import unittest

import numpy as np

from surveyladder.geo import chainage_to_xy, chainage_offset_to_xy, poly_area, poly_centroid, trilaterate_xy


class TestPolyArea(unittest.TestCase):

    def test_poly_area(self):
        polygon = np.array([[0, 0], [4, 0], [4, 3]])
        self.assertEqual(poly_area(polygon), 6)


class TestTrilaterateXY(unittest.TestCase):

    def test_trilaterate_xy_on_line(self):
        A = np.array([0, 0])
        B = np.array([10, 0])
        a = 5
        b = 5
        C = trilaterate_xy(A, a, B, b)
        np.testing.assert_almost_equal(C, [5, 0])

    def test_trilaterate_xy_right_triangle(self):
        A = np.array([0, 0])
        B = np.array([4, 0])
        a = 5
        b = 3
        C = trilaterate_xy(A, a, B, b)
        np.testing.assert_almost_equal(C, [4, 3])

    def test_trilaterate_xy_right_triangle_swapped(self):
        A = np.array([4, 0])
        B = np.array([0, 0])
        a = 3
        b = 5
        C = trilaterate_xy(A, a, B, b)
        np.testing.assert_almost_equal(C, [4, -3])


class TestChainageToXY(unittest.TestCase):

    def test_positive_distance(self):
        np.testing.assert_almost_equal(
            chainage_to_xy(np.array([3, 5]), np.array([6, 9]), 10),
            [9, 13])

    def test_negative_distance(self):
        np.testing.assert_almost_equal(
            chainage_to_xy(np.array([3, 5]), np.array([6, 9]), -5),
            [0, 1])


class TestChainageOffsetToXY(unittest.TestCase):

    def test_positive_offset(self):
        A = np.array([0, 0])
        B = np.array([0, 1])
        a_distance = 5
        perp_distance = 2
        P = chainage_offset_to_xy(A, B, a_distance, perp_distance)
        np.testing.assert_almost_equal(P, [-2, 5])

class TestPolyCentroid(unittest.TestCase):

    def test_pos_square(self):
        # mathematically positive point ordering
        poly = np.array([[0,0], [1,0], [1,2], [0,2]])
        np.testing.assert_almost_equal(poly_centroid(poly), [0.5, 1])

    def test_neg_square(self):
        # mathematically negative point ordering
        poly = np.array([[0,0], [1,0], [1,-2], [0,-2]])
        np.testing.assert_almost_equal(poly_centroid(poly), [0.5, -1])


unittest.main()