auth.py

from datetime import datetime, timedelta
from typing import Optional
from jose import JWTError, jwt
from fastapi import Depends, HTTPException, status
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from dotenv import load_dotenv
import os

load_dotenv()

SECRET_KEY = os.getenv("SECRET_KEY", "changeme-use-a-real-secret-in-production")
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 60 * 24  # 24 hours

# Hardcoded demo user - in production, use a real user DB
DEMO_USERS = {
    "admin": "password123"  # username: password
}

security = HTTPBearer()

def create_access_token(data: dict, expires_delta: Optional[timedelta] = None):
    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 verify_token(credentials: HTTPAuthorizationCredentials = Depends(security)):
    token = credentials.credentials
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Invalid or expired token",
        headers={"WWW-Authenticate": "Bearer"},
    )
    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
    return username

def authenticate_user(username: str, password: str) -> bool:
    return DEMO_USERS.get(username) == password