rfa 0.5.9

use crate::vector_matrix;
use crate::UrsaASTROM;
use crate::utils::*;
use crate::vector_matrix::init::ir::ir;
use crate::vector_matrix::build_rotations::{rx::rx, ry::ry, rz::rz};
use crate::vector_matrix::angle_ops::anpm::anpm;
use crate::prec_nut::c2ixys::c2ixys;
use crate::vector_matrix::matrix_vec_prod::trxpv;
use crate::vector_matrix::copy_ext::cr;
use super::apcs::apcs;
use super::pvtob::pvtob;
/*
**  - - - - - - - -
**   e r a A p c o
**  - - - - - - - -
**
**  For a terrestrial observer, prepare star-independent astrometry
**  parameters for transformations between ICRS and observed
**  coordinates.  The caller supplies the Earth ephemeris, the Earth
**  rotation information and the refraction constants as well as the
**  site coordinates.
**
**  Given:
**     date1  double       TDB as a 2-part...
**     date2  double       ...Julian Date (Note 1)
**     ebpv   double[2][3] Earth barycentric PV (au, au/day, Note 2)
**     ehp    double[3]    Earth heliocentric P (au, Note 2)
**     x,y    double       CIP X,Y (components of unit vector)
**     s      double       the CIO locator s (radians)
**     theta  double       Earth rotation angle (radians)
**     elong  double       longitude (radians, east +ve, Note 3)
**     phi    double       latitude (geodetic, radians, Note 3)
**     hm     double       height above ellipsoid (m, geodetic, Note 3)
**     xp,yp  double       polar motion coordinates (radians, Note 4)
**     sp     double       the TIO locator s' (radians, Note 4)
**     refa   double       refraction constant A (radians, Note 5)
**     refb   double       refraction constant B (radians, Note 5)
**
**  Returned:
**     astrom eraASTROM*   star-independent astrometry parameters:
**      pmt    double       PM time interval (SSB, Julian years)
**      eb     double[3]    SSB to observer (vector, au)
**      eh     double[3]    Sun to observer (unit vector)
**      em     double       distance from Sun to observer (au)
**      v      double[3]    barycentric observer velocity (vector, c)
**      bm1    double       sqrt(1-|v|^2): reciprocal of Lorenz factor
**      bpn    double[3][3] bias-precession-nutation matrix
**      along  double       adjusted longitude (radians)
**      xpl    double       polar motion xp wrt local meridian (radians)
**      ypl    double       polar motion yp wrt local meridian (radians)
**      sphi   double       sine of geodetic latitude
**      cphi   double       cosine of geodetic latitude
**      diurab double       magnitude of diurnal aberration vector
**      eral   double       "local" Earth rotation angle (radians)
**      refa   double       refraction constant A (radians)
**      refb   double       refraction constant B (radians)
**
**  Notes:
**
**  1) The TDB date date1+date2 is a Julian Date, apportioned in any
**     convenient way between the two arguments.  For example,
**     JD(TDB)=2450123.7 could be expressed in any of these ways, among
**     others:
**
**            date1          date2
**
**         2450123.7           0.0       (JD method)
**         2451545.0       -1421.3       (J2000 method)
**         2400000.5       50123.2       (MJD method)
**         2450123.5           0.2       (date & time method)
**
**     The JD method is the most natural and convenient to use in cases
**     where the loss of several decimal digits of resolution is
**     acceptable.  The J2000 method is best matched to the way the
**     argument is handled internally and will deliver the optimum
**     resolution.  The MJD method and the date & time methods are both
**     good compromises between resolution and convenience.  For most
**     applications of this function the choice will not be at all
**     critical.
**
**     TT can be used instead of TDB without any significant impact on
**     accuracy.
**
**  2) The vectors eb, eh, and all the astrom vectors, are with respect
**     to BCRS axes.
**
**  3) The geographical coordinates are with respect to the ERFA_WGS84
**     reference ellipsoid.  TAKE CARE WITH THE LONGITUDE SIGN
**     CONVENTION:  the longitude required by the present function is
**     right-handed, i.e. east-positive, in accordance with geographical
**     convention.
**
**     The adjusted longitude stored in the astrom array takes into
**     account the TIO locator and polar motion.
**
**  4) xp and yp are the coordinates (in radians) of the Celestial
**     Intermediate Pole with respect to the International Terrestrial
**     Reference System (see IERS Conventions), measured along the
**     meridians 0 and 90 deg west respectively.  sp is the TIO locator
**     s', in radians, which positions the Terrestrial Intermediate
**     Origin on the equator.  For many applications, xp, yp and
**     (especially) sp can be set to zero.
**
**     Internally, the polar motion is stored in a form rotated onto the
**     local meridian.
**
**  5) The refraction constants refa and refb are for use in a
**     dZ = A*tan(Z)+B*tan^3(Z) model, where Z is the observed
**     (i.e. refracted) zenith distance and dZ is the amount of
**     refraction.
**
**  6) It is advisable to take great care with units, as even unlikely
**     values of the input parameters are accepted and processed in
**     accordance with the models used.
**
**  7) In cases where the caller does not wish to provide the Earth
**     Ephemeris, the Earth rotation information and refraction
**     constants, the function eraApco13 can be used instead of the
**     present function.  This starts from UTC and weather readings etc.
**     and computes suitable values using other ERFA functions.
**
**  8) This is one of several functions that inserts into the astrom
**     structure star-independent parameters needed for the chain of
**     astrometric transformations ICRS <-> GCRS <-> CIRS <-> observed.
**
**     The various functions support different classes of observer and
**     portions of the transformation chain:
**
**          functions         observer        transformation
**
**       eraApcg eraApcg13    geocentric      ICRS <-> GCRS
**       eraApci eraApci13    terrestrial     ICRS <-> CIRS
**       eraApco eraApco13    terrestrial     ICRS <-> observed
**       eraApcs eraApcs13    space           ICRS <-> GCRS
**       eraAper eraAper13    terrestrial     update Earth rotation
**       eraApio eraApio13    terrestrial     CIRS <-> observed
**
**     Those with names ending in "13" use contemporary ERFA models to
**     compute the various ephemerides.  The others accept ephemerides
**     supplied by the caller.
**
**     The transformation from ICRS to GCRS covers space motion,
**     parallax, light deflection, and aberration.  From GCRS to CIRS
**     comprises frame bias and precession-nutation.  From CIRS to
**     observed takes account of Earth rotation, polar motion, diurnal
**     aberration and parallax (unless subsumed into the ICRS <-> GCRS
**     transformation), and atmospheric refraction.
**
**  9) The context structure astrom produced by this function is used by
**     eraAtioq, eraAtoiq, eraAtciq* and eraAticq*.
**
**  Called:
**     eraIr        initialize r-matrix to identity
**     eraRz        rotate around Z-axis
**     eraRy        rotate around Y-axis
**     eraRx        rotate around X-axis
**     eraAnpm      normalize angle into range +/- pi
**     eraC2ixys    celestial-to-intermediate matrix, given X,Y and s
**     eraPvtob     position/velocity of terrestrial station
**     eraTrxpv     product of transpose of r-matrix and pv-vector
**     eraApcs      astrometry parameters, ICRS-GCRS, space observer
**     eraCr        copy r-matrix
**
**  This revision:   2021 February 24
**
**  Copyright (C) 2013-2021, NumFOCUS Foundation.
**  Derived, with permission, from the SOFA library.  See notes at end of file.
*/


pub fn apco(date1: f64, date2:f64 ,
    ebpv: &[[f64; 3];2], ehp: [f64; 3],
    x: f64, y: f64, s: f64, theta: f64,
    elong: f64, phi: f64, hm: f64,
    xp: f64, yp: f64, sp: f64,
    refa: f64, refb: f64,
    astrom: &mut UrsaASTROM)
{
    let mut r =[[0.0; 3]; 3];
    let mut pvc =[[0.0; 3]; 2];
    let mut pv = [[0.0; 3]; 2];

/* Form the rotation matrix, CIRS to apparent [HA,Dec]. */
   ir(&mut r);
   rz(theta+sp, &mut r);
   ry(-xp, &mut r);
   rx(-yp, &mut r);
   rz(elong, &mut r);

/* Solve for local Earth rotation angle. */
   let mut a = r[0][0];
   let mut b = r[0][1];
   let eral = if  a != 0.0 || b != 0.0 { atan2(b, a) } else {0.0};
   astrom.eral = eral;

/* Solve for polar motion [X,Y] with respect to local meridian. */
   a = r[0][0];
   let mut c = r[0][2];
   astrom.xpl = atan2(c, sqrt(a*a+b*b));
   a = r[1][2];
   b = r[2][2];
   astrom.ypl = if  a != 0.0 || b != 0.0 { -atan2(a, b) } else{0.0};

/* Adjusted longitude. */
   astrom.along = anpm(eral - theta);

/* Functions of latitude. */
   astrom.sphi = sin(phi);
   astrom.cphi = cos(phi);

/* Refraction constants. */
   astrom.refa = refa;
   astrom.refb = refb;

/* Disable the (redundant) diurnal aberration step. */
   astrom.diurab = 0.0;

/* CIO based BPN matrix. */
   c2ixys(x, y, s, &mut r);

/* Observer's geocentric position and velocity (m, m/s, CIRS). */
   pvtob(elong, phi, hm, xp, yp, sp, theta, &mut pvc);

/* Rotate into GCRS. */
   trxpv(&r, &pvc, &mut pv);

/* ICRS <-> GCRS parameters. */
   apcs(date1, date2, &pv, &ebpv, &ehp, astrom);

/* Store the CIO based BPN matrix. */
   cr(&r, &mut astrom.bpn );

/* Finished. */

}