import yaml
import logging


def _yaml_constructor(loader, node):
    return node.value


class Util(object):
    def __init__(self, cfg):
        self.cfg = cfg
        yaml.SafeLoader.add_constructor("tag:yaml.org,2002:python/unicode", _yaml_constructor)


    def load_yaml(data):
        generator = yaml.safe_load_all(data)
        data_list = list(generator)
        return data_list


    def verify_integrity(new_data, schema):
        logger = logging.getLogger('util.verify_integrity')
        try:
            # Verify that updated fields exist
            schema_keys = schema['properties'].keys()
            for prop in new_data.keys():
                if prop not in schema_keys:
                    raise Exception('{} is not a valid field'.format(prop))
        except Exception as e:
            logger.error(e)
            raise e