/***************************** LICENSE START ***********************************

 Copyright 2012 ECMWF and INPE. This software is distributed under the terms
 of the Apache License version 2.0. In applying this license, ECMWF does not
 waive the privileges and immunities granted to it by virtue of its status as
 an Intergovernmental Organization or submit itself to any jurisdiction.

 ***************************** LICENSE END *************************************/

#pragma once

#include <ostream>

#ifdef MAGICS
namespace magics
{
#else
namespace metview
{
#endif

const double MISSING_LOC_VALUE = -99999.;

//=========================================================
// WARNING: we cannot use MvSci here because this code is
// also included in the Magics source!!!
//=========================================================

//! Class for geographical locations
/*! MvLocation is used to store latitude-longitude location values.
 *  Class also provides methods to calculate the distance to another
 *  geographical location
 */
class MvLocation
{
    //! Output operator for MvLocation object
    /*! The output is enclosed in parenthesis and latitude and longitude values
     *  are separated by a comma, for instance:
     * <PRE>
     *      MvLocation loc1(51.46,-1.33);
     *      MvLocation loc2(60.45,25.0);
     *      std::cout << "Locations are: " << loc1 << " and " << loc2 << std::endl;
     * </PRE>
     *  would output the following line:
     * <PRE>
     *      Locations are: (51.46,-1.33) and (60.45,25)
     * </PRE>
     */
    friend std::ostream& operator<<(std::ostream& aStream, const MvLocation& aLocation);

public:
    MvLocation() = default;
    MvLocation(double aLat, double aLong) { set(aLat, aLong); }
    MvLocation& operator=(const MvLocation& aLoc);

    void set(double aLat, double aLong);

    // Checks that the stored location is a valid geographical point
    // Latitude value must be in interval [-90,90] and longitude
    //  value in interval [-360,360], in degrees.
    bool ok() const { return (lat_ <= 90 && lat_ >= -90 && lon_ <= 360 && lon_ >= -360); }

    // Subtracts 360 until the longitude is below 360 (e.g. 360 becomes 0, 370 becomes 10)
    void ensureLongitudeBelow360();

    double latitude() const { return lat_; }
    double y() const { return lat_; }
    double longitude() const { return lon_; }
    double x() const { return lon_; }

    // Returns the cosine of the angular distance to the given point
    double cosOfDistance(const MvLocation& other) const;
    virtual double cosOfDistance(double aLat, double aLon) const;

    // Returns the distance (in radians) to the given point
    double distanceInRadians(const MvLocation& other) const;

    // Returns the distance (in degrees) to the given point
    double distanceInDegrees(const MvLocation& other) const;

    // Returns the distance (in metres) to the given point
    double distanceInMeters(const MvLocation& other) const;

protected:
    // ideally McSci should be used here, but see warning above!
    static double degToRad(double d) { return d * cDegree; }
    static double radToDeg(double r) { return r * cRadian; }
    static double metresToRadians(double m) { return m * cMetreToRadian; }
    static double radiansToMetres(double r) { return r * cRadianToMetre; }

    static const double cRadian;
    static const double cDegree;
    static const double cMetreToRadian;
    static const double cRadianToMetre;
    double lat_{MISSING_LOC_VALUE};
    double lon_{MISSING_LOC_VALUE};
};

// A location from that the distance to other locations are computed. It
// caches some trigonometric values to make the computations faster.
class MvLocationHub : public MvLocation
{
public:
    using MvLocation::MvLocation;
    MvLocationHub& operator=(const MvLocationHub& aLoc);
    double cosOfDistance(double aLat, double aLon) const override;

protected:
    mutable double cosLat_{-1000.};
    mutable double sinLat_{-1000.};
};

//_________________________________________________________________________ MvArea
//! Class for geographical areas (squares on cylindrical projection)
/*! This is another incarnation of MvGeoBox class, used mainly by
 *  MvObsSetIterator. For other usage MvGeoBox is recommended over MvArea.
 */
class MvArea
{
    friend std::ostream& operator<<(std::ostream& aStream, const MvArea& aArea);

public:
    MvArea();
    MvArea(const MvLocation& aLoc1, const MvLocation& aLoc2) { set(aLoc1, aLoc2); }

    void set(const MvLocation& aLoc1, const MvLocation& aLoc2);
    bool inside(const MvLocation& aPoint) const;
    MvLocation lowerLeft() const { return fLowerLeft; }
    MvLocation upperRight() const { return fUpperRight; }

    MvArea& operator=(const MvArea& aLoc);

private:
    MvLocation fLowerLeft;
    MvLocation fUpperRight;
};

//_____________________________________________________________________ MvXSectionLine
//! Class for cross section lines (straight lines on cylindrical projection)
/*! Class can be used to check if any given point is withing the allowed
 *  distance (max delta) from the given line, i.e. close enough to be
 *  considered to be within the line.
 */
class MvXSectionLine
{
    friend std::ostream& operator<<(std::ostream& aStream, const MvXSectionLine& aXSectionLine);

public:
    //! Empty constructor creates a missing line
    MvXSectionLine()
    {
        fLocation1.set(MISSING_LOC_VALUE, MISSING_LOC_VALUE);
        fLocation2.set(MISSING_LOC_VALUE, MISSING_LOC_VALUE);
        fMaxDeltaInMeters = -1;
    }

    //! Constructor, only points defined, no max delta given
    /*! Use method setMaxDelta() to set the maximum allowed distance from the line
     */
    MvXSectionLine(const MvLocation& aLoc1, const MvLocation& aLoc2) :
        fLocation1(aLoc1), fLocation2(aLoc2), fMaxDeltaInMeters(-1)
    {
    }

    //! Constructor, two points and max distance from the line
    MvXSectionLine(const MvLocation& aLoc1, const MvLocation& aLoc2, double aDelta)
    {
        fLocation1 = aLoc1;
        fLocation2 = aLoc2;
        fMaxDeltaInMeters = aDelta;
    }

    //! Set a new line between points aLoc1 and aLoc2
    void setLine(const MvLocation& aLoc1, const MvLocation& aLoc2)
    {
        fLocation1 = aLoc1;
        fLocation2 = aLoc2;
    }

    //! Return the current start point of the line
    MvLocation startPoint() const { return fLocation1; }

    //! Return the current end point of the line
    MvLocation endPoint() const { return fLocation2; }

    //! Set the maximum allowed distance from the line
    void setMaxDelta(double aDelta) { fMaxDeltaInMeters = aDelta; }

    //! Return the current maximum allowed distance from the line
    double maxDelta() const { return fMaxDeltaInMeters; }

    //! Returns true if the given point is within the given proximity of the line
    bool withinDelta(const MvLocation& aLocation) const;

    //! Returns the distance of the given point from the cross section line (in degrees)
    double deltaInDegrees(const MvLocation& aLocation) const;

    //! Returns the distance of the given point from the cross section line (in meters)
    double deltaInMeters(const MvLocation& aLocation) const;

    //! Assignment operator
    MvXSectionLine& operator=(const MvXSectionLine& anXLine);

private:
    //! Returns the nearest point on the line through end points
    MvLocation nearestPointOnXLine(const MvLocation& aLocation) const;

    //! Checks that the closest point on the line is between end points
    bool insideXLine(const MvLocation& aLocation) const;

private:
    MvLocation fLocation1;
    MvLocation fLocation2;
    double fMaxDeltaInMeters;
};

}  // namespace
