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/*

    SPDX-FileCopyrightText: 2018 Valentin Boettcher <valentin@boettcher.cf>


    SPDX-License-Identifier: GPL-2.0-or-later

*/

#include "ksearthshadow.h"

#include "kssun.h"

#include "ksmoon.h"


KSEarthShadow::KSEarthShadow(const KSMoon *moon, const KSSun *sun, const KSPlanet * earth)

    : KSPlanetBase (i18n("Earth Shadow")), m_sun { sun }, m_moon { moon }, m_earth {earth}

{

}


bool KSEarthShadow::shouldUpdate()

{

    return (m_moon->illum() > 0.8);

}


bool KSEarthShadow::isInEclipse()

{

    double dist = angularDistanceTo(m_moon).Degrees() * 60;

    return (dist - m_moon->angSize() / 2) <= m_penumbra_ang;

}


KSEarthShadow::ECLIPSE_TYPE KSEarthShadow::getEclipseType()

{

    double half_a_moon = m_moon->angSize() / 2;

    double dist = angularDistanceTo(m_moon).Degrees() * 60; // arcminutes

    if (dist <= (m_penumbra_ang - half_a_moon))

    {

        if(dist <= (m_umbra_ang - half_a_moon))

            return FULL_UMBRA;

        else

            return FULL_PENUMBRA;

    }

    else if ((dist - half_a_moon) <= m_penumbra_ang)

    {

        return PARTIAL;

    }


    return NONE;

}


bool KSEarthShadow::findGeocentricPosition(const KSNumbers *, const KSPlanetBase *)

{

    updateCoords();

    return true; //TODO: not nice!

}


void KSEarthShadow::updateCoords(const KSNumbers *, bool, const CachingDms *, const CachingDms *, bool )

{

    updateCoords();

}


//TODO: Abort if Null


void KSEarthShadow::updateCoords()

{

    // flip the sun around to get the 'shadow coordinates'

    dms t_ra(m_sun->ra().Degrees() + 180);

    t_ra.reduceToRange(dms::ZERO_TO_2PI);

    dms t_dec(-1 * (m_sun->dec().Degrees()));


    set(t_ra, t_dec);

    Rearth = m_moon->rearth();

}


//NOTE: This can easily be generalized to any three bodies.


void KSEarthShadow::calculateShadowRadius()

{

    double d_sun = m_sun->rearth() * AU_KM;

    double d_moon = m_moon->rearth() * AU_KM;

    double r_sun = m_sun->physicalSize() / 2;

    double r_earth = m_earth->physicalSize() / 2;


    double umbraRad = 1.01 * r_earth + (r_earth - r_sun) / d_sun * d_moon;

    double penumbraRad = 1.01 * r_earth + (r_sun + r_earth) / d_sun * d_moon;


    m_umbra_ang = asin(umbraRad / d_moon) * 60. * 180. / dms::PI;

    m_penumbra_ang = asin(penumbraRad / d_moon) * 60. * 180. / dms::PI;


    return;

}


KSEarthShadow::updateCoords
void updateCoords()
Update the RA/DEC of the shadow.
Definition ksearthshadow.cpp:58

KSEarthShadow::findGeocentricPosition
bool findGeocentricPosition(const KSNumbers *, const KSPlanetBase *Earth=nullptr) override
find the object's current geocentric equatorial coordinates (RA and Dec) This function is pure virtua...
Definition ksearthshadow.cpp:45

KSEarthShadow::shouldUpdate
bool shouldUpdate()
The earths shadow on the moon appears only at new moon so calculating it on other occasions is rather...
Definition ksearthshadow.cpp:15

KSEarthShadow::getEclipseType
ECLIPSE_TYPE getEclipseType()
eclipse
Definition ksearthshadow.cpp:26

KSEarthShadow::KSEarthShadow
KSEarthShadow(const KSMoon *moon, const KSSun *sun, const KSPlanet *earth)
Definition ksearthshadow.cpp:10

KSEarthShadow::isInEclipse
bool isInEclipse()
isInEclipse - a slim version of getEclipseType()
Definition ksearthshadow.cpp:20

KSEarthShadow::ECLIPSE_TYPE
ECLIPSE_TYPE
The ECLIPSE_TYPE enum describes the quality of an eclipse.
Definition ksearthshadow.h:46

KSEarthShadow::calculateShadowRadius
void calculateShadowRadius()
Updates umbra and penumbra radius from the positions of the three bodies.
Definition ksearthshadow.cpp:71

KSMoon
Provides necessary information about the Moon.
Definition ksmoon.h:26

KSMoon::illum
double illum() const
Definition ksmoon.h:49

KSNumbers
There are several time-dependent values used in position calculations, that are not specific to an ob...
Definition ksnumbers.h:43

KSPlanetBase
A subclass of TrailObject that provides additional information needed for most solar system objects.
Definition ksplanetbase.h:50

KSPlanetBase::physicalSize
double physicalSize() const
Definition ksplanetbase.h:192

KSPlanetBase::angSize
double angSize() const
Definition ksplanetbase.h:184

KSPlanetBase::rearth
double rearth() const
Definition ksplanetbase.h:139

KSPlanet
A subclass of KSPlanetBase for seven of the major planets in the solar system (Earth and Pluto have t...
Definition ksplanet.h:33

KSSun
Child class of KSPlanetBase; encapsulates information about the Sun.
Definition kssun.h:24

SkyPoint::dec
const CachingDms & dec() const
Definition skypoint.h:269

SkyPoint::ra
const CachingDms & ra() const
Definition skypoint.h:263

SkyPoint::angularDistanceTo
dms angularDistanceTo(const SkyPoint *sp, double *const positionAngle=nullptr) const
Computes the angular distance between two SkyObjects.
Definition skypoint.cpp:899

SkyPoint::set
void set(const dms &r, const dms &d)
Sets RA, Dec and RA0, Dec0 according to arguments.
Definition skypoint.cpp:63

dms::PI
static constexpr double PI
PI is a const static member; it's public so that it can be used anywhere, as long as dms....
Definition dms.h:385

i18n
QString i18n(const char *text, const TYPE &arg...)