from django.http import HttpRequest
from django.conf import settings

try:
    from allauth.account import app_settings as allauth_settings
    from allauth.utils import (email_address_exists,
                               get_username_max_length)
    from allauth.account.adapter import get_adapter
    from allauth.account.utils import setup_user_email
except ImportError:
    raise ImportError('allauth needs to be added to INSTALLED_APPS.')

from rest_framework import serializers
from requests.exceptions import HTTPError
# Import is needed only if we are using social login, in which
# case the allauth.socialaccount will be declared
try:
    from allauth.socialaccount.helpers import complete_social_login
except ImportError:
    raise ImportError('allauth.socialaccount needs to be installed.')

if 'allauth.socialaccount' not in settings.INSTALLED_APPS:
    raise ImportError('allauth.socialaccount needs to be added to INSTALLED_APPS.')


class SocialLoginSerializer(serializers.Serializer):
    access_token = serializers.CharField(required=False, allow_blank=True)
    code = serializers.CharField(required=False, allow_blank=True)

    def _get_request(self):
        request = self.context.get('request')
        if not isinstance(request, HttpRequest):
            request = request._request
        return request

    def get_social_login(self, adapter, app, token, response):
        """

        :param adapter: allauth.socialaccount Adapter subclass. Usually OAuthAdapter or Auth2Adapter
        :param app: `allauth.socialaccount.SocialApp` instance
        :param token: `allauth.socialaccount.SocialToken` instance
        :param response: Provider's response for OAuth1. Not used in the
        :return: :return: A populated instance of the `allauth.socialaccount.SocialLoginView` instance
        """
        request = self._get_request()
        social_login = adapter.complete_login(request, app, token, response=response)
        social_login.token = token
        return social_login

    def validate(self, attrs):
        view = self.context.get('view')
        request = self._get_request()

        if not view:
            raise serializers.ValidationError(
                'View is not defined, pass it as a context variable'
            )

        adapter_class = getattr(view, 'adapter_class', None)
        if not adapter_class:
            raise serializers.ValidationError('Define adapter_class in view')

        adapter = adapter_class()
        app = adapter.get_provider().get_app(request)

        # More info on code vs access_token
        # http://stackoverflow.com/questions/8666316/facebook-oauth-2-0-code-and-token

        # Case 1: We received the access_token
        if('access_token' in attrs):
            access_token = attrs.get('access_token')

        # Case 2: We received the authorization code
        elif('code' in attrs):
            self.callback_url = getattr(view, 'callback_url', None)
            self.client_class = getattr(view, 'client_class', None)

            if not self.callback_url:
                raise serializers.ValidationError(
                    'Define callback_url in view'
                )
            if not self.client_class:
                raise serializers.ValidationError(
                    'Define client_class in view'
                )

            code = attrs.get('code')

            provider = adapter.get_provider()
            scope = provider.get_scope(request)
            client = self.client_class(
                request,
                app.client_id,
                app.secret,
                adapter.access_token_method,
                adapter.access_token_url,
                self.callback_url,
                scope
            )
            token = client.get_access_token(code)
            access_token = token['access_token']

        else:
            raise serializers.ValidationError('Incorrect input. access_token or code is required.')

        token = adapter.parse_token({'access_token': access_token})
        token.app = app

        try:
            login = self.get_social_login(adapter, app, token, access_token)
            complete_social_login(request, login)
        except HTTPError:
            raise serializers.ValidationError('Incorrect value')

        if not login.is_existing:
            login.lookup()
            login.save(request, connect=True)
        attrs['user'] = login.account.user

        return attrs


class RegisterSerializer(serializers.Serializer):
    username = serializers.CharField(
        max_length=get_username_max_length(),
        min_length=allauth_settings.USERNAME_MIN_LENGTH,
        required=allauth_settings.USERNAME_REQUIRED
    )
    email = serializers.EmailField(required=allauth_settings.EMAIL_REQUIRED)
    password1 = serializers.CharField(required=True, write_only=True)
    password2 = serializers.CharField(required=True, write_only=True)

    def validate_username(self, username):
        username = get_adapter().clean_username(username)
        return username

    def validate_email(self, email):
        email = get_adapter().clean_email(email)
        if allauth_settings.UNIQUE_EMAIL:
            if email and email_address_exists(email):
                raise serializers.ValidationError(
                    "A user is already registered with this e-mail address.")
        return email

    def validate_password1(self, password):
        return get_adapter().clean_password(password)

    def validate(self, data):
        if data['password1'] != data['password2']:
            raise serializers.ValidationError("The two password fields didn't match.")
        return data

    def custom_signup(self, request, user):
        pass

    def get_cleaned_data(self):
        return {
            'username': self.validated_data.get('username', ''),
            'password1': self.validated_data.get('password1', ''),
            'email': self.validated_data.get('email', '')
        }

    def save(self, request):
        adapter = get_adapter()
        user = adapter.new_user(request)
        self.cleaned_data = self.get_cleaned_data()
        adapter.save_user(request, user, self)
        self.custom_signup(request, user)
        setup_user_email(request, user, [])
        return user


class VerifyEmailSerializer(serializers.Serializer):
    key = serializers.CharField()