import pathlib
from functools import partial
from typing import Any, Callable, Dict, Optional, Sequence, Tuple, Type, Union

__all__ = (
    "Types",
    "SYSTEMD_SERVICE_CONFIG",
    "SYSTEMD_NETWORK_CONFIG",
    "SYSTEMD_CONFIG_ROOT",
)


SYSTEMD_CONFIG_ROOT = pathlib.Path("/etc/systemd")
SYSTEMD_NETWORK_CONFIG = SYSTEMD_CONFIG_ROOT / "network"
SYSTEMD_SERVICE_CONFIG = SYSTEMD_CONFIG_ROOT / "system"


class _sdict(dict):
    _help: Optional[str]
    __name__: str


class _Type(type):
    def __new__(metacls, cls, bases, classdict, **kwds):
        individual = dict()
        virtfunc = None
        virtual = ()
        special = dict()
        for key, value in classdict.items():
            if key.startswith("_"):
                if key == "__getattr__":
                    virtfunc = value
                elif key == "__dir__":
                    virtual = tuple(value(None))
                elif key in ("__doc__",):
                    special[key] = value
            else:
                individual[key] = value
        if len(virtual) != 0 and virtfunc is None:  # pragma: nocover
            raise TypeError(
                "Virtual funcs defined, but no func to generate them defined"
            )
        special["_attr"] = tuple(virtual + tuple(individual.keys()))
        special["_vfunc"] = virtfunc
        special["_virtual"] = virtual
        special["_individual"] = individual
        annotations = dict()
        if len(virtual) != 0 and virtfunc is not None:  # pragma: nocover
            anno = virtfunc(None, virtual[0]).__annotations__
            for virtualkey in virtual:
                annotations[virtualkey] = Callable[[*anno.values()], Dict[str, Any]]
        annotations["__dir__"] = Callable[[], Tuple[str]]
        special["__annotations__"] = annotations
        inst = super().__new__(metacls, cls, bases, special, **kwds)
        return inst

    def __getattribute__(self, __name: str) -> Any:
        if __name in (
            "__dict__",
            "__doc__",
            "_attr",
            "__annotations__",
            "_virtual",
            "_vfunc",
            "_individual",
        ):
            return super().__getattribute__(__name)
        if __name in self._virtual:
            return self._vfunc(self, __name)
        if __name in self._individual:
            return partial(self._individual[__name], self)
        raise AttributeError(f"Attribut {__name} not found.")


class Types(metaclass=_Type):
    """Provides helpers for the ansible types"""

    def list(
        self,
        elements: Union[Type[object], str],
        required: bool = False,
        help: Optional[str] = None,
    ) -> dict:
        if not isinstance(elements, str):
            elements = elements.__name__
        option = _sdict(type="list", elements=elements, required=required)
        option._help = help
        return option

    def __dir__(self) -> tuple:
        return (
            "str",
            "dict",
            "bool",
            "int",
            "float",
            "path",
            "raw",
            "jsonarg",
            "json",
            "bytes",
            "bits",
        )

    def __getattr__(self, name: str):
        def argument(
            required: bool = False,
            help: Optional[str] = None,
            choices: Optional[Sequence] = None,
            default: Optional[Any] = None,
        ):
            output = _sdict(type=name, required=required)
            if choices is not None:
                output["choices"] = choices
            if default is not None:
                output["default"] = default
            output._help = help
            return output

        argument.__name__ = name
        return argument