import pytest
from skimage._shared._geometry import polygon_clip, polygon_area

import numpy as np
from numpy.testing import assert_equal, assert_almost_equal

pytest.importorskip("matplotlib")


hand = np.array(
    [
        [1.64516129, 1.16145833],
        [1.64516129, 1.59375],
        [1.35080645, 1.921875],
        [1.375, 2.18229167],
        [1.68548387, 1.9375],
        [1.60887097, 2.55208333],
        [1.68548387, 2.69791667],
        [1.76209677, 2.56770833],
        [1.83064516, 1.97395833],
        [1.89516129, 2.75],
        [1.9516129, 2.84895833],
        [2.01209677, 2.76041667],
        [1.99193548, 1.99479167],
        [2.11290323, 2.63020833],
        [2.2016129, 2.734375],
        [2.25403226, 2.60416667],
        [2.14919355, 1.953125],
        [2.30645161, 2.36979167],
        [2.39112903, 2.36979167],
        [2.41532258, 2.1875],
        [2.1733871, 1.703125],
        [2.07782258, 1.16666667],
    ]
)


def test_polygon_area():
    x = [0, 0, 1, 1]
    y = [0, 1, 1, 0]

    assert_almost_equal(polygon_area(y, x), 1)

    x = [0, 0, 1]
    y = [0, 1, 1]

    assert_almost_equal(polygon_area(y, x), 0.5)

    x = [0, 0, 0.5, 1, 1, 0.5]
    y = [0, 1, 0.5, 1, 0, 0.5]

    assert_almost_equal(polygon_area(y, x), 0.5)


def test_poly_clip():
    x = [0, 1, 2, 1]
    y = [0, -1, 0, 1]

    yc, xc = polygon_clip(y, x, 0, 0, 1, 1)
    assert_equal(polygon_area(yc, xc), 0.5)

    x = [-1, 1.5, 1.5, -1]
    y = [0.5, 0.5, 1.5, 1.5]
    yc, xc = polygon_clip(y, x, 0, 0, 1, 1)
    assert_equal(polygon_area(yc, xc), 0.5)


def test_hand_clip():
    (r0, c0, r1, c1) = (1.0, 1.5, 2.1, 2.5)
    clip_r, clip_c = polygon_clip(hand[:, 1], hand[:, 0], r0, c0, r1, c1)
    assert_equal(clip_r.size, 19)
    assert_equal(clip_r[0], clip_r[-1])
    assert_equal(clip_c[0], clip_c[-1])

    (r0, c0, r1, c1) = (1.0, 1.5, 1.7, 2.5)
    clip_r, clip_c = polygon_clip(hand[:, 1], hand[:, 0], r0, c0, r1, c1)
    assert_equal(clip_r.size, 6)

    (r0, c0, r1, c1) = (1.0, 1.5, 1.5, 2.5)
    clip_r, clip_c = polygon_clip(hand[:, 1], hand[:, 0], r0, c0, r1, c1)
    assert_equal(clip_r.size, 5)