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

"""

Handle loading ply package from system or from the bundled copy

"""

import imp

from distutils.version import StrictVersion

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

_PLY_MIN_VERSION = StrictVersion('3.4')

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

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

# be provided)

_PLY_SEARCH_PATH = ['ply']

for mod_name in _PLY_SEARCH_PATH:

    try:

        mod_info = _find_module(mod_name)

        #mod_lex_info = _find_module(mod_name + '.lex')

    except ImportError:

        continue

    mod = imp.load_module(__name__, *mod_info)

    #mod_lex = imp.load_module(__name__ + '.lex', *mod_lex_info)

    try:

    #    if StrictVersion(mod_lex.__version__) >= _PLY_MIN_VERSION:

    #        break

        break

    except (AttributeError, ValueError):

        # Attribute error if the ply 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(

        "Astropy requires the 'ply' module of minimum version {0}; "

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

        "this warning consult the packager of your Astropy "

        "distribution.".format(_PLY_MIN_VERSION))