"""tests/test_vector.py —— 矢量操作单元测试。"""

import pytest
import geopandas as gpd
from shapely.geometry import Point

from geo_tools.core.vector import (
    add_area_column,
    clip_to_extent,
    dissolve_by,
    drop_invalid_geometries,
    explode_multipart,
    reproject,
    set_crs,
    spatial_join,
)


class TestReproject:
    def test_basic_reproject(self, sample_points_gdf):
        result = reproject(sample_points_gdf, "EPSG:3857")
        assert result.crs.to_epsg() == 3857
        assert len(result) == len(sample_points_gdf)

    def test_reproject_preserves_count(self, sample_points_gdf):
        result = reproject(sample_points_gdf, "EPSG:4490")
        assert len(result) == 3

    def test_reproject_no_crs_raises(self):
        gdf = gpd.GeoDataFrame(geometry=[Point(0, 0)])  # 没有 CRS
        with pytest.raises(ValueError, match="CRS"):
            reproject(gdf, "EPSG:4326")


class TestSetCrs:
    def test_set_crs_on_new_gdf(self):
        gdf = gpd.GeoDataFrame(geometry=[Point(116.4, 39.9)])
        result = set_crs(gdf, "EPSG:4326")
        assert result.crs.to_epsg() == 4326

    def test_overwrite_blocked_by_default(self):
        gdf = gpd.GeoDataFrame(geometry=[Point(0, 0)], crs="EPSG:4326")
        with pytest.raises(ValueError, match="overwrite"):
            set_crs(gdf, "EPSG:3857")

    def test_overwrite_allowed(self):
        gdf = gpd.GeoDataFrame(geometry=[Point(0, 0)], crs="EPSG:4326")
        result = set_crs(gdf, "EPSG:3857", overwrite=True)
        assert result.crs.to_epsg() == 3857


class TestClipToExtent:
    def test_clip_by_bbox(self, sample_points_gdf):
        # 只包含北京（116.4, 39.9）的 bbox
        result = clip_to_extent(sample_points_gdf, (115.0, 38.0, 118.0, 41.0))
        assert len(result) == 1

    def test_clip_by_geodataframe(self, sample_points_gdf, sample_polygon_gdf):
        # polygon 覆盖 115-122E，38-41N，应该包含北京
        result = clip_to_extent(sample_points_gdf, sample_polygon_gdf)
        assert len(result) >= 1


class TestDissolveBy:
    def test_dissolve_by_field(self, sample_multi_polygon_gdf):
        gdf = sample_multi_polygon_gdf.copy()
        gdf["group"] = ["X", "X"]  # 两条都归入同一组
        result = dissolve_by(gdf, by="group")
        assert len(result) == 1

    def test_dissolve_preserves_crs(self, sample_multi_polygon_gdf):
        gdf = sample_multi_polygon_gdf.copy()
        gdf["group"] = ["A", "B"]
        result = dissolve_by(gdf, by="group")
        assert result.crs == gdf.crs


class TestAddAreaColumn:
    def test_area_column_added(self, sample_polygon_gdf):
        result = add_area_column(sample_polygon_gdf, col_name="area_m2")
        assert "area_m2" in result.columns
        assert result["area_m2"].iloc[0] > 0


class TestDropInvalidGeometries:
    def test_drop_invalid(self):
        from shapely.geometry import Polygon
        valid = Polygon([(0, 0), (1, 0), (1, 1), (0, 1)])
        invalid = Polygon([(0, 0), (1, 1), (1, 0), (0, 1)])  # 蝴蝶形
        gdf = gpd.GeoDataFrame(geometry=[valid, invalid], crs="EPSG:4326")
        result = drop_invalid_geometries(gdf)
        assert len(result) == 1

    def test_fix_invalid(self):
        from shapely.geometry import Polygon
        invalid = Polygon([(0, 0), (1, 1), (1, 0), (0, 1)])
        gdf = gpd.GeoDataFrame(geometry=[invalid], crs="EPSG:4326")
        result = drop_invalid_geometries(gdf, fix=True)
        assert len(result) == 1
        assert result.geometry.is_valid.all()