# Copyright 2014 - Mirantis, Inc.
# Copyright 2014 - 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 inspect

from stevedore import extension

from mistral.actions import action_factory
from mistral.actions import generator_factory
from mistral.db.v2 import api as db_api
from mistral import exceptions as exc
from mistral import expressions as expr
from mistral.openstack.common import log as logging
from mistral.services import actions
from mistral import utils
from mistral.utils import inspect_utils as i_utils


# TODO(rakhmerov): Make methods more consistent and granular.

LOG = logging.getLogger(__name__)

ACTIONS_PATH = '../resources/actions'
_ACTION_CTX_PARAM = 'action_context'


# TODO(rakhmerov): It's confusing because we have std.xxx actions and actions
# TODO(rakhmerov): under '../resources/actions' that we also call standard.
def register_standard_actions():
    action_paths = utils.get_file_list(ACTIONS_PATH)

    for action_path in action_paths:
        action_definition = open(action_path).read()
        actions.update_actions(action_definition, scope='public')


def get_registered_actions(**kwargs):
    return db_api.get_actions(**kwargs)


def register_action_class(name, action_class_str, attributes,
                          description=None, input_str=None):
    values = {
        'name': name,
        'action_class': action_class_str,
        'attributes': attributes,
        'description': description,
        'input': input_str,
        'is_system': True,
        'scope': 'public'
    }

    try:
        LOG.debug("Registering action in DB: %s" % name)

        db_api.create_action(values)
    except exc.DBDuplicateEntry:
        LOG.debug("Action %s already exists in DB." % name)


def _clear_system_action_db():
    db_api.delete_actions(is_system=True)


def sync_db():
    _clear_system_action_db()

    register_action_classes()
    register_standard_actions()


def _register_dynamic_action_classes():
    for generator in generator_factory.all_generators():
        actions = generator.create_actions()

        module = generator.base_action_class.__module__
        class_name = generator.base_action_class.__name__

        action_class_str = "%s.%s" % (module, class_name)

        for action in actions:
            attrs = i_utils.get_public_fields(action['class'])

            register_action_class(
                action['name'],
                action_class_str,
                attrs,
                action['description'],
                action['arg_list']
            )


def register_action_classes():
    mgr = extension.ExtensionManager(
        namespace='mistral.actions',
        invoke_on_load=False
    )

    with db_api.transaction():
        for name in mgr.names():
            action_class_str = mgr[name].entry_point_target.replace(':', '.')
            action_class = mgr[name].plugin
            description = i_utils.get_docstring(action_class)
            input_str = i_utils.get_arg_list_as_str(action_class.__init__)

            attrs = i_utils.get_public_fields(mgr[name].plugin)

            register_action_class(
                name,
                action_class_str,
                attrs,
                description=description,
                input_str=input_str
            )

        _register_dynamic_action_classes()


def get_action_db(action_name):
    return db_api.load_action(action_name)


def get_action_class(action_full_name):
    """Finds action class by full action name (i.e. 'namespace.action_name').

    :param action_full_name: Full action name (that includes namespace).
    :return: Action class or None if not found.
    """
    action_db = get_action_db(action_full_name)

    if action_db:
        return action_factory.construct_action_class(
            action_db.action_class,
            action_db.attributes
        )


def get_action_context(task_db):
    return {
        _ACTION_CTX_PARAM: {
            'workflow_name': task_db.execution.wf_name,
            'execution_id': task_db.execution_id,
            'task_id': task_db.id,
            'task_name': task_db.name,
            'task_tags': task_db.tags
        }
    }


def has_action_context(action, attributes):
    action_cls = action_factory.construct_action_class(action, attributes)
    arg_spec = inspect.getargspec(action_cls.__init__)

    return _ACTION_CTX_PARAM in arg_spec.args


def resolve_adhoc_action_name(workbook, action_name):
    action_spec = workbook.get_action(action_name)

    if not action_spec:
        msg = 'Ad-hoc action class is not registered ' \
              '[workbook=%s, action=%s, action_spec=%s]' % \
              (workbook, action_name, action_spec)
        raise exc.ActionException(msg)

    base_cls = get_action_class(action_spec.clazz)

    if not base_cls:
        msg = 'Ad-hoc action base class is not registered ' \
              '[workbook=%s, action=%s, base_class=%s]' % \
              (workbook, action_name, base_cls)
        raise exc.ActionException(msg)

    return action_spec.clazz


def convert_adhoc_action_params(workbook, action_name, params):
    base_params = workbook.get_action(action_name).base_parameters

    if not base_params:
        return {}

    return expr.evaluate_recursively(base_params, params)


def convert_adhoc_action_result(workbook, action_name, result):
    transformer = workbook.get_action(action_name).output

    if not transformer:
        return result

    # Use base action result as a context for evaluating expressions.
    return expr.evaluate_recursively(transformer, result)