text: from django.db import models
  from django import forms
  from django.utils.safestring import mark_safe
  from django.utils.translation import ugettext as _
  from django.forms.models import modelform_factory
  import copy
  from nadmin.sites import site
  from nadmin.util import get_model_from_relation, vendor
  from nadmin.views import BaseAdminPlugin, ModelFormAdminView
  from nadmin.layout import Layout
  
  
  class QuickFormPlugin(BaseAdminPlugin):
  
      def init_request(self, *args, **kwargs):
          if self.request.method == 'GET' and self.request.is_ajax() or self.request.GET.get('_ajax'):
              self.admin_view.add_form_template = 'nadmin/views/quick_form.html'
              self.admin_view.change_form_template = 'nadmin/views/quick_form.html'
              return True
          return False
  
      def get_model_form(self, __, **kwargs):
          if '_field' in self.request.GET:
              defaults = {
                  "form": self.admin_view.form,
                  "fields": self.request.GET['_field'].split(','),
                  "formfield_callback": self.admin_view.formfield_for_dbfield,
              }
              return modelform_factory(self.model, **defaults)
          return __()
  
      def get_form_layout(self, __):
          if '_field' in self.request.GET:
              return Layout(*self.request.GET['_field'].split(','))
          return __()
  
      def get_context(self, context):
          context['form_url'] = self.request.path
          return context
  
  
  class RelatedFieldWidgetWrapper(forms.Widget):
      """
      This class is a wrapper to a given widget to add the add icon for the
      admin interface.
      """
      def __init__(self, widget, rel, add_url, rel_add_url):
          self.needs_multipart_form = widget.needs_multipart_form
          self.attrs = widget.attrs
          self.choices = widget.choices
          self.is_required = widget.is_required
          self.widget = widget
          self.rel = rel
  
          self.add_url = add_url
          self.rel_add_url = rel_add_url
  
          if hasattr(self, 'input_type'):
              self.input_type = widget.input_type
  
      def __deepcopy__(self, memo):
          obj = copy.copy(self)
          obj.widget = copy.deepcopy(self.widget, memo)
          obj.attrs = self.widget.attrs
          memo[id(self)] = obj
          return obj
  
      @property
      def media(self):
          media = self.widget.media + vendor('nadmin.plugin.quick-form.js')
          return media
  
      def render(self, name, value, *args, **kwargs):
          self.widget.choices = self.choices
          output = []
          if self.add_url:
              output.append(u'<a href="%s" title="%s" class="btn btn-primary btn-sm btn-ajax pull-right" data-for-id="id_%s" data-refresh-url="%s"><i class="fa fa-plus"></i></a>'
                            % (
                                self.add_url, (_('Create New %s') % self.rel.to._meta.verbose_name), name,
                                "%s?_field=%s&%s=" % (self.rel_add_url, name, name)))
          output.extend(['<div class="control-wrap" id="id_%s_wrap_container">' % name,
                    self.widget.render(name, value, *args, **kwargs), '</div>'])
          return mark_safe(u''.join(output))
  
      def build_attrs(self, extra_attrs=None, **kwargs):
          "Helper function for building an attribute dictionary."
          self.attrs = self.widget.build_attrs(extra_attrs=None, **kwargs)
          return self.attrs
  
      def value_from_datadict(self, data, files, name):
          return self.widget.value_from_datadict(data, files, name)
  
      def id_for_label(self, id_):
          return self.widget.id_for_label(id_)
  
  
  class QuickAddBtnPlugin(BaseAdminPlugin):
  
      def formfield_for_dbfield(self, formfield, db_field, **kwargs):
          if formfield and self.model in self.admin_site._registry and isinstance(db_field, (models.ForeignKey, models.ManyToManyField)):
              rel_model = get_model_from_relation(db_field)
              if rel_model in self.admin_site._registry and self.has_model_perm(rel_model, 'add'):
                  add_url = self.get_model_url(rel_model, 'add')
                  formfield.widget = RelatedFieldWidgetWrapper(
                      formfield.widget, db_field.rel, add_url, self.get_model_url(self.model, 'add'))
          return formfield
  
  site.register_plugin(QuickFormPlugin, ModelFormAdminView)
  site.register_plugin(QuickAddBtnPlugin, ModelFormAdminView)
  