#oauth.py

# Based on a modified version of oauth.py from the py-gaugette library.
#   https://github.com/guyc/py-gaugette/blob/master/gaugette/oauth.py
#   http://guy.carpenter.id.au/gaugette/blog/2012/11/06/using-google-oauth2-for-devices/
# For more info on oauth for devices, see:
#   https://developers.google.com/accounts/docs/OAuth2ForDevices


import sys
import urllib
import httplib
import os.path
import json
import time
#import gdata.spreadsheet.service

class OAuth:
  def __init__(self, client_id, client_secret):
    self.client_id = client_id
    self.client_secret = client_secret
    self.token = None
    self.device_code = None
    self.verfication_url = None
    self.token_file = 'oauth_token.json'
    self.scope = [
      'https://www.googleapis.com/auth/userinfo.profile',
    ]
    self.host = 'accounts.google.com'
    # httplib.HTTPConnection.debuglevel = 1
    self.conn = httplib.HTTPSConnection(self.host)
    self.load_token()

  def load_token(self):
    token = None
    if os.path.isfile(self.token_file):
      f = open(self.token_file)
      json_token = f.read()
      self.token = json.loads(json_token)
      f.close()

  def save_token(self):
    f = open(self.token_file, 'w')
    f.write(json.dumps(self.token))
    f.close()

  def has_token(self):
    return self.token != None

  def get_user_code(self):
    self.conn.request(
      "POST",
      "/o/oauth2/device/code",
      urllib.urlencode({
        'client_id': self.client_id,
        'scope' : ' '.join(self.scope)
        }),
      {"Content-type": "application/x-www-form-urlencoded"}
      )
    response = self.conn.getresponse()
    if (response.status == 200):
      data = json.loads(response.read())
      self.device_code = data['device_code']
      self.user_code = data['user_code']
      self.verification_url = data['verification_url']
      self.retry_interval = data['interval']
    else:
      print response.status
      print response.read()
      sys.exit()
    return self.user_code

  def get_new_token(self):
    # call get_device_code if not already set
    if not self.user_code:
      self.get_user_code()

    while self.token == None:
      self.conn.request(
        "POST",
        "/o/oauth2/token",
        urllib.urlencode({
          'client_id' : self.client_id,
          'client_secret' : self.client_secret,
          'code' : self.device_code,
          'grant_type' : 'http://oauth.net/grant_type/device/1.0'
          }),
        {"Content-type": "application/x-www-form-urlencoded"}
        )

      response = self.conn.getresponse()
      if (response.status == 200):
        data = json.loads(response.read())
        # print data
        if 'access_token' in data:
          self.token = data
          self.save_token()
        else:
          time.sleep(self.retry_interval + 2)

  def refresh_token(self):
    refresh_token = self.token['refresh_token']
    self.conn.request(
      "POST",
      "/o/oauth2/token",
      urllib.urlencode({
        'client_id' : self.client_id,
        'client_secret' : self.client_secret,
        'refresh_token' : refresh_token,
        'grant_type' : 'refresh_token'
        }),
      {"Content-type": "application/x-www-form-urlencoded"}
      )

    response = self.conn.getresponse()
    if (response.status == 200):
      data = json.loads(response.read())
      if 'access_token' in data:
        self.token = data
        # in fact we NEVER get a new refresh token at this point
        if not 'refresh_token' in self.token:
          self.token['refresh_token'] = refresh_token
          self.save_token()
        return True
    else:
      print("Unexpected response %d to renewal request" % response.status)
      print(response.read())
    return False

  '''
  def spreadsheet_service(self):
    headers = {
      "Authorization": "%s %s" % (self.token['token_type'], self.token['access_token'])
    }
    client = gdata.spreadsheet.service.SpreadsheetsService(additional_headers=headers)
    return client
  '''