"""Authentication module"""
import bcrypt
from datetime import datetime, timedelta
from typing import Optional
import jwt
import os

SECRET_KEY = os.getenv("JWT_SECRET", "your-super-secret-key-change-in-production")
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_HOURS = 24


def hash_password(password: str) -> str:
    return bcrypt.hashpw(password.encode(), bcrypt.gensalt()).decode()


def verify_password(plain: str, hashed: str) -> bool:
    return bcrypt.checkpw(plain.encode(), hashed.encode())


def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -> str:
    to_encode = data.copy()
    expire = datetime.utcnow() + (expires_delta or timedelta(hours=ACCESS_TOKEN_EXPIRE_HOURS))
    to_encode.update({"exp": expire})
    return jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)


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


async def authenticate_user(username: str, password: str) -> Optional[dict]:
    from app.database import get_user_by_username
    user = await get_user_by_username(username)
    if not user:
        return None
    if not verify_password(password, user["password"]):
        return None
    return user