"""
The `compat` module provides support for backwards compatibility with older
versions of python, and compatibility wrappers around optional packages.
"""
# flake8: noqa
import sys
import hmac


PY3 = sys.version_info[0] == 3


if PY3:
    text_type = str
    binary_type = bytes
else:
    text_type = unicode
    binary_type = str

string_types = (text_type, binary_type)


def is_string_type(val):
    return any([isinstance(val, typ) for typ in string_types])


def timedelta_total_seconds(delta):
    try:
        delta.total_seconds
    except AttributeError:
        # On Python 2.6, timedelta instances do not have
        # a .total_seconds() method.
        total_seconds = delta.days * 24 * 60 * 60 + delta.seconds
    else:
        total_seconds = delta.total_seconds()

    return total_seconds


try:
    constant_time_compare = hmac.compare_digest
except AttributeError:
    # Fallback for Python < 2.7
    def constant_time_compare(val1, val2):
        """
        Returns True if the two strings are equal, False otherwise.

        The time taken is independent of the number of characters that match.
        """
        if len(val1) != len(val2):
            return False

        result = 0

        for x, y in zip(val1, val2):
            result |= ord(x) ^ ord(y)

        return result == 0