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/**
 * @file LandDetector.h
 * Abstract interface for land detector algorithms
 *
 * @author Johan Jansen <jnsn.johan@gmail.com>
 */

#ifndef __LAND_DETECTOR_H__
#define __LAND_DETECTOR_H__

#include <uORB/uORB.h>
#include <uORB/topics/vehicle_land_detected.h>

class LandDetector
{
public:

	LandDetector();
	virtual ~LandDetector();

	/**
	* @return true if this task is currently running
	**/
	inline bool isRunning() const {return _taskIsRunning;}

	/**
	* @brief  Tells the Land Detector task that it should exit
	**/
	void shutdown();

	/**
	* @brief Blocking function that should be called from it's own task thread. This method will
	*        run the underlying algorithm at the desired update rate and publish if the landing state changes.
	**/
	void start();

protected:

	/**
	* @brief Pure abstract method that must be overriden by sub-classes. This actually runs the underlying algorithm
	* @return true if a landing was detected and this should be broadcast to the rest of the system
	**/
	virtual bool update() = 0;

	/**
	* @brief Pure abstract method that is called by this class once for initializing the uderlying algorithm (memory allocation,
	*        uORB topic subscription, creating file descriptors, etc.)
	**/
	virtual void initialize() = 0;

	/**
	* @brief Convinience function for polling uORB subscriptions
	* @return true if there was new data and it was successfully copied
	**/
	bool orb_update(const struct orb_metadata *meta, int handle, void *buffer);

	static constexpr uint32_t LAND_DETECTOR_UPDATE_RATE = 50;        /**< Run algorithm at 50Hz */

	static constexpr uint64_t LAND_DETECTOR_TRIGGER_TIME = 2000000;  /**< usec that landing conditions have to hold
                                                                          before triggering a land */

protected:
	orb_advert_t                            _landDetectedPub;           /**< publisher for position in local frame */
	struct vehicle_land_detected_s          _landDetected;              /**< local vehicle position */

private:
	bool _taskShouldExit;                                               /**< true if it is requested that this task should exit */
	bool _taskIsRunning;                                                /**< task has reached main loop and is currently running */
};

#endif //__LAND_DETECTOR_H__