from json import dumps
try:
  from urlparse import parse_qsl
except ImportError:
  from urllib.parse import parse_qsl

from oauthlib.common import to_unicode


def facebook_compliance_fix(session):

  def _compliance_fix(r):
    # if Facebook claims to be sending us json, let's trust them.
    if 'application/json' in r.headers.get('content-type', {}):
      return r

    # Facebook returns a content-type of text/plain when sending their
    # x-www-form-urlencoded responses, along with a 200. If not, let's
    # assume we're getting JSON and bail on the fix.
    if 'text/plain' in r.headers.get('content-type',
                                     {}) and r.status_code == 200:
      token = dict(parse_qsl(r.text, keep_blank_values=True))
    else:
      return r

    expires = token.get('expires')
    if expires is not None:
      token['expires_in'] = expires
    token['token_type'] = 'Bearer'
    r._content = to_unicode(dumps(token)).encode('UTF-8')
    return r

  session.register_compliance_hook('access_token_response', _compliance_fix)
  return session
