# Copyright (C) 2017 Jan Jancar
#
# This file is a part of the Mailman PGP plugin.
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
# more details.
#
# You should have received a copy of the GNU General Public License along with
# this program.  If not, see <http://www.gnu.org/licenses/>.

"""Miscellaneous PGP utilities."""
from pgpy import PGPKey
from public import public


@public
def verifies(verifications):
    """

    :param verifications:
    :type verifications: Sequence[pgpy.types.SignatureVerification]
    :return: bool
    """
    return all(bool(verification) and
               all(not sigsubj.signature.is_expired
                   for sigsubj in verification.good_signatures) for
               verification in verifications)


@public
def hashes(verifications):
    """

    :param verifications:
    :return:
    :rtype: Generator[str]
    """
    for verification in verifications:
        for sigsubj in verification.good_signatures:
            data = sigsubj.signature.hashdata(sigsubj.subject)
            hasher = sigsubj.signature.hash_algorithm.hasher
            hasher.update(data)
            yield hasher.digest()


@public
def key_from_blob(blob):
    """

    :param blob:
    :return:
    """
    keys = PGPKey.from_blob(blob)
    if isinstance(keys, tuple):
        return keys[0]
    else:
        return keys


@public
def key_from_file(file):
    """

    :param file:
    :return:
    """
    keys = PGPKey.from_file(file)
    if isinstance(keys, tuple):
        return keys[0]
    else:
        return keys