from datetime import datetime, timezone
from hashlib import sha256

from backend.app.database import get_connection


def hash_password(password: str) -> str:
    return sha256(password.encode('utf-8')).hexdigest()


def authenticate_user(username: str, password: str):
    password_hash = hash_password(password)
    with get_connection() as conn:
        row = conn.execute(
            'SELECT * FROM users WHERE username = ? AND password_hash = ?',
            (username, password_hash),
        ).fetchone()
    return dict(row) if row else None