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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 "PkPkMeasurement.h"

using namespace std;

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

PkPkMeasurement::PkPkMeasurement(const string& color)
	: Filter(color, CAT_MEASUREMENT)
{
	AddStream(Unit(Unit::UNIT_VOLTS), "trend", Stream::STREAM_TYPE_ANALOG);
	AddStream(Unit(Unit::UNIT_VOLTS), "minmax", Stream::STREAM_TYPE_ANALOG_SCALAR);

	CreateInput("din");
}

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

bool PkPkMeasurement::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 PkPkMeasurement::GetProtocolName()
{
	return "Peak-To-Peak";
}

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

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

	//Get the input data
	auto din = GetInputWaveform(0);
	din->PrepareForCpuAccess();
	size_t len = din->size();

	auto sdin = dynamic_cast<SparseAnalogWaveform*>(din);
	auto udin = dynamic_cast<UniformAnalogWaveform*>(din);

	//Copy Y axis units from input
	SetYAxisUnits(m_inputs[0].GetYAxisUnits(), 0);
	SetYAxisUnits(m_inputs[0].GetYAxisUnits(), 1);

	//Figure out the nominal midpoint of the waveform
	float top = GetTopVoltage(sdin, udin);
	float base = GetBaseVoltage(sdin, udin);
	float midpoint = (top+base)/2;

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

	int64_t		tmin		= 0;
	float		vmin		= FLT_MAX;
	float		vmax		= -FLT_MAX;
	float		last_max	= -FLT_MAX;

	float global_min = FLT_MAX;
	float global_max = -FLT_MAX;

	//For each cycle, find the min and max
	bool		last_was_low	= true;
	bool		first			= true;
	for(size_t i=0; i < len; i++)
	{
		float v = GetValue(sdin, udin, i);
		global_min = min(v, global_min);
		global_max = max(v, global_max);

		//If we're above the midpoint, reset everything and add a new sample
		if(v > midpoint)
		{
			last_was_low = false;

			//Add a sample for the current value (if any)
			if( (tmin > 0) && (last_max > -FLT_MAX/2) )
			{
				//Update duration of the previous sample
				size_t off = cap->size();
				if(off > 0)
					cap->m_durations[off-1] = tmin - cap->m_offsets[off-1];

				float value = last_max - vmin;

				//Add the new sample
				//Discard the first cycle as it might be incomplete
				if(first)
					first = false;
				else
				{
					cap->m_offsets.push_back(tmin);
					cap->m_durations.push_back(0);
					cap->m_samples.push_back(value);
				}
			}

			//Reset
			tmin = 0;
			vmin = FLT_MAX;

			//Accumulate
			vmax = max(vmax, v);
		}

		//Accumulate the lowest peak of this cycle
		//and save it
		else
		{
			if(!last_was_low)
			{
				last_max = vmax;
				vmax = -FLT_MAX;
				last_was_low = true;
			}

			if(v < vmin)
			{
				tmin = ::GetOffset(sdin, udin, i);
				vmin = v;
			}
		}
	}

	SetData(cap, 0);
	cap->MarkModifiedFromCpu();

	m_streams[1].m_value = global_max - global_min;
}
