#ifndef WIFIMODELLOGDIST_H
#define WIFIMODELLOGDIST_H

#include "WiFiModel.h"
#include "LogDistanceModel.h"

/**
 * signal-strength estimation using log-distance model
 */
class WiFiModelLogDist : public WiFiModel {

public:

	/** parameters describing one AP to the model */
	struct APEntry {

		Point3 position_m;	// the AP's position (in meter)
		float txp;			// sending power (-40)
		float exp;			// path-loss-exponent (~2.0 - 4.0)

		/** ctor */
		APEntry(const Point3 position_m, const float txp, const float exp) :
			position_m(position_m), txp(txp), exp(exp) {;}

	};

private:

	/** map of all APs (and their parameters) known to the model */
	std::unordered_map<MACAddress, APEntry> accessPoints;

public:

	/** ctor */
	WiFiModelLogDist() {
		;
	}

	/** make the given AP (and its parameters) known to the model */
	void addAP(const MACAddress& accessPoint, const APEntry& params) {

		// sanity check
		Assert::isBetween(params.txp, -50.0f, -30.0f, "TXP out of bounds [-90:-30]");
		Assert::isBetween(params.exp, 1.0f, 4.0f, "EXP out of bounds [1:4]");

		// add
		accessPoints.insert( std::pair<MACAddress, APEntry>(accessPoint, params) );

	}

	virtual float getRSSI(const MACAddress& accessPoint, const Point3 position_m) const override {

		// try to get the corresponding parameters
		const auto it = accessPoints.find(accessPoint);

		// AP unknown? -> NAN
		if (it == accessPoints.end()) {return NAN;}

		// the access-points' parameters
		const APEntry& params = it->second;

		// free-space (line-of-sight) RSSI
		const float distance_m = position_m.getDistance(params.position_m);
		const float rssiLOS = LogDistanceModel::distanceToRssi(params.txp, params.exp, distance_m);

		// done
		return rssiLOS;

	}

};

#endif // WIFIMODELLOGDIST_H