#include "pch.h"

#include "injector_model.h"
#include "fuel_computer.h"

void InjectorModelBase::prepare() {
	m_massFlowRate = getInjectorMassFlowRate();
	float deadtime = getDeadtime();
	m_deadtime = deadtime;

	postState(deadtime);
}

constexpr float convertToGramsPerSecond(float ccPerMinute) {
	return ccPerMinute * (fuelDensity / 60.f);
}

expected<float> InjectorModel::getAbsoluteRailPressure() const {
	switch (engineConfiguration->injectorCompensationMode) {
		case ICM_FixedRailPressure:
			// Add barometric pressure, as "fixed" really means "fixed pressure above atmosphere"
			return engineConfiguration->fuelReferencePressure + Sensor::get(SensorType::BarometricPressure).value_or(101.325f);
		case ICM_SensedRailPressure:
			if (!Sensor::hasSensor(SensorType::FuelPressureInjector)) {
				firmwareError(OBD_PCM_Processor_Fault, "Fuel pressure compensation is set to use a pressure sensor, but none is configured.");
				return unexpected;
			}

			// TODO: what happens when the sensor fails?
			return Sensor::get(SensorType::FuelPressureInjector);
		default: return unexpected;
	}
}

float InjectorModel::getInjectorFlowRatio() {
	// Compensation disabled, use reference flow.
	if (engineConfiguration->injectorCompensationMode == ICM_None) {
		return 1.0f;
	}

	float referencePressure = engineConfiguration->fuelReferencePressure;
	expected<float> absRailPressure = getAbsoluteRailPressure();

	// If sensor failed, best we can do is disable correction
	if (!absRailPressure) {
		return 1.0f;
	}

	auto map = Sensor::get(SensorType::Map);

	// Map has failed, assume nominal pressure
	if (!map) {
		return 1.0f;
	}

	pressureDelta = absRailPressure.Value - map.Value;

	// Somehow pressure delta is less than 0, assume failed sensor and return default flow
	if (pressureDelta <= 0) {
		return 1.0f;
	}

	pressureRatio = pressureDelta / referencePressure;
	// todo: live data model?
	float flowRatio = sqrtf(pressureRatio);

#if EFI_TUNER_STUDIO
	engine->outputChannels.injectorFlowPressureDelta = pressureDelta;
	engine->outputChannels.injectorFlowPressureRatio = pressureRatio;
#endif // EFI_TUNER_STUDIO

	// TODO: should the flow ratio be clamped?
	return flowRatio;
}

float InjectorModel::getInjectorMassFlowRate() {
	// TODO: injector flow dependent upon temperature/ethanol content?
	auto injectorVolumeFlow = engineConfiguration->injector.flow;

	float flowRatio = getInjectorFlowRatio();

	return flowRatio * convertToGramsPerSecond(injectorVolumeFlow);
}

float InjectorModel::getDeadtime() const {
	return interpolate2d(
		Sensor::get(SensorType::BatteryVoltage).value_or(VBAT_FALLBACK_VALUE),
		engineConfiguration->injector.battLagCorrBins,
		engineConfiguration->injector.battLagCorr
	);
}

void InjectorModel::postState(float deadtime) const {
	engine->engineState.running.injectorLag = deadtime;
}

float InjectorModelBase::getInjectionDuration(float fuelMassGram) const {
	// TODO: support injector nonlinearity correction

	floatms_t baseDuration = fuelMassGram / m_massFlowRate * 1000;

	if (baseDuration <= 0) {
		// If 0 duration, don't correct or add deadtime, just skip the injection.
		return 0.0f;
	}

	// Correct short pulses (if enabled)
	baseDuration = correctShortPulse(baseDuration);

	return baseDuration + m_deadtime;
}

float InjectorModelBase::getFuelMassForDuration(floatms_t duration) const {
	// Convert from ms -> grams
	return duration * m_massFlowRate * 0.001f;
}

float InjectorModel::correctShortPulse(float baseDuration) const {
	switch (engineConfiguration->injectorNonlinearMode) {
	case INJ_PolynomialAdder:
		return correctInjectionPolynomial(baseDuration);
	case INJ_None:
	default:
		return baseDuration;
	}
}

float InjectorModel::correctInjectionPolynomial(float baseDuration) const {
	if (baseDuration > USF2MS(engineConfiguration->applyNonlinearBelowPulse)) {
		// Large pulse, skip correction.
		return baseDuration;
	}

	auto& is = engineConfiguration->injectorCorrectionPolynomial;
	float xi = 1;

	float adder = 0;

	// Add polynomial terms, starting with x^0
	for (size_t i = 0; i < efi::size(is); i++) {
		adder += is[i] * xi;
		xi *= baseDuration;
	}

	return baseDuration + adder;
}