""" Astropy coordinate class for the Sagittarius coordinate system """

# Third-party
import numpy as np

import astropy.units as u
import astropy.coordinates as coord
from astropy.coordinates import frame_transform_graph
from astropy.coordinates.matrix_utilities import matrix_transpose
from astropy.utils.misc import InheritDocstrings

__all__ = ["GD1Koposov10", "GD1"]

class GD1Koposov10(coord.BaseCoordinateFrame, metaclass=InheritDocstrings):
    """
    A Heliocentric spherical coordinate system defined by the orbit
    of the GD1 stream, as described in
    Koposov et al. 2010 (see: `<http://arxiv.org/abs/0907.1085>`_).

    For more information about this class, see the Astropy documentation
    on coordinate frames in :mod:`~astropy.coordinates`.

    Parameters
    ----------
    representation : :class:`~astropy.coordinates.BaseRepresentation` or None
        A representation object or None to have no data (or use the other keywords)

    phi1 : angle_like, optional, must be keyword
        The longitude-like angle corresponding to GD-1's orbit.
    phi2 : angle_like, optional, must be keyword
        The latitude-like angle corresponding to GD-1's orbit.
    distance : :class:`~astropy.units.Quantity`, optional, must be keyword
        The Distance for this object along the line-of-sight.

    pm_phi1_cosphi2 : :class:`~astropy.units.Quantity`, optional, must be keyword
        The proper motion in the longitude-like direction corresponding to
        the GD-1 stream's orbit.
    pm_phi2 : :class:`~astropy.units.Quantity`, optional, must be keyword
        The proper motion in the latitude-like direction perpendicular to the
        GD-1 stream's orbit.
    radial_velocity : :class:`~astropy.units.Quantity`, optional, must be keyword
        The Distance for this object along the line-of-sight.

    """
    default_representation = coord.SphericalRepresentation
    default_differential = coord.SphericalCosLatDifferential

    frame_specific_representation_info = {
        coord.SphericalRepresentation: [
            coord.RepresentationMapping('lon', 'phi1'),
            coord.RepresentationMapping('lat', 'phi2'),
            coord.RepresentationMapping('distance', 'distance')],
    }

    _default_wrap_angle = 180*u.deg

    def __init__(self, *args, **kwargs):
        wrap = kwargs.pop('wrap_longitude', True)
        super().__init__(*args, **kwargs)
        if wrap and isinstance(self._data, (coord.UnitSphericalRepresentation,
                                            coord.SphericalRepresentation)):
            self._data.lon.wrap_angle = self._default_wrap_angle

    # TODO: remove this. This is a hack required as of astropy v3.1 in order
    # to have the longitude components wrap at the desired angle
    def represent_as(self, base, s='base', in_frame_units=False):
        r = super().represent_as(base, s=s, in_frame_units=in_frame_units)
        r.lon.wrap_angle = self._default_wrap_angle
        return r
    represent_as.__doc__ = coord.BaseCoordinateFrame.represent_as.__doc__
    

# Rotation matrix as defined in the Appendix of Koposov et al. (2010)
R = np.array([[-0.4776303088, -0.1738432154, 0.8611897727],
              [0.510844589, -0.8524449229, 0.111245042],
              [0.7147776536, 0.4930681392, 0.4959603976]])

@frame_transform_graph.transform(coord.StaticMatrixTransform, coord.ICRS,
                                 GD1Koposov10)
def icrs_to_gd1():
    """ Compute the transformation from Galactic spherical to
        heliocentric GD1 coordinates.
    """
    return R

@frame_transform_graph.transform(coord.StaticMatrixTransform, GD1Koposov10,
                                 coord.ICRS)
def gd1_to_icrs():
    """ Compute the transformation from heliocentric GD1 coordinates to
        spherical Galactic.
    """
    return matrix_transpose(icrs_to_gd1())


# TODO: remove this in next version
class GD1(GD1Koposov10):
    def __init__(self, *args, **kwargs):
        import warnings
        warnings.warn("This frame is deprecated. Use GD1Koposov10 instead.",
                      DeprecationWarning)
        super().__init__(*args, **kwargs)


trans = frame_transform_graph.get_transform(GD1Koposov10,
                                            coord.ICRS).transforms[0]
frame_transform_graph.add_transform(GD1, coord.ICRS, trans)
trans = frame_transform_graph.get_transform(coord.ICRS,
                                            GD1Koposov10).transforms[0]
frame_transform_graph.add_transform(coord.ICRS, GD1, trans)

@@ -284,57 +284,8 @@
 pose
-%0Afrom astropy.utils.misc import InheritDocstrings
 %0A%0A__
@@ -365,37 +365,8 @@
 rame
-, metaclass=InheritDocstrings
 ):%0A 

remove metaclass