import numpy as np
import pytest
from numpy.testing import assert_array_equal, assert_equal
from scipy import ndimage as ndi

from skimage import data, color, morphology
from skimage.util import img_as_bool
from skimage.morphology import binary, footprints, gray, footprint_rectangle


img = color.rgb2gray(data.astronaut())
bw_img = img > 100 / 255.0


def test_non_square_image():
    footprint = footprint_rectangle((3, 3))
    binary_res = binary.binary_erosion(bw_img[:100, :200], footprint)
    gray_res = img_as_bool(gray.erosion(bw_img[:100, :200], footprint))
    assert_array_equal(binary_res, gray_res)


def test_binary_erosion():
    footprint = footprint_rectangle((3, 3))
    binary_res = binary.binary_erosion(bw_img, footprint)
    gray_res = img_as_bool(gray.erosion(bw_img, footprint))
    assert_array_equal(binary_res, gray_res)


def test_binary_dilation():
    footprint = footprint_rectangle((3, 3))
    binary_res = binary.binary_dilation(bw_img, footprint)
    gray_res = img_as_bool(gray.dilation(bw_img, footprint))
    assert_array_equal(binary_res, gray_res)


def test_binary_closing():
    footprint = footprint_rectangle((3, 3))
    binary_res = binary.binary_closing(bw_img, footprint)
    gray_res = img_as_bool(gray.closing(bw_img, footprint))
    assert_array_equal(binary_res, gray_res)


def test_binary_closing_extensive():
    footprint = np.array([[0, 0, 1], [0, 1, 1], [1, 1, 1]])

    result_default = binary.binary_closing(bw_img, footprint=footprint)
    assert np.all(result_default >= bw_img)

    # mode="min" is expected to be not extensive
    result_min = binary.binary_closing(img, footprint=footprint, mode="min")
    assert not np.all(result_min >= bw_img)


def test_binary_opening():
    footprint = footprint_rectangle((3, 3))
    binary_res = binary.binary_opening(bw_img, footprint)
    gray_res = img_as_bool(gray.opening(bw_img, footprint))
    assert_array_equal(binary_res, gray_res)


def test_binary_opening_anti_extensive():
    footprint = np.array([[0, 0, 1], [0, 1, 1], [1, 1, 1]])

    result_default = binary.binary_opening(bw_img, footprint=footprint)
    assert np.all(result_default <= bw_img)

    # mode="max" is expected to be not extensive
    result_max = binary.binary_opening(bw_img, footprint=footprint, mode="max")
    assert not np.all(result_max <= bw_img)


def _get_decomp_test_data(function, ndim=2):
    if function == 'binary_erosion':
        img = np.ones((17,) * ndim, dtype=np.uint8)
        img[8, 8] = 0
    elif function == 'binary_dilation':
        img = np.zeros((17,) * ndim, dtype=np.uint8)
        img[8, 8] = 1
    else:
        img = data.binary_blobs(32, n_dim=ndim, rng=1)
    return img


@pytest.mark.parametrize(
    "function",
    ["binary_erosion", "binary_dilation", "binary_closing", "binary_opening"],
)
@pytest.mark.parametrize("nrows", (3, 7, 11))
@pytest.mark.parametrize("ncols", (3, 7, 11))
@pytest.mark.parametrize("decomposition", ['separable', 'sequence'])
def test_rectangle_decomposition(function, nrows, ncols, decomposition):
    """Validate footprint decomposition for various shapes.

    comparison is made to the case without decomposition.
    """
    footprint_ndarray = footprint_rectangle((nrows, ncols), decomposition=None)
    footprint = footprint_rectangle((nrows, ncols), decomposition=decomposition)
    img = _get_decomp_test_data(function)
    func = getattr(binary, function)
    expected = func(img, footprint=footprint_ndarray)
    out = func(img, footprint=footprint)
    assert_array_equal(expected, out)


@pytest.mark.parametrize(
    "function",
    ["binary_erosion", "binary_dilation", "binary_closing", "binary_opening"],
)
@pytest.mark.parametrize("m", (0, 1, 2, 3, 4, 5))
@pytest.mark.parametrize("n", (0, 1, 2, 3, 4, 5))
@pytest.mark.parametrize("decomposition", ['sequence'])
@pytest.mark.filterwarnings(
    "ignore:.*falling back to decomposition='separable':UserWarning:skimage"
)
def test_octagon_decomposition(function, m, n, decomposition):
    """Validate footprint decomposition for various shapes.

    comparison is made to the case without decomposition.
    """
    if m == 0 and n == 0:
        with pytest.raises(ValueError):
            footprints.octagon(m, n, decomposition=decomposition)
    else:
        footprint_ndarray = footprints.octagon(m, n, decomposition=None)
        footprint = footprints.octagon(m, n, decomposition=decomposition)
        img = _get_decomp_test_data(function)
        func = getattr(binary, function)
        expected = func(img, footprint=footprint_ndarray)
        out = func(img, footprint=footprint)
        assert_array_equal(expected, out)


@pytest.mark.parametrize(
    "function",
    ["binary_erosion", "binary_dilation", "binary_closing", "binary_opening"],
)
@pytest.mark.parametrize("radius", (1, 2, 5))
@pytest.mark.parametrize("decomposition", ['sequence'])
def test_diamond_decomposition(function, radius, decomposition):
    """Validate footprint decomposition for various shapes.

    comparison is made to the case without decomposition.
    """
    footprint_ndarray = footprints.diamond(radius, decomposition=None)
    footprint = footprints.diamond(radius, decomposition=decomposition)
    img = _get_decomp_test_data(function)
    func = getattr(binary, function)
    expected = func(img, footprint=footprint_ndarray)
    out = func(img, footprint=footprint)
    assert_array_equal(expected, out)


@pytest.mark.parametrize(
    "function",
    ["binary_erosion", "binary_dilation", "binary_closing", "binary_opening"],
)
@pytest.mark.parametrize("shape", [(3, 3, 3), (3, 4, 5)])
@pytest.mark.parametrize("decomposition", ['separable', 'sequence'])
@pytest.mark.filterwarnings(
    "ignore:.*falling back to decomposition='separable':UserWarning:skimage"
)
def test_cube_decomposition(function, shape, decomposition):
    """Validate footprint decomposition for various shapes.

    comparison is made to the case without decomposition.
    """
    footprint_ndarray = footprint_rectangle(shape, decomposition=None)
    footprint = footprint_rectangle(shape, decomposition=decomposition)
    img = _get_decomp_test_data(function, ndim=3)
    func = getattr(binary, function)
    expected = func(img, footprint=footprint_ndarray)
    out = func(img, footprint=footprint)
    assert_array_equal(expected, out)


@pytest.mark.parametrize(
    "function",
    ["binary_erosion", "binary_dilation", "binary_closing", "binary_opening"],
)
@pytest.mark.parametrize("radius", (1, 2, 3))
@pytest.mark.parametrize("decomposition", ['sequence'])
def test_octahedron_decomposition(function, radius, decomposition):
    """Validate footprint decomposition for various shapes.

    comparison is made to the case without decomposition.
    """
    footprint_ndarray = footprints.octahedron(radius, decomposition=None)
    footprint = footprints.octahedron(radius, decomposition=decomposition)
    img = _get_decomp_test_data(function, ndim=3)
    func = getattr(binary, function)
    expected = func(img, footprint=footprint_ndarray)
    out = func(img, footprint=footprint)
    assert_array_equal(expected, out)


def test_footprint_overflow():
    footprint = np.ones((17, 17), dtype=np.uint8)
    img = np.zeros((20, 20), dtype=bool)
    img[2:19, 2:19] = True
    binary_res = binary.binary_erosion(img, footprint)
    gray_res = img_as_bool(gray.erosion(img, footprint))
    assert_array_equal(binary_res, gray_res)


def test_out_argument():
    for func in (binary.binary_erosion, binary.binary_dilation):
        footprint = np.ones((3, 3), dtype=np.uint8)
        img = np.ones((10, 10))
        out = np.zeros_like(img)
        out_saved = out.copy()
        func(img, footprint, out=out)
        assert np.any(out != out_saved)
        assert_array_equal(out, func(img, footprint))


binary_functions = [
    binary.binary_erosion,
    binary.binary_dilation,
    binary.binary_opening,
    binary.binary_closing,
]


@pytest.mark.parametrize("func", binary_functions)
@pytest.mark.parametrize("mode", ['max', 'min', 'ignore'])
def test_supported_mode(func, mode):
    img = np.ones((10, 10), dtype=bool)
    func(img, mode=mode)


@pytest.mark.parametrize("func", binary_functions)
@pytest.mark.parametrize("mode", ["reflect", 3, None])
def test_unsupported_mode(func, mode):
    img = np.ones((10, 10))
    with pytest.raises(ValueError, match="unsupported mode"):
        func(img, mode=mode)


@pytest.mark.parametrize("function", binary_functions)
def test_default_footprint(function):
    footprint = morphology.diamond(radius=1)
    image = np.array(
        [
            [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
            [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
            [0, 0, 1, 1, 1, 1, 1, 1, 0, 0],
            [0, 0, 1, 1, 1, 1, 1, 1, 0, 0],
            [0, 0, 1, 1, 1, 1, 1, 1, 0, 0],
            [0, 0, 1, 1, 1, 0, 0, 1, 0, 0],
            [0, 0, 1, 1, 1, 0, 0, 1, 0, 0],
            [0, 0, 1, 1, 1, 0, 0, 1, 0, 0],
            [0, 0, 1, 1, 1, 1, 1, 1, 0, 0],
            [0, 0, 1, 1, 1, 1, 1, 1, 0, 0],
            [0, 0, 1, 1, 1, 1, 1, 1, 0, 0],
            [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
            [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
        ],
        np.uint8,
    )
    im_expected = function(image, footprint)
    im_test = function(image)
    assert_array_equal(im_expected, im_test)


def test_3d_fallback_default_footprint():
    # 3x3x3 cube inside a 7x7x7 image:
    image = np.zeros((7, 7, 7), bool)
    image[2:-2, 2:-2, 2:-2] = 1

    opened = binary.binary_opening(image)

    # expect a "hyper-cross" centered in the 5x5x5:
    image_expected = np.zeros((7, 7, 7), dtype=bool)
    image_expected[2:5, 2:5, 2:5] = ndi.generate_binary_structure(3, 1)
    assert_array_equal(opened, image_expected)


binary_3d_fallback_functions = [binary.binary_opening, binary.binary_closing]


@pytest.mark.parametrize("function", binary_3d_fallback_functions)
def test_3d_fallback_cube_footprint(function):
    # 3x3x3 cube inside a 7x7x7 image:
    image = np.zeros((7, 7, 7), bool)
    image[2:-2, 2:-2, 2:-2] = 1

    cube = np.ones((3, 3, 3), dtype=np.uint8)

    new_image = function(image, cube)
    assert_array_equal(new_image, image)


def test_2d_ndimage_equivalence():
    image = np.zeros((9, 9), np.uint16)
    image[2:-2, 2:-2] = 2**14
    image[3:-3, 3:-3] = 2**15
    image[4, 4] = 2**16 - 1

    bin_opened = binary.binary_opening(image)
    bin_closed = binary.binary_closing(image)

    footprint = ndi.generate_binary_structure(2, 1)
    ndimage_opened = ndi.binary_opening(image, structure=footprint)
    ndimage_closed = ndi.binary_closing(image, structure=footprint)

    assert_array_equal(bin_opened, ndimage_opened)
    assert_array_equal(bin_closed, ndimage_closed)


def test_binary_output_2d():
    image = np.zeros((9, 9), np.uint16)
    image[2:-2, 2:-2] = 2**14
    image[3:-3, 3:-3] = 2**15
    image[4, 4] = 2**16 - 1

    bin_opened = binary.binary_opening(image)
    bin_closed = binary.binary_closing(image)

    int_opened = np.empty_like(image, dtype=np.uint8)
    int_closed = np.empty_like(image, dtype=np.uint8)
    binary.binary_opening(image, out=int_opened)
    binary.binary_closing(image, out=int_closed)

    assert_equal(bin_opened.dtype, bool)
    assert_equal(bin_closed.dtype, bool)

    assert_equal(int_opened.dtype, np.uint8)
    assert_equal(int_closed.dtype, np.uint8)


def test_binary_output_3d():
    image = np.zeros((9, 9, 9), np.uint16)
    image[2:-2, 2:-2, 2:-2] = 2**14
    image[3:-3, 3:-3, 3:-3] = 2**15
    image[4, 4, 4] = 2**16 - 1

    bin_opened = binary.binary_opening(image)
    bin_closed = binary.binary_closing(image)

    int_opened = np.empty_like(image, dtype=np.uint8)
    int_closed = np.empty_like(image, dtype=np.uint8)
    binary.binary_opening(image, out=int_opened)
    binary.binary_closing(image, out=int_closed)

    assert_equal(bin_opened.dtype, bool)
    assert_equal(bin_closed.dtype, bool)

    assert_equal(int_opened.dtype, np.uint8)
    assert_equal(int_closed.dtype, np.uint8)