treetrail-backend/src/treetrail/security.py

from datetime import datetime, timedelta
from passlib.context import CryptContext

from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from sqlalchemy.orm import joinedload
from pydantic import BaseModel
from jose import JWTError, jwt
from sqlmodel import select

from treetrail.config import conf
from treetrail.models import User, Role, UserRoleLink
from treetrail.database import db_session


# openssl rand -hex 32
# import secrets
# SECRET_KEY = secrets.token_hex(32)
ALGORITHM: str = "HS256"


class Token(BaseModel):
    access_token: str
    token_type: str


class TokenData(BaseModel):
    username: str | None = None


# class User(BaseModel):
#     username: str
#     email: str | None = None
#     full_name: str | None = None
#     disabled: bool = False


oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token", auto_error=False)

pwd_context = CryptContext(schemes=["sha256_crypt", "bcrypt"], deprecated="auto")

credentials_exception = HTTPException(
    status_code=status.HTTP_401_UNAUTHORIZED,
    detail="Could not validate credentials",
    headers={"WWW-Authenticate": "Bearer"},
)

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

async def delete_user(username) -> None:
    async with db_session() as session:
        user_in_db = await get_user(username)
        if user_in_db is None:
            raise SystemExit(f'User {username} does not exist in the database')
        await session.delete(user_in_db)

async def enable_user(username, enable=True) -> None:
    async with db_session() as session:
        user_in_db = await get_user(username)
        if user_in_db is None:
            raise SystemExit(f'User {username} does not exist in the database')
        user_in_db.disabled = not enable # type: ignore
        session.add(user_in_db)
        await session.commit()

async def create_user(username: str, password: str,
                      full_name: str | None = None,
                      email: str | None = None) -> User:
    async with db_session() as session:
        user = await get_user(username)
        if user is None:
            user = User(
                username=username,
                password=get_password_hash(password),
                full_name=full_name,
                email=email,
                disabled=False
            )
            session.add(user)
            await session.commit()
        else:
            user.full_name = full_name # type: ignore
            user.email = email # type: ignore
            user.password = get_password_hash(password) # type: ignore
            await session.commit()
        await session.refresh(user)
    return user

async def get_user(username: str) -> User | None: # type: ignore
    async with db_session() as session:
        query = select(User)\
            .where(User.username==username)\
            .options(joinedload(User.roles)) # type: ignore
        data = await session.exec(query)
        return data.first()

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

async def get_current_user(token: str = Depends(oauth2_scheme)) -> User | None: # type: ignore
    if token is None or token == 'null':
        return None
    try:
        payload = jwt.decode(token, conf.security.secret_key, algorithms=[ALGORITHM])
        username: str = payload.get("sub", '')
        if username == '':
            raise credentials_exception
        token_data = TokenData(username=username)
    except JWTError:
        return None
    user = await get_user(username=token_data.username) # type: ignore
    return user

async def authenticate_user(username: str, password: str):
    user = await get_user(username)
    if not user:
        return False
    if not verify_password(password, user.password):
        return False
    return user

async def get_current_active_user(
    current_user: User | None = Depends(get_current_user)) -> User: # type: ignore
    if current_user is None:
        raise HTTPException(status_code=400, detail="Not authenticated")
    if current_user.disabled:
        raise HTTPException(status_code=400, detail="Inactive user")
    return current_user

async def get_current_roles(user: User | None = Depends(get_current_user)) -> list[Role]: # type: ignore
    roles: list[Role]
    if user is None:
        roles = []
    else:
        roles = user.roles
    return roles

def create_access_token(data: dict, expires_delta: timedelta):
    to_encode = data.copy()
    expire = datetime.utcnow() + expires_delta
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode,
                             conf.security.secret_key,
                             algorithm=ALGORITHM)
    return encoded_jwt

async def add_user_role(username: str, role_id: str):
    async with db_session() as session:
        user_in_db = await get_user(username)
        if user_in_db is None:
            raise SystemExit(f'User {username} does not exist in the database')
        user_role = UserRoleLink(user_id=user_in_db.username, role_id=role_id)
        session.add(user_role)
        await session.commit()

async def add_role(role_id: str) -> Role:
    async with db_session() as session:
        role = Role(name=role_id)
        session.add(role)
        await session.commit()
        await session.refresh(role)
    return role