# 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.

from flask import Flask
import os
from oslo_config import cfg
import oslo_messaging
from python_nemesis.config import collect_sqlalchemy_opts
from python_nemesis.config import register_opts
from python_nemesis.extensions import db
from python_nemesis.extensions import keystone
from python_nemesis.extensions import log


def configure_blueprints(app, blueprints):
    """Register configured blueprints into app object.

    :param app: The application object to which configuration should
                be applied.
    :type app: :py:class:`flask.Flask`
    :param blueprints: list of blueprints to be registered.
    :type blueprints: list(:py:class:`flask.Blueprint`)
    """
    for blueprint in blueprints:
        app.register_blueprint(blueprint)


def configure_app(app):
    """Retrieve App Configuration.

    configure_app first loads default configuration and then attempts
    to override defaults using a file specified in env:NEMESIS_CONFIG.

    :param app: The application object to which configuration should
                be applied.
    :type app: :py:class:`flask.Flask`
    """
    app.config.from_object('python_nemesis.default_config')
    app.config["cfg"] = cfg.CONF
    config_file = os.environ.get(
        "NEMESIS_CONFIG",
        "/etc/nemesis/nemesis.conf")

    register_opts(app.config["cfg"], config_file)
    collect_sqlalchemy_opts(app, app.config["cfg"])


def configure_extensions(app):
    """Initialize extensions for Flask.

    This function is intended for use with the app factory style
    of Flask deployment.

    :param app: The application object to which configuration should
                be applied.
    :type app: :py:class:`flask.Flask`
    """
    db.init_app(app)
    log.init_app(app)
    keystone.init_app(app)


def configure_notifier(app):
    transport = oslo_messaging.get_notification_transport(app.config['cfg'])
    topics = ['nemesis_notifications']
    app.config["notifier"] = oslo_messaging.Notifier(transport,
                                                     'nemesis.api',
                                                     driver='messagingv2',
                                                     topics=topics)


def create_app(app_name=None):
    """Create the flask app.

    This function is intended to be used with the app factory
    style of Flask deployment.

    :param str app_name: Name to be used internally within flask.
    :param blueprints: Blueprints to be registered.
    :type blueprints: list(:py:class:`flask.Blueprint`)
    :returns: The created app.
    :rtype: :py:class:`flask.Flask`
    """
    app = Flask(app_name)
    return app