/**
 * @file	map_averaging.cpp
 *
 * @date Dec 11, 2013
 * @author Andrey Belomutskiy, (c) 2012-2016
 *
 * This file is part of rusEfi - see http://rusefi.com
 *
 * rusEfi is free software; you can redistribute it and/or modify it under the terms of
 * the GNU General Public License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * rusEfi is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program.
 * If not, see <http://www.gnu.org/licenses/>.
 */

#include "main.h"
#include "efilib2.h"
#include "map.h"

#if EFI_MAP_AVERAGING || defined(__DOXYGEN__)

#include "map_averaging.h"
#include "trigger_central.h"
#include "adc_inputs.h"
#include "engine_state.h"
#include "engine_configuration.h"
#include "interpolation.h"
#include "signal_executor.h"
#include "engine.h"
#include "engine_math.h"

#if EFI_SENSOR_CHART || defined(__DOXYGEN__)
#include "sensor_chart.h"
#endif /* EFI_SENSOR_CHART */

#define FAST_MAP_CHART_SKIP_FACTOR 16

static Logging *logger;
/**
 * this instance does not have a real physical pin - it's only used for engine sniffer
 */
static NamedOutputPin mapAveragingPin("map");

/**
 * Running counter of measurements per revolution
 */
static volatile int measurementsPerRevolutionCounter = 0;
/**
 * Number of measurements in previous shaft revolution
 */
static volatile int measurementsPerRevolution = 0;

/**
 * In this lock-free imlementation 'readIndex' is always pointing
 * to the consistent copy of accumulator and counter pair
 */
static int readIndex = 0;
static float accumulators[2];
static int counters[2];

/**
 * Running MAP accumulator
 */
static volatile float mapAccumulator = 0;
/**
 * Running counter of measurements to consider for averaging
 */
static volatile int mapMeasurementsCounter = 0;

/**
 * v_ for Voltage
 */
static float v_averagedMapValue;

EXTERN_ENGINE
;

static scheduling_s startTimer[INJECTION_PIN_COUNT][2];
static scheduling_s endTimer[INJECTION_PIN_COUNT][2];

/**
 * that's a performance optimization: let's not bother averaging
 * if we are outside of of the window
 */
static bool isAveraging = false;

static void startAveraging(void *arg) {
	(void) arg;
	efiAssertVoid(getRemainingStack(chThdSelf()) > 128, "lowstck#9");
	bool wasLocked = lockAnyContext();
	;
	// with locking we would have a consistent state
	mapAccumulator = 0;
	mapMeasurementsCounter = 0;
	isAveraging = true;
	if (!wasLocked)
		chSysUnlockFromIsr()
	;
	turnPinHigh(&mapAveragingPin);
}

#if EFI_PROD_CODE || defined(__DOXYGEN__)
/**
 * This method is invoked from ADC callback.
 * @note This method is invoked OFTEN, this method is a potential bottle-next - the implementation should be
 * as fast as possible
 */
void mapAveragingCallback(adcsample_t adcValue) {
	if (!isAveraging && ENGINE(sensorChartMode) != SC_MAP) {
		return;
	}

	/* Calculates the average values from the ADC samples.*/
	measurementsPerRevolutionCounter++;
	efiAssertVoid(getRemainingStack(chThdSelf()) > 128, "lowstck#9a");

#if (EFI_SENSOR_CHART && EFI_ANALOG_SENSORS) || defined(__DOXYGEN__)
	if (ENGINE(sensorChartMode) == SC_MAP) {
		if (measurementsPerRevolutionCounter % FAST_MAP_CHART_SKIP_FACTOR
				== 0) {
			float voltage = adcToVoltsDivided(adcValue);
			float currentPressure = getMapByVoltage(voltage);
			scAddData(
					getCrankshaftAngleNt(getTimeNowNt() PASS_ENGINE_PARAMETER),
					currentPressure);
		}
	}
#endif /* EFI_SENSOR_CHART */

	/**
	 * Local copy is now safe, but it's an overkill: we only
	 * have one writing thread anyway
	 */
	int readIndexLocal = readIndex;
	int writeIndex = readIndexLocal ^ 1;
	accumulators[writeIndex] = accumulators[readIndexLocal] + adcValue;
	counters[writeIndex] = counters[readIndexLocal] + 1;
	// this would commit the new pair of values
	readIndex = writeIndex;

	// todo: migrate to the lock-free implementation
	chSysLockFromIsr()
	;
	// with locking we would have a consistent state

	mapAccumulator += adcValue;
	mapMeasurementsCounter++;
	chSysUnlockFromIsr()
	;
}
#endif

static void endAveraging(void *arg) {
	(void) arg;
	bool wasLocked = lockAnyContext();
	isAveraging = false;
	// with locking we would have a consistent state
#if EFI_PROD_CODE || defined(__DOXYGEN__)
	v_averagedMapValue = adcToVoltsDivided(
			mapAccumulator / mapMeasurementsCounter);
#endif
	if (!wasLocked)
		chSysUnlockFromIsr()
	;
	turnPinLow(&mapAveragingPin);
}

/**
 * Shaft Position callback used to schedule start and end of MAP averaging
 */
static void mapAveragingCallback(trigger_event_e ckpEventType,
		uint32_t index DECLARE_ENGINE_PARAMETER_S) {
	// this callback is invoked on interrupt thread
	UNUSED(ckpEventType);
	engine->m.beforeMapAveragingCb = GET_TIMESTAMP();
	if (index != CONFIG(mapAveragingSchedulingAtIndex))
		return;

	int rpm = ENGINE(rpmCalculator.rpmValue);
	if (!isValidRpm(rpm))
		return;

	measurementsPerRevolution = measurementsPerRevolutionCounter;
	measurementsPerRevolutionCounter = 0;

	for (int i = 0; i < engineConfiguration->specs.cylindersCount; i++) {
		angle_t samplingStart = ENGINE(engineState.mapAveragingStart[i]);

		angle_t samplingDuration = ENGINE(engineState.mapAveragingDuration);
		if (samplingDuration <= 0) {
			firmwareError("map sampling angle should be positive");
			return;
		}

		angle_t samplingEnd = samplingStart + samplingDuration;
		fixAngle(samplingEnd);
		if (!cisnan(samplingEnd)) {
			// only if value is already prepared
			int structIndex = getRevolutionCounter() % 2;
			// todo: schedule this based on closest trigger event, same as ignition works
			scheduleByAngle(rpm, &startTimer[i][structIndex], samplingStart,
					startAveraging, NULL, &engine->rpmCalculator);
			scheduleByAngle(rpm, &endTimer[i][structIndex], samplingEnd,
					endAveraging, NULL, &engine->rpmCalculator);
			engine->m.mapAveragingCbTime = GET_TIMESTAMP()
					- engine->m.beforeMapAveragingCb;
		}
	}

}

static void showMapStats(void) {
	scheduleMsg(logger, "per revolution %d", measurementsPerRevolution);
}

float getMapVoltage(void) {
	return v_averagedMapValue;
}

#if EFI_PROD_CODE || defined(__DOXYGEN__)

/**
 * Because of MAP window averaging, MAP is only available while engine is spinning
 * @return Manifold Absolute Pressure, in kPa
 */
float getMap(void) {
	if (engineConfiguration->hasFrequencyReportingMapSensor) {
		return getRawMap();
	}

#if EFI_ANALOG_SENSORS || defined(__DOXYGEN__)
	if (!isValidRpm(engine->rpmCalculator.rpmValue))
		return validateMap(getRawMap()); // maybe return NaN in case of stopped engine?
	return validateMap(getMapByVoltage(v_averagedMapValue));
#else
	return 100;
#endif
}
#endif /* EFI_PROD_CODE */

void initMapAveraging(Logging *sharedLogger, Engine *engine) {
	logger = sharedLogger;

//	startTimer[0].name = "map start0";
//	startTimer[1].name = "map start1";
//	endTimer[0].name = "map end0";
//	endTimer[1].name = "map end1";

	addTriggerEventListener(&mapAveragingCallback, "MAP averaging", engine);
	addConsoleAction("faststat", showMapStats);
}

#else

#if EFI_PROD_CODE || defined(__DOXYGEN__)

float getMap(void) {
#if EFI_ANALOG_SENSORS || defined(__DOXYGEN__)
	return getRawMap();
#else
	return NAN;
#endif /* EFI_ANALOG_SENSORS */
}
#endif /* EFI_PROD_CODE */

#endif /* EFI_MAP_AVERAGING */