import warnings

import pytest

import numpy as np
from numpy.testing import assert_equal, assert_allclose
from astropy.wcs.wcs import WCS, FITSFixedWarning
from astropy.time import Time
from astropy.wcs import WCS
from astropy.io.fits import Header
from astropy.io.fits.verify import VerifyWarning
from astropy.coordinates import SkyCoord, Galactic, ICRS
from astropy.units import Quantity
from astropy.wcs.wcsapi.wrappers.sliced_wcs import SlicedLowLevelWCS, sanitize_slices, combine_slices
from astropy.wcs.wcsapi.utils import wcs_info_str
import astropy.units as u

from astropy.coordinates.spectral_coordinate import SpectralCoord

# To test the slicing we start off from standard FITS WCS
# objects since those implement the low-level API. We create
# a WCS for a spectral cube with axes in non-standard order
# and with correlated celestial axes and an uncorrelated
# spectral axis.

HEADER_SPECTRAL_CUBE = """
NAXIS   = 3
NAXIS1  = 10
NAXIS2  = 20
NAXIS3  = 30
CTYPE1  = GLAT-CAR
CTYPE2  = FREQ
CTYPE3  = GLON-CAR
CNAME1  = Latitude
CNAME2  = Frequency
CNAME3  = Longitude
CRVAL1  = 10
CRVAL2  = 20
CRVAL3  = 25
CRPIX1  = 30
CRPIX2  = 40
CRPIX3  = 45
CDELT1  = -0.1
CDELT2  =  0.5
CDELT3  =  0.1
CUNIT1  = deg
CUNIT2  = Hz
CUNIT3  = deg
"""

with warnings.catch_warnings():
    warnings.simplefilter('ignore', VerifyWarning)
    WCS_SPECTRAL_CUBE = WCS(Header.fromstring(HEADER_SPECTRAL_CUBE, sep='\n'))
WCS_SPECTRAL_CUBE.pixel_bounds = [(-1, 11), (-2, 18), (5, 15)]


def test_invalid_slices():
    with pytest.raises(IndexError):
        SlicedLowLevelWCS(WCS_SPECTRAL_CUBE, [None, None, [False, False, False]])

    with pytest.raises(IndexError):
        SlicedLowLevelWCS(WCS_SPECTRAL_CUBE, [None, None, slice(None, None, 2)])

    with pytest.raises(IndexError):
        SlicedLowLevelWCS(WCS_SPECTRAL_CUBE, [None, None, 1000.100])


@pytest.mark.parametrize("item, ndim, expected", (
    ([Ellipsis, 10], 4, [slice(None)] * 3 + [10]),
    ([10, slice(20, 30)], 5, [10, slice(20, 30)] + [slice(None)] * 3),
    ([10, Ellipsis, 8], 10, [10] + [slice(None)] * 8 + [8])
))
def test_sanitize_slice(item, ndim, expected):
    new_item = sanitize_slices(item, ndim)
    # FIXME: do we still need the first two since the third assert
    # should cover it all?
    assert len(new_item) == ndim
    assert all(isinstance(i, (slice, int)) for i in new_item)
    assert new_item == expected


EXPECTED_ELLIPSIS_REPR = """
SlicedLowLevelWCS Transformation

This transformation has 3 pixel and 3 world dimensions

Array shape (Numpy order): (30, 20, 10)

Pixel Dim  Axis Name  Data size  Bounds
        0  None              10  (-1, 11)
        1  None              20  (-2, 18)
        2  None              30  (5, 15)

World Dim  Axis Name  Physical Type     Units
        0  Latitude   pos.galactic.lat  deg
        1  Frequency  em.freq           Hz
        2  Longitude  pos.galactic.lon  deg

Correlation between pixel and world axes:

             Pixel Dim
World Dim    0    1    2
        0  yes   no  yes
        1   no  yes   no
        2  yes   no  yes
"""


def test_ellipsis():

    wcs = SlicedLowLevelWCS(WCS_SPECTRAL_CUBE, Ellipsis)

    assert wcs.pixel_n_dim == 3
    assert wcs.world_n_dim == 3
    assert wcs.array_shape == (30, 20, 10)
    assert wcs.pixel_shape == (10, 20, 30)
    assert wcs.world_axis_physical_types == ['pos.galactic.lat', 'em.freq', 'pos.galactic.lon']
    assert wcs.world_axis_units == ['deg', 'Hz', 'deg']
    assert wcs.pixel_axis_names == ['', '', '']
    assert wcs.world_axis_names == ['Latitude', 'Frequency', 'Longitude']

    assert_equal(wcs.axis_correlation_matrix, [[True, False, True], [False, True, False], [True, False, True]])

    assert len(wcs.world_axis_object_components) == 3
    assert wcs.world_axis_object_components[0] == ('celestial', 1, 'spherical.lat.degree')
    assert wcs.world_axis_object_components[1][:2] == ('spectral', 0)
    assert wcs.world_axis_object_components[2] == ('celestial', 0, 'spherical.lon.degree')

    assert wcs.world_axis_object_classes['celestial'][0] is SkyCoord
    assert wcs.world_axis_object_classes['celestial'][1] == ()
    assert isinstance(wcs.world_axis_object_classes['celestial'][2]['frame'], Galactic)
    assert wcs.world_axis_object_classes['celestial'][2]['unit'] is u.deg

    assert wcs.world_axis_object_classes['spectral'][0] is Quantity
    assert wcs.world_axis_object_classes['spectral'][1] == ()
    assert wcs.world_axis_object_classes['spectral'][2] == {}

    assert_allclose(wcs.pixel_to_world_values(29, 39, 44), (10, 20, 25))
    assert_allclose(wcs.array_index_to_world_values(44, 39, 29), (10, 20, 25))

    assert_allclose(wcs.world_to_pixel_values(10, 20, 25), (29., 39., 44.))
    assert_equal(wcs.world_to_array_index_values(10, 20, 25), (44, 39, 29))

    assert_equal(wcs.pixel_bounds, [(-1, 11), (-2, 18), (5, 15)])

    assert str(wcs) == EXPECTED_ELLIPSIS_REPR.strip()
    assert EXPECTED_ELLIPSIS_REPR.strip() in repr(wcs)


def test_pixel_to_world_broadcasting():
    wcs = SlicedLowLevelWCS(WCS_SPECTRAL_CUBE, Ellipsis)

    assert_allclose(wcs.pixel_to_world_values((29, 29), 39, 44), ((10, 10), (20, 20), (25, 25)))


def test_world_to_pixel_broadcasting():
    wcs = SlicedLowLevelWCS(WCS_SPECTRAL_CUBE, Ellipsis)

    assert_allclose(wcs.world_to_pixel_values((10, 10), 20, 25), ((29., 29.), (39., 39.), (44., 44.)))


EXPECTED_SPECTRAL_SLICE_REPR = """
SlicedLowLevelWCS Transformation

This transformation has 2 pixel and 2 world dimensions

Array shape (Numpy order): (30, 10)

Pixel Dim  Axis Name  Data size  Bounds
        0  None              10  (-1, 11)
        1  None              30  (5, 15)

World Dim  Axis Name  Physical Type     Units
        0  Latitude   pos.galactic.lat  deg
        1  Longitude  pos.galactic.lon  deg

Correlation between pixel and world axes:

           Pixel Dim
World Dim    0    1
        0  yes  yes
        1  yes  yes
"""


def test_spectral_slice():

    wcs = SlicedLowLevelWCS(WCS_SPECTRAL_CUBE, [slice(None), 10])

    assert wcs.pixel_n_dim == 2
    assert wcs.world_n_dim == 2
    assert wcs.array_shape == (30, 10)
    assert wcs.pixel_shape == (10, 30)
    assert wcs.world_axis_physical_types == ['pos.galactic.lat', 'pos.galactic.lon']
    assert wcs.world_axis_units == ['deg', 'deg']
    assert wcs.pixel_axis_names == ['', '']
    assert wcs.world_axis_names == ['Latitude', 'Longitude']

    assert_equal(wcs.axis_correlation_matrix, [[True, True], [True, True]])

    assert wcs.world_axis_object_components == [('celestial', 1, 'spherical.lat.degree'),
                                                ('celestial', 0, 'spherical.lon.degree')]

    assert wcs.world_axis_object_classes['celestial'][0] is SkyCoord
    assert wcs.world_axis_object_classes['celestial'][1] == ()
    assert isinstance(wcs.world_axis_object_classes['celestial'][2]['frame'], Galactic)
    assert wcs.world_axis_object_classes['celestial'][2]['unit'] is u.deg

    assert_allclose(wcs.pixel_to_world_values(29, 44), (10, 25))
    assert_allclose(wcs.array_index_to_world_values(44, 29), (10, 25))

    assert_allclose(wcs.world_to_pixel_values(10, 25), (29., 44.))
    assert_equal(wcs.world_to_array_index_values(10, 25), (44, 29))

    assert_equal(wcs.pixel_bounds, [(-1, 11), (5, 15)])

    assert str(wcs) == EXPECTED_SPECTRAL_SLICE_REPR.strip()
    assert EXPECTED_SPECTRAL_SLICE_REPR.strip() in repr(wcs)


EXPECTED_SPECTRAL_RANGE_REPR = """
SlicedLowLevelWCS Transformation

This transformation has 3 pixel and 3 world dimensions

Array shape (Numpy order): (30, 6, 10)

Pixel Dim  Axis Name  Data size  Bounds
        0  None              10  (-1, 11)
        1  None               6  (-6, 14)
        2  None              30  (5, 15)

World Dim  Axis Name  Physical Type     Units
        0  Latitude   pos.galactic.lat  deg
        1  Frequency  em.freq           Hz
        2  Longitude  pos.galactic.lon  deg

Correlation between pixel and world axes:

             Pixel Dim
World Dim    0    1    2
        0  yes   no  yes
        1   no  yes   no
        2  yes   no  yes
"""


def test_spectral_range():

    wcs = SlicedLowLevelWCS(WCS_SPECTRAL_CUBE, [slice(None), slice(4, 10)])

    assert wcs.pixel_n_dim == 3
    assert wcs.world_n_dim == 3
    assert wcs.array_shape == (30, 6, 10)
    assert wcs.pixel_shape == (10, 6, 30)
    assert wcs.world_axis_physical_types == ['pos.galactic.lat', 'em.freq', 'pos.galactic.lon']
    assert wcs.world_axis_units == ['deg', 'Hz', 'deg']
    assert wcs.pixel_axis_names == ['', '', '']
    assert wcs.world_axis_names == ['Latitude', 'Frequency', 'Longitude']

    assert_equal(wcs.axis_correlation_matrix, [[True, False, True], [False, True, False], [True, False, True]])

    assert len(wcs.world_axis_object_components) == 3
    assert wcs.world_axis_object_components[0] == ('celestial', 1, 'spherical.lat.degree')
    assert wcs.world_axis_object_components[1][:2] == ('spectral', 0)
    assert wcs.world_axis_object_components[2] == ('celestial', 0, 'spherical.lon.degree')

    assert wcs.world_axis_object_classes['celestial'][0] is SkyCoord
    assert wcs.world_axis_object_classes['celestial'][1] == ()
    assert isinstance(wcs.world_axis_object_classes['celestial'][2]['frame'], Galactic)
    assert wcs.world_axis_object_classes['celestial'][2]['unit'] is u.deg

    assert wcs.world_axis_object_classes['spectral'][0] is Quantity
    assert wcs.world_axis_object_classes['spectral'][1] == ()
    assert wcs.world_axis_object_classes['spectral'][2] == {}

    assert_allclose(wcs.pixel_to_world_values(29, 35, 44), (10, 20, 25))
    assert_allclose(wcs.array_index_to_world_values(44, 35, 29), (10, 20, 25))

    assert_allclose(wcs.world_to_pixel_values(10, 20, 25), (29., 35., 44.))
    assert_equal(wcs.world_to_array_index_values(10, 20, 25), (44, 35, 29))

    assert_equal(wcs.pixel_bounds, [(-1, 11), (-6, 14), (5, 15)])

    assert str(wcs) == EXPECTED_SPECTRAL_RANGE_REPR.strip()
    assert EXPECTED_SPECTRAL_RANGE_REPR.strip() in repr(wcs)


EXPECTED_CELESTIAL_SLICE_REPR = """
SlicedLowLevelWCS Transformation

This transformation has 2 pixel and 3 world dimensions

Array shape (Numpy order): (30, 20)

Pixel Dim  Axis Name  Data size  Bounds
        0  None              20  (-2, 18)
        1  None              30  (5, 15)

World Dim  Axis Name  Physical Type     Units
        0  Latitude   pos.galactic.lat  deg
        1  Frequency  em.freq           Hz
        2  Longitude  pos.galactic.lon  deg

Correlation between pixel and world axes:

           Pixel Dim
World Dim    0    1
        0   no  yes
        1  yes   no
        2   no  yes
"""


def test_celestial_slice():

    wcs = SlicedLowLevelWCS(WCS_SPECTRAL_CUBE, [Ellipsis, 5])

    assert wcs.pixel_n_dim == 2
    assert wcs.world_n_dim == 3
    assert wcs.array_shape == (30, 20)
    assert wcs.pixel_shape == (20, 30)
    assert wcs.world_axis_physical_types == ['pos.galactic.lat', 'em.freq', 'pos.galactic.lon']
    assert wcs.world_axis_units == ['deg', 'Hz', 'deg']
    assert wcs.pixel_axis_names == ['', '']
    assert wcs.world_axis_names == ['Latitude', 'Frequency', 'Longitude']

    assert_equal(wcs.axis_correlation_matrix, [[False, True], [True, False], [False, True]])

    assert len(wcs.world_axis_object_components) == 3
    assert wcs.world_axis_object_components[0] == ('celestial', 1, 'spherical.lat.degree')
    assert wcs.world_axis_object_components[1][:2] == ('spectral', 0)
    assert wcs.world_axis_object_components[2] == ('celestial', 0, 'spherical.lon.degree')

    assert wcs.world_axis_object_classes['celestial'][0] is SkyCoord
    assert wcs.world_axis_object_classes['celestial'][1] == ()
    assert isinstance(wcs.world_axis_object_classes['celestial'][2]['frame'], Galactic)
    assert wcs.world_axis_object_classes['celestial'][2]['unit'] is u.deg

    assert wcs.world_axis_object_classes['spectral'][0] is Quantity
    assert wcs.world_axis_object_classes['spectral'][1] == ()
    assert wcs.world_axis_object_classes['spectral'][2] == {}

    assert_allclose(wcs.pixel_to_world_values(39, 44), (12.4, 20, 25))
    assert_allclose(wcs.array_index_to_world_values(44, 39), (12.4, 20, 25))

    assert_allclose(wcs.world_to_pixel_values(12.4, 20, 25), (39., 44.))
    assert_equal(wcs.world_to_array_index_values(12.4, 20, 25), (44, 39))

    assert_equal(wcs.pixel_bounds, [(-2, 18), (5, 15)])

    assert str(wcs) == EXPECTED_CELESTIAL_SLICE_REPR.strip()
    assert EXPECTED_CELESTIAL_SLICE_REPR.strip() in repr(wcs)


EXPECTED_CELESTIAL_RANGE_REPR = """
SlicedLowLevelWCS Transformation

This transformation has 3 pixel and 3 world dimensions

Array shape (Numpy order): (30, 20, 5)

Pixel Dim  Axis Name  Data size  Bounds
        0  None               5  (-6, 6)
        1  None              20  (-2, 18)
        2  None              30  (5, 15)

World Dim  Axis Name  Physical Type     Units
        0  Latitude   pos.galactic.lat  deg
        1  Frequency  em.freq           Hz
        2  Longitude  pos.galactic.lon  deg

Correlation between pixel and world axes:

             Pixel Dim
World Dim    0    1    2
        0  yes   no  yes
        1   no  yes   no
        2  yes   no  yes
"""


def test_celestial_range():

    wcs = SlicedLowLevelWCS(WCS_SPECTRAL_CUBE, [Ellipsis, slice(5, 10)])

    assert wcs.pixel_n_dim == 3
    assert wcs.world_n_dim == 3
    assert wcs.array_shape == (30, 20, 5)
    assert wcs.pixel_shape == (5, 20, 30)
    assert wcs.world_axis_physical_types == ['pos.galactic.lat', 'em.freq', 'pos.galactic.lon']
    assert wcs.world_axis_units == ['deg', 'Hz', 'deg']
    assert wcs.pixel_axis_names == ['', '', '']
    assert wcs.world_axis_names == ['Latitude', 'Frequency', 'Longitude']

    assert_equal(wcs.axis_correlation_matrix, [[True, False, True], [False, True, False], [True, False, True]])

    assert len(wcs.world_axis_object_components) == 3
    assert wcs.world_axis_object_components[0] == ('celestial', 1, 'spherical.lat.degree')
    assert wcs.world_axis_object_components[1][:2] == ('spectral', 0)
    assert wcs.world_axis_object_components[2] == ('celestial', 0, 'spherical.lon.degree')

    assert wcs.world_axis_object_classes['celestial'][0] is SkyCoord
    assert wcs.world_axis_object_classes['celestial'][1] == ()
    assert isinstance(wcs.world_axis_object_classes['celestial'][2]['frame'], Galactic)
    assert wcs.world_axis_object_classes['celestial'][2]['unit'] is u.deg

    assert wcs.world_axis_object_classes['spectral'][0] is Quantity
    assert wcs.world_axis_object_classes['spectral'][1] == ()
    assert wcs.world_axis_object_classes['spectral'][2] == {}

    assert_allclose(wcs.pixel_to_world_values(24, 39, 44), (10, 20, 25))
    assert_allclose(wcs.array_index_to_world_values(44, 39, 24), (10, 20, 25))

    assert_allclose(wcs.world_to_pixel_values(10, 20, 25), (24., 39., 44.))
    assert_equal(wcs.world_to_array_index_values(10, 20, 25), (44, 39, 24))

    assert_equal(wcs.pixel_bounds, [(-6, 6), (-2, 18), (5, 15)])

    assert str(wcs) == EXPECTED_CELESTIAL_RANGE_REPR.strip()
    assert EXPECTED_CELESTIAL_RANGE_REPR.strip() in repr(wcs)


# Now try with a 90 degree rotation

with warnings.catch_warnings():
    warnings.simplefilter('ignore', VerifyWarning)
    WCS_SPECTRAL_CUBE_ROT = WCS(Header.fromstring(
        HEADER_SPECTRAL_CUBE, sep='\n'))
WCS_SPECTRAL_CUBE_ROT.wcs.pc = [[0, 0, 1], [0, 1, 0], [1, 0, 0]]
WCS_SPECTRAL_CUBE_ROT.wcs.crval[0] = 0
WCS_SPECTRAL_CUBE_ROT.pixel_bounds = [(-1, 11), (-2, 18), (5, 15)]

EXPECTED_CELESTIAL_RANGE_ROT_REPR = """
SlicedLowLevelWCS Transformation

This transformation has 3 pixel and 3 world dimensions

Array shape (Numpy order): (30, 20, 5)

Pixel Dim  Axis Name  Data size  Bounds
        0  None               5  (-6, 6)
        1  None              20  (-2, 18)
        2  None              30  (5, 15)

World Dim  Axis Name  Physical Type     Units
        0  Latitude   pos.galactic.lat  deg
        1  Frequency  em.freq           Hz
        2  Longitude  pos.galactic.lon  deg

Correlation between pixel and world axes:

             Pixel Dim
World Dim    0    1    2
        0  yes   no  yes
        1   no  yes   no
        2  yes   no  yes
"""


def test_celestial_range_rot():

    wcs = SlicedLowLevelWCS(WCS_SPECTRAL_CUBE_ROT, [Ellipsis, slice(5, 10)])

    assert wcs.pixel_n_dim == 3
    assert wcs.world_n_dim == 3
    assert wcs.array_shape == (30, 20, 5)
    assert wcs.pixel_shape == (5, 20, 30)
    assert wcs.world_axis_physical_types == ['pos.galactic.lat', 'em.freq', 'pos.galactic.lon']
    assert wcs.world_axis_units == ['deg', 'Hz', 'deg']
    assert wcs.pixel_axis_names == ['', '', '']
    assert wcs.world_axis_names == ['Latitude', 'Frequency', 'Longitude']

    assert_equal(wcs.axis_correlation_matrix, [[True, False, True], [False, True, False], [True, False, True]])

    assert len(wcs.world_axis_object_components) == 3
    assert wcs.world_axis_object_components[0] == ('celestial', 1, 'spherical.lat.degree')
    assert wcs.world_axis_object_components[1][:2] == ('spectral', 0)
    assert wcs.world_axis_object_components[2] == ('celestial', 0, 'spherical.lon.degree')

    assert wcs.world_axis_object_classes['celestial'][0] is SkyCoord
    assert wcs.world_axis_object_classes['celestial'][1] == ()
    assert isinstance(wcs.world_axis_object_classes['celestial'][2]['frame'], Galactic)
    assert wcs.world_axis_object_classes['celestial'][2]['unit'] is u.deg

    assert wcs.world_axis_object_classes['spectral'][0] is Quantity
    assert wcs.world_axis_object_classes['spectral'][1] == ()
    assert wcs.world_axis_object_classes['spectral'][2] == {}

    assert_allclose(wcs.pixel_to_world_values(14, 29, 34), (1, 15, 24))
    assert_allclose(wcs.array_index_to_world_values(34, 29, 14), (1, 15, 24))

    assert_allclose(wcs.world_to_pixel_values(1, 15, 24), (14., 29., 34.))
    assert_equal(wcs.world_to_array_index_values(1, 15, 24), (34, 29, 14))

    assert_equal(wcs.pixel_bounds, [(-6, 6), (-2, 18), (5, 15)])

    assert str(wcs) == EXPECTED_CELESTIAL_RANGE_ROT_REPR.strip()
    assert EXPECTED_CELESTIAL_RANGE_ROT_REPR.strip() in repr(wcs)


HEADER_NO_SHAPE_CUBE = """
NAXIS   = 3
CTYPE1  = GLAT-CAR
CTYPE2  = FREQ
CTYPE3  = GLON-CAR
CRVAL1  = 10
CRVAL2  = 20
CRVAL3  = 25
CRPIX1  = 30
CRPIX2  = 40
CRPIX3  = 45
CDELT1  = -0.1
CDELT2  =  0.5
CDELT3  =  0.1
CUNIT1  = deg
CUNIT2  = Hz
CUNIT3  = deg
"""

with warnings.catch_warnings():
    warnings.simplefilter('ignore', VerifyWarning)
    WCS_NO_SHAPE_CUBE = WCS(Header.fromstring(HEADER_NO_SHAPE_CUBE, sep='\n'))

EXPECTED_NO_SHAPE_REPR = """
SlicedLowLevelWCS Transformation

This transformation has 3 pixel and 3 world dimensions

Array shape (Numpy order): None

Pixel Dim  Axis Name  Data size  Bounds
        0  None            None  None
        1  None            None  None
        2  None            None  None

World Dim  Axis Name  Physical Type     Units
        0  None       pos.galactic.lat  deg
        1  None       em.freq           Hz
        2  None       pos.galactic.lon  deg

Correlation between pixel and world axes:

             Pixel Dim
World Dim    0    1    2
        0  yes   no  yes
        1   no  yes   no
        2  yes   no  yes
"""


def test_no_array_shape():

    wcs = SlicedLowLevelWCS(WCS_NO_SHAPE_CUBE, Ellipsis)

    assert wcs.pixel_n_dim == 3
    assert wcs.world_n_dim == 3
    assert wcs.array_shape is None
    assert wcs.pixel_shape is None
    assert wcs.world_axis_physical_types == ['pos.galactic.lat', 'em.freq', 'pos.galactic.lon']
    assert wcs.world_axis_units == ['deg', 'Hz', 'deg']

    assert_equal(wcs.axis_correlation_matrix, [[True, False, True], [False, True, False], [True, False, True]])

    assert len(wcs.world_axis_object_components) == 3
    assert wcs.world_axis_object_components[0] == ('celestial', 1, 'spherical.lat.degree')
    assert wcs.world_axis_object_components[1][:2] == ('spectral', 0)
    assert wcs.world_axis_object_components[2] == ('celestial', 0, 'spherical.lon.degree')

    assert wcs.world_axis_object_classes['celestial'][0] is SkyCoord
    assert wcs.world_axis_object_classes['celestial'][1] == ()
    assert isinstance(wcs.world_axis_object_classes['celestial'][2]['frame'], Galactic)
    assert wcs.world_axis_object_classes['celestial'][2]['unit'] is u.deg

    assert wcs.world_axis_object_classes['spectral'][0] is Quantity
    assert wcs.world_axis_object_classes['spectral'][1] == ()
    assert wcs.world_axis_object_classes['spectral'][2] == {}

    assert_allclose(wcs.pixel_to_world_values(29, 39, 44), (10, 20, 25))
    assert_allclose(wcs.array_index_to_world_values(44, 39, 29), (10, 20, 25))

    assert_allclose(wcs.world_to_pixel_values(10, 20, 25), (29., 39., 44.))
    assert_equal(wcs.world_to_array_index_values(10, 20, 25), (44, 39, 29))

    assert str(wcs) == EXPECTED_NO_SHAPE_REPR.strip()
    assert EXPECTED_NO_SHAPE_REPR.strip() in repr(wcs)


# Testing the WCS object having some physical types as None/Unknown
HEADER_SPECTRAL_CUBE_NONE_TYPES = {
        'CTYPE1': 'GLAT-CAR',
        'CUNIT1': 'deg',
        'CDELT1': -0.1,
        'CRPIX1': 30,
        'CRVAL1': 10,
        'NAXIS1': 10,
        'CTYPE2': '',
        'CUNIT2': 'Hz',
        'CDELT2':  0.5,
        'CRPIX2': 40,
        'CRVAL2': 20,
        'NAXIS2': 20,
        'CTYPE3': 'GLON-CAR',
        'CUNIT3': 'deg',
        'CDELT3':  0.1,
        'CRPIX3': 45,
        'CRVAL3': 25,
        'NAXIS3': 30
}

WCS_SPECTRAL_CUBE_NONE_TYPES = WCS(header=HEADER_SPECTRAL_CUBE_NONE_TYPES)
WCS_SPECTRAL_CUBE_NONE_TYPES.pixel_bounds = [(-1, 11), (-2, 18), (5, 15)]


EXPECTED_ELLIPSIS_REPR_NONE_TYPES = """
SlicedLowLevelWCS Transformation

This transformation has 3 pixel and 3 world dimensions

Array shape (Numpy order): (30, 20, 10)

Pixel Dim  Axis Name  Data size  Bounds
        0  None              10  (-1, 11)
        1  None              20  (-2, 18)
        2  None              30  (5, 15)

World Dim  Axis Name  Physical Type     Units
        0  None       pos.galactic.lat  deg
        1  None       None              Hz
        2  None       pos.galactic.lon  deg

Correlation between pixel and world axes:

             Pixel Dim
World Dim    0    1    2
        0  yes   no  yes
        1   no  yes   no
        2  yes   no  yes
"""


def test_ellipsis_none_types():

    wcs = SlicedLowLevelWCS(WCS_SPECTRAL_CUBE_NONE_TYPES, Ellipsis)

    assert wcs.pixel_n_dim == 3
    assert wcs.world_n_dim == 3
    assert wcs.array_shape == (30, 20, 10)
    assert wcs.pixel_shape == (10, 20, 30)
    assert wcs.world_axis_physical_types == ['pos.galactic.lat', None, 'pos.galactic.lon']
    assert wcs.world_axis_units == ['deg', 'Hz', 'deg']

    assert_equal(wcs.axis_correlation_matrix, [[True, False, True],
                                               [False, True, False], [True, False, True]])

    assert wcs.world_axis_object_components == [('celestial', 1, 'spherical.lat.degree'),
                                                  ('world', 0, 'value'),
                                                  ('celestial', 0, 'spherical.lon.degree')]

    assert wcs.world_axis_object_classes['celestial'][0] is SkyCoord
    assert wcs.world_axis_object_classes['celestial'][1] == ()
    assert isinstance(wcs.world_axis_object_classes['celestial'][2]['frame'], Galactic)
    assert wcs.world_axis_object_classes['celestial'][2]['unit'] is u.deg

    assert_allclose(wcs.pixel_to_world_values(29, 39, 44), (10, 20, 25))
    assert_allclose(wcs.array_index_to_world_values(44, 39, 29), (10, 20, 25))

    assert_allclose(wcs.world_to_pixel_values(10, 20, 25), (29., 39., 44.))
    assert_equal(wcs.world_to_array_index_values(10, 20, 25), (44, 39, 29))

    assert_equal(wcs.pixel_bounds, [(-1, 11), (-2, 18), (5, 15)])

    assert str(wcs) == EXPECTED_ELLIPSIS_REPR_NONE_TYPES.strip()
    assert EXPECTED_ELLIPSIS_REPR_NONE_TYPES.strip() in repr(wcs)


CASES = [(slice(None), slice(None), slice(None)),
         (slice(None), slice(3, None), slice(3, None)),
         (slice(None), slice(None, 16), slice(None, 16)),
         (slice(None), slice(3, 16), slice(3, 16)),
         (slice(2, None), slice(None), slice(2, None)),
         (slice(2, None), slice(3, None), slice(5, None)),
         (slice(2, None), slice(None, 16), slice(2, 18)),
         (slice(2, None), slice(3, 16), slice(5, 18)),
         (slice(None, 10), slice(None), slice(None, 10)),
         (slice(None, 10), slice(3, None), slice(3, 10)),
         (slice(None, 10), slice(None, 16), slice(None, 10)),
         (slice(None, 10), slice(3, 16), slice(3, 10)),
         (slice(2, 10), slice(None), slice(2, 10)),
         (slice(2, 10), slice(3, None), slice(5, 10)),
         (slice(2, 10), slice(None, 16), slice(2, 10)),
         (slice(2, 10), slice(3, 16), slice(5, 10)),
         (slice(None), 3, 3),
         (slice(2, None), 3, 5),
         (slice(None, 10), 3, 3),
         (slice(2, 10), 3, 5)]


@pytest.mark.parametrize(('slice1', 'slice2', 'expected'), CASES)
def test_combine_slices(slice1, slice2, expected):
    assert combine_slices(slice1, slice2) == expected


def test_nested_slicing():
    # Make sure that if we call slicing several times, the result is the same
    # as calling the slicing once with the final slice settings.
    wcs = WCS_SPECTRAL_CUBE
    sub1 = SlicedLowLevelWCS(
                SlicedLowLevelWCS(
                    SlicedLowLevelWCS(wcs, [slice(None), slice(1, 10), slice(None)]),
                    [3, slice(2, None)]),
                [slice(None), slice(2, 8)])
    sub2 = wcs[3, 3:10, 2:8]
    assert_allclose(sub1.pixel_to_world_values(3, 5),
                    sub2.pixel_to_world_values(3, 5))
    assert not isinstance(sub1._wcs, SlicedLowLevelWCS)


def test_too_much_slicing():
    wcs = WCS_SPECTRAL_CUBE
    with pytest.raises(ValueError, match='Cannot slice WCS: the resulting WCS '
                                         'should have at least one pixel and '
                                         'one world dimension'):
        wcs[0, 1, 2]


HEADER_TIME_1D = """
SIMPLE  = T
BITPIX  = -32
NAXIS   = 1
NAXIS1  = 2048
TIMESYS = 'UTC'
TREFPOS = 'TOPOCENT'
MJDREF  = 50002.6
CTYPE1  = 'UTC'
CRVAL1  = 5
CUNIT1  = 's'
CRPIX1  = 1.0
CDELT1  = 2
OBSGEO-L= -20
OBSGEO-B= -70
OBSGEO-H= 2530
"""


@pytest.fixture
def header_time_1d():
    return Header.fromstring(HEADER_TIME_1D, sep='\n')


@pytest.fixture
def time_1d_wcs(header_time_1d):
    with warnings.catch_warnings():
        warnings.simplefilter('ignore', FITSFixedWarning)
        return WCS(header_time_1d)


def test_1d_sliced_low_level(time_1d_wcs):
    sll = SlicedLowLevelWCS(time_1d_wcs, np.s_[10:20])
    world = sll.pixel_to_world_values([1, 2])
    assert isinstance(world, np.ndarray)
    assert np.allclose(world, [27, 29])


def validate_info_dict(result, expected):
    result_value = result.pop("value")
    expected_value = expected.pop("value")

    np.testing.assert_allclose(result_value, expected_value)
    assert result == expected


def test_dropped_dimensions():
    wcs = WCS_SPECTRAL_CUBE

    sub = SlicedLowLevelWCS(wcs, np.s_[:, :, :])

    assert sub.dropped_world_dimensions == {}

    sub = SlicedLowLevelWCS(wcs, np.s_[:, 2:5, :])

    assert sub.dropped_world_dimensions == {}

    sub = SlicedLowLevelWCS(wcs, np.s_[:, 0])

    waocomp =sub.dropped_world_dimensions.pop("world_axis_object_components")
    assert len(waocomp) == 1 and waocomp[0][0] == "spectral" and waocomp[0][1] == 0
    waocls = sub.dropped_world_dimensions.pop("world_axis_object_classes")
    assert len(waocls) == 1 and "spectral" in waocls and waocls["spectral"][0] == u.Quantity
    validate_info_dict(sub.dropped_world_dimensions, {
        "value": [0.5],
        "world_axis_physical_types": ["em.freq"],
        "world_axis_names": ["Frequency"],
        "world_axis_units": ["Hz"],
        "serialized_classes": False,
        })

    sub = SlicedLowLevelWCS(wcs, np.s_[:, 0, 0])

    waocomp =sub.dropped_world_dimensions.pop("world_axis_object_components")
    assert len(waocomp) == 1 and waocomp[0][0] == "spectral" and waocomp[0][1] == 0
    waocls = sub.dropped_world_dimensions.pop("world_axis_object_classes")
    assert len(waocls) == 1 and "spectral" in waocls and waocls["spectral"][0] == u.Quantity
    validate_info_dict(sub.dropped_world_dimensions, {
        "value": [0.5],
        "world_axis_physical_types": ["em.freq"],
        "world_axis_names": ["Frequency"],
        "world_axis_units": ["Hz"],
        "serialized_classes": False,
        })

    sub = SlicedLowLevelWCS(wcs, np.s_[0, :, 0])

    dwd = sub.dropped_world_dimensions
    wao_classes = dwd.pop("world_axis_object_classes")
    validate_info_dict(dwd, {
        "value": [12.86995801, 20.49217541],
        "world_axis_physical_types": ["pos.galactic.lat", "pos.galactic.lon"],
        "world_axis_names": ["Latitude", "Longitude"],
        "world_axis_units": ["deg", "deg"],
        "serialized_classes": False,
        "world_axis_object_components": [('celestial', 1, 'spherical.lat.degree'), ('celestial', 0, 'spherical.lon.degree')],
        })

    assert wao_classes['celestial'][0] is SkyCoord
    assert wao_classes['celestial'][1] == ()
    assert isinstance(wao_classes['celestial'][2]['frame'], Galactic)
    assert wao_classes['celestial'][2]['unit'] is u.deg

    sub = SlicedLowLevelWCS(wcs, np.s_[5, :5, 12])

    dwd = sub.dropped_world_dimensions
    wao_classes = dwd.pop("world_axis_object_classes")
    validate_info_dict(dwd, {
        "value": [11.67648267, 21.01921192],
        "world_axis_physical_types": ["pos.galactic.lat", "pos.galactic.lon"],
        "world_axis_names": ["Latitude", "Longitude"],
        "world_axis_units": ["deg", "deg"],
        "serialized_classes": False,
        "world_axis_object_components": [('celestial', 1, 'spherical.lat.degree'), ('celestial', 0, 'spherical.lon.degree')],
        })

    assert wao_classes['celestial'][0] is SkyCoord
    assert wao_classes['celestial'][1] == ()
    assert isinstance(wao_classes['celestial'][2]['frame'], Galactic)
    assert wao_classes['celestial'][2]['unit'] is u.deg


def test_dropped_dimensions_4d(cube_4d_fitswcs):

    sub = SlicedLowLevelWCS(cube_4d_fitswcs, np.s_[:, 12, 5, 5])

    dwd = sub.dropped_world_dimensions
    wao_classes = dwd.pop("world_axis_object_classes")
    wao_components = dwd.pop("world_axis_object_components")

    validate_info_dict(dwd, {
        "value": [4.e+00, -2.e+00,  1.e+10],
        "world_axis_physical_types": ["pos.eq.ra", "pos.eq.dec", "em.freq"],
        "world_axis_names": ['Right Ascension', 'Declination', 'Frequency'],
        "world_axis_units": ["deg", "deg", "Hz"],
        "serialized_classes": False,
        })

    assert wao_classes['celestial'][0] is SkyCoord
    assert wao_classes['celestial'][1] == ()
    assert isinstance(wao_classes['celestial'][2]['frame'], ICRS)
    assert wao_classes['celestial'][2]['unit'] is u.deg
    assert wao_classes['spectral'][0:3] == (u.Quantity, (), {})

    assert wao_components[0] == ('celestial', 0, 'spherical.lon.degree')
    assert wao_components[1] == ('celestial', 1, 'spherical.lat.degree')
    assert wao_components[2][0:2] == ('spectral', 0)

    sub = SlicedLowLevelWCS(cube_4d_fitswcs, np.s_[12, 12])

    dwd = sub.dropped_world_dimensions
    wao_classes = dwd.pop("world_axis_object_classes")
    wao_components = dwd.pop("world_axis_object_components")
    validate_info_dict(dwd, {
        "value": [1.e+10, 5.e+00],
        "world_axis_physical_types": ["em.freq", "time"],
        "world_axis_names": ["Frequency", "Time"],
        "world_axis_units": ["Hz", "s"],
        "serialized_classes": False,
        })
    assert wao_components[0][0:2] == ('spectral', 0)
    assert wao_components[1][0] == 'time'
    assert wao_components[1][1] == 0

    assert wao_classes['spectral'][0:3] == (u.Quantity, (), {})
    assert wao_classes['time'][0:3] == (Time, (), {})


def test_pixel_to_world_values_different_int_types():
    int_sliced = SlicedLowLevelWCS(WCS_SPECTRAL_CUBE, np.s_[:, 0, :])
    np64_sliced = SlicedLowLevelWCS(WCS_SPECTRAL_CUBE, np.s_[:, np.int64(0), :])
    pixel_arrays = ([0, 1], [0, 1])
    for int_coord, np64_coord in zip(int_sliced.pixel_to_world_values(*pixel_arrays),
                                     np64_sliced.pixel_to_world_values(*pixel_arrays)):
        assert all(int_coord == np64_coord)


COUPLED_WCS_HEADER = {
    'WCSAXES': 3,
    'CRPIX1': (100 + 1)/2,
    'CRPIX2': (25 + 1)/2,
    'CRPIX3': 1.0,
    'PC1_1': 0.0,
    'PC1_2': -1.0,
    'PC1_3': 0.0,
    'PC2_1': 1.0,
    'PC2_2': 0.0,
    'PC2_3': -1.0,
    'CDELT1': 5,
    'CDELT2': 5,
    'CDELT3': 0.055,
    'CUNIT1': 'arcsec',
    'CUNIT2': 'arcsec',
    'CUNIT3': 'Angstrom',
    'CTYPE1': 'HPLN-TAN',
    'CTYPE2': 'HPLT-TAN',
    'CTYPE3': 'WAVE',
    'CRVAL1': 0.0,
    'CRVAL2': 0.0,
    'CRVAL3': 1.05,

}


def test_coupled_world_slicing():
    fits_wcs = WCS(header=COUPLED_WCS_HEADER)
    sl = SlicedLowLevelWCS(fits_wcs, 0)
    world = fits_wcs.pixel_to_world_values(0,0,0)
    out_pix = sl.world_to_pixel_values(world[0], world[1])

    assert np.allclose(out_pix[0], 0)
