auth.py

import os
from datetime import datetime, timedelta
from typing import Optional

from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from jose import JWTError, jwt
from sqlalchemy.orm import Session
import bcrypt

from database import get_db
from models import User

SECRET_KEY = os.getenv("SECRET_KEY", "change-me-in-production")
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 30

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/auth/login")


def get_password_hash(password: str) -> str:
    return bcrypt.hashpw(password.encode(), bcrypt.gensalt(rounds=10)).decode()


def verify_password(plain_password: str, hashed_password: str) -> bool:
    return bcrypt.checkpw(plain_password.encode(), hashed_password.encode())


def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -> str:
    to_encode = data.copy()
    expire = datetime.utcnow() + (expires_delta or timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES))
    to_encode.update({"exp": expire})
    return jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)


def get_current_user(token: str = Depends(oauth2_scheme), db: Session = Depends(get_db)) -> User:
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        user_id: str = payload.get("sub")
        if user_id is None:
            raise credentials_exception
    except JWTError:
        raise credentials_exception

    user = db.query(User).filter(User.id == int(user_id)).first()
    if user is None or not user.is_active:
        raise credentials_exception
    return user


def require_role(role: str):
    def checker(current_user: User = Depends(get_current_user)):
        if current_user.role != role:
            raise HTTPException(status_code=403, detail=f"Requires {role} role")
        return current_user
    return checker