import requests
import hashlib
import json
import logging
from django.conf import settings
from django.contrib.auth import get_user_model
from django.contrib.auth.backends import ModelBackend

class OAuthBackend(ModelBackend):
    def authenticate(self, code=None):
        resp = requests.post(
            settings.AUTH_TOKEN_ENDPOINT+"token",
            data={
                'grant_type':'authorization_code',
                'code':code,
                'redirect_uri':settings.AUTH_REDIRECT_URL,
                'client_id':settings.AUTH_CLIENT_ID
            },
            headers = {
                'Authorization':'Basic %s'%settings.AUTH_B64
            }
        )
        resp_json = resp.json()
        if 'error' in resp_json:
            logging.warn('OAuth server returned an error: %s'%json.dumps(resp_json))
        else:
            user_info = requests.get(
                settings.AUTH_TOKEN_ENDPOINT+"user",
                headers = {
                    'Authorization': 'Bearer ' + resp_json['access_token']
                }
            ).json()

            usermodel = get_user_model()
            matches = usermodel.objects.filter(icy_id=user_info['uuid'])
            match = None

            if not len(matches):
                user = usermodel.objects.create_user(
                    username = user_info['username'],
                    email = user_info['email'],
                    icy_id = user_info['uuid'],
                    display_name = user_info['display_name']
                )

                if 'privilege' in user_info:
                    priv = user_info['privilege']
                    user.is_superuser = (priv == 5)
                    user.is_staff = (priv > 0)

                user.save()

                match = user
            else:
                match = matches[0]

            match.access_token = resp_json['access_token']

            return match
        return None