import time
from functools import wraps


def retry(ExceptionToCheck, tries=3, delay=5, backoff=2, logger=None):
    """Retry calling the decorated function using an exponential backoff.
    http://www.saltycrane.com/blog/2009/11/trying-out-retry-decorator-python/
    original from: http://wiki.python.org/moin/PythonDecoratorLibrary#Retry
    :param ExceptionToCheck: the exception to check. may be a tuple of
        exceptions to check
    :type ExceptionToCheck: Exception or tuple
    :param tries: number of times to try (not retry) before giving up
    :type tries: int
    :param delay: initial delay between retries in seconds
    :type delay: int
    :param backoff: backoff multiplier e.g. value of 2 will double the delay
        each retry
    :type backoff: int
    :param logger: logger to use. If None, print
    :type logger: logging.Logger instance
    """

    def deco_retry(f):
        @wraps(f)
        def f_retry(*args, **kwargs):
            mtries, mdelay = tries, delay
            while mtries > 1:
                try:
                    return f(*args, **kwargs)
                except ExceptionToCheck as e:
                    timeunit = None
                    divisor = 1
                    if mdelay < 60:
                        timeunit = "seconds"
                        divisor = 1
                    elif timeunit < 3600:
                        timeunit = "minutes"
                        divisor = 60
                    elif timeunit < 3600 * 60:
                        timeunit = "hours"
                        divisor = 3600

                    msg = f"{str(e)}, Retrying in {int(mdelay/divisor)} {timeunit}..."

                    if logger:
                        logger.warning(msg)
                    else:
                        print(msg)
                    time.sleep(mdelay)
                    mtries -= 1
                    mdelay *= backoff
            return f(*args, **kwargs)

        return f_retry  # true decorator

    return deco_retry


if __name__ == "__main__":

    @retry(Exception)
    def testing():
        raise Exception("failed!")

