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* libscopeprotocols                                                                                                    *
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* Copyright (c) 2012-2022 Andrew D. Zonenberg and contributors                                                         *
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#include "../scopehal/scopehal.h"
#include "AutocorrelationFilter.h"

using namespace std;

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Construction / destruction

AutocorrelationFilter::AutocorrelationFilter(const string& color)
	: Filter(color, CAT_MATH)
{
	AddStream(Unit(Unit::UNIT_VOLTS), "data", Stream::STREAM_TYPE_ANALOG);
	CreateInput("din");

	m_maxDeltaName = "Max offset";
	m_parameters[m_maxDeltaName] = FilterParameter(FilterParameter::TYPE_INT, Unit(Unit::UNIT_SAMPLEDEPTH));
	m_parameters[m_maxDeltaName].SetIntVal(1000);
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Factory methods

bool AutocorrelationFilter::ValidateChannel(size_t i, StreamDescriptor stream)
{
	if(stream.m_channel == NULL)
		return false;

	if( (i == 0) && (stream.GetType() == Stream::STREAM_TYPE_ANALOG) )
		return true;

	return false;
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Accessors

string AutocorrelationFilter::GetProtocolName()
{
	return "Autocorrelation";
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Actual decoder logic

void AutocorrelationFilter::Refresh()
{
	if(!VerifyAllInputsOKAndUniformAnalog())
	{
		SetData(NULL, 0);
		return;
	}

	auto din = dynamic_cast<UniformAnalogWaveform*>(GetInputWaveform(0));
	auto len = din->size();

	//Copy the units
	SetYAxisUnits(m_inputs[0].m_channel->GetYAxisUnits(0), 0);

	//Sanity check range
	size_t range = m_parameters[m_maxDeltaName].GetIntVal();
	if( len <= range)
	{
		SetData(NULL, 0);
		return;
	}

	//Set up the output waveform
	auto cap = SetupEmptyUniformAnalogOutputWaveform(din, 0, true);
	cap->PrepareForCpuAccess();
	din->PrepareForCpuAccess();

	size_t end = len - range;
	for(size_t delta=1; delta <= range; delta ++)
	{
		double total = 0;
		for(size_t i=0; i<end; i++)
			total += din->m_samples[i] * din->m_samples[i+delta];

		cap->m_samples.push_back(total / end);
	}

	cap->MarkSamplesModifiedFromCpu();
	SetData(cap, 0);
}
