# -*- coding: utf-8 -*-

import os

import flask

import google.oauth2.credentials
import google_auth_oauthlib.flow
import googleapiclient.discovery

# The CLIENT_SECRETS_FILE variable specifies the name of a file that contains
# the OAuth 2.0 information for this application, including its client_id and
# client_secret.
CLIENT_SECRETS_FILE = "client_secret.json"

# This OAuth 2.0 access scope allows for full read/write access to the
# authenticated user's account and requires requests to use an SSL connection.
SCOPES = ['https://www.googleapis.com/auth/youtube.force-ssl']
API_SERVICE_NAME = 'youtube'
API_VERSION = 'v3'

app = flask.Flask(__name__)
# Note: A secret key is included in the sample so that it works, but if you
# use this code in your application please replace this with a truly secret
# key. See http://flask.pocoo.org/docs/0.12/quickstart/#sessions.
app.secret_key = 'REPLACE ME - this value is here as a placeholder.'


@app.route('/')
def index():
  if 'credentials' not in flask.session:
    return flask.redirect('authorize')

  # Load the credentials from the session.
  credentials = google.oauth2.credentials.Credentials(
      **flask.session['credentials'])

  client = googleapiclient.discovery.build(
      API_SERVICE_NAME, API_VERSION, credentials=credentials)
  
  return channels_list_by_username(client,
    part='snippet,contentDetails,statistics',
    forUsername='GoogleDevelopers')


@app.route('/authorize')
def authorize():
  # Create a flow instance to manage the OAuth 2.0 Authorization Grant Flow
  # steps.
  flow = google_auth_oauthlib.flow.Flow.from_client_secrets_file(
      CLIENT_SECRETS_FILE, scopes=SCOPES)
  flow.redirect_uri = flask.url_for('oauth2callback', _external=True)
  authorization_url, state = flow.authorization_url(
      # This parameter enables offline access which gives your application
      # both an access and refresh token.
      access_type='offline',
      # This parameter enables incremental auth.
      include_granted_scopes='true')

  # Store the state in the session so that the callback can verify that
  # the authorization server response.
  flask.session['state'] = state

  return flask.redirect(authorization_url)


@app.route('/oauth2callback')
def oauth2callback():
  # Specify the state when creating the flow in the callback so that it can
  # verify the authorization server response.
  state = flask.session['state']
  flow = google_auth_oauthlib.flow.Flow.from_client_secrets_file(
      CLIENT_SECRETS_FILE, scopes=SCOPES, state=state)
  flow.redirect_uri = flask.url_for('oauth2callback', _external=True)

  # Use the authorization server's response to fetch the OAuth 2.0 tokens.
  authorization_response = flask.request.url
  flow.fetch_token(authorization_response=authorization_response)

  # Store the credentials in the session.
  # ACTION ITEM for developers:
  #     Store user's access and refresh tokens in your data store if
  #     incorporating this code into your real app.
  credentials = flow.credentials
  flask.session['credentials'] = {
      'token': credentials.token,
      'refresh_token': credentials.refresh_token,
      'token_uri': credentials.token_uri,
      'client_id': credentials.client_id,
      'client_secret': credentials.client_secret,
      'scopes': credentials.scopes
  }

  return flask.redirect(flask.url_for('index'))

def channels_list_by_username(client, **kwargs):
  response = client.channels().list(
    **kwargs
  ).execute()

  return flask.jsonify(**response)


if __name__ == '__main__':
  # When running locally, disable OAuthlib's HTTPs verification. When
  # running in production *do not* leave this option enabled.
  os.environ['OAUTHLIB_INSECURE_TRANSPORT'] = '1'
  app.run('localhost', 8090, debug=True)