import os
import yaml
import copy
import logging
import boto3

logger = logging.getLogger(__name__)

def read_yaml_file(path):
    data = {}
    if os.path.exists(path):
        with open(path, 'r') as config_file_contents:
            logger.debug("Reading config file: {}".format(path))
            try:
                _data = yaml.load(config_file_contents.read())
                if _data:
                    data.update(_data)
            except Exception as e:
                logger.warning("Error reading config file: {} ({})".format(path,e))

    return data


def dict_merge(a, b):
    """ Deep merge to allow proper inheritance for config files"""
    if not a:
        return b

    if not b:
        return a

    if  not isinstance(a, dict) or not isinstance(b, dict):
        raise TypeError

    result = copy.deepcopy(a)
    for k, v in b.items():
        if k in result and isinstance(result[k], dict):
                result[k] = dict_merge(result[k], v)
        else:
            result[k] = copy.deepcopy(v)
    return result


def ensure_dir(path):
    """Creates dir if it does not already exist."""
    if not os.path.exists(path):
        os.makedirs(path)
        logger.info('Created directory: %s', path)


def setup_logging(debug):
    if debug:
        our_level = logging.DEBUG
        # logging.getLogger("botocore").setLevel(logging.INFO)
        boto3.set_stream_logger('')
    else:
        our_level = logging.INFO
        logging.getLogger("botocore").setLevel(logging.CRITICAL)

    formatter = logging.Formatter(
        fmt="[%(asctime)s] - %(name)s - %(message)s",
        datefmt="%Y-%m-%d %H:%M:%S"
    )

    log_handler = logging.StreamHandler()
    log_handler.setFormatter(formatter)
    logger = logging.getLogger("cloudbender")
    logger.addHandler(log_handler)
    logger.setLevel(our_level)
    return logger