from datetime import datetime, timedelta, timezone
from typing import Any, Union, Optional
from jose import jwt
import bcrypt
from app.config.config import settings

def verify_password(plain_password: str, hashed_password: str) -> bool:
    """Compare a plain text password with its bcrypt hash to verify identity."""
    return bcrypt.checkpw(plain_password.encode('utf-8'), hashed_password.encode('utf-8'))

def get_password_hash(password: str) -> str:
    """Generate a bcrypt hash from a plain text password."""
    return bcrypt.hashpw(password.encode('utf-8'), bcrypt.gensalt()).decode('utf-8')

def create_access_token(subject: Union[str, Any], expires_delta: Optional[timedelta] = None) -> str:
    """
    Generate a JSON Web Token (JWT) containing the subject (e.g. username/id).
    Accepts an optional expiration delta, defaulting to the config setting.
    """
    if expires_delta:
        expire = datetime.now(timezone.utc) + expires_delta
    else:
        expire = datetime.now(timezone.utc) + timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
    
    to_encode = {"exp": expire, "sub": str(subject)}
    encoded_jwt = jwt.encode(to_encode, settings.JWT_SECRET_KEY, algorithm=settings.JWT_ALGORITHM)
    return encoded_jwt