import re

from django import http, template

from django.contrib.admin import ModelAdmin

from django.contrib.admin import actions

from django.contrib.auth import authenticate, login

from django.db.models.base import ModelBase

from django.core.exceptions import ImproperlyConfigured

from django.core.urlresolvers import reverse

from django.shortcuts import render_to_response

from django.utils.functional import update_wrapper

from django.utils.safestring import mark_safe

from django.utils.text import capfirst

from django.utils.translation import ugettext_lazy, ugettext as _

from django.views.decorators.cache import never_cache

from django.conf import settings

ERROR_MESSAGE = ugettext_lazy("Please enter a correct username and password. Note that both fields are case-sensitive.")

LOGIN_FORM_KEY = 'this_is_the_login_form'

class AlreadyRegistered(Exception):

    pass

class NotRegistered(Exception):

    pass

class AdminSite(object):

    """

    An AdminSite object encapsulates an instance of the Django admin application, ready

    to be hooked in to your URLconf. Models are registered with the AdminSite using the

    register() method, and the root() method can then be used as a Django view function

    that presents a full admin interface for the collection of registered models.

    """

    index_template = None

    login_template = None

    def __init__(self, name=None, app_name='admin'):

        self._registry = {} # model_class class -> admin_class instance

        self.root_path = None

        if name is None:

            self.name = 'admin'

        else:

            self.name = name

        self.app_name = app_name

        self._actions = {'delete_selected': actions.delete_selected}

        self._global_actions = self._actions.copy()

    def register(self, model_or_iterable, admin_class=None, **options):

        """

        Registers the given model(s) with the given admin class.

        The model(s) should be Model classes, not instances.

        If an admin class isn't given, it will use ModelAdmin (the default

        admin options). If keyword arguments are given -- e.g., list_display --

        they'll be applied as options to the admin class.

        If a model is already registered, this will raise AlreadyRegistered.

        """

        if not admin_class:

            admin_class = ModelAdmin

        # Don't import the humongous validation code unless required

        if admin_class and settings.DEBUG:

            from django.contrib.admin.validation import validate

        else:

            validate = lambda model, adminclass: None

        if isinstance(model_or_iterable, ModelBase):

            model_or_iterable = [model_or_iterable]

        for model in model_or_iterable:

            if model in self._registry:

                raise AlreadyRegistered('The model %s is already registered' % model.__name__)

            # If we got **options then dynamically construct a subclass of

            # admin_class with those **options.

            if options:

                # For reasons I don't quite understand, without a __module__

                # the created class appears to "live" in the wrong place,

                # which causes issues later on.

                options['__module__'] = __name__

                admin_class = type("%sAdmin" % model.__name__, (admin_class,), options)

            # Validate (which might be a no-op)

            validate(admin_class, model)

            # Instantiate the admin class to save in the registry

            self._registry[model] = admin_class(model, self)

    def unregister(self, model_or_iterable):

        """

        Unregisters the given model(s).

        If a model isn't already registered, this will raise NotRegistered.

        """

        if isinstance(model_or_iterable, ModelBase):

            model_or_iterable = [model_or_iterable]

        for model in model_or_iterable:

            if model not in self._registry:

                raise NotRegistered('The model %s is not registered' % model.__name__)

            del self._registry[model]

    def add_action(self, action, name=None):

        """

        Register an action to be available globally.

        """

        name = name or action.__name__

        self._actions[name] = action

        self._global_actions[name] = action

    def disable_action(self, name):

        """

        Disable a globally-registered action. Raises KeyError for invalid names.

        """

        del self._actions[name]

    def get_action(self, name):

        """

        Explicitally get a registered global action wheather it's enabled or

        not. Raises KeyError for invalid names.

        """

        return self._global_actions[name]

    def actions(self):

        """

        Get all the enabled actions as an iterable of (name, func).

        """

        return self._actions.iteritems()

    actions = property(actions)

    def has_permission(self, request):

        """

        Returns True if the given HttpRequest has permission to view

        *at least one* page in the admin site.

        """

    def check_dependencies(self):

        """

        Check that all things needed to run the admin have been correctly installed.

        The default implementation checks that LogEntry, ContentType and the

        auth context processor are installed.

        """

        from django.contrib.admin.models import LogEntry

        from django.contrib.contenttypes.models import ContentType

        if not LogEntry._meta.installed:

        if not ContentType._meta.installed:

    def admin_view(self, view, cacheable=False):

        """

        Decorator to create an admin view attached to this ``AdminSite``. This

        wraps the view and provides permission checking by calling

        ``self.has_permission``.

        You'll want to use this from within ``AdminSite.get_urls()``:

            class MyAdminSite(AdminSite):

                def get_urls(self):

                    from django.conf.urls.defaults import patterns, url

                    urls = super(MyAdminSite, self).get_urls()

                    urls += patterns('',

                        url(r'^my_view/$', self.admin_view(some_view))

                    )

                    return urls

        By default, admin_views are marked non-cacheable using the

        ``never_cache`` decorator. If the view can be safely cached, set

        cacheable=True.

        """

        def inner(request, *args, **kwargs):

            if not self.has_permission(request):

                return self.login(request)

            return view(request, *args, **kwargs)

        if not cacheable:

            inner = never_cache(inner)

        return update_wrapper(inner, view)

    def get_urls(self):

        from django.conf.urls.defaults import patterns, url, include

        def wrap(view, cacheable=False):

            def wrapper(*args, **kwargs):

                return self.admin_view(view, cacheable)(*args, **kwargs)

            return update_wrapper(wrapper, view)

        # Admin-site-wide views.

        urlpatterns = patterns('',

            url(r'^$',

                wrap(self.index),

                name='index'),

            url(r'^logout/$',

                wrap(self.logout),

                name='logout'),

            url(r'^password_change/$',

                wrap(self.password_change, cacheable=True),

                name='password_change'),

            url(r'^password_change/done/$',

                wrap(self.password_change_done, cacheable=True),

                name='password_change_done'),

            url(r'^jsi18n/$',

                wrap(self.i18n_javascript, cacheable=True),

                name='jsi18n'),

            url(r'^r/(?P<content_type_id>\d+)/(?P<object_id>.+)/$',

                'django.views.defaults.shortcut'),

            url(r'^(?P<app_label>\w+)/$',

                wrap(self.app_index),

                name='app_list')

        )

        # Add in each model's views.

        for model, model_admin in self._registry.iteritems():

            urlpatterns += patterns('',

                url(r'^%s/%s/' % (model._meta.app_label, model._meta.module_name),

                    include(model_admin.urls))

            )

        return urlpatterns

    def urls(self):

        return self.get_urls(), self.app_name, self.name

    urls = property(urls)

    def password_change(self, request):

        """

        Handles the "change password" task -- both form display and validation.

        """

        from django.contrib.auth.views import password_change

        if self.root_path is not None:

            url = '%spassword_change/done/' % self.root_path

        else:

            url = reverse('admin:password_change_done', current_app=self.name)

    def password_change_done(self, request):

        """

        Displays the "success" page after a password change.

        """

        from django.contrib.auth.views import password_change_done

    def i18n_javascript(self, request):

        """

        Displays the i18n JavaScript that the Django admin requires.

        This takes into account the USE_I18N setting. If it's set to False, the

        generated JavaScript will be leaner and faster.

        """

        if settings.USE_I18N:

            from django.views.i18n import javascript_catalog

        else:

            from django.views.i18n import null_javascript_catalog as javascript_catalog

        return javascript_catalog(request, packages='django.conf')

    def logout(self, request):

        """

        Logs out the user for the given HttpRequest.

        This should *not* assume the user is already logged in.

        """

        from django.contrib.auth.views import logout

    logout = never_cache(logout)

    def login(self, request):

        """

        Displays the login form for the given HttpRequest.

        """

        from django.contrib.auth.models import User

        # If this isn't already the login page, display it.

        if not request.POST.has_key(LOGIN_FORM_KEY):

            if request.POST:

                message = _("Please log in again, because your session has expired.")

            else:

                message = ""

            return self.display_login_form(request, message)

        # Check that the user accepts cookies.

        if not request.session.test_cookie_worked():

            message = _("Looks like your browser isn't configured to accept cookies. Please enable cookies, reload this page, and try again.")

            return self.display_login_form(request, message)

        else:

            request.session.delete_test_cookie()

        # Check the password.

        username = request.POST.get('username', None)

        password = request.POST.get('password', None)

        user = authenticate(username=username, password=password)

        if user is None:

            message = ERROR_MESSAGE

            if username is not None and u'@' in username:

                # Mistakenly entered e-mail address instead of username? Look it up.

                try:

                    user = User.objects.get(email=username)

                except (User.DoesNotExist, User.MultipleObjectsReturned):

                    message = _("Usernames cannot contain the '@' character.")

                else:

                    if user.check_password(password):

                        message = _("Your e-mail address is not your username."

                                    " Try '%s' instead.") % user.username

                    else:

                        message = _("Usernames cannot contain the '@' character.")

            return self.display_login_form(request, message)

        # The user data is correct; log in the user in and continue.

        else:

            if user.is_active and user.is_staff:

                login(request, user)

                return http.HttpResponseRedirect(request.get_full_path())

            else:

                return self.display_login_form(request, ERROR_MESSAGE)

    login = never_cache(login)

    def index(self, request, extra_context=None):

        """

        Displays the main admin index page, which lists all of the installed

        apps that have been registered in this site.

        """

        app_dict = {}

        user = request.user

        for model, model_admin in self._registry.items():

            app_label = model._meta.app_label

            has_module_perms = user.has_module_perms(app_label)

            if has_module_perms:

                perms = model_admin.get_model_perms(request)

                # Check whether user has any perm for this module.

                # If so, add the module to the model_list.

                if True in perms.values():

                    model_dict = {

                        'name': capfirst(model._meta.verbose_name_plural),

                        'admin_url': mark_safe('%s/%s/' % (app_label, model.__name__.lower())),

                        'perms': perms,

                    }

                    if app_label in app_dict:

                        app_dict[app_label]['models'].append(model_dict)

                    else:

                        app_dict[app_label] = {

                            'name': app_label.title(),

                            'app_url': app_label + '/',

                            'has_module_perms': has_module_perms,

                            'models': [model_dict],

                        }

        # Sort the apps alphabetically.

        app_list = app_dict.values()

        app_list.sort(lambda x, y: cmp(x['name'], y['name']))

        # Sort the models alphabetically within each app.

        for app in app_list:

            app['models'].sort(lambda x, y: cmp(x['name'], y['name']))

        context = {

            'title': _('Site administration'),

            'app_list': app_list,

            'root_path': self.root_path,

        }

        context.update(extra_context or {})

        context_instance = template.RequestContext(request, current_app=self.name)

        return render_to_response(self.index_template or 'admin/index.html', context,

            context_instance=context_instance

        )

    index = never_cache(index)

    def display_login_form(self, request, error_message='', extra_context=None):

        request.session.set_test_cookie()

        context = {

            'title': _('Log in'),

            'app_path': request.get_full_path(),

            'error_message': error_message,

            'root_path': self.root_path,

        }

        context.update(extra_context or {})

        context_instance = template.RequestContext(request, current_app=self.name)

        return render_to_response(self.login_template or 'admin/login.html', context,