from datetime import datetime, timedelta

from django.conf import settings
from .models import User


class ReferrerMiddleware():
    def process_request(self, request):
        if 'ref' in request.GET:
            id = request.GET['ref']
        elif 'referrer' in request.COOKIES:
            id = request.COOKIES['referrer']
        else:
            return

        try:
            id = int(id.strip())
        except (ValueError, TypeError):
            return

        try:
            u = User.objects.get(id=id)
        except User.DoesNotExist:
            return

        request.session['referrer'] = u.id

    def process_response(self, request, response):
        id = request.session.get('referrer')
        if not id:
            return response

        max_age = 365 * 24 * 60 * 60
        expires = (datetime.utcnow() + timedelta(seconds=max_age))
        expires = expires.strftime("%a, %d-%b-%Y %H:%M:%S GMT")
        response.set_cookie('referrer', id,
                            max_age=max_age,
                            expires=expires,
                            domain=settings.SESSION_COOKIE_DOMAIN,
                            secure=settings.SESSION_COOKIE_SECURE or None)
        return response