auth.py

# Copyright (C) 2025 Collabora Limited
# Author: Denys Fedoryshchenko <denys.f@collabora.com>
# SPDX-License-Identifier: LGPL-2.1-or-later

from datetime import datetime, timedelta
from typing import Optional
from jose import JWTError, jwt
from passlib.context import CryptContext
from fastapi import Depends, HTTPException, status, Cookie
from sqlalchemy.orm import Session
from database import SessionLocal
from models import User
from config import SECRET_KEY, ALGORITHM, ACCESS_TOKEN_EXPIRE_MINUTES

# Configuration imported from config.py

pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")


def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


def verify_password(plain_password, hashed_password):
    return pwd_context.verify(plain_password, hashed_password)


def get_password_hash(password):
    return pwd_context.hash(password)


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


def get_current_user(
    access_token: Optional[str] = Cookie(None), db: Session = Depends(get_db)
):
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )

    if not access_token:
        raise credentials_exception

    # Remove "Bearer " prefix if present
    token = (
        access_token.replace("Bearer ", "")
        if access_token.startswith("Bearer ")
        else access_token
    )

    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception
    except JWTError:
        raise credentials_exception

    user = db.query(User).filter(User.username == username).first()
    if user is None:
        raise credentials_exception
    return user


def get_current_user_optional(
    access_token: Optional[str] = Cookie(None), db: Session = Depends(get_db)
):
    """Get current user but return None if not authenticated (no exception)"""
    if not access_token:
        return None

    # Remove "Bearer " prefix if present
    token = (
        access_token.replace("Bearer ", "")
        if access_token.startswith("Bearer ")
        else access_token
    )

    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            return None
    except JWTError:
        return None

    user = db.query(User).filter(User.username == username).first()
    return user