# Licensed under a 3-clause BSD style license - see README.rst

"""

Handle loading six package from system or from the bundled copy

"""

import imp

from distutils.version import StrictVersion

_SIX_MIN_VERSION = StrictVersion('1.5.0')

# Update this to prevent Astropy from using its bundled copy of six

# (but only if some other version of at least _SIX_MIN_VERSION can

# be provided)

_SIX_SEARCH_PATH = ['six', 'sklearn.externals.bundled.six']

def _find_module(name, path=None):

    """

    Alternative to `imp.find_module` that can also search in subpackages.

    """

    parts = name.split('.')

    for part in parts:

        if path is not None:

            path = [path]

        fh, path, descr = imp.find_module(part, path)

    return fh, path, descr

for mod_name in _SIX_SEARCH_PATH:

    try:

        mod_info = _find_module(mod_name)

    except ImportError:

        continue

    mod = imp.load_module(__name__, *mod_info)

    try:

        if StrictVersion(mod.__version__) >= _SIX_MIN_VERSION:

            break

    except (AttributeError, ValueError):

        # Attribute error if the six module isn't what it should be and doesn't

        # have a .__version__; ValueError if the version string exists but is

        # somehow bogus/unparseable

        continue

else:

    raise ImportError(

        "sklearn requires the 'six' module of minimum version {0}; "

        "normally this is bundled with the astropy package so if you get "

        "this warning consult the packager of your sklearn "

        "distribution.".format(_SIX_MIN_VERSION))