from __future__ import annotations

from collections.abc import Sequence

import numpy as np

from app.core.geo import PathPoint


class DemNotConfiguredError(RuntimeError):
    """Raised when DEM access is requested before COG data is configured."""


def elevation_at(lat: float, lon: float, surface: str = "dtm") -> float:
    raise DemNotConfiguredError(
        f"DEM sampling is not configured yet for lat={lat}, lon={lon}, surface={surface}"
    )


def elevations_along(points: Sequence[PathPoint], surface: str = "dtm") -> np.ndarray:
    if not points:
        return np.array([], dtype=float)
    raise DemNotConfiguredError(f"DEM sampling is not configured yet for surface={surface}")