import requests

from django.conf import settings

from vk.exceptions import (TokenNotProvided, CodeNotProvided, InvalidResponse, TokenExpiredException)


class VkApiInterface:
    api_url = settings.VK_API_URL
    v = settings.VK_API_VERSION
    client_id = settings.VK_APP_ID
    client_secret = settings.VK_SECRET_KEY
    access_token_url = settings.VK_ACCESS_TOKEN_URL

    def __init__(self, user_model):
        self.user = user_model
        self.token = user_model.vkauth.vk_token

    @classmethod
    def verify_user_auth(cls, code, redirect_uri):
        if not code:
            raise CodeNotProvided()
        response = requests.get(cls.access_token_url, {
            'client_id': cls.client_id,
            'client_secret': cls.client_secret,
            'redirect_uri': redirect_uri,
            'v': cls.v,
            'code': code
        })
        if response.status_code == 200:
            result = response.json()
            if 'access_token' not in result:
                raise TokenNotProvided()
            return {
                'access_token': result['access_token'],
                'expires_in': result['expires_in'],
                'user_id': result['user_id']
            }
        else:
            raise InvalidResponse()

    def _perform_request(self, method_name, payload):
        payload.update({
            'v': self.v,
            'access_token': self.token
        })
        response = requests.get("{}/{}".format(self.api_url, method_name), payload)
        if response.status_code == 200:
            result = response.json()
            if 'error' in result:
                raise TokenExpiredException(message=result['error'])
            if 'response' not in result:
                raise InvalidResponse()
            return result['response']
        else:
            raise InvalidResponse()

    def get_friends(self, count=5000, order='random', fields=''):
        result = self._perform_request('friends.get', {
            'user_id': self.user.username,
            'count': count,
            'order': order,
            'fields': fields
        })
        return result