# Copyright 2017 FUJITSU LIMITED
#
# 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.

"""
Module contains factories to initializes various applications
of monasca-log-api
"""

import six

import falcon
from oslo_log import log

from monasca_log_api.app.base import error_handlers
from monasca_log_api.app.base import request
from monasca_log_api.app.controller import healthchecks
from monasca_log_api.app.controller.v2 import logs as v2_logs
from monasca_log_api.app.controller.v3 import logs as v3_logs
from monasca_log_api.app.controller import versions
from monasca_log_api import config


def error_trap(app_name):
    """Decorator trapping any error during application boot time"""

    @six.wraps(error_trap)
    def _wrapper(func):

        @six.wraps(_wrapper)
        def _inner_wrapper(*args, **kwargs):
            try:
                return func(*args, **kwargs)
            except Exception:
                logger = log.getLogger(__name__)
                logger.exception('Failed to load application \'%s\'', app_name)
                raise

        return _inner_wrapper

    return _wrapper


def singleton_config(func):
    """Decorator ensuring that configuration is loaded only once."""

    @six.wraps(singleton_config)
    def _wrapper(global_config, **local_conf):
        config.parse_args()
        return func(global_config, **local_conf)

    return _wrapper


@error_trap('version')
def create_version_app(global_conf, **local_conf):
    """Creates Version application"""

    ctrl = versions.Versions()
    controllers = {
        '/': ctrl,   # redirect http://host:port/ down to Version app
                     # avoid conflicts with actual pipelines and 404 error
        '/version': ctrl,  # list all the versions
        '/version/{version_id}': ctrl  # display details of the version
    }

    wsgi_app = falcon.API(
        request_type=request.Request
    )
    for route, ctrl in controllers.items():
        wsgi_app.add_route(route, ctrl)
    return wsgi_app


@error_trap('healthcheck')
def create_healthcheck_app(global_conf, **local_conf):
    """Creates Healthcheck application"""

    ctrl = healthchecks.HealthChecks()
    controllers = {
        '/': ctrl
    }

    wsgi_app = falcon.API(
        request_type=request.Request
    )
    for route, ctrl in controllers.items():
        wsgi_app.add_route(route, ctrl)
    return wsgi_app


@error_trap('api')
@singleton_config
def create_api_app(global_conf, **local_conf):
    """Creates MainAPI application"""

    controllers = {}
    api_version = global_conf.get('api_version')

    if api_version == 'v2.0':
        controllers.update({
            '/log/single': v2_logs.Logs()
        })
    elif api_version == 'v3.0':
        controllers.update({
            '/logs': v3_logs.Logs()
        })

    wsgi_app = falcon.API(
        request_type=request.Request
    )

    for route, ctrl in controllers.items():
        wsgi_app.add_route(route, ctrl)

    error_handlers.register_error_handlers(wsgi_app)

    return wsgi_app