text: # Copyright 2014 Kylincloud
  #
  #    Licensed under the Apache License, Version 2.0 (the "License"); you may
  #    not use this file except in compliance with the License. You may obtain
  #    a copy of the License at
  #
  #         http://www.apache.org/licenses/LICENSE-2.0
  #
  #    Unless required by applicable law or agreed to in writing, software
  #    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  #    License for the specific language governing permissions and limitations
  #    under the License.
  #
  # @author: Yingjun Li <liyingjun1988@gmail.com>
  #
  
  import logging
  
  from django.core.urlresolvers import reverse
  from django.utils.translation import ugettext_lazy as _
  
  from horizon import exceptions
  from horizon import forms
  from horizon import messages
  
  from openstack_dashboard import api
  
  
  LOG = logging.getLogger(__name__)
  
  
  class AddDHCPAgent(forms.SelfHandlingForm):
      network_id = forms.CharField(widget=forms.HiddenInput())
      network_name = forms.CharField(label=_("Network Name"),
                                     widget=forms.TextInput(
                                     attrs={'readonly': 'readonly'}))
      agent = forms.ChoiceField(label=_("New DHCP Agent"),
          help_text=_("Choose an DHCP Agent to attach to."))
  
      def __init__(self, request, *args, **kwargs):
          super(AddDHCPAgent, self).__init__(request, *args, **kwargs)
          initial = kwargs.get('initial', {})
          self.fields['agent'].choices = self._populate_agent_choices(request,
                                                                      initial)
  
      def _populate_agent_choices(self, request, initial):
          network_id = initial.get('network_id')
          agents = initial.get('agents')
          try:
              exist_agents = [agent.id for agent in
                              api.neutron.list_dhcp_agent_hosting_networks(
                                  request, network_id)]
              agent_list = [(agent.id, agent.host) for agent in agents
                            if agent.id not in exist_agents]
              if agent_list:
                  agent_list.insert(0, ("", _("Select a new agent")))
              else:
                  agent_list.insert(0, ("", _("No other agents available.")))
              return agent_list
          except Exception:
              redirect = reverse('horizon:admin:networks:detail',
                                 args=(network_id,))
              msg = _('Unable to list dhcp agents hosting network.')
              exceptions.handle(request, msg, redirect=redirect)
  
      def handle(self, request, data):
          # Get the agent name for message
          agent_name = data['agent']
          for choice in self.fields['agent'].choices:
              if choice[0] == data['agent']:
                  agent_name = choice[1]
          try:
              api.neutron.add_network_to_dhcp_agent(request, data['agent'],
                                                    data['network_id'])
              msg = _('Agent %s was successfully added.') % agent_name
              messages.success(request, msg)
              return True
          except Exception:
              redirect = reverse('horizon:admin:networks:detail',
                                 args=(data['network_id'],))
              msg = _('Failed to add agent %(agent_name)s for '
                      'network %(network)s.') \
                  % {'agent_name': agent_name,
                     'network': data['network_name']}
              exceptions.handle(request, msg, redirect=redirect)
  