from datetime import datetime, timedelta
from typing import Optional
from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from jose import JWTError, jwt
from passlib.context import CryptContext
from sqlalchemy.orm import Session
from app.models.user import User

pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/api/v1/auth/login")
SECRET_KEY = "your-secret-key-here"
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 30

def verify_token(token: str) -> Optional[User]:
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        user_id: str = payload.get("sub")
        if user_id is None:
            raise HTTPException(status_code=401, detail="Token inválido")
        return User(id=user_id)
    except JWTError:
        raise HTTPException(status_code=401, detail="Token inválido o expirado")

async def get_current_user(token: str = Depends(oauth2_scheme)) -> User:
    user = verify_token(token)
    if not user:
        raise HTTPException(status_code=401, detail="Usuario no autenticado")
    return user