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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 "TDRFilter.h"

using namespace std;

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

TDRFilter::TDRFilter(const string& color)
	: Filter(color, CAT_ANALYSIS)
{
	AddStream(Unit(Unit::UNIT_VOLTS), "data", Stream::STREAM_TYPE_ANALOG);
	CreateInput("voltage");

	m_modeName = "Output Format";
	m_parameters[m_modeName] = FilterParameter(FilterParameter::TYPE_ENUM, Unit(Unit::UNIT_COUNTS));
	m_parameters[m_modeName].AddEnumValue("Reflection coefficient", MODE_RHO);
	m_parameters[m_modeName].AddEnumValue("Impedance", MODE_IMPEDANCE);
	m_parameters[m_modeName].SetIntVal(MODE_IMPEDANCE);

	m_portImpedanceName = "Port impedance";
	m_parameters[m_portImpedanceName] = FilterParameter(FilterParameter::TYPE_FLOAT, Unit(Unit::UNIT_OHMS));
	m_parameters[m_portImpedanceName].SetFloatVal(50);

	m_stepStartVoltageName = "Step start";
	m_parameters[m_stepStartVoltageName] = FilterParameter(FilterParameter::TYPE_FLOAT, Unit(Unit::UNIT_VOLTS));
	m_parameters[m_stepStartVoltageName].SetFloatVal(0);

	m_stepEndVoltageName = "Step end";
	m_parameters[m_stepEndVoltageName] = FilterParameter(FilterParameter::TYPE_FLOAT, Unit(Unit::UNIT_VOLTS));
	m_parameters[m_stepEndVoltageName].SetFloatVal(1);

	m_oldMode = MODE_IMPEDANCE;
}

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

bool TDRFilter::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 TDRFilter::GetProtocolName()
{
	return "TDR";
}

void TDRFilter::SetDefaultName()
{
	char hwname[256];
	if(m_parameters[m_modeName].GetIntVal() == MODE_IMPEDANCE)
		snprintf(hwname, sizeof(hwname), "TDRImpedance(%s)", GetInputDisplayName(0).c_str());
	else
		snprintf(hwname, sizeof(hwname), "TDRReflection(%s)", GetInputDisplayName(0).c_str());

	m_hwname = hwname;
	m_displayname = m_hwname;
}

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

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

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

	//Extract parameters
	auto mode = static_cast<OutputMode>(m_parameters[m_modeName].GetIntVal());
	auto z0 = m_parameters[m_portImpedanceName].GetFloatVal();
	auto vlo = m_parameters[m_stepStartVoltageName].GetFloatVal();
	auto vhi = m_parameters[m_stepEndVoltageName].GetFloatVal();
	auto pulseAmplitude = (vhi - vlo);

	//Set up units
	if(mode == MODE_IMPEDANCE)
		SetYAxisUnits(Unit(Unit::UNIT_OHMS), 0);
	else
		SetYAxisUnits(Unit(Unit::UNIT_RHO), 0);

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

	float pulseScale = 1.0 / pulseAmplitude;
	for(size_t i=0; i<len; i++)
	{
		//Reflection coefficient is trivial
		float rho = (din->m_samples[i] - vhi) * pulseScale;

		//Impedance takes a bit more work to calculate
		if(mode == MODE_IMPEDANCE)
			cap->m_samples[i] = z0 * (1 + rho)/(1 - rho);

		else
			cap->m_samples[i] = rho;
	}

	//Reset gain/offset if output mode was changed
	if(mode != m_oldMode)
	{
		AutoscaleVertical(0);
		m_oldMode = mode;
	}

	cap->MarkModifiedFromCpu();
}
