import copy, json, os

CONFIGS_DIR   = os.environ.get('ROUTLIN_LOCATION', '/routlin_location')
CONFIG_FILE   = f'{CONFIGS_DIR}/config.json'
CAPTIVE_QUEUE = f'{CONFIGS_DIR}/.captive-queue'

_config_cache = None
_config_mtime = None


def load_config():
    global _config_cache, _config_mtime
    try:
        mtime = os.path.getmtime(CONFIG_FILE)
        if _config_cache is not None and mtime == _config_mtime:
            return copy.deepcopy(_config_cache)
        with open(CONFIG_FILE) as f:
            data = json.load(f)
        _config_cache = data
        _config_mtime = mtime
        return copy.deepcopy(data)
    except Exception:
        return {}