use crate::vm::{anp, c2s, rxp};

use super::{IauAstrom, IauLdBody, ab, ldn, pmpx};

///  Quick ICRS −> CIRS, multiple deflections

///

///  Quick ICRS, epoch J2000.0, to CIRS transformation, given precomputed

///  star-independent astrometry parameters plus a list of light-

///  deflecting bodies.

///

///  Use of this function is appropriate when efficiency is important and

///  where many star positions are to be transformed for one date.  The

///  star-independent parameters can be obtained by calling one of the

///  functions iauApci[13], iauApcg[13], iauApco[13] or iauApcs[13].

///

///

///  If the only light-deflecting body to be taken into account is the

///  Sun, the iauAtciq function can be used instead.  If in addition the

///  parallax and proper motions are zero, the iauAtciqz function can be

///  used.

///

///  This function is part of the International Astronomical Union's

///  SOFA (Standards of Fundamental Astronomy) software collection.

///

///  Status:  support function.

///

///  Given:

///     rc,dc  double       ICRS RA,Dec at J2000.0 (radians)

///     pr     double       RA proper motion (radians/year, Note 3)

///     pd     double       Dec proper motion (radians/year)

///     px     double       parallax (arcsec)

///     rv     double       radial velocity (km/s, +ve if receding)

///     astrom iauASTROM*   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       longitude + s' (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)

///     n      int          number of bodies (Note 3)

///     b      iauLDBODY[n] data for each of the n bodies (Notes 3,4):

///      bm     double       mass of the body (solar masses, Note 5)

///      dl     double       deflection limiter (Note 6)

///      pv     [2][3]       barycentric PV of the body (au, au/day)

///

///  Returned:

///     ri,di   double    CIRS RA,Dec (radians)

///

///  Notes:

///

///  1) Star data for an epoch other than J2000.0 (for example from the

///     Hipparcos catalog, which has an epoch of J1991.25) will require a

///     preliminary call to iauPmsafe before use.

///

///  2) The proper motion in RA is dRA/dt rather than cos(Dec)*dRA/dt.

///

///  3) The struct b contains n entries, one for each body to be

///     considered.  If n = 0, no gravitational light deflection will be

///     applied, not even for the Sun.

///

///  4) The struct b should include an entry for the Sun as well as for

///     any planet or other body to be taken into account.  The entries

///     should be in the order in which the light passes the body.

///

///  5) In the entry in the b struct for body i, the mass parameter

///     b[i].bm can, as required, be adjusted in order to allow for such

///     effects as quadrupole field.

///

///  6) The deflection limiter parameter b[i].dl is phi^2/2, where phi is

///     the angular separation (in radians) between star and body at

///     which limiting is applied.  As phi shrinks below the chosen

///     threshold, the deflection is artificially reduced, reaching zero

///     for phi = 0.   Example values suitable for a terrestrial

///     observer, together with masses, are as follows:

///

///        body i     b[i].bm        b[i].dl

///

///        Sun        1.0            6e-6

///        Jupiter    0.00095435     3e-9

///        Saturn     0.00028574     3e-10

///

///  7) For efficiency, validation of the contents of the b array is

///     omitted.  The supplied masses must be greater than zero, the

///     position and velocity vectors must be right, and the deflection

///     limiter greater than zero.

///

///  Called:

///     iauPmpx      proper motion and parallax

///     iauLdn       light deflection by n bodies

///     iauAb        stellar aberration

///     iauRxp       product of r-matrix and pv-vector

///     iauC2s       p-vector to spherical

///     iauAnp       normalize angle into range 0 to 2pi

pub fn atciqn(

    rc: f64,

    dc: f64,

    pr: f64,

    pd: f64,

    px: f64,

    rv: f64,

    astrom: &mut IauAstrom,

    n: i32,

    b: &[IauLdBody],

) -> (f64, f64) {

    /* Proper motion and parallax, giving BCRS coordinate direction. */

    let pco = pmpx(rc, dc, pr, pd, px, rv, astrom.pmt, astrom.eb);

    /* Light deflection, giving BCRS natural direction. */

    let pnat = ldn(n, b, &astrom.eb, &pco);

    /* Aberration, giving GCRS proper direction. */

    let ppr = ab(&pnat, &astrom.v, astrom.em, astrom.bm1);

    /* Bias-precession-nutation, giving CIRS proper direction. */

    let pi = &mut [0.0; 3];

    rxp(&astrom.bpn, &ppr, pi);

    /* CIRS RA,Dec. */

    let (w, di) = c2s(pi);

    let ri = anp(w);

    (ri, di)

}