Matroska;

public static class XiphLacingSize
{
	public static async ValueTask<int> Read(IDataQueueReader reader, CancellationToken cancellationToken = default)
	{
		int size = 0;
		do
		{
			var val = await reader.ReadByteAsync(cancellationToken);
			if (val < 0) { return size; }
			if (val < 255) { return size + val; }
			size += 255;
		}
		while (true);
	}

	public static int Read(DataBuffer buffer)
	{
		int size = 0;
		do
		{
			if (buffer.ReadOffset >= buffer.WriteOffset) { return -1; }
			var val = buffer.Buffer[buffer.ReadOffset++];
			if (val < 0) { return size; }
			if (val < 255) { return size + val; }
			size += 255;
		}
		while (true);
	}

	public static async ValueTask Write(IDataQueueWriter writer, int value, CancellationToken cancellationToken = default)
	{
		if (value < 0) { throw new ArgumentOutOfRangeException(nameof(value)); }
		while (value >= 255) { value -= 255; await writer.WriteByteAsync(255, cancellationToken); }
		await writer.WriteByteAsync((byte)value, cancellationToken);
	}

	public static void Write(DataBuffer buffer, int value)
	{
		if (value < 0) { throw new ArgumentOutOfRangeException(nameof(value)); }
		while (value >= 255) { value -= 255; buffer.Buffer[buffer.WriteOffset++] = 255; }
		buffer.Buffer[buffer.WriteOffset++] = (byte)value;
	}
}