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* libscopeprotocols                                                                                                    *
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* Copyright (c) 2012-2024 Andrew D. Zonenberg and contributors                                                         *
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#include "../scopehal/scopehal.h"
#include "BaseMeasurement.h"

using namespace std;

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

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

	CreateInput("din");
}

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

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

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

	return false;
}

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

string BaseMeasurement::GetProtocolName()
{
	return "Base";
}

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

void BaseMeasurement::Refresh()
{
	//Set up input
	auto in = GetInput(0).GetData();
	auto uin = dynamic_cast<UniformAnalogWaveform*>(in);
	auto sin = dynamic_cast<SparseAnalogWaveform*>(in);
	if(!uin && !sin)
	{
		SetData(nullptr, 0);
		return;
	}
	size_t len = in->size();
	PrepareForCpuAccess(sin, uin);

	//Copy input unit to output
	SetYAxisUnits(m_inputs[0].GetYAxisUnits(), 0);
	SetYAxisUnits(m_inputs[0].GetYAxisUnits(), 1);

	//Make a histogram of the waveform
	float vmin = GetMinVoltage(sin, uin);
	float vmax = GetMaxVoltage(sin, uin);
	size_t nbins = 64;
	vector<size_t> hist = MakeHistogram(sin, uin, vmin, vmax, nbins);

	//Set temporary midpoint and range
	float range = (vmax - vmin);
	float mid = range/2 + vmin;

	//Find the highest peak in the first quarter of the histogram
	//This is the base for the entire waveform
	size_t binval = 0;
	size_t idx = 0;
	for(size_t i=0; i<(nbins/4); i++)
	{
		if(hist[i] > binval)
		{
			binval = hist[i];
			idx = i;
		}
	}
	float fbin = (idx + 0.5f)/nbins;
	float global_base = fbin*range + vmin;

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

	float last = vmin;
	int64_t tfall = 0;
	float delta = range * 0.1;

	float fmax = -FLT_MAX;
	float fmin =  FLT_MAX;

	bool first = true;

	vector<float> samples;

	for(size_t i=0; i < len; i++)
	{
		//Wait for a rising edge (end of the low period)
		auto cur = GetValue(sin, uin, i);
		auto tnow = GetOffsetScaled(sin, uin, i);

		//Find falling edge
		if( (cur < mid) && (last >= mid) )
			tfall = tnow;

		//Find rising edge
		if( (cur > mid) && (last <= mid) )
		{
			//Done, add the sample
			if(!samples.empty())
			{
				if(first)
					first = false;

				else
				{
					//Average the middle 50% of the samples.
					//Discard beginning and end as they include parts of the edge
					float sum = 0;
					int64_t count = 0;
					size_t start = samples.size()/4;
					size_t end = samples.size() - start;
					for(size_t j=start; j<=end; j++)
					{
						sum += samples[j];
						count ++;
					}

					float vavg = sum / count;

					fmax = max(fmax, vavg);
					fmin = min(fmin, vavg);

					int64_t tmid = (tnow + tfall) / 2;

					//Update duration for last sample
					size_t n = cap->m_samples.size();
					if(n)
						cap->m_durations[n-1] = tmid - cap->m_offsets[n-1];

					cap->m_offsets.push_back(tmid);
					cap->m_durations.push_back(1);
					cap->m_samples.push_back(vavg);
				}

				samples.clear();
			}
		}

		//If the value is fairly close to the calculated base, average it
		if(fabs(cur - global_base) < delta)
			samples.push_back(cur);

		last = cur;
	}

	cap->MarkModifiedFromCpu();

	//Compute average
	double sum = 0;
	for(auto f : samples)
		sum += f;
	m_streams[1].m_value = sum / samples.size();
}
