from django.conf import settings
from django.contrib import auth
from django.http import HttpResponseRedirect
from django.urls import reverse
from django.utils.http import urlencode
from django.views import View

from authentication.mixins import authenticate
from authentication.utils import build_absolute_uri
from authentication.views.mixins import FlashMessageMixin
from authentication.views.utils import redirect_to_guard_view
from common.utils import get_logger

logger = get_logger(__file__)


class OAuth2AuthRequestView(View):

    def get(self, request):
        log_prompt = "Process OAuth2 GET requests: {}"
        logger.debug(log_prompt.format('Start'))

        query_dict = {
            'client_id': settings.AUTH_OAUTH2_CLIENT_ID, 'response_type': 'code',
            'scope': settings.AUTH_OAUTH2_SCOPE,
            'redirect_uri': build_absolute_uri(
                request, path=reverse(settings.AUTH_OAUTH2_AUTH_LOGIN_CALLBACK_URL_NAME)
            )
        }

        if '?' in settings.AUTH_OAUTH2_PROVIDER_AUTHORIZATION_ENDPOINT:
            separator = '&'
        else:
            separator = '?'
        redirect_url = '{url}{separator}{query}'.format(
            url=settings.AUTH_OAUTH2_PROVIDER_AUTHORIZATION_ENDPOINT,
            separator=separator,
            query=urlencode(query_dict)
        )
        logger.debug(log_prompt.format('Redirect login url'))
        return HttpResponseRedirect(redirect_url)


class OAuth2AuthCallbackView(View, FlashMessageMixin):
    http_method_names = ['get', ]

    def get(self, request):
        """ Processes GET requests. """
        log_prompt = "Process GET requests [OAuth2AuthCallbackView]: {}"
        logger.debug(log_prompt.format('Start'))
        callback_params = request.GET

        if 'code' in callback_params:
            logger.debug(log_prompt.format('Process authenticate'))
            user = authenticate(code=callback_params['code'], request=request)

            if user:
                logger.debug(log_prompt.format('Login: {}'.format(user)))
                auth.login(self.request, user)
                logger.debug(log_prompt.format('Redirect'))
                return HttpResponseRedirect(
                    settings.AUTH_OAUTH2_AUTHENTICATION_REDIRECT_URI
                )

        logger.debug(log_prompt.format('Redirect'))
        redirect_url = settings.AUTH_OAUTH2_PROVIDER_END_SESSION_ENDPOINT or '/'
        return HttpResponseRedirect(redirect_url)


class OAuth2AuthCallbackClientView(View):
    http_method_names = ['get', ]

    def get(self, request):
        return redirect_to_guard_view(query_string='next=client')


class OAuth2EndSessionView(View):
    http_method_names = ['get', 'post', ]

    def get(self, request):
        """ Processes GET requests. """
        log_prompt = "Process GET requests [OAuth2EndSessionView]: {}"
        logger.debug(log_prompt.format('Start'))
        return self.post(request)

    def post(self, request):
        """ Processes POST requests. """
        log_prompt = "Process POST requests [OAuth2EndSessionView]: {}"
        logger.debug(log_prompt.format('Start'))

        logout_url = settings.LOGOUT_REDIRECT_URL or '/'

        # Log out the current user.
        if request.user.is_authenticated:
            logger.debug(log_prompt.format('Log out the current user: {}'.format(request.user)))
            auth.logout(request)

            logout_url = settings.AUTH_OAUTH2_PROVIDER_END_SESSION_ENDPOINT
            if settings.AUTH_OAUTH2_LOGOUT_COMPLETELY and logout_url:
                logger.debug(log_prompt.format('Log out OAUTH2 platform user session synchronously'))
                return HttpResponseRedirect(logout_url)

        logger.debug(log_prompt.format('Redirect'))
        return HttpResponseRedirect(logout_url)