# Copyright (c) 2013 Mirantis 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 as jsonlib

import yaml as yamllib
from yaql.language import specs
from yaql.language import yaqltypes

from murano.dsl import constants
from murano.dsl import dsl
from murano.dsl import dsl_types
from murano.dsl import helpers

if hasattr(yamllib, 'CSafeLoader'):
    yaml_loader = yamllib.CSafeLoader
else:
    yaml_loader = yamllib.SafeLoader


def _construct_yaml_str(self, node):
    # Override the default string handling function
    # to always return unicode objects
    return self.construct_scalar(node)

yaml_loader.add_constructor(u'tag:yaml.org,2002:str', _construct_yaml_str)
# Unquoted dates like 2013-05-23 in yaml files get loaded as objects of type
# datetime.data which causes problems in API layer when being processed by
# oslo.serialization.jsonutils. Therefore, make unicode string out of
# timestamps until jsonutils can handle dates.
yaml_loader.add_constructor(u'tag:yaml.org,2002:timestamp',
                            _construct_yaml_str)


@dsl.name('io.murano.system.Resources')
class ResourceManager(object):
    def __init__(self, context):
        murano_class = helpers.get_type(helpers.get_caller_context(context))
        self._package = murano_class.package

    @staticmethod
    @specs.parameter('owner', dsl.MuranoTypeParameter(nullable=True))
    @specs.inject('receiver', yaqltypes.Receiver())
    @specs.meta(constants.META_NO_TRACE, True)
    def string(receiver, name, owner=None, binary=False):
        path = ResourceManager._get_package(owner, receiver).get_resource(name)
        mode = 'rb' if binary else 'rU'
        with open(path, mode) as file:
            return file.read()

    @classmethod
    @specs.parameter('owner', dsl.MuranoTypeParameter(nullable=True))
    @specs.inject('receiver', yaqltypes.Receiver())
    @specs.meta(constants.META_NO_TRACE, True)
    def json(cls, receiver, name, owner=None):
        return jsonlib.loads(cls.string(receiver, name, owner))

    @classmethod
    @specs.parameter('owner', dsl.MuranoTypeParameter(nullable=True))
    @specs.inject('receiver', yaqltypes.Receiver())
    @specs.meta(constants.META_NO_TRACE, True)
    def yaml(cls, receiver, name, owner=None):
        return yamllib.load(
            cls.string(receiver, name, owner), Loader=yaml_loader)

    @staticmethod
    def _get_package(owner, receiver):
        if owner is None:
            if isinstance(receiver, dsl_types.MuranoObjectInterface):
                return receiver.extension._package
            murano_class = helpers.get_type(helpers.get_caller_context())
        else:
            murano_class = owner.type
        return murano_class.package