"""Run with python -m unittest discover -s blender/scripts -p test_patch_geometry.py."""
import unittest
from patch_geometry import (area, barycentric, cell_fragments, clip_rect,
                            interpolate_uv, project_triangle, visible_triangles)


class GeometryTests(unittest.TestCase):
    def test_perspective_correct(self):
        points = project_triangle([(-1, -1, 0, 1), (2, -2, 0, 2), (-4, 4, 0, 4)])
        p = tuple((a + b + c) / 3 for a, b, c in zip(*points))
        self.assertAlmostEqual(sum(barycentric(p)), 1)
        uv = interpolate_uv(p, [(0, 0), (1, 0), (0, 1)])
        self.assertAlmostEqual(uv[0], 2 / 7)
        self.assertAlmostEqual(uv[1], 1 / 7)

    def test_quad_both_loop_triangles_cover_square(self):
        corners = [(-1, -1, 0, 1), (1, -1, 0, 1), (1, 1, 0, 1), (-1, 1, 0, 1)]
        fragments = []
        for indices in ((0, 1, 2), (0, 2, 3)):
            fragments.extend(cell_fragments([corners[k] for k in indices], 3, 2, lambda _: True))
        self.assertAlmostEqual(sum(area(list(p)) for _, _, p in fragments), 1)
        for i, j, poly in fragments:
            self.assertTrue(all(i / 3 - 1e-12 <= p[0] <= (i + 1) / 3 + 1e-12 for p in poly))
            self.assertTrue(all(j / 2 - 1e-12 <= p[1] <= (j + 1) / 2 + 1e-12 for p in poly))

    def test_frustum_and_near_clipping(self):
        poly = project_triangle([(-2, -1, -2, 1), (1, -1, 0, 1), (0, 2, 0, 1)])
        self.assertGreater(len(poly), 2)
        for p in poly:
            self.assertTrue(0 <= p[0] <= 1 and 0 <= p[1] <= 1)
            self.assertAlmostEqual(sum(barycentric(p)), 1)
            self.assertTrue(all(w >= -1e-12 for w in barycentric(p)))

    def test_behind_camera_is_empty(self):
        self.assertEqual(project_triangle([(-1, -1, 0, -1), (1, -1, 0, -1), (0, 1, 0, -1)]), [])

    def test_wide_uv_triangle_does_not_wrap(self):
        poly = project_triangle([(-1, -1, 0, 1), (1, -1, 0, 1), (-1, 1, 0, 1)])
        uvs = [(0.02, 0.1), (0.98, 0.1), (0.02, 0.9)]
        self.assertEqual([interpolate_uv(p, uvs) for p in poly], uvs)

    def test_seam_islands_remain_independent(self):
        p = (0, 0, 1, 0.5, 0.25, 0.25)
        left = interpolate_uv(p, [(0, 0), (.1, 0), (0, .1)])
        right = interpolate_uv(p, [(.9, .9), (1, .9), (.9, 1)])
        self.assertLess(left[0], .1)
        self.assertGreater(right[0], .9)

    def test_hidden_rejected(self):
        tri = project_triangle([(-1, -1, 0, 1), (1, -1, 0, 1), (-1, 1, 0, 1)])
        self.assertEqual(list(visible_triangles(tri, lambda _: False, 1, 1)), [])

    def test_mixed_visibility_conservative(self):
        tri = project_triangle([(-1, -1, 0, 1), (1, -1, 0, 1), (-1, 1, 0, 1)])
        accepted = list(visible_triangles(tri, lambda w: w[1] < .4, 1, 1))
        self.assertTrue(accepted)
        self.assertTrue(all(barycentric(p)[1] < .4 for t in accepted for p in t))
        self.assertLess(sum(area(list(t)) for t in accepted), .5)

    def test_unresolved_depth_limit_rejected(self):
        tri = project_triangle([(-1, -1, 0, 1), (1, -1, 0, 1), (-1, 1, 0, 1)])
        self.assertEqual(list(visible_triangles(tri, lambda w: w[1] < .4, 1, 1, depth=10)), [])

    def test_uv_tile_clips_without_repeating(self):
        poly = clip_rect([(-.2, .1), (.2, .1), (.2, .9)], 0, 1, 0, 1)
        self.assertTrue(all(0 <= p[0] <= .2 for p in poly))


if __name__ == '__main__':
    unittest.main()