"""
settings.py should include the following:

    ANGEL_CLIENT_ID = '...'
    ANGEL_CLIENT_SECRET = '...'

Optional scope to include 'email' and/or 'messages' separated by space:

    ANGEL_AUTH_EXTRA_ARGUMENTS = {'scope': 'email messages'}

More information on scope can be found at https://angel.co/api/oauth/faq
"""
from urllib import urlencode

try:
    import json as simplejson
except ImportError:
    try:
        import simplejson
    except ImportError:
        from django.utils import simplejson

from social_auth.backends import BaseOAuth2, OAuthBackend
from social_auth.utils import dsa_urlopen


ANGEL_SERVER = 'angel.co'
ANGEL_AUTHORIZATION_URL = 'https://angel.co/api/oauth/authorize/'
ANGEL_ACCESS_TOKEN_URL = 'https://angel.co/api/oauth/token/'
ANGEL_CHECK_AUTH = 'https://api.angel.co/1/me/'


class AngelBackend(OAuthBackend):
    name = 'angel'

    def get_user_id(self, details, response):
        return response['id']

    def get_user_details(self, response):
        """Return user details from Angel account"""
        username = response['angellist_url'].split('/')[-1]
        first_name = response['name'].split(' ')[0]
        last_name = response['name'].split(' ')[-1]
        email = response['email']
        return {
            'username': username,
            'first_name': first_name,
            'last_name': last_name,
            'email': email,
        }


class AngelAuth(BaseOAuth2):
    """Angel OAuth mechanism"""
    AUTHORIZATION_URL = ANGEL_AUTHORIZATION_URL
    ACCESS_TOKEN_URL = ANGEL_ACCESS_TOKEN_URL
    AUTH_BACKEND = AngelBackend
    SETTINGS_KEY_NAME = 'ANGEL_CLIENT_ID'
    SETTINGS_SECRET_NAME = 'ANGEL_CLIENT_SECRET'
    REDIRECT_STATE = False
    STATE_PARAMETER = False

    def user_data(self, access_token, *args, **kwargs):
        """Loads user data from service"""
        params = {'access_token': access_token}
        url = ANGEL_CHECK_AUTH + '?' + urlencode(params)
        try:
            return simplejson.load(dsa_urlopen(url))
        except ValueError:
            return None


# Backend definition
BACKENDS = {
    'angel': AngelAuth,
}