"""Common FastAPI dependencies: DB session and current authenticated user."""

from __future__ import annotations

import uuid
from typing import Annotated

from fastapi import Depends
from fastapi.security import OAuth2PasswordBearer
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.config import settings
from app.core.database import get_db
from app.core.exceptions import AuthenticationError
from app.core.security import decode_access_token
from app.models.user import User
from app.repositories.user_repo import UserRepository

oauth2_scheme = OAuth2PasswordBearer(
    tokenUrl=f"{settings.api_v1_prefix}/auth/login",
    auto_error=False,
)

DbSession = Annotated[AsyncSession, Depends(get_db)]


async def get_current_user(
    session: DbSession,
    token: Annotated[str | None, Depends(oauth2_scheme)],
) -> User:
    if not token:
        raise AuthenticationError("Not authenticated")

    subject = decode_access_token(token)
    try:
        user_id = uuid.UUID(subject)
    except ValueError as exc:
        raise AuthenticationError("Invalid token subject") from exc

    user = await UserRepository(session).get(user_id)
    if user is None:
        raise AuthenticationError("User not found")
    if not user.is_active:
        raise AuthenticationError("Inactive user")
    return user


CurrentUser = Annotated[User, Depends(get_current_user)]