# Copyright (C) 2019 NTT DATA
# 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.

"""
Request Body validating middleware.

"""

import functools
import webob

from tacker._i18n import _
from tacker.api.validation import validators
from tacker.common import exceptions


def schema(request_body_schema):
    """Register a schema to validate request body.

    Registered schema will be used for validating request body just before
    API method executing.

    :param dict request_body_schema: a schema to validate request body

    """

    def add_validator(func):
        @functools.wraps(func)
        def wrapper(*args, **kwargs):
            schema_validator = validators._SchemaValidator(
                request_body_schema)
            try:
                schema_validator.validate(kwargs['body'])
            except KeyError:
                raise webob.exc.HTTPBadRequest(
                    explanation=_("Malformed request body"))

            return func(*args, **kwargs)
        return wrapper

    return add_validator


def query_schema(query_params_schema):
    """Register a schema to validate request query parameters.

    Registered schema will be used for validating request query params just
    before API method executing.

    :param query_params_schema: A dict, the JSON-Schema for validating the
                                query parameters.
    """

    def add_validator(func):
        @functools.wraps(func)
        def wrapper(*args, **kwargs):
            # NOTE(tpatil): The second argument of the method
            # calling this method should always be 'request'.
            if 'request' in kwargs:
                req = kwargs['request']
            else:
                req = args[1]

            try:
                req.GET.dict_of_lists()
            except UnicodeDecodeError:
                msg = _('Query string is not UTF-8 encoded')
                raise exceptions.ValidationError(msg)

            query_opts = {}
            query_opts.update(req.GET)
            schema_validator = validators._SchemaValidator(
                query_params_schema)
            schema_validator.validate(query_opts)

            return func(*args, **kwargs)

        return wrapper

    return add_validator
