Source code for httk.atomistic.sites_numeric_view

"""
A view presenting any sites backend as a NumericSites object (the plain-numpy presentation).
"""

from functools import cached_property
from typing import Any, Self

from httk.core import unwrap

from ._vector_guards import require_numpy
from .numeric_sites import NumericSites
from .sites import Sites
from .sites_backend import SitesBackend
from .sites_like import SitesLike
from .sites_view import SitesView




class SitesNumericView(SitesView, NumericSites):
    """
    A view presenting an underlying sites backend as a ``NumericSites`` object.

    This view is a genuine ``NumericSites``, so it can be passed anywhere one is accepted. Its exact
    ``Sites`` is built lazily from the backend on first access. Like a ``NumericSites`` it requires
    numpy (raising :class:`ImportError` otherwise).
    """

    _backend: SitesBackend

    def __new__(cls, obj: SitesLike, **hints: Any) -> Self:
        if isinstance(obj, cls):
            return obj
        require_numpy()
        backend = cls._prepare_backend(obj, hints)
        instance = super().__new__(cls)
        instance._backend = backend
        return instance

    def __init__(self, obj: SitesLike, **hints: Any) -> None:
        pass

    # Build then assign so a failed exact presentation leaves the shadow unmaterialized.
    def _fill_sites(self) -> None:
        NumericSites.__init__(self, Sites(self._backend.reduced_coords, self._backend.precision))

    @cached_property
    def _sites(self) -> Sites:  # type: ignore[override]  # pyright: ignore[reportIncompatibleVariableOverride]
        self._fill_sites()
        return self.__dict__["_sites"]



    def unwrap(self) -> Any:
        return unwrap(self._backend)