# Copyright 2020 VEXXHOST, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Keystone Operator

This module maintains the operator for Keystone which does everything from
deployment to taking care of rotating fernet & credentials keys."""

import base64
import os
import kopf

from cryptography import fernet

from openstack_operator import filters
from openstack_operator import utils

MEMCACHED = True

TOKEN_EXPIRATION = 86400
FERNET_ROTATION_INTERVAL = 3600
ACTIVE_KEYS = int(TOKEN_EXPIRATION / FERNET_ROTATION_INTERVAL) + 2


def _is_keystone_deployment(name, **_):
    return name == 'keystone'


def create_or_rotate_fernet_repository(name):
    """Create or rotate fernet tokens

    This will happen when it sees a Keystone deployment that we manage and it
    will initialize (or rotate) the fernet repository.
    """

    data = utils.get_secret('openstack', 'keystone-%s' % (name))

    # Stage an initial key 0 if we don't have anything.
    if data is None:
        data = {'0': fernet.Fernet.generate_key().decode('utf-8')}

    # Get highest key number
    sorted_keys = [int(k) for k in data.keys()]
    sorted_keys.sort()
    next_key = str(max(sorted_keys) + 1)

    # Promote key 0 to primary
    data[next_key] = data['0']
    sorted_keys.append(int(next_key))

    # Stage a new key
    data['0'] = fernet.Fernet.generate_key().decode('utf-8')

    # Determine the keys to keep and drop others
    keys_to_keep = [0] + sorted_keys[-ACTIVE_KEYS:]
    keys = {k: base64.b64encode(v.encode('utf-8')).decode('utf-8')
            for k, v in data.items() if int(k) in keys_to_keep}

    # Update secret
    utils.create_or_update('keystone/secret-fernet.yml.j2', name=name,
                           keys=keys, adopt=True)


@kopf.timer('apps', 'v1', 'daemonsets',
            when=kopf.all_([filters.managed, _is_keystone_deployment]),
            interval=FERNET_ROTATION_INTERVAL)
def create_or_rotate_fernet(**_):
    """Create or rotate fernet keys

    This will happen when it sees a Keystone deployment that we manage and it
    will initialize (or rotate) the fernet repository.
    """

    create_or_rotate_fernet_repository('fernet')
    create_or_rotate_fernet_repository('credential')


def create_or_resume(name, spec, **_):
    """Create and re-sync any Keystone instances

    This function is called when a new resource is created but also when we
    start the service up for the first time.
    """

    config_hash = utils.generate_hash(spec)
    conn = utils.get_openstack_connection()
    auth_url = conn.config.auth["auth_url"]
    password = os.getenv("OS_PASSWORD")
    project_name = conn.config.auth["project_name"]
    region_name = conn.config.get_region_name()
    username = conn.config.auth["username"]
    utils.create_or_update('keystone/secret-init.yml.j2',
                           auth_url=auth_url,
                           password=password,
                           project_name=project_name,
                           region_name=region_name,
                           username=username)
    # (TODO)Replace the current admin url

    # deploy mysql
    db_config = utils.ensure_mysql_cluster("keystone", spec["mysql"])

    # deploy memcached

    # keystone config
    utils.create_or_update('keystone/secret-config.yml.j2',
                           password=db_config["PASSWORD"],
                           TOKEN_EXPIRATION=TOKEN_EXPIRATION,
                           ACTIVE_KEYS=ACTIVE_KEYS)

    # deploy keystone
    utils.create_or_update('keystone/daemonset.yml.j2',
                           name=name, spec=spec,
                           config_hash=config_hash)
    utils.create_or_update('keystone/service.yml.j2',
                           name=name, spec=spec)
    if "ingress" in spec:
        utils.create_or_update('keystone/ingress.yml.j2',
                               spec=spec)


def update(spec, **_):
    """Update a keystone

    This function updates the deployment for keystone if there are any
    changes that happen within it.
    """
    if "ingress" in spec:
        utils.create_or_update('keystone/ingress.yml.j2',
                               spec=spec)