#ifndef BEACONPROBABILITYFREE_H
#define BEACONPROBABILITYFREE_H

#include "BeaconProbability.h"
#include "BeaconMeasurements.h"
#include "model/BeaconModel.h"
#include "../../math/Distributions.h"
#include "../../data/Timestamp.h"

#include "../../floorplan/v2/Floorplan.h"

#include <unordered_map>

/**
 * compare BeaconMeasurements within predictions of a given model.
 * predictions are just based on the distance to the observed beacon.
 */
class BeaconObserverFree : public BeaconProbability {

private:

	const float sigma = 8.0f;

	const float sigmaPerSecond = 3.0f;

	/** the RSSI prediction model */
    BeaconModel& model;

	/** the map's floorplan */
	Floorplan::IndoorMap* map;

public:

    /** ctor */
    BeaconObserverFree(const float sigma, BeaconModel& model) : sigma(sigma), model(model) {

	}

    /** provides the probability for a specific point in space */
    double getProbability(const Point3& pos_m, const Timestamp curTime, const BeaconMeasurements& obs) const {

		double prob = 1.0;
        int numMatchingBeacons = 0;

		// process each measured AP
        for (const BeaconMeasurement& entry : obs.entries) {

			// sanity check
			Assert::isFalse(entry.getTimestamp().isZero(), "wifi measurement without timestamp. coding error?");

            // updating the beacons sended txp if available
            if(entry.getBeacon().getTXP() != 0.0f){
                //TODO: check if this works
                model.updateBeacon(entry);
            }

			// get the model's RSSI (if possible!)
            const float modelRSSI = model.getRSSI(entry.getBeacon().getMAC(), pos_m);

			// NaN? -> AP not known to the model -> skip
			if (modelRSSI != modelRSSI) {continue;}


			// the scan's RSSI
			const float scanRSSI = entry.getRSSI();

			// the measurement's age
			const Timestamp age = curTime - entry.getTimestamp();

			Assert::isTrue(age.ms() >= 0, "found a negative wifi measurement age. this does not make sense");
			Assert::isTrue(age.ms() <= 40000, "found a 40 second old wifi measurement. maybe there is a coding error?");

			// sigma grows with measurement age
			const float sigma = this->sigma + this->sigmaPerSecond * age.sec();

			// update probability
			prob *= Distribution::Normal<double>::getProbability(modelRSSI, sigma, scanRSSI);
			//prob *= Distribution::Region<double>::getProbability(modelRSSI, sigma, scanRSSI);

            ++numMatchingBeacons;

		}

		// sanity check
        Assert::isTrue(numMatchingBeacons > 0, "not a single measured Beacon was matched against known ones. coding error? model error?");

		return prob;

	}

};

#endif // WIFIPROBABILITYFREE_H