using System;

namespace ScreenConnect;

public class YuvDecoder : YuvCodecBase<IMultiCallCoder>
{
	public YuvDecoder(int streamCount, Func<int, IMultiCallCoder> coderCreatorFunc)
		: base(streamCount, coderCreatorFunc)
	{
	}

	protected unsafe override void Process(byte* data, int width, int height, int stride, int lumaSize, int chromaSize, int yuvSize, byte* yuvPointer)
	{
		byte* ptr = yuvPointer;
		byte* ptr2 = ptr + lumaSize;
		byte* outputData = ptr2 + chromaSize;
		switch (base.StreamCount)
		{
		case 1:
			ReadThroughCoder(base.Coders[0], yuvPointer, yuvSize, isEndOfBlock: true);
			break;
		case 2:
			ReadThroughCoder(base.Coders[0], ptr, lumaSize, isEndOfBlock: true);
			ReadThroughCoder(base.Coders[1], ptr2, chromaSize * 2, isEndOfBlock: true);
			break;
		case 3:
			ReadThroughCoder(base.Coders[0], ptr, lumaSize, isEndOfBlock: true);
			ReadThroughCoder(base.Coders[1], ptr2, chromaSize, isEndOfBlock: true);
			ReadThroughCoder(base.Coders[2], outputData, chromaSize, isEndOfBlock: true);
			break;
		default:
			throw new ArgumentOutOfRangeException();
		}
		byte* ptr3 = data;
		for (int i = 0; i < height; i++)
		{
			byte* ptr4 = ptr3;
			for (int j = 0; j < width; j++)
			{
				int num = 4096 * *(ptr++);
				int num2 = *(ptr2++) - 128;
				int num3 = *(outputData++) - 128;
				*(ptr4++) = Clamp(num + 7258 * num2 + 2048 >> 12);
				*(ptr4++) = Clamp(num - 1410 * num2 - 2925 * num3 + 2048 >> 12);
				*(ptr4++) = Clamp(num + 5743 * num3 + 2048 >> 12);
				*(ptr4++) = byte.MaxValue;
			}
			ptr3 += stride;
		}
	}

	protected static byte Clamp(int v)
	{
		return (byte)(((v & -256) == 0) ? ((uint)v) : ((v >= 0) ? 255u : 0u));
	}
}