# Copyright 2017, Google LLC 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 __future__ import absolute_import
import io

from google.api_core import protobuf_helpers as protobuf


class VisionHelpers(object):
    """A set of convenience methods to make the Vision GAPIC easier to use.

    This class should be considered abstract; it is used as a superclass
    in a multiple-inheritance construction alongside the applicable GAPIC.
    See the :class:`~google.cloud.vision_v1.ImageAnnotatorClient`.
    """
    def annotate_image(self, request, retry=None, timeout=None):
        """Run image detection and annotation for an image.

        Example:
            >>> from google.cloud.vision_v1 import ImageAnnotatorClient
            >>> client = ImageAnnotatorClient()
            >>> request = {
            ...     'image': {
            ...         'source': {'image_uri': 'https://foo.com/image.jpg'},
            ...     },
            ... }
            >>> response = client.annotate_image(request)

        Args:
            request (:class:`~.vision_v1.types.AnnotateImageRequest`)
            options (:class:`google.gax.CallOptions`): Overrides the default
                settings for this call, e.g, timeout, retries, etc.

        Returns:
            :class:`~.vision_v1.types.AnnotateImageResponse` The API response.
        """
        # If the image is a file handler, set the content.
        image = protobuf.get(request, 'image')
        if hasattr(image, 'read'):
            img_bytes = image.read()
            protobuf.set(request, 'image', {})
            protobuf.set(request, 'image.content', img_bytes)
            image = protobuf.get(request, 'image')

        # If a filename is provided, read the file.
        filename = protobuf.get(image, 'source.filename', default=None)
        if filename:
            with io.open(filename, 'rb') as img_file:
                protobuf.set(request, 'image.content', img_file.read())
                protobuf.set(request, 'image.source', None)

        # This method allows features not to be specified, and you get all
        # of them.
        protobuf.setdefault(request, 'features', self._get_all_features())
        r = self.batch_annotate_images([request], retry=retry, timeout=timeout)
        return r.responses[0]

    def _get_all_features(self):
        """Return a list of all features.

        Returns:
            list: A list of all available features.
        """
        answer = []
        for key, value in self.enums.Feature.Type.__dict__.items():
            if key.upper() != key:
                continue
            if not isinstance(value, int) or value == 0:
                continue
            answer.append({'type': value})
        return answer
