# Copyright 2016 - IBM Corp.
# Copyright 2016 Catalyst IT 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.

from oslo_log import log as logging
from pecan import rest
import wsmeext.pecan as wsme_pecan

from mistral.api import access_control as acl
from mistral.api.controllers.v2 import resources
from mistral.api.controllers.v2 import types
from mistral import context as auth_ctx
from mistral.db.v2 import api as db_api
from mistral import exceptions as exc
from mistral.services import triggers
from mistral.utils import rest_utils

LOG = logging.getLogger(__name__)

UPDATE_NOT_ALLOWED = ['exchange', 'topic', 'event']
CREATE_MANDATORY = set(['exchange', 'topic', 'event', 'workflow_id'])


class EventTriggersController(rest.RestController):
    @rest_utils.wrap_wsme_controller_exception
    @wsme_pecan.wsexpose(resources.EventTrigger, types.uuid)
    def get(self, id):
        """Returns the specified event_trigger."""
        acl.enforce('event_triggers:get', auth_ctx.ctx())

        LOG.debug('Fetch event trigger [id=%s]', id)

        # Use retries to prevent possible failures.
        r = rest_utils.create_db_retry_object()
        db_model = r.call(db_api.get_event_trigger, id)

        return resources.EventTrigger.from_db_model(db_model)

    @rest_utils.wrap_wsme_controller_exception
    @wsme_pecan.wsexpose(resources.EventTrigger, body=resources.EventTrigger,
                         status_code=201)
    def post(self, event_trigger):
        """Creates a new event trigger."""
        acl.enforce('event_triggers:create', auth_ctx.ctx())

        values = event_trigger.to_dict()
        input_keys = [k for k in values if values[k]]

        if CREATE_MANDATORY - set(input_keys):
            raise exc.EventTriggerException(
                "Params %s must be provided for creating event trigger." %
                CREATE_MANDATORY
            )

        if values.get('scope') == 'public':
            acl.enforce('event_triggers:create:public', auth_ctx.ctx())

        LOG.debug('Create event trigger: %s', values)

        db_model = rest_utils.rest_retry_on_db_error(
            triggers.create_event_trigger
        )(
            name=values.get('name', ''),
            exchange=values.get('exchange'),
            topic=values.get('topic'),
            event=values.get('event'),
            workflow_id=values.get('workflow_id'),
            scope=values.get('scope'),
            workflow_input=values.get('workflow_input'),
            workflow_params=values.get('workflow_params'),
        )

        return resources.EventTrigger.from_db_model(db_model)

    @rest_utils.wrap_wsme_controller_exception
    @wsme_pecan.wsexpose(resources.EventTrigger, types.uuid,
                         body=resources.EventTrigger)
    def put(self, id, event_trigger):
        """Updates an existing event trigger.

        The exchange, topic and event can not be updated. The right way to
        change them is to delete the event trigger first, then create a new
        event trigger with new params.
        """
        acl.enforce('event_triggers:update', auth_ctx.ctx())

        values = event_trigger.to_dict()

        for field in UPDATE_NOT_ALLOWED:
            if values.get(field):
                raise exc.EventTriggerException(
                    "Can not update fields %s of event trigger." %
                    UPDATE_NOT_ALLOWED
                )

        LOG.debug('Update event trigger: [id=%s, values=%s]', id, values)

        @rest_utils.rest_retry_on_db_error
        def _update_event_trigger():
            with db_api.transaction():
                # ensure that event trigger exists
                db_api.get_event_trigger(id)

                return triggers.update_event_trigger(id, values)

        db_model = _update_event_trigger()

        return resources.EventTrigger.from_db_model(db_model)

    @rest_utils.wrap_wsme_controller_exception
    @wsme_pecan.wsexpose(None, types.uuid, status_code=204)
    def delete(self, id):
        """Delete event trigger."""
        acl.enforce('event_triggers:delete', auth_ctx.ctx())

        LOG.debug("Delete event trigger [id=%s]", id)

        @rest_utils.rest_retry_on_db_error
        def _delete_event_trigger():
            with db_api.transaction():
                event_trigger = db_api.get_event_trigger(id)

                triggers.delete_event_trigger(event_trigger.to_dict())

        _delete_event_trigger()

    @rest_utils.wrap_wsme_controller_exception
    @wsme_pecan.wsexpose(resources.EventTriggers, types.uuid, int,
                         types.uniquelist, types.list, types.uniquelist,
                         bool, types.jsontype)
    def get_all(self, marker=None, limit=None, sort_keys='created_at',
                sort_dirs='asc', fields='', all_projects=False, **filters):
        """Return all event triggers."""
        acl.enforce('event_triggers:list', auth_ctx.ctx())

        if all_projects:
            acl.enforce('event_triggers:list:all_projects', auth_ctx.ctx())

        LOG.debug(
            "Fetch event triggers. marker=%s, limit=%s, sort_keys=%s, "
            "sort_dirs=%s, fields=%s, all_projects=%s, filters=%s", marker,
            limit, sort_keys, sort_dirs, fields, all_projects, filters
        )

        return rest_utils.get_all(
            resources.EventTriggers,
            resources.EventTrigger,
            db_api.get_event_triggers,
            db_api.get_event_trigger,
            resource_function=None,
            marker=marker,
            limit=limit,
            sort_keys=sort_keys,
            sort_dirs=sort_dirs,
            fields=fields,
            all_projects=all_projects,
            **filters
        )
