"""tests/test_geometry.py —— 几何运算单元测试。"""

import pytest
from shapely.geometry import LineString, Point, Polygon

import geo_tools
from geo_tools.core.geometry import (
    buffer_geometry,
    bounding_box,
    centroid,
    contains,
    convex_hull,
    difference,
    distance_between,
    fix_geometry,
    intersect,
    intersects,
    is_valid_geometry,
    unary_union,
    union,
    within,
)


class TestIsValidGeometry:
    def test_valid_polygon(self):
        poly = Polygon([(0, 0), (1, 0), (1, 1), (0, 1)])
        assert is_valid_geometry(poly) is True

    def test_none_returns_false(self):
        assert is_valid_geometry(None) is False

    def test_invalid_self_intersecting(self):
        # 蝴蝶形（自相交）
        bowtie = Polygon([(0, 0), (1, 1), (1, 0), (0, 1)])
        assert is_valid_geometry(bowtie) is False


class TestFixGeometry:
    def test_fix_bowtie(self):
        bowtie = Polygon([(0, 0), (1, 1), (1, 0), (0, 1)])
        assert not bowtie.is_valid
        fixed = fix_geometry(bowtie)
        assert fixed is not None
        assert fixed.is_valid

    def test_valid_geometry_unchanged(self):
        poly = Polygon([(0, 0), (1, 0), (1, 1), (0, 1)])
        fixed = fix_geometry(poly)
        assert fixed.is_valid
        assert fixed.area == pytest.approx(poly.area)

    def test_none_returns_none(self):
        assert fix_geometry(None) is None


class TestBufferGeometry:
    def test_point_buffer(self):
        pt = Point(0, 0)
        buf = buffer_geometry(pt, 1.0)
        assert buf.area > 3.0  # π * r² ≈ 3.14

    def test_zero_distance_returns_point_like(self):
        pt = Point(0, 0)
        buf = buffer_geometry(pt, 0.0)
        # buffer(0) on point may return empty or point
        assert buf is not None


class TestSetOperations:
    @pytest.fixture
    def poly_a(self):
        return Polygon([(0, 0), (2, 0), (2, 2), (0, 2)])

    @pytest.fixture
    def poly_b(self):
        return Polygon([(1, 0), (3, 0), (3, 2), (1, 2)])

    def test_intersection(self, poly_a, poly_b):
        result = intersect(poly_a, poly_b)
        assert result.area == pytest.approx(2.0)

    def test_union(self, poly_a, poly_b):
        result = union(poly_a, poly_b)
        assert result.area == pytest.approx(6.0)

    def test_difference(self, poly_a, poly_b):
        result = difference(poly_a, poly_b)
        assert result.area == pytest.approx(2.0)

    def test_unary_union(self, poly_a, poly_b):
        result = unary_union([poly_a, poly_b])
        assert result.area == pytest.approx(6.0)


class TestSpatialRelations:
    def test_contains_true(self):
        big = Polygon([(0, 0), (10, 0), (10, 10), (0, 10)])
        small = Polygon([(1, 1), (2, 1), (2, 2), (1, 2)])
        assert contains(big, small) is True

    def test_within(self):
        big = Polygon([(0, 0), (10, 0), (10, 10), (0, 10)])
        small = Polygon([(1, 1), (2, 1), (2, 2), (1, 2)])
        assert within(small, big) is True

    def test_distance(self):
        p1 = Point(0, 0)
        p2 = Point(3, 4)
        assert distance_between(p1, p2) == pytest.approx(5.0)