import re
import settings

from django.contrib.auth import REDIRECT_FIELD_NAME
from django.contrib.auth import login as auth_login
from django.contrib.auth.forms import AuthenticationForm
from django.contrib.sites.models import Site, RequestSite
from django.http import HttpResponseRedirect
from django.shortcuts import render_to_response
from django.views.decorators.cache import never_cache
from django.template import RequestContext
from django.utils.translation import ugettext as _

# CURRENTLY A MIRROR IMAGE OF django.auth.views.login
# Just without the csrf decorator.
@never_cache
def login(request, template_name='registration/login.html',
          redirect_field_name=REDIRECT_FIELD_NAME,
          authentication_form=AuthenticationForm):
    """Displays the login form and handles the login action."""

    redirect_to = request.REQUEST.get(redirect_field_name, '')
    
    if request.method == "POST":
        form = authentication_form(data=request.POST)
        if form.is_valid():
            # Light security check -- make sure redirect_to isn't garbage.
            if not redirect_to or ' ' in redirect_to:
                redirect_to = settings.LOGIN_REDIRECT_URL
            
            # Heavier security check -- redirects to http://example.com should 
            # not be allowed, but things like /view/?param=http://example.com 
            # should be allowed. This regex checks if there is a '//' *before* a
            # question mark.
            elif '//' in redirect_to and re.match(r'[^\?]*//', redirect_to):
                    redirect_to = settings.LOGIN_REDIRECT_URL
            
            # Okay, security checks complete. Log the user in.
            auth_login(request, form.get_user())

            if request.session.test_cookie_worked():
                request.session.delete_test_cookie()

            return HttpResponseRedirect(redirect_to)

    else:
        form = authentication_form(request)
    
    request.session.set_test_cookie()
    
    if Site._meta.installed:
        current_site = Site.objects.get_current()
    else:
        current_site = RequestSite(request)
    
    return render_to_response(template_name, {
        'form': form,
        redirect_field_name: redirect_to,
        'site': current_site,
        'site_name': current_site.name,
    }, context_instance=RequestContext(request))

# CURRENTLY A MIRROR IMAGE OF django.auth.views.logout
def logout(request, next_page=None, template_name='registration/logged_out.html', redirect_field_name=REDIRECT_FIELD_NAME):
    "Logs out the user and displays 'You are logged out' message."
    from django.contrib.auth import logout
    logout(request)
    if next_page is None:
        redirect_to = request.REQUEST.get(redirect_field_name, '')
        if redirect_to:
            return HttpResponseRedirect(redirect_to)
        else:
            return render_to_response(template_name, {
                'title': _('Logged out')
            }, context_instance=RequestContext(request))
    else:
        # Redirect to this page until the session has been cleared.
        return HttpResponseRedirect(next_page or request.path)
