a.rb

require 'google/api_client'
require 'google/api_client/client_secrets'
require 'google/api_client/auth/installed_app'
require 'google/api_client/auth/storage'
require 'google/api_client/auth/storages/file_store'
require 'fileutils'
require 'gmail'

APPLICATION_NAME = 'Google Calendar API Quickstart'
CLIENT_SECRETS_PATH = 'client_secret.json'
CREDENTIALS_PATH = File.join(Dir.home, '.credentials',
                             "calendar-quickstart.json")
SCOPE = ['https://www.googleapis.com/auth/calendar', 'https://mail.google.com']

class Mcalendar < Google::APIClient # EXTEND GOOGLE API ?!



def initialize 
#BLA ?
end

def authorize
  FileUtils.mkdir_p(File.dirname(CREDENTIALS_PATH))

  file_store = Google::APIClient::FileStore.new(CREDENTIALS_PATH)
  storage = Google::APIClient::Storage.new(file_store)
  auth = storage.authorize

  if auth.nil? || (auth.expired? && auth.refresh_token.nil?)
    app_info = Google::APIClient::ClientSecrets.load(CLIENT_SECRETS_PATH)
    flow = Google::APIClient::InstalledAppFlow.new({
      :client_id => app_info.client_id,
      :client_secret => app_info.client_secret,
      :scope => SCOPE})
    auth = flow.authorize(storage)
    puts "Credentials saved to #{CREDENTIALS_PATH}" unless auth.nil?
  end
  auth
end


#buggy stuff
def by_status(sStatus , eID)
  bsEvents = client.execute!(:api_method => calendar_api.events.list,
  :parameter => { 'calendarId' => 'primary', 'eventId' => eID})

  bsEvents.data.items.each do |compare|
    if compare.attendees[0].responseStatus == sStatus
      return bsEvents.data.items
    end
  end
end

#Class end
end

#Init stuff 
m = Mcalendar.new
client = m.(:application_name => APPLICATION_NAME)
#client = Google::APIClient.new(:application_name => APPLICATION_NAME) -> NORMALY THIS WORKS
client.authorization = m.authorize # THIS ?! m. ?
calendar_api = client.discovered_api('calendar', 'v3')
mail_api = client.discovered_api('gmail', 'v1')