auth.py

from datetime import datetime, timedelta, timezone
from jose import JWTError, jwt
import bcrypt
from fastapi import Depends, HTTPException
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from sqlalchemy.orm import Session
from database import get_db
import models
import os

SECRET_KEY  = os.getenv("SECRET_KEY", "change-me-to-a-long-random-secret")
ALGORITHM   = "HS256"
EXPIRE_DAYS = 7

bearer_scheme = HTTPBearer()


def hash_password(password: str) -> str:
    return bcrypt.hashpw(password.encode(), bcrypt.gensalt()).decode()


def verify_password(plain: str, hashed: str) -> bool:
    return bcrypt.checkpw(plain.encode(), hashed.encode())


def create_access_token(user_id: int) -> str:
    expire  = datetime.now(timezone.utc) + timedelta(days=EXPIRE_DAYS)
    payload = {"sub": str(user_id), "exp": expire}
    return jwt.encode(payload, SECRET_KEY, algorithm=ALGORITHM)


def get_current_user(
    credentials: HTTPAuthorizationCredentials = Depends(bearer_scheme),
    db: Session = Depends(get_db),
) -> models.User:
    token = credentials.credentials
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        user_id = int(payload.get("sub"))
    except (JWTError, TypeError, ValueError):
        raise HTTPException(status_code=401, detail="Invalid or expired token")

    user = db.query(models.User).filter(models.User.id == user_id).first()
    if not user:
        raise HTTPException(status_code=401, detail="User not found")
    return user