from sqlalchemy.ext.asyncio import AsyncSession
from fastapi import Depends
from fastapi.security import OAuth2PasswordBearer
from typing import Callable
from datetime import datetime
from fooder.db import get_db_session
from fooder.domain import User
from fooder.repository import Repository
from fooder.utils.datetime import utc_now
from fooder.exc import Unauthorized, NotFound
from fooder.utils.jwt import AccessToken


class Context:
    """
    Main API context, aggregating dependencies
    """

    def __init__(
        self,
        repo: Repository,
        clock: Callable[[], datetime] = utc_now,
    ) -> None:
        self.repo = repo
        self.clock = clock
        self._user: User | None = None

    def set_user(self, user: User) -> None:
        self._user = user

    @property
    def user(self) -> User:
        if self._user is None:
            raise Unauthorized()
        return self._user


class ContextDependency:
    """
    Context dependency
    """

    def __call__(
        self,
        session: AsyncSession = Depends(get_db_session),
    ):
        return Context(repo=Repository(session))


_oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/token")


class AuthContextDependency:
    """
    Context dependency for authorized endpoints
    """

    async def __call__(
        self,
        token: str = Depends(_oauth2_scheme),
        session: AsyncSession = Depends(get_db_session),
    ) -> Context:
        ctx = Context(repo=Repository(session))
        user_id = AccessToken.decode(token).sub
        try:
            user = await ctx.repo.user.get_by_id(user_id)
        except NotFound:
            raise Unauthorized()
        ctx.set_user(user)
        return ctx