"""Unit tests for the grid-tiling / geometry helpers (INDL-49). No DB required."""
import pytest

from src.core.exceptions import ValidationError
from src.core.utils.geometry import (
    build_plot_grid,
    validate_polygon_geojson,
)


def test_build_grid_count_and_non_overlap():
    polys = build_plot_grid(
        origin_lat=45.4215, origin_lng=-75.6972,
        rows=5, cols=4, plot_width_m=1.2, plot_length_m=2.4, gap_m=0.3,
    )
    assert len(polys) == 20
    # Every polygon is a valid rectangle with positive area.
    assert all(p.is_valid and p.area > 0 for p in polys)
    # No two plots overlap (they may touch only with gap=0).
    for i in range(len(polys)):
        for j in range(i + 1, len(polys)):
            inter = polys[i].intersection(polys[j])
            assert inter.area == pytest.approx(0.0, abs=1e-12)


def test_build_grid_zero_gap_touches_but_no_overlap():
    polys = build_plot_grid(
        origin_lat=0.0, origin_lng=0.0,
        rows=2, cols=2, plot_width_m=2, plot_length_m=2, gap_m=0.0,
    )
    assert len(polys) == 4
    for i in range(len(polys)):
        for j in range(i + 1, len(polys)):
            assert polys[i].intersection(polys[j]).area == pytest.approx(0.0, abs=1e-12)


def test_validate_rejects_non_polygon():
    with pytest.raises(ValidationError):
        validate_polygon_geojson({"type": "Point", "coordinates": [0, 0]})


def test_validate_rejects_too_few_points():
    with pytest.raises(ValidationError):
        validate_polygon_geojson({"type": "Polygon", "coordinates": [[[0, 0], [1, 1]]]})


def test_validate_accepts_valid_polygon():
    geom = validate_polygon_geojson({
        "type": "Polygon",
        "coordinates": [[[0, 0], [0, 1], [1, 1], [1, 0], [0, 0]]],
    })
    assert geom.is_valid and geom.area > 0