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* libscopeprotocols                                                                                                    *
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* Copyright (c) 2012-2023 Andrew D. Zonenberg and contributors                                                         *
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#include "../scopehal/scopehal.h"
#include "PeriodMeasurement.h"

using namespace std;

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

PeriodMeasurement::PeriodMeasurement(const string& color)
	: Filter(color, CAT_MEASUREMENT)
{
	AddStream(Unit(Unit::UNIT_FS), "trend", Stream::STREAM_TYPE_ANALOG);
	AddStream(Unit(Unit::UNIT_FS), "avg", Stream::STREAM_TYPE_ANALOG_SCALAR);

	//Set up channels
	CreateInput("din");
}

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

bool PeriodMeasurement::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 PeriodMeasurement::GetProtocolName()
{
	return "Period";
}

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

void PeriodMeasurement::Refresh()
{
	//Make sure we've got valid inputs
	if(!VerifyAllInputsOK())
	{
		SetData(NULL, 0);
		return;
	}

	auto din = GetInputWaveform(0);
	din->PrepareForCpuAccess();
	auto uadin = dynamic_cast<UniformAnalogWaveform*>(din);
	auto sadin = dynamic_cast<SparseAnalogWaveform*>(din);
	auto uddin = dynamic_cast<UniformDigitalWaveform*>(din);
	auto sddin = dynamic_cast<SparseDigitalWaveform*>(din);
	vector<int64_t> edges;

	//Auto-threshold analog signals at 50% of full scale range
	if(uadin)
		FindZeroCrossings(uadin, GetAvgVoltage(uadin), edges);
	else if(sadin)
		FindZeroCrossings(sadin, GetAvgVoltage(sadin), edges);

	//Just find edges in digital signals
	else if(uddin)
		FindZeroCrossings(uddin, edges);
	else
		FindZeroCrossings(sddin, edges);

	//We need at least one full cycle of the waveform to have a meaningful frequency
	if(edges.size() < 2)
	{
		SetData(NULL, 0);
		return;
	}

	//Create the output
	auto cap = SetupEmptySparseAnalogOutputWaveform(din, 0, true);
	cap->m_timescale = 1;
	cap->PrepareForCpuAccess();

	size_t elen = edges.size();
	for(size_t i=0; i < (elen - 2); i+= 2)
	{
		//measure from edge to 2 edges later, since we find all zero crossings regardless of polarity
		int64_t start = edges[i];
		int64_t end = edges[i+2];

		int64_t delta = end - start;

		cap->m_offsets.push_back(start);
		cap->m_durations.push_back(round(delta));
		cap->m_samples.push_back(delta);
	}

	SetData(cap, 0);

	cap->MarkModifiedFromCpu();

	//For the scalar average output, find the total number of zero crossings and divide by the spacing
	//(excluding partial cycles at start and end).
	//This gives us twice our frequency (since we count both zero crossings) so divide by two again
	double ncycles = (elen - 1) / 2;
	double interval = edges[elen-1] - edges[0];
	m_streams[1].m_value = interval / ncycles;
}
