#    Copyright (C) 2013 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 taskflow import exceptions as exc
from taskflow import states
from taskflow import test


class TransitionTest(test.TestCase):
    _DISALLOWED_TPL = "Transition from '%s' to '%s' was found to be disallowed"
    _NOT_IGNORED_TPL = "Transition from '%s' to '%s' was not ignored"

    def assertTransitionAllowed(self, from_state, to_state):
        msg = self._DISALLOWED_TPL % (from_state, to_state)
        self.assertTrue(self.check_transition(from_state, to_state), msg=msg)

    def assertTransitionIgnored(self, from_state, to_state):
        msg = self._NOT_IGNORED_TPL % (from_state, to_state)
        self.assertFalse(self.check_transition(from_state, to_state), msg=msg)

    def assertTransitionForbidden(self, from_state, to_state):
        self.assertRaisesRegex(
            exc.InvalidState,
            self.transition_exc_regexp,
            self.check_transition,
            from_state,
            to_state,
        )

    def assertTransitions(
        self, from_state, allowed=None, ignored=None, forbidden=None
    ):
        for a in allowed or []:
            self.assertTransitionAllowed(from_state, a)
        for i in ignored or []:
            self.assertTransitionIgnored(from_state, i)
        for f in forbidden or []:
            self.assertTransitionForbidden(from_state, f)


class CheckFlowTransitionTest(TransitionTest):
    def setUp(self):
        super().setUp()
        self.check_transition = states.check_flow_transition
        self.transition_exc_regexp = '^Flow transition.*not allowed'

    def test_to_same_state(self):
        self.assertTransitionIgnored(states.SUCCESS, states.SUCCESS)

    def test_rerunning_allowed(self):
        self.assertTransitionAllowed(states.SUCCESS, states.RUNNING)

    def test_no_resuming_from_pending(self):
        self.assertTransitionIgnored(states.PENDING, states.RESUMING)

    def test_resuming_from_running(self):
        self.assertTransitionAllowed(states.RUNNING, states.RESUMING)

    def test_bad_transition_raises(self):
        self.assertTransitionForbidden(states.FAILURE, states.SUCCESS)


class CheckTaskTransitionTest(TransitionTest):
    def setUp(self):
        super().setUp()
        self.check_transition = states.check_task_transition
        self.transition_exc_regexp = '^Task transition.*not allowed'

    def test_from_pending_state(self):
        self.assertTransitions(
            from_state=states.PENDING,
            allowed=(states.RUNNING,),
            ignored=(
                states.PENDING,
                states.REVERTING,
                states.SUCCESS,
                states.FAILURE,
                states.REVERTED,
            ),
        )

    def test_from_running_state(self):
        self.assertTransitions(
            from_state=states.RUNNING,
            allowed=(
                states.SUCCESS,
                states.FAILURE,
            ),
            ignored=(
                states.REVERTING,
                states.RUNNING,
                states.PENDING,
                states.REVERTED,
            ),
        )

    def test_from_success_state(self):
        self.assertTransitions(
            from_state=states.SUCCESS,
            allowed=(states.REVERTING,),
            ignored=(
                states.RUNNING,
                states.SUCCESS,
                states.PENDING,
                states.FAILURE,
                states.REVERTED,
            ),
        )

    def test_from_failure_state(self):
        self.assertTransitions(
            from_state=states.FAILURE,
            allowed=(states.REVERTING,),
            ignored=(
                states.FAILURE,
                states.RUNNING,
                states.PENDING,
                states.SUCCESS,
                states.REVERTED,
            ),
        )

    def test_from_reverting_state(self):
        self.assertTransitions(
            from_state=states.REVERTING,
            allowed=(states.REVERT_FAILURE, states.REVERTED),
            ignored=(
                states.RUNNING,
                states.REVERTING,
                states.PENDING,
                states.SUCCESS,
            ),
        )

    def test_from_reverted_state(self):
        self.assertTransitions(
            from_state=states.REVERTED,
            allowed=(states.PENDING,),
            ignored=(
                states.REVERTING,
                states.REVERTED,
                states.RUNNING,
                states.SUCCESS,
                states.FAILURE,
            ),
        )


class CheckRetryTransitionTest(CheckTaskTransitionTest):
    def setUp(self):
        super().setUp()
        self.check_transition = states.check_retry_transition
        self.transition_exc_regexp = '^Retry transition.*not allowed'

    def test_from_success_state(self):
        self.assertTransitions(
            from_state=states.SUCCESS,
            allowed=(states.REVERTING, states.RETRYING),
            ignored=(
                states.RUNNING,
                states.SUCCESS,
                states.PENDING,
                states.FAILURE,
                states.REVERTED,
            ),
        )

    def test_from_retrying_state(self):
        self.assertTransitions(
            from_state=states.RETRYING,
            allowed=(states.RUNNING,),
            ignored=(
                states.RETRYING,
                states.SUCCESS,
                states.PENDING,
                states.FAILURE,
                states.REVERTED,
            ),
        )
