# Support code for building a C extension with crypto from OpenSSL
#
# Copyright (c) 2016-present, Gregory Szorc (original code for zstd)
#               2017-present, Thomas Waldmann (mods to make it more generic, code for openssl)
# All rights reserved.
#
# This software may be modified and distributed under the terms
# of the BSD license. See the LICENSE file for details.

import os


def crypto_ext_kwargs(**kwargs):
    """amend kwargs with crypto stuff for a distutils.extension.Extension initialization.

    kwargs: distutils.extension.Extension kwargs that should be amended
    returns: amended kwargs
    """
    def multi_join(paths, *path_segments):
        """apply os.path.join on a list of paths"""
        return [os.path.join(*(path_segments + (path, ))) for path in paths]

    system_prefix = os.environ.get('BORG_OPENSSL_PREFIX')
    if system_prefix:
        print('Detected system OpenSSL')
    else:
        raise Exception('Could not find OpenSSL lib/headers, please set BORG_OPENSSL_PREFIX')

    include_dirs = kwargs.get('include_dirs', [])
    include_dirs += multi_join(['include'], system_prefix)

    library_dirs = kwargs.get('library_dirs', [])
    library_dirs += multi_join(['lib'], system_prefix)

    libraries = kwargs.get('libraries', [])
    libraries += ['crypto', ]

    ret = dict(**kwargs)
    ret.update(dict(include_dirs=include_dirs, library_dirs=library_dirs, libraries=libraries))
    return ret