from django import forms, template
from django.forms.formsets import all_valid
from django.forms.models import modelform_factory, modelformset_factory, inlineformset_factory
from django.forms.models import BaseInlineFormSet
from django.contrib.contenttypes.models import ContentType
from django.contrib.admin import widgets
from django.contrib.admin import helpers
from django.contrib.admin.util import unquote, flatten_fieldsets, get_deleted_objects, model_ngettext, model_format_dict
from django.contrib import messages
from django.views.decorators.csrf import csrf_protect
from django.core.exceptions import PermissionDenied, ValidationError
from django.db import models, transaction
from django.db.models.fields import BLANK_CHOICE_DASH
from django.http import Http404, HttpResponse, HttpResponseRedirect
from django.shortcuts import get_object_or_404, render_to_response
from django.utils.decorators import method_decorator
from django.utils.datastructures import SortedDict
from django.utils.functional import update_wrapper
from django.utils.html import escape
from django.utils.safestring import mark_safe
from django.utils.functional import curry
from django.utils.text import capfirst, get_text_list
from django.utils.translation import ugettext as _
from django.utils.translation import ungettext, ugettext_lazy
from django.utils.encoding import force_unicode

HORIZONTAL, VERTICAL = 1, 2
# returns the <ul> class for a given radio_admin field
get_ul_class = lambda x: 'radiolist%s' % ((x == HORIZONTAL) and ' inline' or '')

class IncorrectLookupParameters(Exception):
    pass

# Defaults for formfield_overrides. ModelAdmin subclasses can change this
# by adding to ModelAdmin.formfield_overrides.

FORMFIELD_FOR_DBFIELD_DEFAULTS = {
    models.DateTimeField: {
        'form_class': forms.SplitDateTimeField,
        'widget': widgets.AdminSplitDateTime
    },
    models.DateField:       {'widget': widgets.AdminDateWidget},
    models.TimeField:       {'widget': widgets.AdminTimeWidget},
    models.TextField:       {'widget': widgets.AdminTextareaWidget},
    models.URLField:        {'widget': widgets.AdminURLFieldWidget},
    models.IntegerField:    {'widget': widgets.AdminIntegerFieldWidget},
    models.BigIntegerField: {'widget': widgets.AdminIntegerFieldWidget},
    models.CharField:       {'widget': widgets.AdminTextInputWidget},
    models.ImageField:      {'widget': widgets.AdminFileWidget},
    models.FileField:       {'widget': widgets.AdminFileWidget},
}

csrf_protect_m = method_decorator(csrf_protect)

class BaseModelAdmin(object):
    """Functionality common to both ModelAdmin and InlineAdmin."""
    __metaclass__ = forms.MediaDefiningClass

    raw_id_fields = ()
    fields = None
    exclude = None
    fieldsets = None
    form = forms.ModelForm
    filter_vertical = ()
    filter_horizontal = ()
    radio_fields = {}
    prepopulated_fields = {}
    formfield_overrides = {}
    readonly_fields = ()

    def __init__(self):
        overrides = FORMFIELD_FOR_DBFIELD_DEFAULTS.copy()
        overrides.update(self.formfield_overrides)
        self.formfield_overrides = overrides

    def formfield_for_dbfield(self, db_field, **kwargs):
        """
        Hook for specifying the form Field instance for a given database Field
        instance.

        If kwargs are given, they're passed to the form Field's constructor.
        """
        request = kwargs.pop("request", None)

        # If the field specifies choices, we don't need to look for special
        # admin widgets - we just need to use a select widget of some kind.
        if db_field.choices:
            return self.formfield_for_choice_field(db_field, request, **kwargs)

        # ForeignKey or ManyToManyFields
        if isinstance(db_field, (models.ForeignKey, models.ManyToManyField)):
            # Combine the field kwargs with any options for formfield_overrides.
            # Make sure the passed in **kwargs override anything in
            # formfield_overrides because **kwargs is more specific, and should
            # always win.
            if db_field.__class__ in self.formfield_overrides:
                kwargs = dict(self.formfield_overrides[db_field.__class__], **kwargs)

            # Get the correct formfield.
            if isinstance(db_field, models.ForeignKey):
                formfield = self.formfield_for_foreignkey(db_field, request, **kwargs)
            elif isinstance(db_field, models.ManyToManyField):
                formfield = self.formfield_for_manytomany(db_field, request, **kwargs)

            # For non-raw_id fields, wrap the widget with a wrapper that adds
            # extra HTML -- the "add other" interface -- to the end of the
            # rendered output. formfield can be None if it came from a
            # OneToOneField with parent_link=True or a M2M intermediary.
            if formfield and db_field.name not in self.raw_id_fields:
                formfield.widget = widgets.RelatedFieldWidgetWrapper(formfield.widget, db_field.rel, self.admin_site)

            return formfield

        # If we've got overrides for the formfield defined, use 'em. **kwargs
        # passed to formfield_for_dbfield override the defaults.
        for klass in db_field.__class__.mro():
            if klass in self.formfield_overrides:
                kwargs = dict(self.formfield_overrides[klass], **kwargs)
                return db_field.formfield(**kwargs)

        # For any other type of field, just call its formfield() method.
        return db_field.formfield(**kwargs)

    def formfield_for_choice_field(self, db_field, request=None, **kwargs):
        """
        Get a form Field for a database Field that has declared choices.
        """
        # If the field is named as a radio_field, use a RadioSelect
        if db_field.name in self.radio_fields:
            # Avoid stomping on custom widget/choices arguments.
            if 'widget' not in kwargs:
                kwargs['widget'] = widgets.AdminRadioSelect(attrs={
                    'class': get_ul_class(self.radio_fields[db_field.name]),
                })
            if 'choices' not in kwargs:
                kwargs['choices'] = db_field.get_choices(
                    include_blank = db_field.blank,
                    blank_choice=[('', _('None'))]
                )
        return db_field.formfield(**kwargs)

    def formfield_for_foreignkey(self, db_field, request=None, **kwargs):
        """
        Get a form Field for a ForeignKey.
        """
        db = kwargs.get('using')
        if db_field.name in self.raw_id_fields:
            kwargs['widget'] = widgets.ForeignKeyRawIdWidget(db_field.rel, using=db)
        elif db_field.name in self.radio_fields:
            kwargs['widget'] = widgets.AdminRadioSelect(attrs={
                'class': get_ul_class(self.radio_fields[db_field.name]),
            })
            kwargs['empty_label'] = db_field.blank and _('None') or None

        return db_field.formfield(**kwargs)

    def formfield_for_manytomany(self, db_field, request=None, **kwargs):
        """
        Get a form Field for a ManyToManyField.
        """
        # If it uses an intermediary model that isn't auto created, don't show
        # a field in admin.
        if not db_field.rel.through._meta.auto_created:
            return None
        db = kwargs.get('using')

        if db_field.name in self.raw_id_fields:
            kwargs['widget'] = widgets.ManyToManyRawIdWidget(db_field.rel, using=db)
            kwargs['help_text'] = ''
        elif db_field.name in (list(self.filter_vertical) + list(self.filter_horizontal)):
            kwargs['widget'] = widgets.FilteredSelectMultiple(db_field.verbose_name, (db_field.name in self.filter_vertical))

        return db_field.formfield(**kwargs)

    def _declared_fieldsets(self):
        if self.fieldsets:
            return self.fieldsets
        elif self.fields:
            return [(None, {'fields': self.fields})]
        return None
    declared_fieldsets = property(_declared_fieldsets)

    def get_readonly_fields(self, request, obj=None):
        return self.readonly_fields

class ModelAdmin(BaseModelAdmin):
    "Encapsulates all admin options and functionality for a given model."

    list_display = ('__str__',)
    list_display_links = ()
    list_filter = ()
    list_select_related = False
    list_per_page = 100
    list_editable = ()
    search_fields = ()
    date_hierarchy = None
    save_as = False
    save_on_top = False
    ordering = None
    inlines = []

    # Custom templates (designed to be over-ridden in subclasses)
    add_form_template = None
    change_form_template = None
    change_list_template = None
    delete_confirmation_template = None
    delete_selected_confirmation_template = None
    object_history_template = None

    # Actions
    actions = []
    action_form = helpers.ActionForm
    actions_on_top = True
    actions_on_bottom = False
    actions_selection_counter = True

    def __init__(self, model, admin_site):
        self.model = model
        self.opts = model._meta
        self.admin_site = admin_site
        self.inline_instances = []
        for inline_class in self.inlines:
            inline_instance = inline_class(self.model, self.admin_site)
            self.inline_instances.append(inline_instance)
        if 'action_checkbox' not in self.list_display and self.actions is not None:
            self.list_display = ['action_checkbox'] +  list(self.list_display)
        if not self.list_display_links:
            for name in self.list_display:
                if name != 'action_checkbox':
                    self.list_display_links = [name]
                    break
        super(ModelAdmin, self).__init__()

    def get_urls(self):
        from django.conf.urls.defaults import patterns, url

        def wrap(view):
            def wrapper(*args, **kwargs):
                return self.admin_site.admin_view(view)(*args, **kwargs)
            return update_wrapper(wrapper, view)

        info = self.model._meta.app_label, self.model._meta.module_name

        urlpatterns = patterns('',
            url(r'^$',
                wrap(self.changelist_view),
                name='%s_%s_changelist' % info),
            url(r'^add/$',
                wrap(self.add_view),
                name='%s_%s_add' % info),
            url(r'^(.+)/history/$',
                wrap(self.history_view),
                name='%s_%s_history' % info),
            url(r'^(.+)/delete/$',
                wrap(self.delete_view),
                name='%s_%s_delete' % info),
            url(r'^(.+)/$',
                wrap(self.change_view),
                name='%s_%s_change' % info),
        )
        return urlpatterns

    def urls(self):
        return self.get_urls()
    urls = property(urls)

    def _media(self):
        from django.conf import settings

        js = ['js/core.js', 'js/admin/RelatedObjectLookups.js',
              'js/jquery.min.js', 'js/jquery.init.js']
        if self.actions is not None:
            js.extend(['js/actions.min.js'])
        if self.prepopulated_fields:
            js.append('js/urlify.js')
            js.append('js/prepopulate.min.js')
        if self.opts.get_ordered_objects():
            js.extend(['js/getElementsBySelector.js', 'js/dom-drag.js' , 'js/admin/ordering.js'])

        return forms.Media(js=['%s%s' % (settings.ADMIN_MEDIA_PREFIX, url) for url in js])
    media = property(_media)

    def has_add_permission(self, request):
        "Returns True if the given request has permission to add an object."
        opts = self.opts
        return request.user.has_perm(opts.app_label + '.' + opts.get_add_permission())

    def has_change_permission(self, request, obj=None):
        """
        Returns True if the given request has permission to change the given
        Django model instance.

        If `obj` is None, this should return True if the given request has
        permission to change *any* object of the given type.
        """
        opts = self.opts
        return request.user.has_perm(opts.app_label + '.' + opts.get_change_permission())

    def has_delete_permission(self, request, obj=None):
        """
        Returns True if the given request has permission to change the given
        Django model instance.

        If `obj` is None, this should return True if the given request has
        permission to delete *any* object of the given type.
        """
        opts = self.opts
        return request.user.has_perm(opts.app_label + '.' + opts.get_delete_permission())

    def get_model_perms(self, request):
        """
        Returns a dict of all perms for this model. This dict has the keys
        ``add``, ``change``, and ``delete`` mapping to the True/False for each
        of those actions.
        """
        return {
            'add': self.has_add_permission(request),
            'change': self.has_change_permission(request),
            'delete': self.has_delete_permission(request),
        }

    def queryset(self, request):
        """
        Returns a QuerySet of all model instances that can be edited by the
        admin site. This is used by changelist_view.
        """
        qs = self.model._default_manager.get_query_set()
        # TODO: this should be handled by some parameter to the ChangeList.
        ordering = self.ordering or () # otherwise we might try to *None, which is bad ;)
        if ordering:
            qs = qs.order_by(*ordering)
        return qs

    def get_fieldsets(self, request, obj=None):
        "Hook for specifying fieldsets for the add form."
        if self.declared_fieldsets:
            return self.declared_fieldsets
        form = self.get_form(request, obj)
        fields = form.base_fields.keys() + list(self.get_readonly_fields(request, obj))
        return [(None, {'fields': fields})]

    def get_form(self, request, obj=None, **kwargs):
        """
        Returns a Form class for use in the admin add view. This is used by
        add_view and change_view.
        """
        if self.declared_fieldsets:
            fields = flatten_fieldsets(self.declared_fieldsets)
        else:
            fields = None
        if self.exclude is None:
            exclude = []
        else:
            exclude = list(self.exclude)
        exclude.extend(kwargs.get("exclude", []))
        exclude.extend(self.get_readonly_fields(request, obj))
        # if exclude is an empty list we pass None to be consistant with the
        # default on modelform_factory
        exclude = exclude or None
        defaults = {
            "form": self.form,
            "fields": fields,
            "exclude": exclude,
            "formfield_callback": curry(self.formfield_for_dbfield, request=request),
        }
        defaults.update(kwargs)
        return modelform_factory(self.model, **defaults)

    def get_changelist(self, request, **kwargs):
        """
        Returns the ChangeList class for use on the changelist page.
        """
        from django.contrib.admin.views.main import ChangeList
        return ChangeList

    def get_object(self, request, object_id):
        """
        Returns an instance matching the primary key provided. ``None``  is
        returned if no match is found (or the object_id failed validation
        against the primary key field).
        """
        queryset = self.queryset(request)
        model = queryset.model
        try:
            object_id = model._meta.pk.to_python(object_id)
            return queryset.get(pk=object_id)
        except (model.DoesNotExist, ValidationError):
            return None

    def get_changelist_form(self, request, **kwargs):
        """
        Returns a Form class for use in the Formset on the changelist page.
        """
        defaults = {
            "formfield_callback": curry(self.formfield_for_dbfield, request=request),
        }
        defaults.update(kwargs)
        return modelform_factory(self.model, **defaults)

    def get_changelist_formset(self, request, **kwargs):
        """
        Returns a FormSet class for use on the changelist page if list_editable
        is used.
        """
        defaults = {
            "formfield_callback": curry(self.formfield_for_dbfield, request=request),
        }
        defaults.update(kwargs)
        return modelformset_factory(self.model,
            self.get_changelist_form(request), extra=0,
            fields=self.list_editable, **defaults)

    def get_formsets(self, request, obj=None):
        for inline in self.inline_instances:
            yield inline.get_formset(request, obj)

    def log_addition(self, request, object):
        """
        Log that an object has been successfully added.

        The default implementation creates an admin LogEntry object.
        """
        from django.contrib.admin.models import LogEntry, ADDITION
        LogEntry.objects.log_action(
            user_id         = request.user.pk,
            content_type_id = ContentType.objects.get_for_model(object).pk,
            object_id       = object.pk,
            object_repr     = force_unicode(object),
            action_flag     = ADDITION
        )

    def log_change(self, request, object, message):
        """
        Log that an object has been successfully changed.

        The default implementation creates an admin LogEntry object.
        """
        from django.contrib.admin.models import LogEntry, CHANGE
        LogEntry.objects.log_action(
            user_id         = request.user.pk,
            content_type_id = ContentType.objects.get_for_model(object).pk,
            object_id       = object.pk,
            object_repr     = force_unicode(object),
            action_flag     = CHANGE,
            change_message  = message
        )

    def log_deletion(self, request, object, object_repr):
        """
        Log that an object has been successfully deleted. Note that since the
        object is deleted, it might no longer be safe to call *any* methods
        on the object, hence this method getting object_repr.

        The default implementation creates an admin LogEntry object.
        """
        from django.contrib.admin.models import LogEntry, DELETION
        LogEntry.objects.log_action(
            user_id         = request.user.id,
            content_type_id = ContentType.objects.get_for_model(self.model).pk,
            object_id       = object.pk,
            object_repr     = object_repr,
            action_flag     = DELETION
        )

    def action_checkbox(self, obj):
        """
        A list_display column containing a checkbox widget.
        """
        return helpers.checkbox.render(helpers.ACTION_CHECKBOX_NAME, force_unicode(obj.pk))
    action_checkbox.short_description = mark_safe('<input type="checkbox" id="action-toggle" />')
    action_checkbox.allow_tags = True

    def get_actions(self, request):
        """
        Return a dictionary mapping the names of all actions for this
        ModelAdmin to a tuple of (callable, name, description) for each action.
        """
        # If self.actions is explicitally set to None that means that we don't
        # want *any* actions enabled on this page.
        if self.actions is None:
            return []

        actions = []

        # Gather actions from the admin site first
        for (name, func) in self.admin_site.actions:
            description = getattr(func, 'short_description', name.replace('_', ' '))
            actions.append((func, name, description))

        # Then gather them from the model admin and all parent classes,
        # starting with self and working back up.
        for klass in self.__class__.mro()[::-1]:
            class_actions = getattr(klass, 'actions', [])
            # Avoid trying to iterate over None
            if not class_actions:
                continue
            actions.extend([self.get_action(action) for action in class_actions])

        # get_action might have returned None, so filter any of those out.
        actions = filter(None, actions)

        # Convert the actions into a SortedDict keyed by name
        # and sorted by description.
        actions.sort(lambda a,b: cmp(a[2].lower(), b[2].lower()))
        actions = SortedDict([
            (name, (func, name, desc))
            for func, name, desc in actions
        ])

        return actions

    def get_action_choices(self, request, default_choices=BLANK_CHOICE_DASH):
        """
        Return a list of choices for use in a form object.  Each choice is a
        tuple (name, description).
        """
        choices = [] + default_choices
        for func, name, description in self.get_actions(request).itervalues():
            choice = (name, description % model_format_dict(self.opts))
            choices.append(choice)
        return choices

    def get_action(self, action):
        """
        Return a given action from a parameter, which can either be a callable,
        or the name of a method on the ModelAdmin.  Return is a tuple of
        (callable, name, description).
        """
        # If the action is a callable, just use it.
        if callable(action):
            func = action
            action = action.__name__

        # Next, look for a method. Grab it off self.__class__ to get an unbound
        # method instead of a bound one; this ensures that the calling
        # conventions are the same for functions and methods.
        elif hasattr(self.__class__, action):
            func = getattr(self.__class__, action)

        # Finally, look for a named method on the admin site
        else:
            try:
                func = self.admin_site.get_action(action)
            except KeyError:
                return None

        if hasattr(func, 'short_description'):
            description = func.short_description
        else:
            description = capfirst(action.replace('_', ' '))
        return func, action, description

    def construct_change_message(self, request, form, formsets):
        """
        Construct a change message from a changed object.
        """
        change_message = []
        if form.changed_data:
            change_message.append(_('Changed %s.') % get_text_list(form.changed_data, _('and')))

        if formsets:
            for formset in formsets:
                for added_object in formset.new_objects:
                    change_message.append(_('Added %(name)s "%(object)s".')
                                          % {'name': force_unicode(added_object._meta.verbose_name),
                                             'object': force_unicode(added_object)})
                for changed_object, changed_fields in formset.changed_objects:
                    change_message.append(_('Changed %(list)s for %(name)s "%(object)s".')
                                          % {'list': get_text_list(changed_fields, _('and')),
                                             'name': force_unicode(changed_object._meta.verbose_name),
                                             'object': force_unicode(changed_object)})
                for deleted_object in formset.deleted_objects:
                    change_message.append(_('Deleted %(name)s "%(object)s".')
                                          % {'name': force_unicode(deleted_object._meta.verbose_name),
                                             'object': force_unicode(deleted_object)})
        change_message = ' '.join(change_message)
        return change_message or _('No fields changed.')

    def message_user(self, request, message):
        """
        Send a message to the user. The default implementation
        posts a message using the django.contrib.messages backend.
        """
        messages.info(request, message)

    def save_form(self, request, form, change):
        """
        Given a ModelForm return an unsaved instance. ``change`` is True if
        the object is being changed, and False if it's being added.
        """
        return form.save(commit=False)

    def save_model(self, request, obj, form, change):
        """
        Given a model instance save it to the database.
        """
        obj.save()

    def save_formset(self, request, form, formset, change):
        """
        Given an inline formset save it to the database.
        """
        formset.save()

    def render_change_form(self, request, context, add=False, change=False, form_url='', obj=None):
        opts = self.model._meta
        app_label = opts.app_label
        ordered_objects = opts.get_ordered_objects()
        context.update({
            'add': add,
            'change': change,
            'has_add_permission': self.has_add_permission(request),
            'has_change_permission': self.has_change_permission(request, obj),
            'has_delete_permission': self.has_delete_permission(request, obj),
            'has_file_field': True, # FIXME - this should check if form or formsets have a FileField,
            'has_absolute_url': hasattr(self.model, 'get_absolute_url'),
            'ordered_objects': ordered_objects,
            'form_url': mark_safe(form_url),
            'opts': opts,
            'content_type_id': ContentType.objects.get_for_model(self.model).id,
            'save_as': self.save_as,
            'save_on_top': self.save_on_top,
            'root_path': self.admin_site.root_path,
        })
        if add and self.add_form_template is not None:
            form_template = self.add_form_template
        else:
            form_template = self.change_form_template
        context_instance = template.RequestContext(request, current_app=self.admin_site.name)
        return render_to_response(form_template or [
            "admin/%s/%s/change_form.html" % (app_label, opts.object_name.lower()),
            "admin/%s/change_form.html" % app_label,
            "admin/change_form.html"
        ], context, context_instance=context_instance)

    def response_add(self, request, obj, post_url_continue='../%s/'):
        """
        Determines the HttpResponse for the add_view stage.
        """
        opts = obj._meta
        pk_value = obj._get_pk_val()

        msg = _('The %(name)s "%(obj)s" was added successfully.') % {'name': force_unicode(opts.verbose_name), 'obj': force_unicode(obj)}
        # Here, we distinguish between different save types by checking for
        # the presence of keys in request.POST.
        if request.POST.has_key("_continue"):
            self.message_user(request, msg + ' ' + _("You may edit it again below."))
            if request.POST.has_key("_popup"):
                post_url_continue += "?_popup=1"
            return HttpResponseRedirect(post_url_continue % pk_value)

        if request.POST.has_key("_popup"):
            return HttpResponse('<script type="text/javascript">opener.dismissAddAnotherPopup(window, "%s", "%s");</script>' % \
                # escape() calls force_unicode.
                (escape(pk_value), escape(obj)))
        elif request.POST.has_key("_addanother"):
            self.message_user(request, msg + ' ' + (_("You may add another %s below.") % force_unicode(opts.verbose_name)))
            return HttpResponseRedirect(request.path)
        else:
            self.message_user(request, msg)

            # Figure out where to redirect. If the user has change permission,
            # redirect to the change-list page for this object. Otherwise,
            # redirect to the admin index.
            if self.has_change_permission(request, None):
                post_url = '../'
            else:
                post_url = '../../../'
            return HttpResponseRedirect(post_url)

    def response_change(self, request, obj):
        """
        Determines the HttpResponse for the change_view stage.
        """
        opts = obj._meta
        pk_value = obj._get_pk_val()

        msg = _('The %(name)s "%(obj)s" was changed successfully.') % {'name': force_unicode(opts.verbose_name), 'obj': force_unicode(obj)}
        if request.POST.has_key("_continue"):
            self.message_user(request, msg + ' ' + _("You may edit it again below."))
            if request.REQUEST.has_key('_popup'):
                return HttpResponseRedirect(request.path + "?_popup=1")
            else:
                return HttpResponseRedirect(request.path)
        elif request.POST.has_key("_saveasnew"):
            msg = _('The %(name)s "%(obj)s" was added successfully. You may edit it again below.') % {'name': force_unicode(opts.verbose_name), 'obj': obj}
            self.message_user(request, msg)
            return HttpResponseRedirect("../%s/" % pk_value)
        elif request.POST.has_key("_addanother"):
            self.message_user(request, msg + ' ' + (_("You may add another %s below.") % force_unicode(opts.verbose_name)))
            return HttpResponseRedirect("../add/")
        else:
            self.message_user(request, msg)
            return HttpResponseRedirect("../")

    def response_action(self, request, queryset):
        """
        Handle an admin action. This is called if a request is POSTed to the
        changelist; it returns an HttpResponse if the action was handled, and
        None otherwise.
        """

        # There can be multiple action forms on the page (at the top
        # and bottom of the change list, for example). Get the action
        # whose button was pushed.
        try:
            action_index = int(request.POST.get('index', 0))
        except ValueError:
            action_index = 0

        # Construct the action form.
        data = request.POST.copy()
        data.pop(helpers.ACTION_CHECKBOX_NAME, None)
        data.pop("index", None)

        # Use the action whose button was pushed
        try:
            data.update({'action': data.getlist('action')[action_index]})
        except IndexError:
            # If we didn't get an action from the chosen form that's invalid
            # POST data, so by deleting action it'll fail the validation check
            # below. So no need to do anything here
            pass

        action_form = self.action_form(data, auto_id=None)
        action_form.fields['action'].choices = self.get_action_choices(request)

        # If the form's valid we can handle the action.
        if action_form.is_valid():
            action = action_form.cleaned_data['action']
            select_across = action_form.cleaned_data['select_across']
            func, name, description = self.get_actions(request)[action]

            # Get the list of selected PKs. If nothing's selected, we can't
            # perform an action on it, so bail. Except we want to perform
            # the action explicitly on all objects.
            selected = request.POST.getlist(helpers.ACTION_CHECKBOX_NAME)
            if not selected and not select_across:
                # Reminder that something needs to be selected or nothing will happen
                msg = _("Items must be selected in order to perform "
                        "actions on them. No items have been changed.")
                self.message_user(request, msg)
                return None

            if not select_across:
                # Perform the action only on the selected objects
                queryset = queryset.filter(pk__in=selected)

            response = func(self, request, queryset)

            # Actions may return an HttpResponse, which will be used as the
            # response from the POST. If not, we'll be a good little HTTP
            # citizen and redirect back to the changelist page.
            if isinstance(response, HttpResponse):
                return response
            else:
                return HttpResponseRedirect(request.get_full_path())
        else:
            msg = _("No action selected.")
            self.message_user(request, msg)
            return None

    @csrf_protect_m
    @transaction.commit_on_success
    def add_view(self, request, form_url='', extra_context=None):
        "The 'add' admin view for this model."
        model = self.model
        opts = model._meta

        if not self.has_add_permission(request):
            raise PermissionDenied

        ModelForm = self.get_form(request)
        formsets = []
        if request.method == 'POST':
            form = ModelForm(request.POST, request.FILES)
            if form.is_valid():
                new_object = self.save_form(request, form, change=False)
                form_validated = True
            else:
                form_validated = False
                new_object = self.model()
            prefixes = {}
            for FormSet, inline in zip(self.get_formsets(request), self.inline_instances):
                prefix = FormSet.get_default_prefix()
                prefixes[prefix] = prefixes.get(prefix, 0) + 1
                if prefixes[prefix] != 1:
                    prefix = "%s-%s" % (prefix, prefixes[prefix])
                formset = FormSet(data=request.POST, files=request.FILES,
                                  instance=new_object,
                                  save_as_new=request.POST.has_key("_saveasnew"),
                                  prefix=prefix, queryset=inline.queryset(request))
                formsets.append(formset)
            if all_valid(formsets) and form_validated:
                self.save_model(request, new_object, form, change=False)
                form.save_m2m()
                for formset in formsets:
                    self.save_formset(request, form, formset, change=False)

                self.log_addition(request, new_object)
                return self.response_add(request, new_object)
        else:
            # Prepare the dict of initial data from the request.
            # We have to special-case M2Ms as a list of comma-separated PKs.
            initial = dict(request.GET.items())
            for k in initial:
                try:
                    f = opts.get_field(k)
                except models.FieldDoesNotExist:
                    continue
                if isinstance(f, models.ManyToManyField):
                    initial[k] = initial[k].split(",")
            form = ModelForm(initial=initial)
            prefixes = {}
            for FormSet, inline in zip(self.get_formsets(request),
                                       self.inline_instances):
                prefix = FormSet.get_default_prefix()
                prefixes[prefix] = prefixes.get(prefix, 0) + 1
                if prefixes[prefix] != 1:
                    prefix = "%s-%s" % (prefix, prefixes[prefix])
                formset = FormSet(instance=self.model(), prefix=prefix,
                                  queryset=inline.queryset(request))
                formsets.append(formset)

        adminForm = helpers.AdminForm(form, list(self.get_fieldsets(request)),
            self.prepopulated_fields, self.get_readonly_fields(request),
            model_admin=self)
        media = self.media + adminForm.media

        inline_admin_formsets = []
        for inline, formset in zip(self.inline_instances, formsets):
            fieldsets = list(inline.get_fieldsets(request))
            readonly = list(inline.get_readonly_fields(request))
            inline_admin_formset = helpers.InlineAdminFormSet(inline, formset,
                fieldsets, readonly, model_admin=self)
            inline_admin_formsets.append(inline_admin_formset)
            media = media + inline_admin_formset.media

        context = {
            'title': _('Add %s') % force_unicode(opts.verbose_name),
            'adminform': adminForm,
            'is_popup': request.REQUEST.has_key('_popup'),
            'show_delete': False,
            'media': mark_safe(media),
            'inline_admin_formsets': inline_admin_formsets,
            'errors': helpers.AdminErrorList(form, formsets),
            'root_path': self.admin_site.root_path,
            'app_label': opts.app_label,
        }
        context.update(extra_context or {})
        return self.render_change_form(request, context, form_url=form_url, add=True)

    @csrf_protect_m
    @transaction.commit_on_success
    def change_view(self, request, object_id, extra_context=None):
        "The 'change' admin view for this model."
        model = self.model
        opts = model._meta

        obj = self.get_object(request, unquote(object_id))

        if not self.has_change_permission(request, obj):
            raise PermissionDenied

        if obj is None:
            raise Http404(_('%(name)s object with primary key %(key)r does not exist.') % {'name': force_unicode(opts.verbose_name), 'key': escape(object_id)})

        if request.method == 'POST' and request.POST.has_key("_saveasnew"):
            return self.add_view(request, form_url='../add/')

        ModelForm = self.get_form(request, obj)
        formsets = []
        if request.method == 'POST':
            form = ModelForm(request.POST, request.FILES, instance=obj)
            if form.is_valid():
                form_validated = True
                new_object = self.save_form(request, form, change=True)
            else:
                form_validated = False
                new_object = obj
            prefixes = {}
            for FormSet, inline in zip(self.get_formsets(request, new_object),
                                       self.inline_instances):
                prefix = FormSet.get_default_prefix()
                prefixes[prefix] = prefixes.get(prefix, 0) + 1
                if prefixes[prefix] != 1:
                    prefix = "%s-%s" % (prefix, prefixes[prefix])
                formset = FormSet(request.POST, request.FILES,
                                  instance=new_object, prefix=prefix,
                                  queryset=inline.queryset(request))

                formsets.append(formset)

            if all_valid(formsets) and form_validated:
                self.save_model(request, new_object, form, change=True)
                form.save_m2m()
                for formset in formsets:
                    self.save_formset(request, form, formset, change=True)

                change_message = self.construct_change_message(request, form, formsets)
                self.log_change(request, new_object, change_message)
                return self.response_change(request, new_object)

        else:
            form = ModelForm(instance=obj)
            prefixes = {}
            for FormSet, inline in zip(self.get_formsets(request, obj), self.inline_instances):
                prefix = FormSet.get_default_prefix()
                prefixes[prefix] = prefixes.get(prefix, 0) + 1
                if prefixes[prefix] != 1:
                    prefix = "%s-%s" % (prefix, prefixes[prefix])
                formset = FormSet(instance=obj, prefix=prefix,
                                  queryset=inline.queryset(request))
                formsets.append(formset)

        adminForm = helpers.AdminForm(form, self.get_fieldsets(request, obj),
            self.prepopulated_fields, self.get_readonly_fields(request, obj),
            model_admin=self)
        media = self.media + adminForm.media

        inline_admin_formsets = []
        for inline, formset in zip(self.inline_instances, formsets):
            fieldsets = list(inline.get_fieldsets(request, obj))
            readonly = list(inline.get_readonly_fields(request, obj))
            inline_admin_formset = helpers.InlineAdminFormSet(inline, formset,
                fieldsets, readonly, model_admin=self)
            inline_admin_formsets.append(inline_admin_formset)
            media = media + inline_admin_formset.media

        context = {
            'title': _('Change %s') % force_unicode(opts.verbose_name),
            'adminform': adminForm,
            'object_id': object_id,
            'original': obj,
            'is_popup': request.REQUEST.has_key('_popup'),
            'media': mark_safe(media),
            'inline_admin_formsets': inline_admin_formsets,
            'errors': helpers.AdminErrorList(form, formsets),
            'root_path': self.admin_site.root_path,
            'app_label': opts.app_label,
        }
        context.update(extra_context or {})
        return self.render_change_form(request, context, change=True, obj=obj)

    @csrf_protect_m
    def changelist_view(self, request, extra_context=None):
        "The 'change list' admin view for this model."
        from django.contrib.admin.views.main import ERROR_FLAG
        opts = self.model._meta
        app_label = opts.app_label
        if not self.has_change_permission(request, None):
            raise PermissionDenied

        # Check actions to see if any are available on this changelist
        actions = self.get_actions(request)

        # Remove action checkboxes if there aren't any actions available.
        list_display = list(self.list_display)
        if not actions:
            try:
                list_display.remove('action_checkbox')
            except ValueError:
                pass

        ChangeList = self.get_changelist(request)
        try:
            cl = ChangeList(request, self.model, list_display, self.list_display_links, self.list_filter,
                self.date_hierarchy, self.search_fields, self.list_select_related, self.list_per_page, self.list_editable, self)
        except IncorrectLookupParameters:
            # Wacky lookup parameters were given, so redirect to the main
            # changelist page, without parameters, and pass an 'invalid=1'
            # parameter via the query string. If wacky parameters were given
            # and the 'invalid=1' parameter was already in the query string,
            # something is screwed up with the database, so display an error
            # page.
            if ERROR_FLAG in request.GET.keys():
                return render_to_response('admin/invalid_setup.html', {'title': _('Database error')})
            return HttpResponseRedirect(request.path + '?' + ERROR_FLAG + '=1')

        # If the request was POSTed, this might be a bulk action or a bulk
        # edit. Try to look up an action or confirmation first, but if this
        # isn't an action the POST will fall through to the bulk edit check,
        # below.
        action_failed = False
        selected = request.POST.getlist(helpers.ACTION_CHECKBOX_NAME)

        # Actions with no confirmation
        if (actions and request.method == 'POST' and
                'index' in request.POST and '_save' not in request.POST):
            if selected:
                response = self.response_action(request, queryset=cl.get_query_set())
                if response:
                    return response
                else:
                    action_failed = True
            else:
                msg = _("Items must be selected in order to perform "
                        "actions on them. No items have been changed.")
                self.message_user(request, msg)
                action_failed = True

        # Actions with confirmation
        if (actions and request.method == 'POST' and
                helpers.ACTION_CHECKBOX_NAME in request.POST and
                'index' not in request.POST and '_save' not in request.POST):
            if selected:
                response = self.response_action(request, queryset=cl.get_query_set())
                if response:
                    return response
                else:
                    action_failed = True

        # If we're allowing changelist editing, we need to construct a formset
        # for the changelist given all the fields to be edited. Then we'll
        # use the formset to validate/process POSTed data.
        formset = cl.formset = None

        # Handle POSTed bulk-edit data.
        if (request.method == "POST" and self.list_editable and
                '_save' in request.POST and not action_failed):
            FormSet = self.get_changelist_formset(request)
            formset = cl.formset = FormSet(request.POST, request.FILES, queryset=cl.result_list)
            if formset.is_valid():
                changecount = 0
                for form in formset.forms:
                    if form.has_changed():
                        obj = self.save_form(request, form, change=True)
                        self.save_model(request, obj, form, change=True)
                        form.save_m2m()
                        change_msg = self.construct_change_message(request, form, None)
                        self.log_change(request, obj, change_msg)
                        changecount += 1

                if changecount:
                    if changecount == 1:
                        name = force_unicode(opts.verbose_name)
                    else:
                        name = force_unicode(opts.verbose_name_plural)
                    msg = ungettext("%(count)s %(name)s was changed successfully.",
                                    "%(count)s %(name)s were changed successfully.",
                                    changecount) % {'count': changecount,
                                                    'name': name,
                                                    'obj': force_unicode(obj)}
                    self.message_user(request, msg)

                return HttpResponseRedirect(request.get_full_path())

        # Handle GET -- construct a formset for display.
        elif self.list_editable:
            FormSet = self.get_changelist_formset(request)
            formset = cl.formset = FormSet(queryset=cl.result_list)

        # Build the list of media to be used by the formset.
        if formset:
            media = self.media + formset.media
        else:
            media = self.media

        # Build the action form and populate it with available actions.
        if actions:
            action_form = self.action_form(auto_id=None)
            action_form.fields['action'].choices = self.get_action_choices(request)
        else:
            action_form = None

        selection_note_all = ungettext('%(total_count)s selected',
            'All %(total_count)s selected', cl.result_count)

        context = {
            'module_name': force_unicode(opts.verbose_name_plural),
            'selection_note': _('0 of %(cnt)s selected') % {'cnt': len(cl.result_list)},
            'selection_note_all': selection_note_all % {'total_count': cl.result_count},
            'title': cl.title,
            'is_popup': cl.is_popup,
            'cl': cl,
            'media': media,
            'has_add_permission': self.has_add_permission(request),
            'root_path': self.admin_site.root_path,
            'app_label': app_label,
            'action_form': action_form,
            'actions_on_top': self.actions_on_top,
            'actions_on_bottom': self.actions_on_bottom,
            'actions_selection_counter': self.actions_selection_counter,
        }
        context.update(extra_context or {})
        context_instance = template.RequestContext(request, current_app=self.admin_site.name)
        return render_to_response(self.change_list_template or [
            'admin/%s/%s/change_list.html' % (app_label, opts.object_name.lower()),
            'admin/%s/change_list.html' % app_label,
            'admin/change_list.html'
        ], context, context_instance=context_instance)

    @csrf_protect_m
    def delete_view(self, request, object_id, extra_context=None):
        "The 'delete' admin view for this model."
        opts = self.model._meta
        app_label = opts.app_label

        obj = self.get_object(request, unquote(object_id))

        if not self.has_delete_permission(request, obj):
            raise PermissionDenied

        if obj is None:
            raise Http404(_('%(name)s object with primary key %(key)r does not exist.') % {'name': force_unicode(opts.verbose_name), 'key': escape(object_id)})

        # Populate deleted_objects, a data structure of all related objects that
        # will also be deleted.
        (deleted_objects, perms_needed) = get_deleted_objects((obj,), opts, request.user, self.admin_site)

        if request.POST: # The user has already confirmed the deletion.
            if perms_needed:
                raise PermissionDenied
            obj_display = force_unicode(obj)
            self.log_deletion(request, obj, obj_display)
            obj.delete()

            self.message_user(request, _('The %(name)s "%(obj)s" was deleted successfully.') % {'name': force_unicode(opts.verbose_name), 'obj': force_unicode(obj_display)})

            if not self.has_change_permission(request, None):
                return HttpResponseRedirect("../../../../")
            return HttpResponseRedirect("../../")

        context = {
            "title": _("Are you sure?"),
            "object_name": force_unicode(opts.verbose_name),
            "object": obj,
            "deleted_objects": deleted_objects,
            "perms_lacking": perms_needed,
            "opts": opts,
            "root_path": self.admin_site.root_path,
            "app_label": app_label,
        }
        context.update(extra_context or {})
        context_instance = template.RequestContext(request, current_app=self.admin_site.name)
        return render_to_response(self.delete_confirmation_template or [
            "admin/%s/%s/delete_confirmation.html" % (app_label, opts.object_name.lower()),
            "admin/%s/delete_confirmation.html" % app_label,
            "admin/delete_confirmation.html"
        ], context, context_instance=context_instance)

    def history_view(self, request, object_id, extra_context=None):
        "The 'history' admin view for this model."
        from django.contrib.admin.models import LogEntry
        model = self.model
        opts = model._meta
        app_label = opts.app_label
        action_list = LogEntry.objects.filter(
            object_id = object_id,
            content_type__id__exact = ContentType.objects.get_for_model(model).id
        ).select_related().order_by('action_time')
        # If no history was found, see whether this object even exists.
        obj = get_object_or_404(model, pk=unquote(object_id))
        context = {
            'title': _('Change history: %s') % force_unicode(obj),
            'action_list': action_list,
            'module_name': capfirst(force_unicode(opts.verbose_name_plural)),
            'object': obj,
            'root_path': self.admin_site.root_path,
            'app_label': app_label,
        }
        context.update(extra_context or {})
        context_instance = template.RequestContext(request, current_app=self.admin_site.name)
        return render_to_response(self.object_history_template or [
            "admin/%s/%s/object_history.html" % (app_label, opts.object_name.lower()),
            "admin/%s/object_history.html" % app_label,
            "admin/object_history.html"
        ], context, context_instance=context_instance)

    #
    # DEPRECATED methods.
    #
    def __call__(self, request, url):
        """
        DEPRECATED: this is the old way of URL resolution, replaced by
        ``get_urls()``. This only called by AdminSite.root(), which is also
        deprecated.

        Again, remember that the following code only exists for
        backwards-compatibility. Any new URLs, changes to existing URLs, or
        whatever need to be done up in get_urls(), above!

        This function still exists for backwards-compatibility; it will be
        removed in Django 1.3.
        """
        # Delegate to the appropriate method, based on the URL.
        if url is None:
            return self.changelist_view(request)
        elif url == "add":
            return self.add_view(request)
        elif url.endswith('/history'):
            return self.history_view(request, unquote(url[:-8]))
        elif url.endswith('/delete'):
            return self.delete_view(request, unquote(url[:-7]))
        else:
            return self.change_view(request, unquote(url))

class InlineModelAdmin(BaseModelAdmin):
    """
    Options for inline editing of ``model`` instances.

    Provide ``name`` to specify the attribute name of the ``ForeignKey`` from
    ``model`` to its parent. This is required if ``model`` has more than one
    ``ForeignKey`` to its parent.
    """
    model = None
    fk_name = None
    formset = BaseInlineFormSet
    extra = 3
    max_num = None
    template = None
    verbose_name = None
    verbose_name_plural = None
    can_delete = True

    def __init__(self, parent_model, admin_site):
        self.admin_site = admin_site
        self.parent_model = parent_model
        self.opts = self.model._meta
        super(InlineModelAdmin, self).__init__()
        if self.verbose_name is None:
            self.verbose_name = self.model._meta.verbose_name
        if self.verbose_name_plural is None:
            self.verbose_name_plural = self.model._meta.verbose_name_plural

    def _media(self):
        from django.conf import settings
        js = ['js/jquery.min.js', 'js/jquery.init.js', 'js/inlines.min.js']
        if self.prepopulated_fields:
            js.append('js/urlify.js')
            js.append('js/prepopulate.min.js')
        if self.filter_vertical or self.filter_horizontal:
            js.extend(['js/SelectBox.js' , 'js/SelectFilter2.js'])
        return forms.Media(js=['%s%s' % (settings.ADMIN_MEDIA_PREFIX, url) for url in js])
    media = property(_media)

    def get_formset(self, request, obj=None, **kwargs):
        """Returns a BaseInlineFormSet class for use in admin add/change views."""
        if self.declared_fieldsets:
            fields = flatten_fieldsets(self.declared_fieldsets)
        else:
            fields = None
        if self.exclude is None:
            exclude = []
        else:
            exclude = list(self.exclude)
        exclude.extend(kwargs.get("exclude", []))
        exclude.extend(self.get_readonly_fields(request, obj))
        # if exclude is an empty list we use None, since that's the actual
        # default
        exclude = exclude or None
        defaults = {
            "form": self.form,
            "formset": self.formset,
            "fk_name": self.fk_name,
            "fields": fields,
            "exclude": exclude,
            "formfield_callback": curry(self.formfield_for_dbfield, request=request),
            "extra": self.extra,
            "max_num": self.max_num,
            "can_delete": self.can_delete,
        }
        defaults.update(kwargs)
        return inlineformset_factory(self.parent_model, self.model, **defaults)

    def get_fieldsets(self, request, obj=None):
        if self.declared_fieldsets:
            return self.declared_fieldsets
        form = self.get_formset(request).form
        fields = form.base_fields.keys() + list(self.get_readonly_fields(request, obj))
        return [(None, {'fields': fields})]

    def queryset(self, request):
        return self.model._default_manager.all()

class StackedInline(InlineModelAdmin):
    template = 'admin/edit_inline/stacked.html'

class TabularInline(InlineModelAdmin):
    template = 'admin/edit_inline/tabular.html'