#137 gdtest_sphinx_mixed_roles

"""Package demonstrating mixed Sphinx cross-reference roles."""

__version__ = "0.1.0"
__all__ = ["Registry", "register", "lookup", "validate_entry"]


class Registry:
    """
    A registry that maps names to types.

    Use :py:func:`register` to add entries, or call
    :py:meth:`Registry.get` directly.

    Parameters
    ----------
    strict
        If True, raises :py:exc:`KeyError` on missing lookups.
    """

    def __init__(self, strict: bool = False):
        self.strict = strict
        self._entries: dict = {}

    def get(self, name: str) -> type:
        """
        Get a registered type by name.

        Checks :py:attr:`Registry.strict` to decide behavior on
        missing keys. Raises :py:exc:`KeyError` if strict mode
        is enabled and the name is not found.

        Parameters
        ----------
        name
            The registered name to look up.

        Returns
        -------
        type
            The registered type.

        Raises
        ------
        KeyError
            If the name is not registered and strict mode is on.
        """
        if name in self._entries:
            return self._entries[name]
        if self.strict:
            raise KeyError(name)
        return type(None)

    def add(self, name: str, cls: type) -> None:
        """
        Add a type to the registry.

        See also :py:func:`register` for the module-level helper.

        Parameters
        ----------
        name
            The name to register under.
        cls
            The type to register.
        """
        self._entries[name] = cls

    @property
    def names(self) -> list:
        """
        List all registered names.

        Returns
        -------
        list
            A list of registered name strings.
        """
        return list(self._entries.keys())


_default_registry = Registry()


def register(name: str, cls: type) -> None:
    """
    Register a type in the default :py:class:`Registry`.

    Calls :py:meth:`Registry.add` on the default instance.

    Parameters
    ----------
    name
        The name to register under.
    cls
        The type to register.
    """
    _default_registry.add(name, cls)


def lookup(name: str) -> type:
    """
    Look up a type in the default :py:class:`Registry`.

    Delegates to :py:meth:`Registry.get`. May raise
    :py:exc:`KeyError` in strict mode.

    Parameters
    ----------
    name
        The name to look up.

    Returns
    -------
    type
        The registered type.
    """
    return _default_registry.get(name)


def validate_entry(entry: dict) -> bool:
    """
    Validate a registry entry dict.

    An entry must have ``"name"`` and ``"cls"`` keys. The ``"cls"``
    value should be passable to :py:func:`register`. If invalid,
    raises :py:exc:`ValueError`.

    Checks :py:attr:`Registry.strict` on the default registry
    to determine validation level.

    Parameters
    ----------
    entry
        A dict with ``"name"`` and ``"cls"`` keys.

    Returns
    -------
    bool
        True if the entry is valid.

    Raises
    ------
    ValueError
        If the entry dict is missing required keys.
    """
    if "name" not in entry or "cls" not in entry:
        raise ValueError("Entry must have 'name' and 'cls' keys")
    return True