#ifndef WIFIPROBABILITYFREE_H
#define WIFIPROBABILITYFREE_H

#include "WiFiProbability.h"
#include "model/WiFiModel.h"
#include "../../math/Distributions.h"
#include "VAPGrouper.h"
#include "../../floorplan/v2/Floorplan.h"

#include <unordered_map>

/**
 * compare WiFi-Measurements within predictions of a given model.
 * predictions are just based on the distance to the access-point.
 */
class WiFiObserverFree : public WiFiProbability {

private:

	const float sigma = 8.0f;

	const float sigmaPerSecond = 3.0f;

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

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

public:

	WiFiObserverFree(const float sigma, WiFiModel& model) : sigma(sigma), model(model) {

	}

	double getProbability(const Point3& pos_m, const Timestamp curTime, const WiFiMeasurements& obs) const {

		double prob = 1.0;
		int numMatchingAPs = 0;

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

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

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

			++numMatchingAPs;

		}

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

		return prob;

	}

	template <typename Node> double getProbability(const Node& n, const Timestamp curTime, const WiFiMeasurements& obs, const int age_ms = 0) const {
		throw Exception("todo??");
	}

};

#endif // WIFIPROBABILITYFREE_H