#ifndef INDOOR_IMU_COMPASSDETECTION_H
#define INDOOR_IMU_COMPASSDETECTION_H

#include "MagnetometerData.h"
#include "PoseDetection.h"

#include "../../data/Timestamp.h"
#include "../../math/MovingAverageTS.h"
#include "../../math/MovingStdDevTS.h"
#include "../../geo/Point3.h"
#include "../../Assertions.h"

#include "CompassDetectionPlot.h"

#include <cmath>
#include <vector>


/**
 * custom compass implementation, similar to turn-detection
 */
class CompassDetection {

private:

	#ifdef WITH_DEBUG_PLOT
		CompassDetectionPlot plot;
	#endif

//	struct {
//		Eigen::Matrix3f rotationMatrix = Eigen::Matrix3f::Identity();
//		bool isKnown = false;
//		Timestamp lastEstimation;
//	} orientation;

	MovingAverageTS<MagnetometerData> avgIn = MovingAverageTS<MagnetometerData>(Timestamp::fromMS(150), MagnetometerData(0,0,0));

	//MovingStdDevTS<MagnetometerData> stdDev = MovingStdDevTS<MagnetometerData>(Timestamp::fromMS(2000), MagnetometerData(0,0,0));
	MovingStdDevTS<float> stdDev = MovingStdDevTS<float>(Timestamp::fromMS(1500), 0);

	PoseDetection* pose = nullptr;
	int numMagReadings = 0;

public:

	/** ctor */
	CompassDetection(PoseDetection* pose) : pose(pose) {
		;
	}

	/** add magnetometer readings, returns the current heading, or NAN (if unstable/unknown) */
	float addMagnetometer(const Timestamp& ts, const MagnetometerData& mag) {

		++numMagReadings;

		// get the current magnetometer-reading as vector
		//Eigen::Vector3f vec; vec << mag.x, mag.y, mag.z;
		const Vector3 vec(mag.x, mag.y, mag.z);

		// rotate it into our desired coordinate system, where the smartphone lies flat on the ground
		//Eigen::Vector3f _curMag = pose->getMatrix() * vec;
		const Vector3 _curMag = pose->getMatrix() * vec;

		//avgIn.add(ts, MagnetometerData(_curMag(0), _curMag(1), _curMag(2)));
		avgIn.add(ts, MagnetometerData(_curMag.x, _curMag.y, _curMag.z));
		const MagnetometerData curMag = avgIn.get();
		//const MagnetometerData curMag =MagnetometerData(_curMag.x, _curMag.y, _curMag.z);

		// calculate standard-deviation
		//stdDev.add(ts, curMag);
		//const float dev = std::max(stdDev.get().x, stdDev.get().y);


		// calculate angle
		// https://aerocontent.honeywell.com/aero/common/documents/myaerospacecatalog-documents/Defense_Brochures-documents/Magnetic__Literature_Application_notes-documents/AN203_Compass_Heading_Using_Magnetometers.pdf
		const float mx = curMag.x;
		const float my = curMag.y;
		const float tmp = std::atan2(my, mx);
		//const float tmp = (my > 0) ? (M_PI*0.5 - std::atan(mx/my)) : (M_PI*1.5 - atan(mx/my));

		// http://www.magnetic-declination.com/
		// http://davidegironi.blogspot.de/2013/01/avr-atmega-hmc5883l-magnetometer-lib-01.html
		const float declination = 3.0f / 180.0f * M_PI;		// GERMANY!
		const float curHeading = - tmp + declination;
		float resHeading;
		bool stable = true;

		// calculate standard-deviation within a certain timeframe
		stdDev.add(ts, curHeading);

		// if the standard-deviation is too high,
		// the compass is considered unstable
		if (numMagReadings < 250 || stdDev.get() > 0.30) {
			resHeading = NAN;
			stable = false;
		} else {
			resHeading = curHeading;
			stable = true;
		}

		#ifdef WITH_DEBUG_PLOT
			plot.add(ts, curHeading, stable, mag, curMag);
		#endif

		// done
		return resHeading;

	}

};

#endif // INDOOR_IMU_COMPASSDETECTION_H