# Copyright (c) 2013 Mirantis 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.

import eventlet
import flask
from keystoneclient.middleware import auth_token
from oslo.config import cfg
from werkzeug import exceptions as werkzeug_exceptions

from savanna.api import v10 as api_v10
from savanna import context
from savanna.db import api as db_api
from savanna.middleware import auth_valid
from savanna.openstack.common import log
from savanna.openstack.common.middleware import debug
from savanna.plugins import base as plugins_base
from savanna.utils import api as api_utils
from savanna.utils import patches
from savanna.utils import scheduler

LOG = log.getLogger(__name__)

eventlet.monkey_patch(
    os=True, select=True, socket=True, thread=True, time=True)

# Patches minidom's writexml to avoid excess whitespaces in generated xml
# configuration files that brakes Hadoop.
patches.patch_minidom_writexml()

opts = [
    cfg.StrOpt('os_auth_protocol',
               default='http',
               help='Protocol used to access OpenStack Identity service'),
    cfg.StrOpt('os_auth_host',
               default='127.0.0.1',
               help='IP or hostname of machine on which OpenStack Identity '
                    'service is located'),
    cfg.StrOpt('os_auth_port',
               default='35357',
               help='Port of OpenStack Identity service'),
    cfg.StrOpt('os_admin_username',
               default='admin',
               help='This OpenStack user is used to verify provided tokens. '
                    'The user must have admin role in <os_admin_tenant_name> '
                    'tenant'),
    cfg.StrOpt('os_admin_password',
               default='nova',
               help='Password of the admin user'),
    cfg.StrOpt('os_admin_tenant_name',
               default='admin',
               help='Name of tenant where the user is admin')
]

CONF = cfg.CONF
CONF.register_opts(opts)


def make_app():
    """App builder (wsgi)

    Entry point for Savanna REST API server
    """
    app = flask.Flask('savanna.api')

    @app.route('/', methods=['GET'])
    def version_list():
        context.set_ctx(None)
        return api_utils.render({
            "versions": [
                {"id": "v1.0", "status": "CURRENT"}
            ]
        })

    @app.teardown_request
    def teardown_request(_ex=None):
        # TODO(slukjanov): how it'll work in case of exception?
        if context.has_ctx():
            if flask.request.path != '/':
                try:
                    session = context.session()
                    if session.transaction:
                        session.transaction.commit()
                except Exception, e:
                    return api_utils.internal_error(
                        500, 'Internal Server Error', e)

        context.set_ctx(None)

    app.register_blueprint(api_v10.rest, url_prefix='/v1.0')

    db_api.configure_db()
    scheduler.setup_scheduler(app)
    plugins_base.setup_plugins()

    def make_json_error(ex):
        status_code = (ex.code
                       if isinstance(ex, werkzeug_exceptions.HTTPException)
                       else 500)
        description = (ex.description
                       if isinstance(ex, werkzeug_exceptions.HTTPException)
                       else str(ex))
        return api_utils.render({'error': status_code,
                                 'error_message': description},
                                status=status_code)

    for code in werkzeug_exceptions.default_exceptions.iterkeys():
        app.error_handler_spec[None][code] = make_json_error

    if CONF.debug and not CONF.log_exchange:
        LOG.debug('Logging of request/response exchange could be enabled using'
                  ' flag --log-exchange')

    if CONF.log_exchange:
        app.wsgi_app = debug.Debug.factory(app.config)(app.wsgi_app)

    app.wsgi_app = auth_valid.filter_factory(app.config)(app.wsgi_app)

    app.wsgi_app = auth_token.filter_factory(
        app.config,
        auth_host=CONF.os_auth_host,
        auth_port=CONF.os_auth_port,
        auth_protocol=CONF.os_auth_protocol,
        admin_user=CONF.os_admin_username,
        admin_password=CONF.os_admin_password,
        admin_tenant_name=CONF.os_admin_tenant_name
    )(app.wsgi_app)

    return app
