backend/app/core/security.py

import hashlib
import logging
import secrets
from datetime import datetime, timedelta, timezone
from typing import Optional

from jose import JWTError, jwt
from passlib.context import CryptContext

from app.core.config import settings

pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
logger = logging.getLogger(__name__)


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


def verify_password(plain: str, hashed: str) -> bool:
    return pwd_context.verify(plain, hashed)


def generate_session_id() -> str:
    """Unique session ID stored in DB — invalidates old sessions."""
    return secrets.token_hex(32)


def generate_password_reset_token() -> str:
    return secrets.token_urlsafe(48)


def hash_password_reset_token(token: str) -> str:
    return hashlib.sha256(token.encode("utf-8")).hexdigest()


def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -> str:
    to_encode = data.copy()
    expire = datetime.now(timezone.utc) + (
        expires_delta or timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
    )
    to_encode["exp"] = expire
    if "sub" in to_encode:
        to_encode["sub"] = str(to_encode["sub"])
    return jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)


def decode_token(token: str) -> Optional[dict]:
    try:
        payload = jwt.decode(
            token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM]
        )
        return payload
    except JWTError as e:
        logger.warning("JWT decode error: %s", e)
        return None