# Copyright 2016 Google 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.

"""Google Cloud Endpoints sample application.

Demonstrates how to create a simple echo API as well as how to deal with
various authentication methods.
"""

import base64
import json
import logging

from flask import Flask, jsonify, request

from flask_cors import cross_origin

from six.moves import http_client


app = Flask(__name__)


def _base64_decode(encoded_str):
    # Add paddings manually if necessary.
    num_missed_paddings = 4 - len(encoded_str) % 4
    if num_missed_paddings != 4:
        encoded_str += b'=' * num_missed_paddings
    return base64.b64decode(encoded_str).decode('utf-8')


@app.route('/echo', methods=['POST'])
def echo():
    """Simple echo service."""
    message = request.get_json().get('message', '')
    return jsonify({'message': message})


# [START endpoints_auth_info_backend]
def auth_info():
    """Retrieves the authenication information from Google Cloud Endpoints."""
    encoded_info = request.headers.get('X-Endpoint-API-UserInfo', None)

    if encoded_info:
        info_json = _base64_decode(encoded_info)
        user_info = json.loads(info_json)
    else:
        user_info = {'id': 'anonymous'}

    return jsonify(user_info)
# [START endpoints_auth_info_backend]


@app.route('/auth/info/googlejwt', methods=['GET'])
def auth_info_google_jwt():
    """Auth info with Google signed JWT."""
    return auth_info()


@app.route('/auth/info/googleidtoken', methods=['GET'])
def auth_info_google_id_token():
    """Auth info with Google ID token."""
    return auth_info()


@app.route('/auth/info/firebase', methods=['GET'])
@cross_origin(send_wildcard=True)
def auth_info_firebase():
    """Auth info with Firebase auth."""
    return auth_info()


@app.errorhandler(http_client.INTERNAL_SERVER_ERROR)
def unexpected_error(e):
    """Handle exceptions by returning swagger-compliant json."""
    logging.exception('An error occured while processing the request.')
    response = jsonify({
        'code': http_client.INTERNAL_SERVER_ERROR,
        'message': 'Exception: {}'.format(e)})
    response.status_code = http_client.INTERNAL_SERVER_ERROR
    return response


if __name__ == '__main__':
    # This is used when running locally. Gunicorn is used to run the
    # application on Google App Engine. See entrypoint in app.yaml.
    app.run(host='127.0.0.1', port=8080, debug=True)