/* +------------------------------------------------------------------------+
   |                     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/CMatrixD.h>
#include <mrpt/poses/CPose3DPDF.h>
#include <mrpt/poses/CPose3DQuatPDF.h>
#include <mrpt/poses/CPosePDF.h>

namespace mrpt::poses
{
class CPosePDFGaussian;
class CPose3DPDFGaussian;

/** Declares a class that represents a Probability Density function (PDF) of a
 * 3D pose using a quaternion \f$ p(\mathbf{x}) = [x ~ y ~ z ~ qr ~ qx ~ qy ~
 * qz]^\top \f$.
 *
 *   This class implements that PDF using a mono-modal Gaussian distribution
 * storing the information matrix instead of its inverse, the covariance matrix.
 *     See mrpt::poses::CPose3DQuatPDF for more details, or
 *     mrpt::poses::CPose3DPDF for classes based on Euler angles instead.
 *
 *  Uncertainty of pose composition operations (\f$ y = x \oplus u \f$) is
 * implemented in the methods "CPose3DQuatPDFGaussianInf::operator+=" and
 * "CPose3DQuatPDF::jacobiansPoseComposition".
 *
 *  For further details on implemented methods and the theory behind them,
 *  see <a
 * href="http://www.mrpt.org/6D_poses:equivalences_compositions_and_uncertainty"
 * >this report</a>.
 *
 * \sa CPose3DQuat, CPose3DQuatPDF, CPose3DPDF, CPose3DQuatPDFGaussian
 * \ingroup poses_pdf_grp
 */
class CPose3DQuatPDFGaussianInf : public CPose3DQuatPDF
{
	// This must be added to any CSerializable derived class:
	DEFINE_SERIALIZABLE(CPose3DQuatPDFGaussianInf, mrpt::poses)
	using self_t = CPose3DQuatPDFGaussianInf;

   public:
	/** Default constructor - set all values to zero. */
	CPose3DQuatPDFGaussianInf();

	/** Constructor which left all the member uninitialized, for using when
	 * speed is critical - as argument, use UNINITIALIZED_QUATERNION. */
	CPose3DQuatPDFGaussianInf(
		mrpt::math::TConstructorFlags_Quaternions constructor_dummy_param);

	/** Constructor from a default mean value, information matrix equals to
	 * zero. */
	explicit CPose3DQuatPDFGaussianInf(const CPose3DQuat& init_Mean);

	/** Constructor with mean and inverse covariance (information matrix). */
	CPose3DQuatPDFGaussianInf(
		const CPose3DQuat& init_Mean,
		const mrpt::math::CMatrixDouble77& init_CovInv);

	/** The mean value */
	CPose3DQuat mean;
	/** The 7x7 information matrix (the inverse of the covariance) */
	mrpt::math::CMatrixDouble77 cov_inv;

	inline const CPose3DQuat& getPoseMean() const { return mean; }
	inline CPose3DQuat& getPoseMean() { return mean; }

	void getMean(CPose3DQuat& mean_pose) const override { mean_pose = mean; }
	bool isInfType() const override { return true; }

	std::tuple<cov_mat_t, type_value> getCovarianceAndMean() const override
	{
		return {cov_inv.inverse_LLt(), mean};
	}

	/** Returns the information (inverse covariance) matrix (a STATE_LEN x
	 * STATE_LEN matrix) \sa getMean, getCovarianceAndMean */
	void getInformationMatrix(mrpt::math::CMatrixDouble77& inf) const override
	{
		inf = cov_inv;
	}

	/** Copy operator, translating if necesary (for example, between particles
	 * and gaussian representations) */
	void copyFrom(const CPose3DQuatPDF& o) override;

	/** Save the PDF to a text file, containing the 3D pose in the first line (x
	 * y z qr qx qy qz), then the information matrix in the next 7 lines. */
	bool saveToTextFile(const std::string& file) const override;

	/** this = p (+) this. This can be used to convert a PDF from local
	 * coordinates to global, providing the point (newReferenceBase) from which
	 *   "to project" the current pdf. Result PDF substituted the currently
	 * stored one in the object. */
	void changeCoordinatesReference(const CPose3DQuat& newReferenceBase);

	/** this = p (+) this. This can be used to convert a PDF from local
	 * coordinates to global, providing the point (newReferenceBase) from which
	 *   "to project" the current pdf. Result PDF substituted the currently
	 * stored one in the object. */
	void changeCoordinatesReference(const CPose3D& newReferenceBase) override;

	/** Draws a single sample from the distribution */
	void drawSingleSample(CPose3DQuat& outPart) const override;
	/** Draws a number of samples from the distribution, and saves as a list of
	 * 1x7 vectors, where each row contains a (x,y,z,qr,qx,qy,qz) datum */
	void drawManySamples(
		size_t N,
		std::vector<mrpt::math::CVectorDouble>& outSamples) const override;
	/** Returns a new PDF such as: NEW_PDF = (0,0,0) - THIS_PDF */
	void inverse(CPose3DQuatPDF& o) const override;

	/** Unary - operator, returns the PDF of the inverse pose.  */
	inline CPose3DQuatPDFGaussianInf operator-() const
	{
		CPose3DQuatPDFGaussianInf p(mrpt::math::UNINITIALIZED_QUATERNION);
		this->inverse(p);
		return p;
	}

	/** Makes: thisPDF = thisPDF + Ap, where "+" is pose composition (both the
	 * mean, and the covariance matrix are updated). */
	void operator+=(const CPose3DQuat& Ap);
	/** Makes: thisPDF = thisPDF + Ap, where "+" is pose composition (both the
	 * mean, and the covariance matrix are updated) (see formulas in
	 * jacobiansPoseComposition ). */
	void operator+=(const CPose3DQuatPDFGaussianInf& Ap);
	/** Makes: thisPDF = thisPDF - Ap, where "-" is pose inverse composition
	 * (both the mean, and the covariance matrix are updated). */
	void operator-=(const CPose3DQuatPDFGaussianInf& Ap);

	/** Evaluates the PDF at a given point */
	double evaluatePDF(const CPose3DQuat& x) const;
	/** Evaluates the ratio PDF(x) / PDF(MEAN), that is, the normalized PDF in
	 * the range [0,1] */
	double evaluateNormalizedPDF(const CPose3DQuat& x) const;

};	// End of class def.

bool operator==(
	const CPose3DQuatPDFGaussianInf& p1, const CPose3DQuatPDFGaussianInf& p2);
/** Pose composition for two 3D pose Gaussians  \sa
 * CPose3DQuatPDFGaussianInf::operator += */
CPose3DQuatPDFGaussianInf operator+(
	const CPose3DQuatPDFGaussianInf& x, const CPose3DQuatPDFGaussianInf& u);
/** Inverse pose composition for two 3D pose Gaussians  \sa
 * CPose3DQuatPDFGaussianInf::operator -= */
CPose3DQuatPDFGaussianInf operator-(
	const CPose3DQuatPDFGaussianInf& x, const CPose3DQuatPDFGaussianInf& u);

/** Dumps the mean and covariance matrix to a text stream. */
std::ostream& operator<<(
	std::ostream& out, const CPose3DQuatPDFGaussianInf& obj);

}  // namespace mrpt::poses
