from datetime import datetime, timedelta
import jwt
from typing import Optional
import bcrypt

from constants import *

# JWT Helper Functions
def create_token(user_id: int, username: str) -> str:
    expire = datetime.now() + timedelta(hours=ACCESS_TOKEN_EXPIRE_HOURS)
    payload = {
        "user_id": user_id,
        "username": username,
        "exp": expire
    }
    return jwt.encode(payload, JWT_SECRET_KEY, algorithm=JWT_ALGORITHM)


def verify_token(token: str) -> Optional[dict]:
    try:
        payload = jwt.decode(token, JWT_SECRET_KEY, algorithms=[JWT_ALGORITHM])
        return payload
    except jwt.ExpiredSignatureError:
        return None
    except jwt.InvalidTokenError:
        return None


def verify_password(plain_password: str, hashed_password: str) -> bool:
    return bcrypt.checkpw(plain_password.encode("utf-8"), hashed_password.encode("utf-8"))

def get_password_hash(password: str) -> str:
    return bcrypt.hashpw(password.encode("utf-8"), bcrypt.gensalt()).decode("utf-8")