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/**
 * @file VtolLandDetector.cpp
 * Land detection algorithm for VTOL
 *
 * @author Roman Bapst <bapstroma@gmail.com>
 */

#include "VtolLandDetector.h"
#include <drivers/drv_hrt.h>

namespace landdetection
{

VtolLandDetector::VtolLandDetector() : MulticopterLandDetector(),
	_paramHandle(),
	_params(),
	_airspeedSub(-1),
	_parameterSub(-1),
	_airspeed{},
	_was_in_air(false),
	_airspeed_filtered(0)
{
	_paramHandle.maxAirSpeed = param_find("LNDFW_AIRSPD_MAX");
}

void VtolLandDetector::initialize()
{
	MulticopterLandDetector::initialize();
	_airspeedSub = orb_subscribe(ORB_ID(airspeed));

	// download parameters
	updateParameterCache(true);
}

void VtolLandDetector::updateSubscriptions()
{
	MulticopterLandDetector::updateSubscriptions();

	orb_update(ORB_ID(airspeed), _airspeedSub, &_airspeed);
}

LandDetectionResult VtolLandDetector::update()
{
	updateSubscriptions();
	updateParameterCache(false);

	// this is returned from the mutlicopter land detector
	bool landed = get_landed_state();

	// for vtol we additionally consider airspeed
	if (hrt_elapsed_time(&_airspeed.timestamp) < 500 * 1000) {
		_airspeed_filtered = 0.95f * _airspeed_filtered + 0.05f * _airspeed.true_airspeed_m_s;

	} else {
		// if airspeed does not update, set it to zero and rely on multicopter land detector
		_airspeed_filtered = 0.0f;
	}

	// only consider airspeed if we have been in air before to avoid false
	// detections in the case of wind on the ground
	if (_was_in_air && _airspeed_filtered > _params.maxAirSpeed) {
		landed = false;
	}

	_was_in_air = !landed;

	_state = (landed) ? LANDDETECTION_RES_LANDED : LANDDETECTION_RES_FLYING;

	return _state;
}

void VtolLandDetector::updateParameterCache(const bool force)
{
	MulticopterLandDetector::updateParameterCache(force);

	bool updated;
	parameter_update_s paramUpdate;

	orb_check(_parameterSub, &updated);

	if (updated) {
		orb_copy(ORB_ID(parameter_update), _parameterSub, &paramUpdate);
	}

	if (updated || force) {
		param_get(_paramHandle.maxAirSpeed, &_params.maxAirSpeed);
	}
}

}