# Copyright 2013 - Mirantis, Inc.
# Copyright 2015 - StackStorm, 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 json

from oslo_log import log as logging
from pecan import rest
import wsme
from wsme import types as wtypes
import wsmeext.pecan as wsme_pecan

from mistral.api.controllers import resource
from mistral.api.controllers.v2 import action_execution
from mistral.api.controllers.v2 import types
from mistral.db.v2 import api as db_api
from mistral.engine import rpc
from mistral import exceptions as exc
from mistral.utils import rest_utils
from mistral.workbook import parser as spec_parser
from mistral.workflow import data_flow
from mistral.workflow import states


LOG = logging.getLogger(__name__)


class Task(resource.Resource):
    """Task resource."""

    id = wtypes.text
    name = wtypes.text

    workflow_name = wtypes.text
    workflow_execution_id = wtypes.text

    state = wtypes.text
    "state can take one of the following values: \
    IDLE, RUNNING, SUCCESS, ERROR, DELAYED"

    result = wtypes.text
    published = types.jsontype
    processed = bool

    created_at = wtypes.text
    updated_at = wtypes.text

    # Add this param to make Mistral API work with WSME 0.8.0 or higher version
    reset = wsme.wsattr(bool, mandatory=True)

    @classmethod
    def sample(cls):
        return cls(
            id='123e4567-e89b-12d3-a456-426655440000',
            workflow_name='flow',
            workflow_execution_id='123e4567-e89b-12d3-a456-426655440000',
            name='task',
            state=states.SUCCESS,
            result='task result',
            published={'key': 'value'},
            processed=True,
            created_at='1970-01-01T00:00:00.000000',
            updated_at='1970-01-01T00:00:00.000000',
            reset=True
        )


class Tasks(resource.Resource):
    """A collection of tasks."""

    tasks = [Task]

    @classmethod
    def sample(cls):
        return cls(tasks=[Task.sample()])


def _get_task_resource_with_result(task_ex):
    task = Task.from_dict(task_ex.to_dict())
    task.result = json.dumps(data_flow.get_task_execution_result(task_ex))

    return task


def _get_task_resources_with_results(wf_ex_id=None):
    filters = {}

    if wf_ex_id:
        filters['workflow_execution_id'] = wf_ex_id

    with db_api.transaction():
        task_exs = db_api.get_task_executions(**filters)
        tasks = [_get_task_resource_with_result(t_e) for t_e in task_exs]

    return Tasks(tasks=tasks)


class TasksController(rest.RestController):
    action_executions = action_execution.TasksActionExecutionController()

    @rest_utils.wrap_wsme_controller_exception
    @wsme_pecan.wsexpose(Task, wtypes.text)
    def get(self, id):
        """Return the specified task."""
        LOG.info("Fetch task [id=%s]" % id)

        task_ex = db_api.get_task_execution(id)

        return _get_task_resource_with_result(task_ex)

    @wsme_pecan.wsexpose(Tasks)
    def get_all(self):
        """Return all tasks within the execution."""
        LOG.info("Fetch tasks")

        return _get_task_resources_with_results()

    @rest_utils.wrap_wsme_controller_exception
    @wsme_pecan.wsexpose(Task, wtypes.text, body=Task)
    def put(self, id, task):
        """Update the specified task execution.

        :param id: Task execution ID.
        :param task: Task execution object.
        """
        LOG.info("Update task execution [id=%s, task=%s]" % (id, task))

        task_ex = db_api.get_task_execution(id)
        task_spec = spec_parser.get_task_spec(task_ex.spec)
        task_name = task.name or None
        reset = task.reset

        if task_name and task_name != task_ex.name:
            raise exc.WorkflowException('Task name does not match.')

        wf_ex = db_api.get_workflow_execution(task_ex.workflow_execution_id)
        wf_name = task.workflow_name or None

        if wf_name and wf_name != wf_ex.name:
            raise exc.WorkflowException('Workflow name does not match.')

        if task.state != states.RUNNING:
            raise exc.WorkflowException(
                'Invalid task state. Only updating task to rerun is supported.'
            )

        if task_ex.state != states.ERROR:
            raise exc.WorkflowException(
                'The current task execution must be in ERROR for rerun.'
                ' Only updating task to rerun is supported.'
            )

        if not task_spec.get_with_items() and not reset:
            raise exc.WorkflowException(
                'Only with-items task has the option to not reset.'
            )

        rpc.get_engine_client().rerun_workflow(
            wf_ex.id,
            task_ex.id,
            reset
        )

        task_ex = db_api.get_task_execution(id)

        return _get_task_resource_with_result(task_ex)


class ExecutionTasksController(rest.RestController):
    @wsme_pecan.wsexpose(Tasks, wtypes.text)
    def get_all(self, workflow_execution_id):
        """Return all tasks within the workflow execution."""
        LOG.info("Fetch tasks.")

        return _get_task_resources_with_results(workflow_execution_id)
