from datetime import datetime, timedelta
from typing import Optional
import jwt
from fastapi import Depends, HTTPException, status
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from sqlalchemy.orm import Session
from database import get_db
from models.user import User
import os

SECRET_KEY = os.getenv("JWT_SECRET", "change-me-in-production")
ALGORITHM = os.getenv("JWT_ALGORITHM", "HS256")
ACCESS_TOKEN_EXPIRE_MINUTES = int(os.getenv("ACCESS_TOKEN_EXPIRE_MINUTES", "30"))

security = HTTPBearer()


def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -> str:
    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 decode_access_token(token: str) -> dict:
    try:
        return jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
    except jwt.ExpiredSignatureError:
        raise HTTPException(status_code=401, detail="Token expirado")
    except jwt.InvalidTokenError:
        raise HTTPException(status_code=401, detail="Token inválido")


def get_current_user(
    credentials: HTTPAuthorizationCredentials = Depends(security),
    db: Session = Depends(get_db),
) -> User:
    token = credentials.credentials
    payload = decode_access_token(token)
    email: str = payload.get("sub")
    if email is None:
        raise HTTPException(status_code=401, detail="No se pudo validar el token")
    user = db.query(User).filter(User.email == email).first()
    if user is None:
        raise HTTPException(status_code=401, detail="Usuario no encontrado")
    return user