# -*- coding: utf-8 -*-

#    Copyright (C) 2014 Yahoo! Inc. All 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.

from concurrent import futures

from taskflow.engines.action_engine import executor
from taskflow.utils import misc
from taskflow.utils import persistence_utils as pu
from taskflow.utils import reflection

# NOTE(skudriashev): This is protocol events, not related to the task states.
PENDING = 'PENDING'
RUNNING = 'RUNNING'
SUCCESS = 'SUCCESS'
FAILURE = 'FAILURE'
PROGRESS = 'PROGRESS'

# Remote task actions.
EXECUTE = 'execute'
REVERT = 'revert'

# Remote task action to event map.
ACTION_TO_EVENT = {
    EXECUTE: executor.EXECUTED,
    REVERT: executor.REVERTED
}

# NOTE(skudriashev): A timeout which specifies request expiration period.
REQUEST_TIMEOUT = 60

# NOTE(skudriashev): A timeout which controls for how long a queue can be
# unused before it is automatically deleted. Unused means the queue has no
# consumers, the queue has not been redeclared, the `queue.get` has not been
# invoked for a duration of at least the expiration period. In our case this
# period is equal to the request timeout, once request is expired - queue is
# no longer needed.
QUEUE_EXPIRE_TIMEOUT = REQUEST_TIMEOUT


class Request(object):
    """Represents request with execution results. Every request is created in
    the PENDING state and is expired within the given timeout.
    """

    def __init__(self, task, uuid, action, arguments, progress_callback,
                 timeout, **kwargs):
        self._task = task
        self._task_cls = reflection.get_class_name(task)
        self._uuid = uuid
        self._action = action
        self._event = ACTION_TO_EVENT[action]
        self._arguments = arguments
        self._progress_callback = progress_callback
        self._kwargs = kwargs
        self._watch = misc.StopWatch(duration=timeout).start()
        self._state = PENDING
        self.result = futures.Future()

    def __repr__(self):
        return "%s:%s" % (self._task_cls, self._action)

    @property
    def uuid(self):
        return self._uuid

    @property
    def task_cls(self):
        return self._task_cls

    @property
    def expired(self):
        """Check if request has expired.

        When new request is created its state is set to the PENDING, creation
        time is stored and timeout is given via constructor arguments.

        Request is considered to be expired when it is in the PENDING state
        for more then the given timeout (it is not considered to be expired
        in any other state).
        """
        if self._state == PENDING:
            return self._watch.expired()
        return False

    def to_dict(self):
        """Return json-serializable request, converting all `misc.Failure`
        objects into dictionaries.
        """
        request = dict(task_cls=self._task_cls, task_name=self._task.name,
                       task_version=self._task.version, action=self._action,
                       arguments=self._arguments)
        if 'result' in self._kwargs:
            result = self._kwargs['result']
            if isinstance(result, misc.Failure):
                request['result'] = ('failure', pu.failure_to_dict(result))
            else:
                request['result'] = ('success', result)
        if 'failures' in self._kwargs:
            failures = self._kwargs['failures']
            request['failures'] = {}
            for task, failure in failures.items():
                request['failures'][task] = pu.failure_to_dict(failure)
        return request

    def set_result(self, result):
        self.result.set_result((self._task, self._event, result))

    def set_running(self):
        self._state = RUNNING
        self._watch.stop()

    def on_progress(self, event_data, progress):
        self._progress_callback(self._task, event_data, progress)