import os


def is_production():
    return not os.environ.get('DEV_MODE', '').lower() in ('1', 'true', 'yes')


def is_pro():
    return bool(os.environ.get('LICENSE', '').strip())


def get_credentials_key():
    """Return a Fernet-compatible key derived from the CREDENTIALS_KEY environment variable,
    or None if not set. SHA-256 hashes the raw string to produce 32 bytes, which are then
    URL-safe base64-encoded as required by Fernet."""
    import base64
    import hashlib
    key_str = os.environ.get('CREDENTIALS_KEY', '')
    if not key_str:
        return None
    raw = hashlib.sha256(key_str.encode()).digest()
    return base64.urlsafe_b64encode(raw)