# Copyright 2017 AT&T Intellectual Property.  All other rights reserved.
#
# 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 falcon

from shipyard_airflow import policy
from shipyard_airflow.control.base import BaseResource
from shipyard_airflow.common.notes.notes import MAX_VERBOSITY
from shipyard_airflow.control.helpers.notes import NOTES as notes_helper
from shipyard_airflow.db.db import AIRFLOW_DB, SHIPYARD_DB
from shipyard_airflow.errors import ApiError


# /api/v1.0/actions/{action_id}/steps/{step_id}
class ActionsStepsResource(BaseResource):
    """
    The actions steps resource is the steps of an action
    """
    @policy.ApiEnforcer(policy.GET_ACTION_STEP)
    def on_get(self, req, resp, **kwargs):
        """
        Return step details for an action step
        :returns: a json object describing a step
        """
        resp.body = self.to_json(
            self.get_action_step(
                action_id=kwargs['action_id'],
                step_id=kwargs['step_id'],
                verbosity=req.context.verbosity
            )
        )
        resp.status = falcon.HTTP_200

    def get_action_step(self, action_id, step_id, verbosity=MAX_VERBOSITY):
        """Retrieve a single step

        :param action_id: the action_id containing the target step
        :param step_id: the step to retrieve
        :param verbosity: the level of detail to return for the step. Defaults
            to the highest level of detail.

        Interacts with airflow and the shipyard database to return the
        requested step invoked through shipyard.
        """
        action = self.get_action_db(action_id=action_id)

        if action is None:
            raise ApiError(
                title='Action not found',
                description='Unknown action {}'.format(action_id),
                status=falcon.HTTP_404)

        # resolve the ids for lookup of steps
        dag_id = action['dag_id']
        dag_execution_date = action['dag_execution_date']

        # get the action steps from shipyard db
        steps = self.get_tasks_db(dag_id, dag_execution_date)
        step_notes = notes_helper.get_step_notes(
            action_id=action_id,
            step_id=step_id,
            verbosity=verbosity
        )
        for idx, step in enumerate(steps):
            if step_id == step['task_id']:
                step['index'] = idx + 1
                step['notes'] = []
                for note in step_notes:
                    step['notes'].append(note.view())
                return step

        # if we didn't find it, 404
        raise ApiError(
            title='Step not found',
            description='Unknown step {}'.format(step_id),
            status=falcon.HTTP_404)

    def get_action_db(self, action_id):
        """
        Wrapper for call to the shipyard database to get an action
        :returns: a dictionary of action details.
        """
        return SHIPYARD_DB.get_action_by_id(
            action_id=action_id)

    def get_tasks_db(self, dag_id, execution_date):
        """
        Wrapper for call to the airflow db to get all tasks for a dag run
        :returns: a list of task dictionaries
        """
        return AIRFLOW_DB.get_tasks_by_id(
            dag_id=dag_id, execution_date=execution_date)