auth.py

from datetime import UTC, datetime, timedelta
import jwt
from fastapi.security import OAuth2PasswordBearer
from pwdlib import PasswordHash
from typing import Annotated
from fastapi import Depends, status, HTTPException
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

import models
from database import get_db


from config import settings

password_hash = PasswordHash.recommended()


oauth2_scheme = OAuth2PasswordBearer(tokenUrl="api/users/token")


def hash_password(password: str) -> str:
    return password_hash.hash(password)


def verify_password(password: str, hashed_password: str) -> bool:
    return password_hash.verify(password, hashed_password)


def create_access_token(data: dict, expires_delta: timedelta | None = None) -> str:
    to_encode = data.copy()
    if expires_delta:
        expire = datetime.now(UTC) + expires_delta
    else:
        expire = datetime.now(UTC) + timedelta(
            minutes=settings.access_token_expire_minutes
        )

    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(
        to_encode,
        settings.secret_key.get_secret_value(),
        settings.algorithm,
    )

    return encoded_jwt


def verify_access_token(token: str) -> str | None:
    try:
        payload = jwt.decode(
            token,
            settings.secret_key.get_secret_value(),
            settings.algorithm,
            options={"require": ["exp", "sub"]},
        )
    except jwt.InvalidTokenError:
        return None
    else:
        return payload.get("sub")


async def get_current_user(
    token: Annotated[str, Depends(oauth2_scheme)],
    db: Annotated[AsyncSession, Depends(get_db)],
) -> models.User:
    user_id = verify_access_token(token=token)

    if user_id is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid or expired token",
            headers={"WWW-Authenticate": "Bearer"},
        )

    try:
        user_id_int = int(user_id)
    except (TypeError, ValueError):
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="invalid token",
            headers={"WWW-Authenticate": "Bearer"},
        )

    result = await db.execute(select(models.User).where(models.User.id == user_id_int))
    user = result.scalars().first()

    if not user:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="invalid token",
            headers={"WWW-Authenticate": "Bearer"},
        )

    return user


CurrentUser = Annotated[models.User, Depends(get_current_user)]