#
# This file is part of pretix (Community Edition).
#
# Copyright (C) 2014-2020 Raphael Michel and contributors
# Copyright (C) 2020-2021 rami.io GmbH and contributors
#
# This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
# Public License as published by the Free Software Foundation in version 3 of the License.
#
# ADDITIONAL TERMS APPLY: Pursuant to Section 7 of the GNU Affero General Public License, additional terms are
# applicable granting you additional permissions and placing additional restrictions on your usage of this software.
# Please refer to the pretix LICENSE file to obtain the full terms applicable to this work. If you did not receive
# this file, see <https://pretix.eu/about/en/license>.
#
# 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 Affero General Public License for more
# details.
#
# You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
# <https://www.gnu.org/licenses/>.
#
import hashlib

from django.core.signing import BadSignature, TimestampSigner


def get_token(request, answer):
    if not request.session.session_key:
        request.session.create()
    payload = '{}:{}'.format(request.session.session_key, answer.pk)
    signer = TimestampSigner()
    return signer.sign(hashlib.sha1(payload.encode()).hexdigest())


def check_token(request, answer, token):
    payload = hashlib.sha1('{}:{}'.format(request.session.session_key, answer.pk).encode()).hexdigest()
    signer = TimestampSigner()
    try:
        return payload == signer.unsign(token, max_age=3600 * 24)
    except BadSignature:
        return False