#include <assert.h>
#include "VideoStream_ReadMotionVectors.h"
#include "MpegVideoState.h"
#include "MPEG2/MotionCodeTable.h"

using namespace VideoStream;

ReadMotionVectors::ReadMotionVectors()
    : m_hrSize(0)
    , m_vrSize(0)
    , m_motionVector(nullptr)
{
}

ReadMotionVectors::~ReadMotionVectors()
{
}

void ReadMotionVectors::SetRSizes(uint8 hsize, uint8 vsize)
{
	m_hrSize = hsize;
	m_vrSize = vsize;
	m_motionVectorReader.SetRSizes(hsize, vsize);
}

void ReadMotionVectors::SetMotionVector(int16* motionVector)
{
	m_motionVector = motionVector;
}

void ReadMotionVectors::Reset()
{
	m_programState = STATE_INIT;
}

void ReadMotionVectors::Execute(void* context, Framework::CBitStream& stream)
{
	MPEG_VIDEO_STATE* state(reinterpret_cast<MPEG_VIDEO_STATE*>(context));
	PICTURE_HEADER& pictureHeader(state->pictureHeader);
	BLOCK_DECODER_STATE& decoderState(state->blockDecoderState);

	while(1)
	{
		switch(m_programState)
		{
		case STATE_INIT:
			goto Label_Init;
		case STATE_SINGLE_READVECTOR:
			goto Label_Single_ReadVector;
		case STATE_DOUBLE_FIRST_READFIELDSELECT:
			goto Label_Double_First_ReadFieldSelect;
		case STATE_DOUBLE_FIRST_READVECTOR:
			goto Label_Double_First_ReadVector;
		case STATE_DOUBLE_SECOND_READFIELDSELECT:
			goto Label_Double_Second_ReadFieldSelect;
		case STATE_DOUBLE_SECOND_READVECTOR:
			goto Label_Double_Second_ReadVector;
		case STATE_DONE:
			goto Label_Done;
		default:
			assert(0);
		}

	Label_Init:
		if(decoderState.motionVectorCount == 1)
		{
			m_motionVectorReader.Reset();
			m_programState = STATE_SINGLE_READVECTOR;
		}
		else
		{
			m_programState = STATE_DOUBLE_FIRST_READFIELDSELECT;
		}
		continue;

	Label_Single_ReadVector:
		m_motionVectorReader.Execute(context, stream);
		m_motionVector[0] = ReadMotionVector::ComputeMotionVector(m_motionVector[0], decoderState.motionCode[0], decoderState.motionResidual[0], m_hrSize);
		m_motionVector[1] = ReadMotionVector::ComputeMotionVector(m_motionVector[1], decoderState.motionCode[1], decoderState.motionResidual[1], m_vrSize);
		m_programState = STATE_DONE;
		continue;

	Label_Double_First_ReadFieldSelect:
	{
		uint8 fieldSelect = static_cast<uint8>(stream.GetBits_MSBF(1));
		m_motionVectorReader.Reset();
		m_programState = STATE_DOUBLE_FIRST_READVECTOR;
	}
		continue;

	Label_Double_First_ReadVector:
		m_motionVectorReader.Execute(context, stream);
		m_programState = STATE_DOUBLE_SECOND_READFIELDSELECT;
		continue;

	Label_Double_Second_ReadFieldSelect:
	{
		uint8 fieldSelect = static_cast<uint8>(stream.GetBits_MSBF(1));
		m_motionVectorReader.Reset();
		m_programState = STATE_DOUBLE_SECOND_READVECTOR;
	}
		continue;

	Label_Double_Second_ReadVector:
		m_motionVectorReader.Execute(context, stream);
		m_programState = STATE_DONE;
		continue;

	Label_Done:
		return;
	}
}