from collections.abc import Iterable
from typing import Any, ClassVar, Self, cast

from sqlalchemy.orm import DeclarativeBase, MappedAsDataclass
from sqlalchemy.sql.selectable import ForUpdateParameter

from fansifter_common.adapters.db.base import Database

from .query import Query
from .utils import delete_instance, refresh_instance, save_instance


class ModelMixin:
    """Mixin that adds save/delete/refresh/query to any DeclarativeBase subclass.

    Usage in a project::

        class Model(ModelMixin, MappedAsDataclass, DeclarativeBase):
            __db__ = db
            type_annotation_map = {str: sa.Text, datetime: NaiveUTCDateTime}
    """

    __db__: ClassVar[Database]

    # --- Instance methods ---

    def save(self, *, flush: bool = False) -> Self:
        return save_instance(self.__db__, instance=self, flush=flush)

    def delete(self, *, flush: bool = False) -> None:
        delete_instance(self.__db__, instance=self, flush=flush)

    def refresh(
        self,
        *,
        attribute_names: Iterable[str] | None = None,
        with_for_update: ForUpdateParameter = None,
    ) -> None:
        refresh_instance(
            self.__db__,
            instance=cast(Any, self),
            attribute_names=attribute_names,
            with_for_update=with_for_update,
        )

    # --- Descriptors ---

    query = Query[Self].as_descriptor()


class Model(ModelMixin, MappedAsDataclass, DeclarativeBase):
    """Ready-to-use base model. Set ``__db__`` on this class to configure the database."""

    __db__: ClassVar[Database]