from pathlib import Path

import numpy as np
import pytest
import rasterio
from rasterio.transform import from_origin

from app.core.dem import DemNotConfiguredError, elevation_at, elevations_along
from app.core.geo import PathPoint


def write_test_dem(path: Path) -> None:
    data = np.array([[10.0, 11.0], [20.0, 21.0]], dtype="float32")
    transform = from_origin(24.0, 61.0, 1.0, 1.0)
    with rasterio.open(
        path,
        "w",
        driver="GTiff",
        height=2,
        width=2,
        count=1,
        dtype=data.dtype,
        crs="EPSG:4326",
        transform=transform,
        nodata=-9999.0,
    ) as dataset:
        dataset.write(data, 1)


def test_elevation_at_samples_geotiff(tmp_path: Path) -> None:
    write_test_dem(tmp_path / "test_dem.tif")

    assert elevation_at(60.5, 24.5, dem_path=tmp_path) == 10.0
    assert elevation_at(59.5, 25.5, dem_path=tmp_path) == 21.0


def test_elevations_along_samples_all_points(tmp_path: Path) -> None:
    write_test_dem(tmp_path / "test_dem.tif")
    points = [
        PathPoint(lat=60.5, lon=24.5, distance_m=0),
        PathPoint(lat=59.5, lon=25.5, distance_m=1),
    ]

    result = elevations_along(points, dem_path=tmp_path)

    assert result.tolist() == [10.0, 21.0]


def test_elevation_at_errors_without_covering_tile(tmp_path: Path) -> None:
    write_test_dem(tmp_path / "test_dem.tif")

    with pytest.raises(DemNotConfiguredError):
        elevation_at(10.0, 10.0, dem_path=tmp_path)