/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2023, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */
#pragma once

#include <mrpt/math/CMatrixF.h>
#include <mrpt/math/TPoint3D.h>
#include <mrpt/obs/CObservation.h>	// INVALID_LANDMARK_ID
#include <mrpt/poses/CPoint3D.h>
#include <mrpt/poses/CPointPDFGaussian.h>
#include <mrpt/serialization/CSerializable.h>
#include <mrpt/system/datetime.h>
#include <mrpt/vision/CFeature.h>

#include <memory>

namespace mrpt::maps
{
/** The class for storing "landmarks" (visual or laser-scan-extracted
 * features,...)
 *
 *  The descriptors for each kind of descriptor are stored in the vector
 * "features", which
 *   will typically consists of only 1 element, or 2 elements for landmarks
 * obtained from stereo images.
 *
 * \sa CLandmarksMap
 * \ingroup mrpt_vision_grp
 */
class CLandmark : public mrpt::serialization::CSerializable
{
	DEFINE_SERIALIZABLE(CLandmark, mrpt::maps)

   public:
	/** The type for the IDs of landmarks. */
	using TLandmarkID = int64_t;

	/** The set of features from which the landmark comes. */
	std::vector<mrpt::vision::CFeature> features;

	/** The mean of the landmark 3D position. */
	mrpt::math::TPoint3D pose_mean;
	/** The "normal" to the landmark, i.e. a unitary 3D vector towards the
	 * viewing direction, or a null vector if not applicable */
	mrpt::math::TPoint3D normal;
	float pose_cov_11{}, pose_cov_22{}, pose_cov_33{}, pose_cov_12{},
		pose_cov_13{}, pose_cov_23{};

	/** An ID for the landmark (see details next...)
	 *  This ID was introduced in the version 3 of this class (21/NOV/2006),
	 *and its aim is
	 *  to provide a way for easily establishing correspondences between
	 *landmarks detected
	 *  in sequential image frames. Thus, the management of this field should
	 *be:
	 *		- In 'servers' (classes/modules/... that detect landmarks from
	 *images):
	 *A different ID must be assigned to every landmark (e.g. a sequential
	 *counter), BUT only in the case of being sure of the correspondence of one
	 *landmark with another one in the past (e.g. tracking).
	 *		- In 'clients': This field can be ignored, but if it is used, the
	 *advantage is solving the correspondence between landmarks detected in
	 *consequentive instants of time: Two landmarks with the same ID
	 *<b>correspond</b> to the same physical feature, BUT it should not be
	 *expected the inverse to be always true.
	 *
	 * Note that this field is never fill out automatically, it must be set by
	 *the programmer if used.
	 */
	TLandmarkID ID = mrpt::obs::INVALID_LANDMARK_ID;

	/** The last time that this landmark was observed. */
	mrpt::system::TTimeStamp timestampLastSeen{INVALID_TIMESTAMP};

	/** The number of times that this landmark has been seen. */
	uint32_t seenTimesCount{0};

	/** Returns the pose as an object:
	 */
	void getPose(mrpt::poses::CPointPDFGaussian& p) const;

	void getPose(mrpt::poses::CPoint3D& p, mrpt::math::CMatrixDouble& COV) const
	{
		mrpt::poses::CPointPDFGaussian pdf;
		getPose(pdf);
		p = pdf.mean;
		COV = mrpt::math::CMatrixDouble(pdf.cov);
	}

	/** Sets the pose from an object:
	 */
	void setPose(const mrpt::poses::CPointPDFGaussian& p);

	/** Gets the type of the first feature in its feature vector. The vector
	 * must not be empty.
	 */
	mrpt::vision::TKeyPointMethod getType() const
	{
		ASSERT_(!features.empty());
		return features[0].type;
	}

	/** Creates one feature in the vector "features", calling the appropriate
	 * constructor of the smart pointer, so after calling this method
	 * "features[0]" is a valid pointer to a CFeature object.
	 */
	void createOneFeature() { features.resize(1); }

	/** Default constructor */
	CLandmark() = default;

	/** Virtual destructor  */
	~CLandmark() override;

   protected:
	/** Auxiliary variable
	 */
	static TLandmarkID m_counterIDs;

};	// End of class definition

}  // namespace mrpt::maps
